Question about homemade laminate scales "mycarta"

[Langadune]

First... I know, I know... It's more efficient and cost-effective to buy ready-made micarta; but I'm working towards making some knives for family gifts and I want every part to be handmade. That being said...

I've previously made to successful batches of scales using the 3M fiberglass resin. (I'll eventually get around to using West Systems... but I don't have the extra $$$ right now). They turned out pretty good. Then I tried another batch last weekend, forgetting that it was 30 or 40 degrees warmer/hotter outside than my previous two attempts. My working time was significantly shorter, as in the stuff was starting to gel at around 10 minutes. I used the recommended amount of hardener but am thinking now I might want to reduce that.

Has anyone had a similar experience? I'm worried that reducing the amount of hardener will result in the resin not settting up at all.

 

[Stacy E. Apelt - Bladesmith]

3M fiberglass resin can be adjusted in set time for temperature. For 60F, double the hardener. For 90F cut it in half.

You also can cool the resin before mixing at the standard ratio. This will slow the set rate, too.







A better solution is to use a slower hardener, like the West System 209 extra slow hardener, with the 105 resin.....but you know taht

 

[tjswarbrick]

I used Bondo fiberglass resin and had a similar experience.
My first batch was in the summer (~ 80 deg F), and I had to make the block thinner than I planned because the resin set so fast.
Next batch was in the winter (~ 50 deg F), and I used just a dab less hardener. I felt like I had all the time in the world.
In both cases I left it in the press for 3 days, and let it cure for over 2 weeks before I went to use it.
The first batch does seem slightly more brittle and plasticky. 2nd batch feels more like a natural material (both used a burlap material base.)
I've beat on both with wooden batons (they're mounted on Becker knives) with no ill effects.

From what I've read, you could use a little less hardener, but if you don't use enough it won't set. I don't even measure the hardener - just try to use about as much of the tube, percentagewise, as I used of the can of resin.

 

[Langadune]

I tried another batch this weekend with slightly less than recommended hardener. I managed to get all the strips saturated before the resin started to harden, however, it never fully hardened in the strips after clamped. I let is sit for two days before removed the clamps to check it. The resin that oozed out the sized hardened nicely but the denim did not. They were definitely saturated but there's just no hardness again. Hard to say what the issue is now.