Attachment_1_Part_2_Specifications_PORE_149469.pdf

Point Reyes Lighthouse Collection Condition Survey – 100% Final

Prepared for:

National Park Service Point Reyes National Seashore, California

Prepared by:

San Francisco, California July 27, 2017

Collection Condition Survey, Point Reyes Lighthouse July 27, 2017 ARCHITECTURAL RESOURCES GROUP i

Table of Contents

1. Survey Summary

1.1 Introduction

1.2 Project Team

1.3 Methodology

2. Condition Assessment and Recommendations

2.1 General Topics

2.2 Fresnel Lens

2.3 Clockworks - Non-Ferrous Metals

2.4 Clockworks - Ferrous Metals

2.5 Lightship Lens

2.6 Stationary Equipment in Fog Signal Equipment Building

APPENDIX A. Nzilani Glass Conservation Report ...................................................... A-1

APPENDIX B. RLA Conservation Report .................................................................... B-1

APPENDIX C. SMP Recommendations .......................................................................C-1

APPENDIX D. ARG/CS Stationary Equipment Report ................................................ D-1

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1. Survey Summary

1.1 Introduction

Architectural Resources Group (ARG) has prepared this Collection Condition Survey to serve as an update of current conditions at selected objects at Point Reyes National Seashore, and provide recommendations for future treatment and maintenance. The First Order Fresnel lens and clockworks, built in 1867 and installed in 1870, are in fair condition for their age and exposure. The clockworks and lens frame assemblies are comprised of multiple materials, including brass, bronze, cast and wrought iron. This survey also includes the lightship lens inside the Visitor Center, which is in good condition, and the stationary equipment inside the Fog Signal Equipment Building which is in poor condition.

The contents of this assessment include an overview of the project methodology and site survey; general recommendations for object treatment, including moving, packing, and workspaces; and specific descriptions of existing conditions and recommendations for each object type/component: the First Order Fresnel lens, non-ferrous metals at the clockworks and lens structure, ferrous metals at the clockworks, the Fresnel lightship lens, and the stationary equipment in the Fog Signal Equipment Building. For each topic, a thorough summary, often compiling multiple conservator’s reports, is provided. The full text of each team member’s report has been included in the appendices.

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1.2 Project Team

Client National Park Service Denver Service Center and Point Reyes National Seashore

Debra Olson-Suarez Project Manager

Deborah Morgan Museum Curator

Prime Architect/Conservator Architectural Resources Group, Inc.

Kitty Vieth, AIA, LEEP AP Principal-in-Charge

Lacey Bubnash, AIA Project Manager, Architect/ Conservator

Lyles McBratney Conservator

Glass Conservator Nzilani Glass Conservation

Ariana Makau Principal Conservator

Chloe Castro Studio Manager

Metals Conservator RLA Conservation

Rosa Lowinger Principal Conservator

Christina Varvi Senior Conservator

Historic Clockworks Specialist Standard Metal Products

Kevin Binkert Principal

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1.3 Methodology

The Collection Condition Survey provides information on the status and condition of the objects surveyed. This report has been developed using information gathered from meetings and interviews with NPS staff and volunteers, archival research and previous reports, and field investigation. The methodology employed for this report meets the standards and requirements set forth in the following documents:

• The Secretary of the Interior’s Standards for the Treatment of Historic Properties

• The AIC Code of Ethics and Guidelines for Practice

Meetings On May 22, 2017 the project kick-off meeting was held via conference call with personnel from NPS and ARG. The project schedule, site visit, available background documents, and report contents were discussed. Additional correspondence was carried out via email on an as-needed basis with key NPS staff, ARG personnel, and ARG subconsultants in order to confirm direction on the assessment and development of the report.

Field Investigation and Condition Assessments The project team, including ARG and the consultant team, conducted a site visit at the Point Reyes Lighthouse on June 8, 2017. The Fresnel lens, clockworks, lightship lens in the Visitor Center, and stationary equipment in the Fog Signal Equipment Building were all surveyed at that time. The weather during the assessment was damp and very foggy. Both natural daylight and artificial lighting were used during the survey. The primary method of evaluation was close visual inspection and photo documentation. Non-destructive elemental analysis was performed at the Fresnel lens and clockworks using a handheld x-ray florescence spectrometer.

XRF

spectrum from the bronze armature holding lens;

the large spikes are at copper and zinc, indicating the primary elements that make up the metal (2017).

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2. Condition Assessment and Recommendations

For each topic or object component, existing conditions are described and then followed by treatment recommendations. Some recommendations offer options based on the desired level of treatment. In those instances, NPS museum staff, such as Program Managers, Collections Managers, and Curators, will need to direct the level of treatment based on the object’s significance, access, interpretive goals and future maintenance schedules.

2.1 General Topics

General Guidelines for Treatment of Historic Objects It is advised that subcontractors involved in lens and clockwork conservation activities have a minimum of ten years’ experience with similar projects and be familiar with the Secretary of Interior Standards for Historic Buildings and the Code of Ethics of the American Institute for Conservation. A Conservation Plan, verifying existing conditions and detailing procedures to be performed and materials to be used must be prepared by the subcontractor and submitted prior to the commencement of any physical treatments at the lens or clockworks. Following work, a Final Treatment Report must be prepared to document all materials and methods used in treatments, and to provide a record for Park Museum staff.

