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Old 03-26-14, 10:16 AM
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MassiveD
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  • How to prevent the work from bonding on the mold? Wrap an inner tube around it? Use resin only for the first coat?
Just about anything will stop it from bonding to the mold. Packing tape with some light wax. Plastic wrap.

I would saw a mold out of plywood and make holes for clamps. I made a set of fenders about 10 years ago, and they came out fine, but the deal way that they spring back form the mold, so you get a larger radius than you want. I was making them for 700c tires, and used a 26" rim for a mold. That worked out OK but the ends were straighter than the middle. So the next time I do the same thing I will make the ends a compound curve so they get tighter radius. I am sure there is some perfect formula, but it worked out pretty well regardless. Often it takes two shots to get stuff perfect.

Epoxy will bond to rubber.

Not sure what you mean by first coat only. I used epoxy for glue, and for the final finish. WEST is the best, but it is not UV proof. You need to top coat with UV varnish, but in my case I didn't bother. On a boat I would have, but for this I figured it wouldn't see enough sun. If you park it outside, or live in Florida, don't count on that.


  • I'm not not sure how to clamp the strips on the mold, if needed;

Veneer is very light, so you need a lot of clamps, and a backing strip. The basic rule is that the pressure spreads out in a V of 90 degrees so if your object was 1" thick the clamps would apply 1.44" pressure. What this means on thin veneer is that you are getting virtually nothing more than the contact patch. You can use backing strips to spread the pressure. Or a lot of stapples (not so good on the top sheet). WEST needs very little pressure, but you need to get it tight enough to close the glue lines for the best look.

The executive set-up is a fire hose filled compressed air. I have that for building bows.

The ghetto method is using string and wedges You wrap with string and insert multiple wedges. Where there is a will there is a way.

You veneer is an advantage because it bends easily, but that gives you problems with clamping.

There is a picture here of a non-standard wedges approach:

http://leatherwall.bowsite.com/TF/lw...s=5&CATEGORY=3

http://leatherwall.bowsite.com/tf/lw...=19&CATEGORY=3


  • Not sure how thick the fender needs to be;

I would guess 3-4 mm A wood or bamboo fender needs a little beef to survive I amde mine too thick. Just play it by ear. You know how rough you are on stuff, and as you add layers it will become strong enough. Remember the hardware ads structure. Also. I added a light layer of glass to the inside, so as to protect it from mud and water. If you do that, you need to assume that will add some structure, so you want to quit with the wood layers while it is still a little flimsy. If you glass only one side, you need to epoxy the rest. And you need to be aware that you might get a little sectional change if you freeze just one side.

The good thing about glass is that it allows you to see how much spring you get from the lams, and then correct a little before you glass.


  • Should I worry about mixing the grain direction

It is positive, but not necessary.
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