DIY Carbon fiber barrel?

[Mram10us]

This would be the vacuum bagging...distributes resin evenly throughout the part and pulls off any excess.

What's it weigh? What did you leave at the muzzle end in terms of steel length/diameter prior to threading?

Fixed the dry problem by using more epoxy. The heat shrink tape squeezes out the excess that i dont get by tight layups.
It weighs 43.0 oz finished with brake. I just left a small shoulder of .060". Dont think i needed to since the cf is strong enough and faced off.

 

[birdiemc]

I've been thinking about this for a few years now... did lots of research a while back...haven't ever got around to actually buying the stuff to dive in, but my plan was to build a "lathe" of sorts...basically rig up a motor with a way to hold on to the barrel and spin it. Then for simplicity, rig up a second motor to drive a lead screw, with variable speed control. Look at a bait cast reel...same concept, incorporate an "eye" on the leadscrew to thread a carbon filament through, which would control the filament being wound onto the barrel. Variable speed so you can vary the winding angle. As for wetting the filament, something along the lines of a a milk jug filled with epoxy, poke holes for in and out, run the filament through, size of "out" hole determines how much epoxy remains on the filament.

 

[P7M13]

@Mram10us , that first barrel is awesome. I'm envious!
Great thread, thanks for the entertainment!
I used to row in college, and we had a very tight budget, so I was one of the pukes repairing hulls and oars with CF, and spent an inordinate amount of time working with it. Fascinating stuff!
Talk about a rabbit's hole when you get into the material composition. CF is simple. The epoxies and what other fibers to add become complex, especially when you started to evaluate the force vectors involved.
Some of the things I learned along the way:

• for maximum strength, CF really shines when it's applied under a fair amount of tensile stress. Hence, wrapped stuff was heavily pulled on as it was wrapped onto the mandrel / structure. This stress is much harder to achieve in a layup.
• Ideally multiple fibers would be woven onto the barrel. If you've ever looked at weaving your own rope, though technically it may be called braiding, there's a whole lot of motion going on there. That would be one fun machine to design and build.
• If I were using a woven sock, I'd want to get one that had an inside diameter just a skosh smaller than my barrel so it goes on with inherent tension.
• Just like laminating wood, we would do multiple layer/cure/finish cycles to produce exceptionally strong structures in repairs. I have seen big boats built this way too. Time consuming, though.
• I built a CF tube, with the intent of using it as a suppressor housing, using the multiple layering method and changing fiber direction. Incredibly strong, but I never did anything with it because at the time I did not have a stamp. Prolly a good idea to sacrifice it to destructive strength tests.
• Using different materials compounds the increase in strength like alloying metals. IIRC, Kevlar and CF have very different directional strength moduli, and combining the two leverages the positive properties of each one. Some of the aramid fibers produced now are simply amazing, lighter and stronger than Kevlar.
• Heat cure gives you a *much* stronger structure than something with a 50:50 resin/catalyst mix like the junk they sell in stores. For the most part, I used West System epoxy (I knew them as Gougeon Brothers back then), which is a 5:1 resin/catalyst ratio.
• Some epoxies are thixotropic - meaning they become much more fluid when under vibration. This *really* simplifies the impregnation process.
• As you may have discovered, when mixed, epoxy is an exothermic compound. The more you mix, the shorter your pot life. I have made the mistake of mixing too much, watched as the epoxy melted the mix pot and became a smoking pile of stinky yuck on the floor.
• Use PPE with epoxy. The stuff is nasty, and I developed a sensitivity to it where it now causes rashes on my skin if exposed by touch. (no, I didn't wear gloves at first).
• Unless you have a "hot oil bladder press", vacuum is the absolute best way to get a uniform preg/form made. Though I haven't used it in a decade, I still have a Gast 1023 vacuum pump for this, which will pull a good vacuum down to 80 Torr (26 to 27" Hg).

just watched some vids on the process and i think it might be easier to use the shrink tape over the wet cf material for the barrels. I could be wrong.

You may already know the answer, but I found that shrink tube does not even come close to providing the necessary pressure to do much as far as epoxy extrusion.

Stainless & Titanium slivers/chips, CF also doesn't fester because your body doesn't recognize it as foreign.

Stainless and CF, my body sure recognized is as foreign. CF was like fiberglass wool. Stainless always came with nasty infections (machine shop chips). I got pretty good with an exacto or safety razor blade.