Protection measures are necessary before and during construction activities at the lighthouse and during any conservation treatments. Contractors must implement protection precautions any time construction activities may occur at the lighthouse and the entire time the objects are in storage. Protection may have to be removed and reconfigured during the course of the project, but we recommend that it remain in place through final completion of construction.

Packing and Moving We recommend that lens and clockwork protection be designed to withstand and prevent:

• Shock, vibration and impact

• Sudden changes in temperature and humidity

• Mishandling and exposure to unintended substances like paint, chemicals, or abrasive construction dust

• Theft, vandalism, and loss

Disassembly will be required to remove all components of the lens and clockworks from the lighthouse. Use soft padding and cushioning materials to cover objects, whole or disassembled, where vulnerable to impact. Typical protection materials include polyethylene foam and sheeting, neoprene, polyester batting, soft fiberboard, plywood, non-abrasive paper, preservation tape, and various fasteners and other accessories. The conservator may need to work with an experienced art handler to build crates, shoring, support armatures, or other

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framing devices when needed to support protection measures or lens and clockwork components. Protection assemblies are to be self-supporting and self-bracing. Use caution when assembling crates and support structure to prevent nails, screws, or other attachments from scratching, contacting or piercing artwork. Do not attach protection materials directly to objects. Line the interior of crates with protective, padding materials and label crates with a numbering and cataloging system.

Labeling and documentation of crates shall include step by step photographic documentation corresponding to the labeling and sequence of packing. Show steps to pack which can be reversed when unpacking and redone when repacking. Ensure that lens and clockwork components are appropriately and consistently unpacked and repacked during work and all archival packing materials are retained in original crates or containers.

Considerations for Workspaces and Storage Areas Before moving any objects to an offsite workspace, complete a general facilities report for the location and provide proof of insurance to NPS museum staff. Work and storage areas must have adequate capacity to ensure access to all object components and allow storage of the objects in a neat and orderly fashion. The storage areas must be completely secure from unauthorized entries and interior storage areas should have functioning fire/smoke detectors, alarms and have fire extinguishers that are readily accessible.

Store all lens and clockworks components so they can be easily moved without disturbing other components and to prevent damage while in storage.

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2.2 Fresnel Lens

Constructed in France in 1867, the First Order Fresnel Lens is composed of 24 columnar panels, each comprised of 43 prisms for a total of 1,032 prisms. The lens remains in place inside the lantern of the Point Reyes Lighthouse, although it is not in active use as a navigation aid. The glass itself has a greenish hue, which may indicate that it was fabricated with lead as a network modifier. The existing conditions and recommendations made by the project glass conservator are summarized here; see Appendix A: Nzilani Glass Conservation Report for more detail and a full schedule of deteriorated lens components.

Above left: historic photo of Point Reyes lens dating to 1927 (Source: PORE archives). Above right: existing conditions at lens panel 23 including typical chips at prism edges (Source: Nzilani Glass Conservation, 2017).

Existing Conditions - Glass The following existing conditions were observed and documented at the Fresnel lens:

• “Chips” are defined as less than 5mm (a little less than 1/4 an inch).

• “Losses” are defined as more than 5mm.

• “Cracks” are defined as a shear within the body of the glass.

There are at least 437 chips of 5mm or less on the glass prisms. Most of these chips and losses are “oyster” cracks. These are shallow semi-circular losses that are shaped similarly to an oyster shell, which occur due to an impact on the angled edge of a prism. There are at least 129 losses of 5mm or more in the prism glass, as well as at least 19 cracks.

There is one bullseye piece (panel #19) that has multiple structural cracks and losses. There is a protective film on the interior face of the bulls-eye and the two prisms directly above and below to hold the broken pieces in place. Per NPS records, some of the cracks in this piece were adhered in 2008 with “Simple Fix Outdoor Glue Pen”. We assume that existing repair was meant to be temporary. Although we were unable to identify an ingredients list for this consumer

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product, it is highly likely that this adhesive will turn increasingly yellow with more exposure to heat and UV light. This concern is applicable to a lesser degree in the protective adhesive film.

We recommend that the film and adhesive remain in place while the lighthouse is being dismantled in order to stabilize and temporarily consolidate the glass pieces.

There are at least 11 areas where accretions are present, most of which appear to be small paint drips. At least 16 prisms show small inclusions (original manufacturer flaws, such as a bubble) within the body of the glass. At least three of the prisms have visible scratches.

Existing Conditions - Putty The glass prisms are secured to the brass superstructure with litharge glazing putty and wood shims. Historically the litharge was composed of linseed oil, calcium carbonate, and lead carbonate.

The litharge putty is mostly intact where the catadioptric and dioptric panels are installed. There are some areas of loss, which have been filled during prior repair campaigns. A previous litharge assessment was carried out by NPS in 2004 and noted powdering, missing, or loose litharge locations. That assessment remains accurate; conditions do not appear to have improved or deteriorated significantly since then.

