Homebrew Micarta - Failed

S

SGP

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Jan 3, 2009
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My first attempt at making a composite didn't turn out so great, so I'd like to share some thoughts on what went wrong for the benefit of anyone else that might be trying this, and I'd appreciate some help working around the limitations i've got to deal with. First, i don't have a shop. I've got about a square yard of my porch covered in waxed paper, and it's the end of October in NH, so frost, rain, and dark at 5:30 are the orders of the day. Second, I decided linen micarta was cooler (also cheaper) than denim or canvas, so instead of prepping 15 to 20 layers, i wound up with more than 60, and had to mix multiple batches of resin on the fly, in the dark, long after i'd planned on being done. This was for a finished piece roughly 1.25" thick. Only the bottom half of the stack actually cured properly, and I believe I misjudged the hardener amount on all but the first mix. any suggestions for my next attempt?
 
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Hello! Good on ya for trying!:D A question for ya, Did you put it under pressure? if not try stacking a cement block or 2 on top of it if you dont have a vice.
 
I tried the big batch thing first... got through half the stack before it hardened in the bowl, about tweny minutes. cheap Bondo brand resin, but i couldn't justify $70 for the slow-cure marine stuff. I'll definately be more careful with the ratios next time, though.
It was held under a 2x6 and 80 pounds of freeweights, and the half that did set up properly came out lookin very good. just loose layers at the top.
I'm cerainly looking forward to giving it another shot, good messy fun!
 
Try using clamps with smooth hardwood or something more rigid to sandwich it. I do mine between two pieces of thick Corian. Ask a shop for some scraps if there is one near you.
 
Any tips on working with resin in the cold? It's getting down below freezing overnight, and peaking anywhere between 50 and 65 during the day. Don't know if that might've been effecting the outcome, but i was lead to believe that it will cure, if slowly, at temps below 60, and freezing will just stop the reaction, ready to resume again once the temperature rises again. Am I mistaken?
 
I made some a while back & it turned out pretty good. After layering the material and epoxy I wrapped the whole package in wax paper. Then I put it between 2 boards & clamped it down with big c-clamps. I also set it over a mop bucket to catch the drip. Maybe you could set it just inside the door where it is warmer after you have it all ready to go with an old pan underneath it.
 
I've used Bondo resin before and this recipe wored well for me

1 cup resin + 1teaspoon hardener

I tried this idea out once and it worked well.

Use wax paper long enough to wrap completeley around the unclamped slab and place it on a board.

Stack all your layers neatly on the board while still dry.

Hammer a nail through the very end approx. 1/4" in from the end. Make sure the nail is deeper than your desired end thickness of slab.

Now fold all but 1 over the top of the nail.

Mix resin and start coating. Pour resin in a line down the center of the slab. use a paint scraper to quickly smear the resin. Don't worry if the edges are a little dry. the surplus in the center will squeeze through those spots when clamped.

If your using a material thats very thin or easy for the resin to soak through it's ok to only resin every two layers and be fine. I've used felt a few times going every other layer with no problems.

Resin the whole slab wrap the wax paper over put another board on top and clamp as thighly as possible with c-clamps.

Using the nail trick speeds the process up quite a bit but you will have to pull the nail and lose the end of the slab.

Another trick is to use boards thick and wide enough to put spacers on the outside of the slab but between the boards. This is to assist in gettin a nice even slab instad of a lopsided one from uneven clamping pressure.

My guess is that your curing issue had more to do with not enough hardener or not mixed well enough than the temperature. Purely speculation though

hope this helps ya out
-Josh
 
In that temp zone with the humidity/cold etc it may cure about Mid-June for U!!! Sorry.:grumpy:
Even here in the Desert it won't cure unless it get to the proper temp AKA 60-80 deg F. Humidity is a big negatory for the curing process.
What Josh said is on the money but if you want easier repeatable results buy some epoxy.
Luckily I have a local supplier where I can get a 1/2 gal of 60min cure for like $38. You can get about the same on Ebay if you shop around.
It doesn't stink near as bad and winds up being cheaper without the lost batch headache and expense.
NEXT: Watch a bunch of vids on Utube about making surfboards or just type Epoxy there are some well made ones out there.

Lastly;;; Before you make your batch see what the fabric looks like wet first.
Always get the strangest looks when looking at fabric and I spit on my fingers, then smear the fabric to test the finished color:D
 
Temp restrictions should be printed on your can of epoxy.
Make a tent over your next try, and heat it with a hair dryer.

Leadfoot
 
when i do large blocks i put the epoxy in my fridge
then whenn its all set up and pressed i hit the steel plates with a blast heater

once the epoxy kicks off it builds heat on its own so in then cut the heat off and let it go

now all that said my avg block size is 6x10x3.5 thats alot of mass to cure

and no im not making layers im making "burl"
 
This is what I do with epoxy. let it set up at room temp or at least 70 degrees. After a few hours I use a big cooler with a 60 watt light bulb in it to do the first cure. Then use a 100 watt bulb for a second cure. The exact temp I go for and the time it stays at temp depends on the epoxy. It helps to get one big enough to put whatever you use to clamp the stuff together right in the cooler.
 
Thanks for all the help! just finished another slab, and it looks great so far. I believe temperature wasn't a problem for the first attempt, i assume, just poor planning. Pouring resin directly onto the linen and using a solid spreader, instead of applying wiith a brush, seemed to make the biggest gain in working ease. The scales should be cut out and on my Spyderco D'Allara and Smith and Wesson 65 in a week or two.
 
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