Acraglas , WTF almost a fire.

Kelly Timoffee

Kelly Timoffee

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So, got an acraglas kit and did a rifle when I got home from work.

Mixed everything as per instructions , used the fiberglass they included , filled the stock , secured it, set it in the corner, come back and the leftover product was bubbling, smoking and so hot I couldn't touch it!!

3-5 minutes it was brick hard and porous.

I checked everything I did , numerous times after thinking it was Kelly again, nope, mixed properly.

Is that normal with the left over or did something goes sideways?
 
Kelly Timoffee said:
So, got an acraglas kit and did a rifle when I got home from work.

Mixed everything as per instructions , used the fiberglass they included , filled the stock , secured it, set it in the corner, come back and the leftover product was bubbling, smoking and so hot I couldn't touch it!!

3-5 minutes it was brick hard and porous.

I checked everything I did , numerous times after thinking it was Kelly again, nope, mixed properly.

Is that normal with the left over or did something goes sideways?
Click to expand...

Normal when mixing 2 part epoxies and body filler ect that require a catalyst to chemically cure. I have seen fires start in plastic garbage bins after someone tossed a mixing board into it. Melted a nice hole before it got extinguished. Mix it on a metal pie plate and discard in a metal container.
 
Curing epoxy is exothermic. A chemist will probably tell you the heat is how the longchain polyesters are formed - or something. My guess is the leftover resin was in a small round container with just about the least amount of surface area for its volume, and the centre is what was overheating.
 
sounds like too much catalyst to me.
Also could be too close to a heat register or heat source.
ambient room temps could play a role if they are up around 30C
and thickness of the area you tried to fill.

I work with composites so have an idea how to start a fire with them hehehe or how not too :)
I don't like acraglass personally and prefer a 2 part epoxy blend.

One time at band camp I was crammed up under the bow of a 17ft sangster edging the new floor into the inner hull and I left a small pot of catalyzed resin under there in my hurry to get my suit and respirator mask and airlines off, I just forgot it. Was probably 2 cups of polyester resin left in the pot.
Only took about 10 minutes to see the smoke and smell the over cooking resin. Scooped it outta there with a garden shovel and tossed it on the lawn and hit it with a hose.
another minute or so the boat would have been on fire for sure.

the flash points of polyester based resins and epoxies falls between 22 and 32C so some care should be taken.

just google the safety data sheet for acraglass. Mixed properly it has a very high flashpoint at 100C so I would think either the acraglass was mixed with too much catalyst or it is quite possible it was reacting chemically with the stock material it was being bonded too.
here is the Brownells safety data sheet.
https://www.brownells.com/userdocs/... DYE TRY-PAK – GREEN, 1 OZ. - 080_default.pdf
 
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I was in my shop at a comfortable 65 degrees with no nearby heat sources.

I sure hope it was just from the large amount I had left over in the cup, and I definitely hope that the compound in the stock didn't heat the same way, that would be a piss poor bedding compound result.

I think maple leaf nailed it as I mized about 1.25 oz and only used about half an oz, the center did harden first an it bubbled up around the edges.

Still not very comforting knowing that is now secured into your rifle stock .
 
Don't forget about them lin-seed oil saturated rags either.
Fruk'n'ear bernt me house down one Christmas.
Spruced up me Walnut cabnits and stuck the rag and oil in an end cupbored.
Few whishkeys, berd gitt'in roastitted and such and me noze started tuh twitch.
One smell dint sniff qwite rite.
Found that rag jest start'in tuh ember.
OHHHLEE CHIT
 
kamlooky said:
Don't forget about them lin-seed oil saturated rags either.
Fruk'n'ear bernt me house down one Christmas.
Spruced up me Walnut cabnits and stuck the rag and oil in an end cupbored.
Few whishkeys, berd gitt'in roastitted and such and me noze started tuh twitch.
One smell dint sniff qwite rite.
Found that rag jest start'in tuh ember.
OHHHLEE CHIT
Click to expand...

I have used countless products over the years repairing anything from jet skis to semi hoods , never have I ever had surplus product start to smoke , and I’ve even tried to do that intentionally.

Just hope my little project cured proper , guess I’ll find out in the morning , no flames in the bedroom window so the shop is still standing.
 
I’ve used lots of epoxies, polyester resins and bondo repairing boats. As mentioned by another, they’re exothermic (give off heat when they cure). If you get it spread out into a relatively thin layer, like when bedding a rifle or glassing a big repair on a boat, the heat can dissipate and it’s no problem. If you leave it in the pot the heat from the chemical reaction keeps heating, and the heat speeds up the reaction, making more heat, until maybe a toxic smelly smoulder is sitting there waiting for a combustion source.
 
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Yep, what they said!