Treatment and Repair Recommendations – Glass and Putty

• Document all phases of treatment with high-resolution digital photography.

• The treatment of any and all damage of the glass prisms should be overseen by a trained glass conservator. The crack/chips and loss repair should be executed by a conservator with experience color-matching and forming areas of loss in “clear” glass.

• The multiple cracks in the bullseye on #19 should be stabilized with museum–grade epoxy such as HXTAL NYL-1. It should be noted that although the crack lines will be diminished, they will remain visible at close range. We recommend this treatment because it is such a significant (and large) part of the lens. A properly executed repair of this type should last 50 years or more in a lighthouse environment.

• Repair the three other upper catadioptric prisms that have significant losses, although it may be more cost effective to replace rather than repair them. The losses are of a significant size and they detract from the visual experience of the Fresnel lens. But, they are at the top of the lens, and less visible than pieces closer to eye-level. We defer to the client as to which of the two acceptable treatments they wish to pursue. An initial rough estimate has determined that small prisms can be replaced for an approximate cost of $1000 each, with an exact estimate to be determined upon taking more precise measurements.

• Smaller losses could be filled with an appropriate conservation-grade epoxy such as HXTAL NYL-1. We recommend that most, if not all losses should be treated, as these are of significant size and they detract from the visual experience of the Fresnel lens.

• Chips should be treated with the same methodology as the losses above, at the discretion of the conservator in conjunction with the NPS. We suggest that smaller chips do not need to be treated.

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• The cracks should be treated with the same conservation-grade epoxy, as these may affect the structural integrity of the respective prisms.

• The exterior and interior accretions should be reduced with an appropriate aqueous solvent solution, based on conservator testing.

• The installation of air monitoring devices can identify if deteriorated litharge is airborne in quantities that could pose a lead hazard. Replace missing glazing putty and consider stabilizing friable putty locations with a conservation-grade consolidating resin (such as B72). A custom putty mix of linseed oil, calcium carbonate, and pigment is recommended to match the existing putty.

Maintenance and Cleaning Recommendations – Glass and Putty

• We recommend replacing Woolite with a conservation-grade non-ionic surfactant such as Triton X-100 or synthetic detergent such as Orvus for routine maintenance cleaning activities.

• Other than changing the composition of the glass surface cleaning solution, the existing maintenance regimen for the glass prisms can still be performed by the lighthouse volunteers.

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2.3 Clockworks and Metal Lens Structure – Non-Ferrous

Metals The 6,000 pound First Order Fresnel lens inside the Point Reyes Lighthouse rests on a clockworks mechanism that rotates the lens using gears and a counterweight. When operating as designed, the clockworks mechanism should make one full rotation every two minutes, creating a light pattern of one flash every five seconds. The lens is attached via brass supports and a bronze superstructure that also supports and holds the individual prisms. The clockwork internal assembly is made of brass and housed inside a painted iron housing. Some brass components have an existing lacquer coating on them, and the conditions of lacquered pieces have been noted separately from those that remain uncoated. The existing condition descriptions and recommendations made by the metals conservator and historic clock specialist are summarized here. See Appendices B and C for the full text of those consultant reports.

Above: view of central clockworks assembly, including lacquered brass components (Source: RLA Conservation 2017).

Existing Conditions – Lacquered Brass Clockworks According to staff and volunteers, there is an Incralac® coating over the polished brass elements that make up most of the clockwork mechanisms, but there is no maintenance protocol for maintaining the coating. The lacquered brass clockworks appear to be in fair condition with no structural concerns noted.

The lacquer coating appears to be intact through over 50% of the surfaces. In areas where the coating is intact and the surface is still brightly polished, there are often hairline scratches in the metal surface, likely the result of polishing. The lacquer coating is now in the early stages of failure, especially on top/horizontal surfaces. There are no large areas of lifting, blanching, or flaking, but there are small circular pits that precede more widespread coating failure

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throughout the majority of the polished surfaces. Areas where the coating is failing are likely areas of abrasion and mechanical wear.

Tarnish was noted in select areas either below the lacquer coating or where the coating has completely worn away. There is significant tarnish on the spool around which the steel cable is wrapped. There is likely a loss of coating on this surface due to repeated abrasion. Abrasion and associated tarnish were also observed on the governor at the top of the assembly, on gears, as well as on the top sides of horizontally oriented gear spindles. Additional tarnish, below the lacquer, was noted at the north side on the top/horizontal surfaces. At this area, the door to the internal clockworks faces north. The entrance to the lighthouse structure is also on the north side and the mechanism crank is located in this area. This door to the internal clockworks is likely opened the most out of all four openings and thus subjected to more atmospheric salts, chlorides, moisture, etc. In localized areas, small pits of green copper corrosion were observed.

Within the brass clockworks assembly, there are some ferrous metal elements including the large anchor bolts, the steel cable, as well as several spindles that connect lacquered brass pieces. These elements do not appear to have a protective coating on them and corrosion was observed on most of those components.

