Working with epoxy


Brendon_t

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I've got a question for the epoxy guys. I'm going to be pouring a west systems epoxy track with 10% by weight powdered graphite.

I did a little test pour in a shallow track last night and got A LOT of bubbles. I was pouring directly from my mixing cup.

Any ideas here?  The channel I'm pouring is 1/2"x1/2" by 36".

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Torch or a heat gun.  As the epoxy cures, it creates the bubbles.  Just wave the torch or heat gun over it and the bubbles go away.  It's a little time consuming as you wait for it to cure.  I usually check on it about every 10 or 15 minutes or so.

And don't try to fill all at once if it's a big area.  Fill 1/3 or 1/2 at a time.

Edited by TIODS
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Some of the bubbles will go away as it cures.  I would not expect to fill it all in one try.   Fill it, scrape and sand flush, then add a finish coat of epoxy to fill in the bubbles and level it off.  

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Kev, will a hair dryer work? I don't have either a torch or heat gun.

Good thoughts on doing it in stages.

I've never tried with a hair dryer - Might be worth a test.  A small torch kit from HD/Lowes/Menards is cheap and good to have in the shop if you're going to play with epoxy.

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I'll give it a try.  If I have to, I suppose I can grab my cigar torch although something about that sounds like a bad idea. 

I'm also going to give vibration a try. I didn't think about it until it was too late but I figure the butt end of the ros on the wood might agitate the epoxy enough for the bubbles to rise.

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I wonder if the slow-set hardener or fast hardener is less bubble prone?

A 100 w incadescent bulb also might give you just enough heat.  Rig up a drop light a few feet over project and see what happens.  

But T's method seems pretty simple.  

 

 

 

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I've got a question for the epoxy guys. I'm going to be pouring a west systems epoxy track with 10% by weight powdered graphite.

I did a little test pour in a shallow track last night and got A LOT of bubbles. I was pouring directly from my mixing cup.

Any ideas here?  The channel I'm pouring is 1/2"x1/2" by 36".

Is that a repair job you're doing Brendon? Sorry to ask, I'm just curious and not familiar with epoxy.

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No, I'm building two spear guns. Rather than cut the channel for the spear out of wood, as is the common practice, I'm going to inlay a strip of graphite laced epoxy for the strip and once cured fully, I'll cut the channel into that.

So why?   Well.. I don't freaking know. Graphite laced epoxy will have much less friction than wood,  The temp won't change the inside track since I'm only cutting it .010" oversized and I think it'll look cool. A custom builder in Australia told me about the technique and I just ran with it.  He claims he gets about 30 feet/second of speed with epoxy tracks over wood.

Edited by Brendon_t
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No, I'm building two spear guns. Rather than cut the channel for the spear out of wood, as is the common practice, I'm going to inlay a strip of graphite laced epoxy for the strip and once cured fully, I'll cut the channel into that.

So why?   Well.. I don't freaking know. Graphite laced epoxy will have much less friction than wood,  The temp won't change the inside track since I'm only cutting it .010" oversized and I think it'll look cool. A custom builder in Australia told me about the technique and I just ran with it.  He claims he gets about 30 feet/second of speed with epoxy tracks over wood.

Cool!

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I've been out for a few days / weeks and just saw this thread.  What I'd do to avoid bubbles is brush on a seal coat of straight epoxy and let it tack up.  Once that happens then you should be able to do some pouring without getting the bubbles.  I've found that adding heat to the epoxy causes more bubbles (at least with west system; others it works really well).  Best I can gather is that the heat warms up the wood (whether from a heat gun or from the curing process) and the wood begins to off gas.  As luck would have it, it almost always happens at the peak of the cure when it's warmest and coincidentally when the mix is beginning to thicken.  Once it gets too thick, the bubbles cant escape and get trapped. 

 

By brushing on a seal coat first, it basically seals the wood and greatly reduces (don't want to say eliminate) off gas getting into the thicker mix.  If you really want to play it safe, let the seal coat cure, then give a light sanding, wipe with acetone and do the pours. 

 

Good luck!

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So, adding powdered graphite to epoxy makes it look awesome.  It also makes you stir the crap out of it and makes it quite frothy.

For the record,  a hairdryer does not work but a normal bic lighter held on it does. 

Just watch your fingers. 

I bet you'll go to HF and get a cheap ass propane torch next time! Yeah, we want pics

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I'll snap some pics tomorrow after I clean it up a bit. Knowing that epoxy settles, I taped the sides and over filled it so it kind of looks like crap right now.  Once I plane it down, I'll have a better idea of the finished product. 

As for highlightes' I'm not too sure. It looks like a very very deep black to me, but I'm black blue purple color blind so maybe I'm not the best person to ask.

after burning my fingers a few times. I went down to the liquor store down the street and bought a  cheap torch. Worked great.

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