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Posted By: Bill Graham Acraglass curing - 01/28/18 04:58 AM
Mending a long crack in a cheek ear in a sidekick. Was careful to mix 50/50 of the Acraglass ingredients (no dye added), and mixed for 4 minutes. The mend is holding, but the excess that squeezed out when I wrapped it with surgical tubing is soft. This makes me wonder if what’s in the crack is soft as well. I will still be using the superglue technique for the rest of the inlettjng. Do I have a problem, or need longer time to cure?
Posted By: Frank46 Re: Acraglass curing - 01/28/18 05:18 AM
Just happened to have a newly purchased box of the Acraglass Gell sitting by my computer. It does say to let it sit for about ten hours then take the barreled action out of the wood clean it up then reassemble and let sit for a couple days to further cure. having said all that here goes. Could be that the ambient temp in your house will not allow the acraglass to cure in the allotted time as per the instructions. The colder it is the longer the cure time will be. One solution would be to set up the stock near a heat source like a table lamp to get the temps up and help speed up the cure. Been a cold winter this year and we have had record low temps here in Louisiana so North Carolina would be even colder further north. A good check would be the acraglass on the outside of the wood if setup under a lamp then should also have setup in the wood.
Posted By: Stanton Hillis Re: Acraglass curing - 01/28/18 11:46 AM
I used some AG last week to mend a tiny sliver of wood that had split off by the top tang on a double I'm refinishing. It was only 44 degrees in my old shop when I mixed the stuff, and it was so stiff I could hardly get it to mix. But, I used it anyway and hung the stock over one of these little oil-filled electric radiator-looking heaters they used to sell. I let it hang over that low heat overnight and it was cured hard next day. The AG I was using is several yrs. old, so no worry about the age of it as long as it isn't hardened in the jar.

I'd put it over very low heat for a day and let it harden. Should be fine.

SRH
Posted By: mark Re: Acraglass curing - 01/28/18 01:16 PM
I always save the left over glue so I can see how it hardens up.
Posted By: Bill Graham Re: Acraglass curing - 01/28/18 01:54 PM
The consensus is that a little focused heat to finish up the curing? I can set the stock near a heat vent in the floor.
Posted By: SKB Re: Acraglass curing - 01/28/18 02:17 PM
When AG gets hard in the container put it in some hot water and it softens up and mixes well. Works for the gel or the liquid.
Posted By: keith Re: Acraglass curing - 01/28/18 02:49 PM
As long as your ratio was correct and you mixed thoroughly, I'd have to agree that the reason it is still soft is due to curing temperature. The stuff inside the crack will be just as soft as what squeezed out. I wouldn't get the area too warm because most epoxies begin to break down and soften at around 160 degrees. Keep your clamps or rubber tubing in place until it is fully cured.

And next time, consider using Titebond II wood glue for repairing cracks in non-oily wood. In cracks and other close fitting joints, it is stronger than the wood, and it makes a less visible joint in walnut than epoxy. Epoxy may be a better choice for cracks that can't be clamped completely closed or where larger gaps need filled. However, bubba repairs like that have no place on nice guns.
Posted By: Kutter Re: Acraglass curing - 01/28/18 03:08 PM
I use the Acra-Gel, it's a 50-50 mix.
Sometimes it takes longer to harden up if I eye-ball the 50/50 a bit off.

I always prop the just glued up assembly under a 75w pre-AlGore litebulb in a simple desk swinglamp fixture. Down close but not touching to assembly. I leave it on for several hours.
It makes the glue set up quicker,,'turn over' is term I hear often.
I take the metal out when it's set up firmly (comes apart easy at this point,,may not later if you leave it together for a couple days!) and then put it back together again,,about the 10hr mark but sometimes less.
The glue is still somewhat rubbery sometimes yet , sometimes harder. depends on the temp around it.
I keep a room temp of 63 in the winter so I usually get the former.
I leave some excess on the mixing paper to check the stuff as mark does. That helps alot.

Then just reassemble and leave it for a couple days or so to cure.
It'll harden up by it's chemical hocus pocus. Makes it's own heat I understand in curing.
Posted By: Byrddog Re: Acraglass curing - 01/28/18 03:43 PM
Acraglass is 1950's technology. If the prereacted resin crystallizes it really should be tossed. With todays polymers that will not happen The soft result is caused by moisture affecting the components, stunting the reaction. if you can cook out the moisture it may harden but then you never know if a good repair has been accomplished. Use a good quality slow cure 1:1 epoxy for better results.
Posted By: Byrddog Re: Acraglass curing - 01/28/18 03:46 PM
Acraglass is 1950's technology. If the prereacted resin crystallizes it really should be tossed. With todays polymers that will not happen The soft result is caused by moisture affecting the components, stunting the reaction. if you can cook out the moisture it may harden but then you never know if a good repair has been accomplished. Use a good quality slow cure 1:1 epoxy for better results.
Posted By: Brittany Man Re: Acraglass curing - 01/28/18 04:57 PM
B. Graham

Are you using Acraglass (red box) as you stated or Acraglass gel?

The mix ratio is 4:1 for Acraglass (resin to hardener) & 1:1 for Acraglass gel (green box).

If you use way too much hardener with Acraglass it will not cure.
Posted By: KY Jon Re: Acraglass curing - 01/28/18 05:13 PM
Oxygen will inhibit curing. You will get a uncured surface layer and it will be less cured just under neath. Just use heat to help finish the cure. Time does the same thing. But your repaired area will not have exposure to air so it should be more cured. I just run a heat gun over the surface to finish the curing in that area then trim off the excess.
Posted By: Bill Graham Re: Acraglass curing - 01/28/18 07:48 PM
Originally Posted By: Brittany Man
Are you using Acraglass (red box) as you stated or Acraglass gel?

Sorry. Gel. I forget there’s the other kind.
Posted By: Kutter Re: Acraglass curing - 01/28/18 10:11 PM
I remember the 4min stir process for the acra-glas.
I haven't used that stuff in years and haven't missed it running all over the place either.

I really didn't know if they had a specific time on the mixing of the 2 componets of the acra-gel (4min or what ever),,but I mix it much longer than that just gently stirring and folding it over with a screwdriver as I listen to a few extra songs on the radidio. Never had a problem w/a batch not curing. Just some take longer than others,,I figure my mix ratio is a bit off (eyeballed) or the temp is low in the room. It's rather brisk right now.

I sometimes put the mixed and ready to go gob of goo under the before mentioned light bulb for a minute or less, before use.
It warms & thins it considerably if you need it to be so for application (cracks and such).
Or just do a part of the supply and leave the rest a stiffer mix.
The heated and thinned stuff will set up rather quickly,,like within an hour or even less. That can be used to your advantage sometimes too.

I've used the 'steel' mix acra=gell on occasion too. Don't know where I got the stuff I have,can't remember actually buying it. Someone must have either given it to me or I got it cheap somewhere.

Mixes 1-1 IIRC and works well for certain projects. Usually use that for building up wood that'll be used for a tracer pattern or a form. Saves using the Acra-Gel for that.
Not something I use on a gun in general. At least I'd not want it to show!

I generally have a odd project of two around the shop that continually need epoxy/glass filler in some form or another.
Split tool handles, a stock pattern as mentioned above that needs voids filled, ect.
Seems I usually mix too much glas up when doing a job, so instead of letting it go to waste, I use the extra on those odd jobs sitting around. They get done that way,,sometime.
I still leave a small bit on the mixing paper to use for checking the curing of the orig mix.
Posted By: Bill Graham Re: Acraglass curing - 01/31/18 07:15 PM
More time and a warmed environment was all it took. All is well.
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