Treatment and Repair Recommendations – Lacquered Brass Clockworks Material repair and finish recommendations:

• Document all phases of treatment with high-resolution digital photography.

• Work with a machinist to document and catalogue all elements of the clockworks assembly.

• Disassemble clockworks assembly in preparation for treatment.

• Remove extant motor oil from all surfaces.

• Chemically strip extant lacquer from all surfaces.

• Mechanically remove copper and ferrous corrosion products and passivate surfaces as necessary.

• Polish brass surfaces to a mirror finish, removing tarnish and micro scratches from the various mechanical components. Deeper surface scratches will not be mitigated through general surface polishing.

• Re-apply and maintain a clear, high-gloss lacquer (brand names include Incralac or Permalac, but there are many commercially-available lacquer coatings on the market) coating to maintain the high-polish surfaces of the brass. Consider a product that can also be applied to ferrous metal and take into account recommended mechanical cleaning procedures (below) when selecting a coating and determining the necessary coating thickness.

• Apply a clear carnauba-based paste wax to all lacquered surfaces as an added, sacrificial layer of protection against the corrosive coastal environment.

o Prior to application, test the solubility of the wax with the type of lubricant that will be used for the clockworks assembly. If the wax is soluble in the lubricant, it may not make sense to wax the individual pieces.

• Work with machinist to re-assemble the clockworks mechanisms.

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o Considering applying a more robust, reversible material (such as a water-based clear coating) to the surface of the brass cylinder around which the steel cable is spooled to minimize surface abrasion.

Mechanical treatment recommendations:

• Re-machine movement bushings

• Consider drilling an oil hole above each bushing during re-machining to improve future oiling and flushing of contaminants.

• Consider running gears completely dry (without oil) in the future. Oil attracts grit, which wears down the mechanism more quickly. To better understand the impacts of running the gears dry, it could be tested and more closely evaluated during restoration work.

• Following disassembly, more closely inspect steel pinions that mate with the brass gears and consider re-machining them. Also consider running these pinions dry in the future.

• Consider replacement of the steel cable with a new stainless steel cable. Corrosion is active at this cable, and options for full refinishing are limited due to the dense make-up of the cable.

o Re-machine the pulley bearings and shafts at the same time.

• Following disassembly, more closely inspect the carrier wheels and consider renewing their bushings and shafts if needed.

• Re-wire light bulb for safety. Consider replacing bulb with a low-wattage incandescent bulb.

• Replace damaged or missing fasteners on the movement, including clutch and bearing caps.

• Adjust the governor.

Maintenance Recommendations:

• Clean gears 2 to 3 times a year to keep them free of grit. Scrub with a stiff bristle nylon brush and a mild solvent (coordinate brush and solvent selection with lacquer coating properties, as recommended above). Test cleaning protocols during restoration work to confirm that lacquer can withstand scrubbing without damage to coating or metal substrate.

• Apply a corrosion-inhibiting lubricant (such as Boeshield T9) to unpainted ferrous metal surfaces as rust inhibitor. Start with quarterly applications but increase frequency if any signs of corrosion appear.

• No regularly recurring or routinely scheduled replacement of individual components is recommended at this time.

Existing Conditions –Un-Lacquered Brass Components None of the brass surfaces at either the interior or exterior of the doors are lacquered and general tarnish and pitting were observed throughout. All doorknobs are also very burnished and detail is being lost around the edges due to abrasion and wear. Minor green corrosion was noted at the connections between the doorknobs and hinges with the painted ferrous metal.

Localized tarnishing from fingerprints was observed throughout each of the doors, but was most noticeable at the south side where there is a large brass plate attached to the door versus a

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glass window. Discoloration and green corrosion products from an unknown liquid splatter were also noted on this surface. Minor pitting was observed throughout the hinges. What appears to be white polish residue was observed in recesses at the east side. There is extant black, blue, and red paint in certain recesses of the decorative plate at the south side. Black appears to be the bottom layer, then blue followed by red. The extant paint is crazing and is likely unstable.

The interior brass surfaces at each of the doors exhibit similar conditions. However, these surfaces do not get polished. The glass frames are tarnished with some black pitting throughout the surfaces. Several flathead screws are missing. A piece of trim at the north side is loose.

The large gear that encircles the connection between the lens and lower clockworks assembly housing is uncoated brass. The surfaces are routinely lubricated to facilitate movement.

However, the element is tarnished in areas that do not receive constant abrasion. The vertical gear component is a combination of ferrous metal and brass. The majority of these surfaces are lubricated as well. There is some tarnish and pitting on the brass and ferrous corrosion on the steel. The top/horizontal surfaces around the bottom of the brass cone are very tarnished.

Extending up from the lower painted ferrous clockworks housing is a brass frame/armature that supports the lens. They also include the nuts on the undersides at the connection to the painted ferrous metal. These elements are not lacquered. At the time of inspection, the surfaces had been polished recently and the surfaces were already exhibiting tarnish on top surfaces where atmospheric pollutants can sit and dwell. Pitting and green corrosion products were observed towards the tops of each column, where the elements begin to slope outwards. The back sides that face the interior of the lens are not polished and exhibit extensive tarnishing and pitting.

