Howard Posted March 24, 2015 Author Report Share Posted March 24, 2015 Tested these flours for what? Hardness? Strength? Sandability of fillets? If that is the case, I have some fine ground polenta I might use as a replacement for the 30/100 grit walnut shell I use in my lamination mixes to prevent squeeze out of the epoxy under clamping pressure. Or plain old corn meal? Mild mannered fish coating by day. High tech epoxy thixotropic by night? Quote Link to comment Share on other sites More sharing options...
PAR Posted March 25, 2015 Report Share Posted March 25, 2015 Standard physical properties, compared to published and also previously self tested filler combinations, plus base lines. Tensile and flexural modulus and strength, compression, water absorption, hardness (shore D usually), texture under knife (spreadability, typically without "folding") and finish, though on structural applications I'll include distortion limits, bend to yield, etc. A simple trick to prevent joint starvation is monofilament. Select a fishing string thickness that you can live with if the glue line is about 1/3rd to 1/2 as wide. Place the monofilament in the joint, possibly after a very light dusting with spray adhesive, so it stays put. I usually place it just inboard of the edge, to allow aggressive sanding without it showing up in the glue line. Smear the goo as normal and clamp until the joint is closed. The monofilament will hold the joint open enough for the epoxy to have a place to live and it'll slightly bury into the clamped pieces, if soft enough. It can't swell with moisture, is inert, so it's not going to rot, etc. Quote Link to comment Share on other sites More sharing options...
Howard Posted March 25, 2015 Author Report Share Posted March 25, 2015 To clarify, when you say a bag of wheat flour, you are talking about Gold Medal, White Lily, etc? Also, with respect to rot, thickeners like Cabosil, lime, etc. are essentially inorganic inert minerals. These various flours.......wheat, wood, rice, etc, are organic products that under the right conditions of moisture and air will decompose, and it doesn't take long. They are a food source for all manner of yeast, bacteria, etc. Is it well established that once encapsulated in epoxy, that is no longer an issue, or can these literally rot out of or decompose out of the cured epoxy, weakening it over time? That has always been my biggest concern using them. Quote Link to comment Share on other sites More sharing options...
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