Monday, June 8, 2009

Progress. Notes on Epoxy.

Edge banded the centerboard, painted the inside of the lockers prior to gluing up the top. Recycled some masts and sails from the Dartmouth sailing team. Scribed and fit both the mast step and forward seat tops.

The real key in working with epoxy is to pre-plan as much of the job as possible before mixing the sticky stuff. I reuse LDPE sheet over and over as does the boatshop. This always forms the bottom layer of what ever I do since the hardened epoxy will lift right off. Gloves are essential, I've used many kinds; latex, nitril, vinyl. Good fit keeps the tactile sense useful and eliminates tears from baggy fingers. A pair of nitril ones will serve for a few times, I wipe them clean with a paper towel. Paper towels are also essential as they keep the phone & drill clean too. Plain old white vinegar will clean brushes and tools if you get to them before the stuff kicks.
To edge band, first finish the form with rasp & 36 grit abrasive. I use a bonded cloth from Klingspor, which I can vacuum off. It is non-loading and cuts a long time. put down drip sheet of LDPE. Cut strips of kevlar using a really sharp knife or razor blade. I will pull a thread at the correct width so I can follow the grain with the cutting tool along a very straight line. Kevlar is hard to cut. Pull the strip tightly along the edge to be banded and tape down both sides. The concept is to replace the screws, putty, and metal of brass half oval with resin and Kevlar. once the fabric is stretched into place, mix a small amount of epoxy and work it into the fabric wetting it compltely and soaking any raw wood underneath. More paper tape may be stretched over the top at right angles to apply pressure for complete contact between the fabric, epoxy and substrate. Wait about 4 hrs for the epoxy to get to the "soft" cure state. Remove the tape and reposition any errant strands. MAS epoxies can be recoated without hesitation. If it has been more than 12 hrs. with West System or System Three, you should either sand the surface to remove Amine blush or use a solvent. Working with epoxy is similar to camping. The goal is to stay clean and dry.

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