Plastic Stock Stiffening

std7mag

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So did you use an arrow with the body filler?
No, they were experiments.
The arrow cut length wise was just epoxied in. I think the epoxy may have done more than the actual 2 halves of the arrow.

The light weight body filler, after about a weeks time was primed with some zinc chromate primer that i had from working on aircraft.

Definitely use the adhesion promoter!!!
 

44hunter45

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I have not seen that particular stock, but used standard epoxy on my Ruger American and it worked well.
This I use only Devcon Steel for action bedding. But I've also had good success stiffening plastic stocks with plain table top epoxy. It is not cheap either, but I have it gallon jugs left over from my epoxy top reloading bench project.
 

hseII

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Due to cure time I’m starting to think an epoxy would be a better choice than the glass filler. I plan to get the rifle from my LGS today when it comes in & make the call.
 

ImBillT

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Bondo?

The carbon arrow shaft seems great.

Never discount polyester resin. It’s cheap, it sets up fast, and it’s stiffer than epoxy. Epoxy is not always necessary, and sometimes it isn’t even the best choice.
 

hseII

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Bondo?

The carbon arrow shaft seems great.

Never discount polyester resin. It’s cheap, it sets up fast, and it’s stiffer than epoxy. Epoxy is not always necessary, and sometimes it isn’t even the best choice.
I picked up short strand body filler, yes bondo.

After reading that it will take more time to cure & then must be sealed, I’m beginning to believe epoxy might be better.

I’m going to look for poly resin now. Rifle didn’t arrive today anyway.
 

p_ham

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I picked up short strand body filler, yes bondo.

After reading that it will take more time to cure & then must be sealed, I’m beginning to believe epoxy might be better.

I’m going to look for poly resin now. Rifle didn’t arrive today anyway.
The body filler takes roughly 10-15mins to kick, it's fully hardened in 20-30min and can be sanded and sealed. Filler is 0 VOC once cured.
This is all dictated by ambient temperature, but since it's a chemical reaction it's very predictable.
Use either blue or red activator, it's hard to tell when the white stuff is mixed.
 

ImBillT

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I picked up short strand body filler, yes bondo.

After reading that it will take more time to cure & then must be sealed, I’m beginning to believe epoxy might be better.

I’m going to look for poly resin now. Rifle didn’t arrive today anyway.
I really don’t know what would be best for this purpose.

Polyester resin is stiffer, cheaper, faster, and usually more sandable than epoxy.

Epoxy is usually used when the part needs more flexibility, will be subject to severe impact, requires a longer working time, is so thick that the heat generated by curing polyester would result in damaging temperatures(it will set itself on fire if you try to cast a thick block), with certain synthetic fibers that polyester doesn’t adhere to well, and on certain surfaces that polyester will not adhere to well.

There are absolutely purposes for which one or the other is substantially better suited, but there is also a lot of overlap.

Bondo and similar body fillers are polyester resin with a lightweight, sandable, thixotropic adative. I’ve never used a fiber reinforced filler, so I’m not sure what they’re like. Plain polyester resin is pretty handy to have around and useful for quite a few things especially with the addition of chopped or milled fibers, or micro balloons. I’ve bedded actions with vinyl ester resin and milled glass. I prefer it over JB Weld and Marine Tex, but it’s pretty runny without enough glass in it. It gives you more time than polyester, but it’s more expensive as well.
 
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hseII

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I really don’t know what would be best for this purpose.

Polyester resin is stiffer, cheaper, faster, and usually more sandable than epoxy.

Epoxy is usually used when the part needs more flexibility, will be subject to severe impact, requires a longer working time, is so thick that the heat generated by curing polyester would result in damaging temperatures(it will set itself on fire if you try to cast a thick block), with certain synthetic fibers that polyester doesn’t adhere to well, and on certain surfaces that polyester will not adhere to well.

There are absolutely purposes for which one or the other is substantially better suited, but there is also a lot of overlap.

Bondo and similar body fillers are polyester resin with a lightweight, sandable, thixotropic adative. I’ve never used a fiber reinforced filler, so I’m not sure what they’re like. Plain polyester resin is pretty handy to have around and useful for quite a few things especially with the addition of chopped or milled fibers, or micro balloons. I’ve bedded actions with vinyl ester resin and milled glass. I prefer it over JB Weld and Marine Tex, but it’s pretty runny without enough glass in it. It gives you more time than polyester, but it’s more expensive as well.

This is what I got.

 

ImBillT

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p_ham

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Never tried it. I assume it’s like Bondo body filler with chopped strands mixed in. That’s different from plain polyester resin with chopped strand mixed in, but I’m really not sure how different. It should be considerably stronger than regular Bondo, and lighter than just mixing chopped strand with polyester resin.
It's the difference between cement and concrete.
Also, body filler, including stranded, is polyester resin based. It just fillers to give it more body and make it easier to work. Most versions use talc as their filler, which is why they soak up moisture. Some of the higher end glass fillers don't have talc, bit a lot still do. The really high end stuff uses aluminum as filler and is very moisture resistant. The lightweight fillers use microballoons and talc.
 

OntarioHunter

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Very interesting and informative thread. Thanks guys! I glass bedded my Springfield back in the early eighties. In those days floating barrels was sort of a new concept and not highly thought of ... yet. I bedded mine to the end of barrel trough. In an attempt to resolve flyer issues I removed most of the barrel bedding material two years ago. It was some kind of proprietary brownish glass/epoxy stuff for guns. I was surprised at how much the stock has twisted over the years. It was apparent from having to dig past the glass into the wood at some points to free up the barrel. I only floated the barrel to 3" above the receiver but last night I finished floating it to length of cartridge/chamber from the end of closed bolt. Some sources advise floating it to the receiver and some say to the chamber. Again, I noticed how the barrel was being bound up significantly more on one side of the stock's trough.

I wish I'd read some of this stuff before taking my rifle to Africa. I rebedded the action and last minute replacement barrel a little more than two days before leaving in August. It zeroed fine at the range here and hit the mark with first and only shot at the range there so figured I was okay to go. No! Made a mess of the poor hartbeest the next morning. Back at the range that afternoon the Springfield was all over the paper. Later that night I discovered the action was loose from bedding. Apparently the epoxy wasn't fully cured when I zeroed it and shrank during the flight to Africa. She's shooting well enough now. No more flyers and MOA. I think it's time to try tweaking my loads for sub MOA ... when components finally become available again. I may remove the bedding and replace it with something advised by you guys. Doesn't look like there was a perfect mating of metal to fiberglass. I suspect I poured the bedding material into stock when it was still too runny.
 
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David658

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Very informative thread for a muzzleloader guy - there's lots of moving parts to this suppository gun stuff. I thought, apparently incorrectly, that a plastic stock would be the solution for my M77 issues, but over the past few weeks have learned different. I hope bedding and floating my action and barrel in my wood stock works - this stock stiffening process seems like a mess. i'll find out at the range.
 
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