The inner-facing surfaces at the tops of the support beams have been painted the same magenta color as the adjacent ferrous surfaces.

Treatment and Repair Recommendations –Un-Lacquered Brass Components

• Document all phases of treatment with high-resolution digital photography.

• Dry-brush surfaces to remove particulate matter.

• Damp-clean all surfaces with a solution of a conservation-grade detergent and distilled water using microfiber cloths.

• Damp-rinse all surfaces using distilled water on microfiber cloths and dry with cotton cloths.

• Mechanically remove any copper and/or ferrous corrosion products.

• Apply a benzotriazole passivating solution to areas where corrosion was excavated and allow to dwell for 24 hours. This passivating solution will make the metal surface unreactive. Remove any crystals that have formed with a chip brush and clear surfaces with denatured alcohol.

• Remove extant lubricating oil from all surfaces.

• Chemically and/or mechanically remove paint and putty transfer material as well as polish residue from door surfaces, gears, and bearings. Polish tarnished surfaces to a level that meets approval by senior NPS museum staff.

• Door knobs and the exterior plate of the south door should receive localized polishing and only where absolutely necessary to minimize any additional loss of surface

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decoration/relief. The application of a lacquer coating would provide protection from additional abrasion, but would be slight visual change to the previously uncoated pieces.

• If preservation of all previous paint remnants is desired by senior NPS museum staff, consolidate and stabilize extant paint remnants on exterior of south door relief panel.

• To maintain the high-polish surfaces at the front surfaces of the decorative brass frame, apply a clear, protective lacquer coating to each brass frame.

• Apply a sacrificial, protective, carnauba-based wax coating to all brass surfaces. Allow wax to dry and lightly buff with cotton cloths.

• Replace missing hardware and screws in kind and secure any loose elements.

Existing Conditions – Bronze Lens Frame The vertical metal supports in which the individual glass pieces are inserted are made of bronze.

The majority of the associated hardware is also non-ferrous metal. Ferrous bolts were noted at the anchor point between the vertical lens frame components and the uncoated brass elements of the lens support structure. Upon close-up visual inspection, there appears to be a bronze powder/pigment coating over top of the bronze frame. The surface is generally a very dull, medium to dark brown color, though there are highlights of lighter gold colors in more protected areas of the surface that may not have received as much weathering, such as corners and concealed edges inside the lens. The original surface was most likely golden in color versus the now tarnished brown.

The individual frame components appear to be in fair condition with no structural concerns noted. Bright blue/green copper corrosion products were observed at both the interior and exterior surfaces of the lens frame. At the exterior, the majority of this shade of corrosion was noted toward the very top/peak of the lens frame, near the ceiling, on the top sides of the protruding spines.

More muted, olive green areas of corrosion were observed throughout the lower 2/3 of the visible surfaces of the exterior, again primarily on the top surfaces where salts/chlorides and moisture likely accumulate on the surface. There are areas where the applied bronze powder coating is chipped, worn, or missing altogether. The more stable, olive green corrosion is visible in areas of coating loss or where the coating binder has begun to break down, exposing the bronze powder pigments. At the interior, this discoloration was observed on the vertical interior surfaces of the fins throughout the top dome section. At these surfaces, it appears to be the applied coating that is exhibiting corrosion, not the bronze substrate itself.

There are also trace areas of blue and white paint schemes at the horizontal exterior band connection between the top sloping frame elements and the central bullseye lens cylinder frame elements. Numerical graphite labels for the individual frame elements were observed in three different locations at both the interior and exterior of the framework.

Treatment and Repair Recommendations – Bronze Lens Frame

• Document all phases of treatment with high-resolution digital photography.

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• Dry-brush surfaces to remove particulate matter.

• Conduct solubility testing of the bronze paint areas to attempt to determine the binder medium.

• Consider stabilizing old fragments/remnants of white and blue paint. These remnants may provide clues to previous finishes. It is recommended that areas of graphite numerical labeling be retained, stabilized, and preserved.

• Conduct archival research to determine if there is extant written or photographic information that gives insight into the original intent of the painted bronze powder surface.

o Provide mock-ups to the client based on findings in order to select color, texture and sheen.

• Damp clean surfaces with a solution of distilled water and a conservation-grade detergent.

• Based on research findings and direction from senior NPS museum staff, remove corroded and tarnished bronze powder paint down to bare bronze, leaving areas of original graphite numbers intact (retain up to 1” of original paint surface around the edges of the numbers, where possible).

• If deemed appropriate by senior NPS museum staff, stabilize paint layer over which the numbers were applied with a conservation-grade adhesive. Apply a reversible, protective clear coating over top of the numbers to further consolidate and protect the surface.

• Mechanically remove extant green copper corrosion products that were not removed by stripping the deteriorated bronze powder paint.

• If necessary, apply a copper corrosion passivation solution (benzotriazole) to bronze surfaces and allow to dwell for 24 hours.

o Brush away any crystals with a chip brush and clear surface with denatured alcohol.

