Making a better bedding compound - 04/03/24
As a composites guy, you won't see me spend money on the brittle brownells garbage when the time comes to bed a rifle.
I've been bedding rifles since 2003 and its quite trivial compared to building a $15k moose hunting boat or a $6k freight sled.
There's a severe lack of knowledge about release agents, additives and even the process. Even most gunsmiths are clueless about epoxy composition as well.
About the cleanest bedding jobs I've seen are BSA1917hunter's bedding jobs. Not gonna go into detail about the "bedding" part.
But rather a few "process" and formulation tips:
Only clean the roughened stock area with stove alcohol. It's the only cleaner and thinner that won't compromise adhesion or react negatively with the epoxy.
Start with a high strenth 30 minute resin like permatex 2 ton or devcon 2 ton. No jb weld, its garbage. I like the permatex because its rated to -65 below. Permatex has a radical portfolio over a broad spectrum of chemical products. Moreso than devcon.
Though the 2 ton shear strength is sufficient, the raw resin can be improved by adding a substrate. I like trimming down either fiberglass or kevlar cloth into 1/4" pulp. This really improves strength against torquing down action screws. It also strengthens the epoxy in the recoil lug area. Think "zytel ruger stock" here. Your doing the same thing with the long-strand pulp as a substrate.
Cool the unmixed resin in fridge before mixing. It'll give you a few more minutes of working time before it heats up.
Mix the raw epoxy first. *Set aside a teaspoon full of freshly mixed resin.
Combine the mixed resin (by volume) 50/50 with the fiberglass or kevlar pulp. Just because it appears thickened, its not.
As the resin heats up, it'll slump badly. So you have to continue thickening the viscosity of the resin with cabosil (fumed silica). Go nice and thick.
With that teaspoon of raw resin, thin it with stove alcohol. This is the penetrating coat that enhances the mechanical bond.
I'm not sure if it's a capillary effect, or a polarity thing but it works extremely well. Brush that thinned resin over the roughed area to be bedded.
I've tested this out on a thin piece of cured fiberglass, I punched 2 holes with a needle. I poured unthinned resin over one hole, and epoxy thinned with alchol over the other. Next day, the thinned resin left a puddle of cured resin on the backside the pin hole. The unthinned resin didn't penetrate the pin hole. So you can imagine what this prep coat will do for promoting adhesion. **This trick was taught to me by an epoxy chemist/epoxy brand owner who formulated my boat resin.
Release agents:
Wipe down the metal parts and action screws with partall #2 mold realease wax. It can also be used to fill voids or thread holes. Molding clay is fking stupid for this purpose.
With a brush or with an hvlp detail gun, apply 2 coats of partall # 10 release agent to the action and screws. This is the "green stuff" in your dumba ss, overpriced brownells kit.
You can tint the bedding compound whatever color you want, with epoxy die. Let the bedding job cure at room temp on a low humidity day.
Wear gloves, eyewear and a mask.
To get epoxy off your skin, dish soap and a few slices of orange, lemon or lime works well. The oils in the rind and the acidity of the fruit will take the epoxy right off your skin.
Or don't and eat a bag of doritos during the bedding job and lick the cheese off your fingers. I could give a flying fk about yalls health and safety choices.
I've been bedding rifles since 2003 and its quite trivial compared to building a $15k moose hunting boat or a $6k freight sled.
There's a severe lack of knowledge about release agents, additives and even the process. Even most gunsmiths are clueless about epoxy composition as well.
About the cleanest bedding jobs I've seen are BSA1917hunter's bedding jobs. Not gonna go into detail about the "bedding" part.
But rather a few "process" and formulation tips:
Only clean the roughened stock area with stove alcohol. It's the only cleaner and thinner that won't compromise adhesion or react negatively with the epoxy.
Start with a high strenth 30 minute resin like permatex 2 ton or devcon 2 ton. No jb weld, its garbage. I like the permatex because its rated to -65 below. Permatex has a radical portfolio over a broad spectrum of chemical products. Moreso than devcon.
Though the 2 ton shear strength is sufficient, the raw resin can be improved by adding a substrate. I like trimming down either fiberglass or kevlar cloth into 1/4" pulp. This really improves strength against torquing down action screws. It also strengthens the epoxy in the recoil lug area. Think "zytel ruger stock" here. Your doing the same thing with the long-strand pulp as a substrate.
Cool the unmixed resin in fridge before mixing. It'll give you a few more minutes of working time before it heats up.
Mix the raw epoxy first. *Set aside a teaspoon full of freshly mixed resin.
Combine the mixed resin (by volume) 50/50 with the fiberglass or kevlar pulp. Just because it appears thickened, its not.
As the resin heats up, it'll slump badly. So you have to continue thickening the viscosity of the resin with cabosil (fumed silica). Go nice and thick.
With that teaspoon of raw resin, thin it with stove alcohol. This is the penetrating coat that enhances the mechanical bond.
I'm not sure if it's a capillary effect, or a polarity thing but it works extremely well. Brush that thinned resin over the roughed area to be bedded.
I've tested this out on a thin piece of cured fiberglass, I punched 2 holes with a needle. I poured unthinned resin over one hole, and epoxy thinned with alchol over the other. Next day, the thinned resin left a puddle of cured resin on the backside the pin hole. The unthinned resin didn't penetrate the pin hole. So you can imagine what this prep coat will do for promoting adhesion. **This trick was taught to me by an epoxy chemist/epoxy brand owner who formulated my boat resin.
Release agents:
Wipe down the metal parts and action screws with partall #2 mold realease wax. It can also be used to fill voids or thread holes. Molding clay is fking stupid for this purpose.
With a brush or with an hvlp detail gun, apply 2 coats of partall # 10 release agent to the action and screws. This is the "green stuff" in your dumba ss, overpriced brownells kit.
You can tint the bedding compound whatever color you want, with epoxy die. Let the bedding job cure at room temp on a low humidity day.
Wear gloves, eyewear and a mask.
To get epoxy off your skin, dish soap and a few slices of orange, lemon or lime works well. The oils in the rind and the acidity of the fruit will take the epoxy right off your skin.
Or don't and eat a bag of doritos during the bedding job and lick the cheese off your fingers. I could give a flying fk about yalls health and safety choices.