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.