• Based on the selection of senior NPS museum staff during mock-ups, apply a marine-grade paint system that mimics the original intent of the bronze powder paint. This paint system would provide corrosion protection for the bronze frame, but would need to be carefully selected based on research findings and interpretation goals. It would also need to be carefully applied to avoid damaging any stabilized paint or graphite remnants.

• Where possible clean and re-use original hardware.

o If found appropriate by senior NPS museum staff, mild steel hardware should be replaced with bronze or stainless steel.

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2.4 Clockworks – Ferrous Metals

The external housing for the clockworks is made of ferrous metal, likely a combination of cast and wrought iron like the lighthouse itself. The existing condition descriptions and recommendations made by the metals conservator is summarized here. See Appendix B for the full text of the consultant report.

Existing Conditions – Ferrous Metals at Clockworks Housing The exterior surfaces of the painted ferrous metal housing and lens support appear to be in good condition with no structural concerns noted. The colors on these surfaces are currently black and magenta. NPS senior museum staff does not believe that these are the original colors.

What we believe to be red oxide primer is easily visible below the black paint where the top coat has been chipped or worn away. A hint of a possible white primer was observed at an area of magenta top coat loss at one of the clockworks housing doors while an area of possible red primer was noted on a vertical surface above the vertical rolling brass bearings.

The most prevalent condition is abrasion along with associated coating loss and ferrous corrosion. The areas of corrosion appear to be stable; they are dark brown whereas active corrosion tends to be brighter orange in color. Most of the abrasion and paint loss appears to be along the bottom edges of the clockworks casing, particularly in the black paint. This is not surprising as these areas are at floor level. There are also a lot of chips and losses at the black level below the rolling brass bearings. The painted surfaces at the connection between the clockworks housing and the lens support (behind the rolling brass bearings) are the most abraded and do not appear to have a black top coat, just the red oxide primer. Overall there is approximately 20-25% of surface loss throughout the black paint and approximately 10-15% loss in the magenta areas. The magenta losses are primarily at the upper lens support, at the landings and steps up to the central light source.

The interior vertical surfaces of the lower clockworks housing have been painted white. There is evidence that the surfaces have either been painted multiple times or there is a white primer;

one can see additional paint layers below the existing top coat. The interior surfaces at the south side are in the best condition. The majority of the white surfaces are discolored, having yellowed over time. There are varying degrees of abrasion through to the ferrous metal substrate as well as general paint loss, associated ferrous corrosion, and corrosion staining of the paint. There are also areas at the west side where there appears to be blistering corrosion blooms developing below the paint surface, primarily towards the bottom surfaces. The paint at the north side is also exhibiting checking/crazing. There are grease splatters in localized areas that have also discolored the surface.

The “ceiling” of the lower clockworks housing has been painted black. There are chips and losses around the edge of the center opening as well as associated ferrous corrosion and corrosion runoff staining at one side. The color is generally faded. The interior of the central column was difficult to view with all of the mechanical equipment in the housing, but there appears to be few remnants of black paint.

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Treatment and Repair Recommendations – Ferrous Metals

• Document all phases of treatment with high-resolution digital photography.

• Collect paint samples from multiple areas throughout the exterior and interior of the painted ferrous elements for paint analysis (including possible lead content) and color matching.

• Conduct archival research to see if there is any written or photographic documentation of these elements that would suggest previous color schemes. If so, compare findings with the completed paint analysis.

• Prepare coating mock-ups for NPS senior museum staff review and approval. These mock-ups will establish a successful coating system and methodology that provides protection to the ferrous metal substrate and meets NPS interpretive goals in its appearance.

• After the housing and lens support components have been de-installed and removed offsite, the existing coatings are to be removed down to bare metal.

• Remove and passivate any areas of ferrous corrosion.

• Apply an industrial and marine-grade zinc-rich primer to all previously-painted ferrous metal surfaces via the approved application methodology.

• Apply a two-part epoxy interlayer to all surfaces via the approved application methodology.

• Apply one to two coats of an industrial and marine-grade top coat to surfaces in the approved color scheme and application methodology.

• Note: When selecting a paint system, we recommend the selected contractor consult with both an industrial paint supplier to determine the most abrasion-resistant paint system as well as with a machinist to ensure that any potential increases in overall film thickness will not negatively impact or impede the clockworks mechanism, particularly at the various locations of rolling bearings. If this is the case, alternative coatings should be investigated.

• Provide color swatches of each material as well as color codes for documentation and future reference.

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2.5 Lightship Lens

The smaller Fresnel lightship lens, dating to c. 1920, is on display in the Lighthouse Visitor Center. Some of the prisms of this smaller lens appear to be set with litharge putty, and some appear to have a seamless run through the next section. Without further investigation, it is difficult to say how many prisms were cast individually or in a different cast configuration.

Existing Conditions There are at least 10 chips of 5mm or less on the glass prisms. Most, if not all, of these chips are “oyster” cracks. The interior and exterior of this lens and its housing has a layer of cobwebs.