Buddy of mine nearly burned down the wood shop on base, trying to save time by mixing a whole bucket of glass resin at once, instead of in smaller batches... Pretty exciting, and expensive lesson!

Flat shallow trays! Minimum amounts of resins and catalysts that you can manage, and a clear line on an outside door, if you want to play with the stuff indoors regularly.
 




Well , separated it this morning.It's hard and solid , the recoil lug area will be fine.

Looks like it will be usable, the odd void it created , very discolored and a bit porous.

I'll trim it up and hopefully be the end of it, never had such bad luck as I've had with this rifle.
 
in my opinion, the acraglass chemically reacted to your stock
I may have missed it before but what stock is that you are filling?
 
45ACPKING said:
in my opinion, the acraglass chemically reacted to your stock
I may have missed it before but what stock is that you are filling?
Click to expand...

A Vanguard S2 , I have to respectfully disagree as the result was the same in the mixing cup.

But maybe a reaction with the supplied fiberglass? just a thought.

The other common denominators were the mixing stick, mixing cup and/or product itself.

But now I want to determine what went wrong.
 
Kelly Timoffee said:
A Vanguard S2 , I have to respectfully disagree as the result was the same in the mixing cup.

But maybe a reaction with the supplied fiberglass? just a thought.

The other common denominators were the mixing stick, mixing cup and/or product itself.

But now I want to determine what went wrong.
Click to expand...

ya without being there to see what happened it's tough to tell from here hehehe
I've used various products over the years but have had exothermic chemical reactions between different products and different stock makers.
In that link I posted back a bit there is the safety data sheet for acraglass.
If you scroll down it , it lists materials that it will react with. The reaction is pretty much as you described and though it is hard to tell from the pics.... it "could" be a possibility.

to put things into context.... I am a composite stock maker among other things and along the road I have caused a few chemical reactions myself haha :)
 
Not saying your issue is the same as mine was. As my issue with accuraglas was from probably 30+ years ago. I had used accuraglass on wood stocks successfully many times. A shooting buddy started selling HS Precision composite rifle stocks .So I acquired a few of them. I do not think HS now makes any stocks the way or with the material like they did 30 years ago. These stocks required a pillar as the composite was quite soft. My first attempt was to pore pillars with accuraglass . This turned out to be a disaster . The accuraglass in a large volume ,I think my pillars were about 7/8" diameter would bubble up and billow out of the pillar hole. When accuraglass was used to bed the action , it worked a bit better but still unsatisfactory. When I changed to a different product all the problem's went away. My conclusion was the accuraglass formula and the composite in the HS stocks reacted with each other causing the bubbling up.
So you might try a different product and have better results.
I have used accuraglass on other composite stocks without problems.
 
45ACPKING said:
ya without being there to see what happened it's tough to tell from here hehehe
I've used various products over the years but have had exothermic chemical reactions between different products and different stock makers.
In that link I posted back a bit there is the safety data sheet for acraglass.
If you scroll down it , it lists materials that it will react with. The reaction is pretty much as you described and though it is hard to tell from the pics.... it "could" be a possibility.

to put things into context.... I am a composite stock maker among other things and along the road I have caused a few chemical reactions myself haha :)
Click to expand...

I wonder if something in the air or vapor would have enough contamination to do this.

If it was just the stock or just the mixing cup I wouldn't be as concerned but to be on both concerns me, but , I may just go back to my panel boner, costly but flawless , and it has a media in it so you cannot over clamp it.

I don't mind learning through destructive processes either, ;) .
 
This takes me back 50 years...

It is so easy to add too much hardener and experience what you did... I did it several times long ago... you can slow that reaction down by pouring the mix out onto a flat area so it doesn't "boil" in the cup... left in the cup the heat just accelerates the process. Poured in the stock and with the metal in place the heat is absorbed and doesn't build up as it does in the cup...

The AcraGlas Gel is much easier to use.
 
Kelly Timoffee said:
I wonder if something in the air or vapor would have enough contamination to do this.

If it was just the stock or just the mixing cup I wouldn't be as concerned but to be on both concerns me, but , I may just go back to my panel boner, costly but flawless , and it has a media in it so you cannot over clamp it.

I don't mind learning through destructive processes either, ;) .
Click to expand...
Post 3 is correct. It was not a reaction to the stock or any contamination.
 
Kelly Timoffee said:
I wonder if something in the air or vapor would have enough contamination to do this.

If it was just the stock or just the mixing cup I wouldn't be as concerned but to be on both concerns me, but , I may just go back to my panel boner, costly but flawless , and it has a media in it so you cannot over clamp it.

I don't mind learning through destructive processes either, ;) .
Click to expand...
Post 3 is correct. It was not a reaction to the stock or any contamination.
 
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