__BOND CORK TO METAL (002).pdf

BOND CORK TO METAL

RELEASE ASSEMBLY 1030-5802

1.1 Material and Tooling

1.2 Safety

1.3 Metal Surface Preparation

1.4 Bond Cork to Metal

1. 5 Bond Test - Cork to Metal

1.6 Trim & Dress Cork

1.1 MATERIALS & TOOLS:

• 1030-5803 Release Assembly, Supplied By NSWC

• Composite Cork ABL5 1/4in / Supplier / Ecore International, 800-322-1923

• RF-4000/RF-66 Adhesive Kit Part Number RF-2314-1 or Bulk RF-4000 Epoxy Resin and RF-66

Curing Agent (Pot Life 180 min. @ 70 degrees) / Supplier, EB Roberts,800-374-3872

• Isopropyl Alcohol, 99.8% / Mcmaster-Carr, Part Number 3190K811

• 100 grit sand paper

• Dry Lent Free Cloth

• Loctite 495 Instant Adhesive / Macaster-Carr, Part Number 7520A12

• Gram Scale

• Small Putty Knife

• Dremel Tool With 100 grit sanding drum

• Utility Knife

• Steel Rule Dies to punch out cork

• Small Foam or Bristle Brush

• Clamp Fixtures, see illustration #1 & #2

1.2 Safety:

• Use solvents and adhesives in well ventilated area

• Wear latex or nitrile gloves and adequate eye protection

Note: Store all component in an area 65 degrees F or higher for 24 hours. Air temperature must be 65 degrees F or higher during bonding process.

1.3 Metal Surface Preparations

A. Mask all areas where cork and adhesive will not be applied.

B. Cut cork .0625 over finish size dimension of release assembly via of a steel rule die, so the cork can be dressed to size after adhesive has cured. (preferably with a dremel tool and sanding drum). Record part number and PO number on matrix.

C. Wipe the two sides and front of release assembly with IPA using a clean white cotton cloth to degrease before sanding application areas. Continue wiping with a clean area of cloth until the surfaces appear to be clean and to allow metal to dry visually.

D. Sand the front and sides of bonding areas to provide a good surface for adhesion using

100 grit or finer aluminum oxide sandpaper and wipe entire part with dry cloth to remove grit.

E. Wipe bonding side of cork with IPA and a clean cotton cloth. Wipe the cork surface twice with a clean area of the cloth. It is acceptable to see some cork particles continue to come up with each wipe. Allow cork to dry for 60 minutes. Begin applying cork to release assembly within 8 hours of the end of the dry time. Record dry start and stop times for cork in the sign-off matrix.

F. Wipe release assembly sanded areas with IPA and clean cotton cloth. Continue wiping until cloths appear clean (use clean area of cloth with each wipe). Allow metal to dry for at least 5 minutes before applying adhesive. Apply adhesive and cork to release assembly within six hours of the dry time. Record dry start and stop times for metal in the sign-off matrix.

1.4 Bond Cork to Release Assembly, Small Quantity Run

A. Mix first batch of RF-4000 epoxy resin with RF66 curing agent (1 to .55 Mix Ratio by weight). Mix thoroughly, then let adhesive sweat for 15 minutes before applying. Record the PN, PO, LOT, DOE, weight and times in the sign-off matrix. A cure test sample shall be made for each batch of adhesive mixed with appropriate labeling and identification (cure sample should approximately 1/8” thick X 1” X 1”. Sample shall be placed alongside the release assembly during cure. Cure sample shall not be placed under pressure. Once the sample has cured, durometer measurement using Shore A hardness shall taken.

B. Use a small foam or bristle brush, to apply a thin uniform coating of adhesive onto the front surface of release assembly and a thin uniform coating of adhesive onto the front piece of cork.

Clamp and cure at ambient temperature for 30 hours (see clamping illustration #1) Thickness of applied adhesive is not crucial as long as all bonding areas are covered. Bond line thickness is determined by the clamping force and is not critical for this application.

C. Clamping pressure must be applied to part before the end of the pot life of the each batch of adhesive mixed. Do not exceed any special pressure requirements or limitations of the part.

Record the time at which clamping force is attained and the ambient temperature in the sign-off matrix

D. After the witness sample has reached a Shore A hardness of 50, remove clamping force, record time in sign-off matrix form

E. Before applying cork to sides of release assembly wipe with IPA and clean cotton rag (use a clean area of rag with each wipe).

F. Mix second batch of RF-4000 epoxy resin with RF66 curing agent (1 to .55 Mix Ratio by weight). Mix thoroughly, then let adhesive sweat for 15 minutes before applying. Record the PN, PO, Lot, DOE, weight and times in the sign-off matrix.

B. G. Use a small foam or bristle brush, to apply a thin uniform coating of adhesive onto the two side surfaces of release assembly and a thin uniform coating of adhesive onto the side pieces of cork including the end surface butting up to edge of cork on the front of the release assembly. Before applying cork the front chamfer areas need to be filled with cork paste

(see illustration #3). Cork paste consist of one part adhesive to one part cork powder (cork power can be made with a Dremel tool/100 girt sanding drum and a piece of cork sheet).

After chamfer have been filled with cork paste apply cork side pieces, clamp and cure at ambient temperature for 30 hours (see clamping illustration #2). Record the time at which clamping force is attained and the ambient temperature in the sign-off matrix. Place cure teat sample along side the release assembly during curing (reference 1.4 A). Once the sample has cured, durometer measurement using Shore A hardness shall taken.

1.5 Bond Test - Cork to Metal

After clamping pressure has been removed and with hand pressure see if there is any delamination along the edges, if so use Loctite 495 instant adhesive to repair. If delamination is more than 10 % the cork will have to be remove and process redone.

1.6 Trim/Dress Cork

A. With a Dremel tool and a 100 girt sanding drum sand cork to release assembly contour, see dwg 1030-5802.

B. Remove masking tape and wipe release assembly with IPA.