There does not appear to be an active insect infestation.

Repair and Maintenance Recommendations

• Chips should be treated with the same methodology as the losses described under 2.2 above, at the discretion of the conservator in conjunction with the NPS. The epoxy fills should only be executed by a trained conservator. We suggest that not all chips may need to be treated.

• Any exterior and interior surface dust and biological debris should be reduced with dry cleaning methods. These should include dry brush and vacuuming. The glass surface cleaning solution to be used for the Lightship Lens should be the same as recommended for the First Order lens—replacing any Woolite with a conservation-grade non-ionic surfactant such as Triton X-100 or synthetic detergent such as Orvus.

ARCHITECTURAL RESOURCES GROUP 18

2.6 Stationary Equipment in Fog Signal Equipment

Building The stationary equipment inside the Fog Signal Equipment Building was evaluated by a separate conservation team from the Fresnel lens and clockworks. See Appendix D for the full report, including a full page assessment for each item:

• Air compressor tank

• Generator and batteries

• Gage Board

• Diaphones (2 items)

• Air compressors (2 items)

• Panel Board

• Diesel Fuel Panel

Existing Conditions The ferrous metals are actively corroding and the coatings are failing at all objects. The failing coatings have been identified as lead-containing and pose a serious hazard to visitors and allow for accelerated deterioration of the objects. All previous hazardous materials testing should be consulted in conjunction with this report, and additional testing may be warranted at enclosed equipment locations and components. Non-metal objects are similarly in poor condition, including wood gouges, graffiti, and crazing finishes at the gage board.

Treatment and Repair Recommendations There are two primary treatment approaches we recommend for this equipment, which would address hazards associated with the lead-based paint and stabilize the objects.

• One approach would be conservation, during which only flaking coatings would be removed and the equipment sealed with a clear coating to encapsulate the lead paint.

• The second would be restoration, during which deteriorated coatings would be removed via wire brush or blast cleaning, the surface prepared, corrosion removed down to bare metal, a corrosion inhibitor applied, and the equipment recoated using a durable coating system appropriate for ferrous metals in caustic marine environments.

Either treatment approach will treat the lead paint; the conservation approach will preserve more original historic fabric but will also require more maintenance and frequent re-coating.

The restoration approach will require less frequent refinishing, but will produce a “like new” appearance for some of the pieces. We recommend NPS senior museum staff select the treatment that better fits their maintenance, interpretation, and exhibit design goals.

Appendix A: Nzilani Glass Conservation Report

Nzilani Glass Conservation, Inc. © 2017

3246 Ettie Street #4 Oakland, CA 94609 amakau@nzilani.com 510.821.2742

Point Reyes Lighthouse Condition Assessment

Existing Conditions & Concerns

- “Chips” are defined as less than 5mm. (a little less than ½ an inch)

- “Losses” are defined as more than 5mm.

- “Cracks” are defined as a shear within the body of the glass.

There are 24 columnar panels, comprised of 43 prisms each, that make up the body of this First order Fresnel Lens, with a total of 1,032 prisms. When referring to numbered prisms or panels, we have used the numbers stamped into the brass frame to refer to the column directly to the Proper Left. The glass itself has a greenish hue, which may indicate that it was fabricated with lead as a network modifier.

On examination, we discovered that there are at least 437 chips of 5mm or less on the glass prisms. Most of these chips and losses are “oyster” cracks. These are shallow semi-circular losses that are shaped similarly to an oyster shell, which occur due to an impact on the angled edge of a prism. (See figs. 1 – 4)

There are at least 129 losses of 5mm or more in the prism glass, as well as at least 19 cracks. There is one bullseye piece (#19) that has multiple structural cracks and losses. There is a protective film on the interior face of the bulls-eye and the two prisms directly above and below, that is holding the broken pieces in place.

Some of the cracks in this piece were adhered in 2008 with “Simple Fix Outdoor Glue Pen”. There appears to be very slight adhesive yellowing, which is visible only on close inspection. (See figs. 4 – 5)

There are at least 11 areas where accretions are present, most of which appear to be small paint drips. At least 16 prisms show small inclusions (original manufacturer flaws, such as a bubble) within the body of the glass. At least three of the prisms have visible scratches. (See fig. 6) mailto:amakau@nzilani.com

The litharge putty is mostly intact where the Catadioptric and Dioptric panels are installed. There are some areas of loss, which have been filled during prior repair campaigns. It was difficult to assess how the prisms were installed into the metal grooves; though it appears that they were set in sections. There appears to be a numbering system labeled in pencil in the triangle-shaped areas where the prism ends are puttied into the brass hardware. This was possibly meant to originally install the prisms in their correct orders. (See figs. 7 – 9).

Chips Cracks Losses Accretions Inclusions

Totals 437 19 123 11 16

Exterior Chips Cracks Losses Accretions Inclusions

Totals 332 15 103 1 15

Interior Chips Cracks Losses Accretions Inclusions

Totals 105 4 20 10 1

Conservation and Repair Recommendations

General Assessment The treatment of any and all damage of the glass prisms should be overseen by a trained glass conservator. The crack/chips and loss repair should be executed by a conservator with experience color-matching and forming areas of loss in “clear” glass.

The cleaning portion of the treatment in preparation for crack/chip repair can be undertaken by a volunteer team after consultation and training in conjunction with a conservator.

General cleaning can continue independent of a conservator after changing the cleaning solution. See below for details.

Bullseye Repair The multiple cracks in the bullseye on #19 should be stabilized with museum– grade epoxy if the client wants to retain the original parts of the lens.

• It should be noted that although the crack lines will be diminished, they will remain visible at close range. We recommend this treatment because it is such a significant (and large) part of the lens.

• The existing “Simple-Fix Outdoor Glue Pen” repair was meant to be temporary. Without finding the MSDS or an ingredients list for this consumer product, it is highly likely that this adhesive will turn increasingly yellow with more exposure to heat and UV light. This is applicable to a lesser degree in the protective adhesive film. It should remain in place while the lighthouse is being dismantled in order to stabilize and temporarily consolidate the glass pieces.

Smaller Prism Repair – Major Loss

• There are at least three other upper catadioptric prisms that have significant losses that it may be more cost effective to replace them. The losses are of a significant size and they detract from the visual experience of the Fresnel lens. But, they are at the top of the lens, and less visible than pieces closer to eye-level. We defer to the client as to which of the two acceptable treatments they wish to pursue.

• An initial rough estimate has determined that small prisms can be replaced with new glass for an approximate cost of $1000 each, with an exact estimate to be determined upon taking more precise measurements. Please be aware this is only an approximate cost estimate for the fabrication of one prism, and does not include any shipping costs, or other miscellaneous fees.

Smaller Prism Repair – Minor Loss

• Smaller losses should be filled with an appropriate conservation-grade epoxy that has been developed to have the same refractive index as glass. This material should only be utilized by a trained conservator. We recommend that most, if not all losses should be treated, as these are of significant size and they detract from the visual experience of the Fresnel lens.

• Chips should be treated with the same methodology as the losses above, at the discretion of the conservator in conjunction with the NPS. It may be determined that not all chips are required to be filled. The epoxy fills should only be executed by a trained conservator. We suggest that not all chips need to be treated. Treatment of any amount of the 400+ chips can be determined in conjunction with the NPS curator(s)—with a recommended focus on the chips at eye-level.

• The cracks should be treated with the same conservation-grade epoxy, as these may affect the structural integrity of the respective prisms. This material should only be utilized by a trained conservator.

Surface Accretions The exterior and interior accretions should be reduced with an appropriate aqueous solvent solution, based on conservator testing.

Maintenance and cleaning recommendations

• The existing maintenance regimen for the glass includes a very dilute solution of “3 parts water, 1 part [isopropyl] alcohol, and 2 drops of Woolite per quart of distilled water.” The Woolite was possibly added to act as a light surfactant. Nzilani recommends replacing the Woolite with a conservation-grade non-ionic surfactant such as Triton X-100 or synthetic detergent such as Orvus.

• Other than changing the composition of the glass surface cleaning solution, the existing maintenance regimen for the glass prisms can still be performed by the lighthouse volunteers.

Small Fresnel Lens in Visitor Center

Existing Conditions & Concerns

• There are 16 prisms to each section, that make up the body of the 375mm

Fresnel Lens, which is housed in the Visitor’s Center. Some of the prisms of this smaller lens appear to be set with litharge putty, and some appear to have a seamless run through the next section. Without further investigation, it is difficult to say how many prisms were cast individually or in a different cast configuration.

• Upon examination of this smaller lens, we discovered that there are at least 10 chips of 5mm or less on the glass prisms. Most, if not all, of these chips are “oyster” cracks. (See figs. 10 – 12)

• The interior and exterior of this lens and it’s housing has a layer of cobwebs.

There does not appear to be an active insect infestation.

Conservation or repair recommendations

• Chips should be treated with the same methodology as the losses above, at the discretion of the conservator in conjunction with the NPS. It may be determined that not all chips are required to be filled. The epoxy fills should only be executed by a trained conservator. We suggest that not all chips may need to be treated. Treatment can be determined in conjunction with the NPS curator(s)—with a recommended focus on the chips at eye-level.

• Any exterior and interior accretions should be reduced with an appropriate aqueous solvent solution, based on conservator testing. This type of treatment should be completed by trained conservators.

• Any exterior and interior surface dust and biological debris should be reduced with dry cleaning methods. These should include dry brush and vacuuming. This method may be taught to volunteers.

Maintenance and cleaning recommendations

• The glass surface cleaning solution to be used for the Lightship Lens should be the same as recommended for the First Order lens—replacing any Woolite with a conservation-grade non-ionic surfactant such as Triton X-100 or synthetic detergent such as Orvus.

• The existing maintenance regimen for surface dusting the Lightship Lens can still be performed by the lighthouse volunteers.

Fig. 1. Chips on Lens panel 23. Fig. 2. Chips on Lens panel 2.

Fig. 3. Chips on Lens panel 24. Fig. 4.