Will "not" using a release agent in the roll-wrap method shown, absolutely prevent de-bonding of the barrel from the wrap?

I have used this. Worked very well but it's messy. Only time it became a problem was when expoxy would extrude into the plastic between the layers.

4. Temperature - how hot does a 7mm get ahead of the chamber after 5 rounds?

Easy enough to check with a IR thermometer from HF. I used a trash barrel to fire-form a bunch of 6.5x55 Improved brass, where I'd fast fire through a box of 50 at a time. The barrel would get >140°F after ~15 rounds, so I'd let it cool.
When you get into high temp epoxies, your choices get really small, really fast. Above a certain temperature the cured epoxy breaks down. IIRC, the highest temperature ones were in the range of 350° to 450°F

 

[Mram10us]

@Mram10us , that first barrel is awesome. I'm envious!
Great thread, thanks for the entertainment!
I used to row in college, and we had a very tight budget, so I was one of the pukes repairing hulls and oars with CF, and spent an inordinate amount of time working with it. Fascinating stuff!
Talk about a rabbit's hole when you get into the material composition. CF is simple. The epoxies and what other fibers to add become complex, especially when you started to evaluate the force vectors involved.
Some of the things I learned along the way:

• for maximum strength, CF really shines when it's applied under a fair amount of tensile stress. Hence, wrapped stuff was heavily pulled on as it was wrapped onto the mandrel / structure. This stress is much harder to achieve in a layup.
• Ideally multiple fibers would be woven onto the barrel. If you've ever looked at weaving your own rope, though technically it may be called braiding, there's a whole lot of motion going on there. That would be one fun machine to design and build.
• If I were using a woven sock, I'd want to get one that had an inside diameter just a skosh smaller than my barrel so it goes on with inherent tension.
• Just like laminating wood, we would do multiple layer/cure/finish cycles to produce exceptionally strong structures in repairs. I have seen big boats built this way too. Time consuming, though.
• I built a CF tube, with the intent of using it as a suppressor housing, using the multiple layering method and changing fiber direction. Incredibly strong, but I never did anything with it because at the time I did not have a stamp. Prolly a good idea to sacrifice it to destructive strength tests.
• Using different materials compounds the increase in strength like alloying metals. IIRC, Kevlar and CF have very different directional strength moduli, and combining the two leverages the positive properties of each one. Some of the aramid fibers produced now are simply amazing, lighter and stronger than Kevlar.
• Heat cure gives you a *much* stronger structure than something with a 50:50 resin/catalyst mix like the junk they sell in stores. For the most part, I used West System epoxy (I knew them as Gougeon Brothers back then), which is a 5:1 resin/catalyst ratio.
• Some epoxies are thixotropic - meaning they become much more fluid when under vibration. This *really* simplifies the impregnation process.
• As you may have discovered, when mixed, epoxy is an exothermic compound. The more you mix, the shorter your pot life. I have made the mistake of mixing too much, watched as the epoxy melted the mix pot and became a smoking pile of stinky yuck on the floor.
• Use PPE with epoxy. The stuff is nasty, and I developed a sensitivity to it where it now causes rashes on my skin if exposed by touch. (no, I didn't wear gloves at first).
• Unless you have a "hot oil bladder press", vacuum is the absolute best way to get a uniform preg/form made. Though I haven't used it in a decade, I still have a Gast 1023 vacuum pump for this, which will pull a good vacuum down to 80 Torr (26 to 27" Hg).

You may already know the answer, but I found that shrink tube does not even come close to providing the necessary pressure to do much as far as epoxy extrusion.
Stainless and CF, my body sure recognized is as foreign. CF was like fiberglass wool. Stainless always came with nasty infections (machine shop chips). I got pretty good with an exacto or safety razor blade.
I have used this. Worked very well but it's messy. Only time it became a problem was when expoxy would extrude into the plastic between the layers.
Easy enough to check with a IR thermometer from HF. I used a trash barrel to fire-form a bunch of 6.5x55 Improved brass, where I'd fast fire through a box of 50 at a time. The barrel would get >140°F after ~15 rounds, so I'd let it cool.
When you get into high temp epoxies, your choices get really small, really fast. Above a certain temperature the cured epoxy breaks down. IIRC, the highest temperature ones were in the range of 350° to 450°F

Thank you for the compliment and advice. It seems like i have a decent handle on the process with the shrink tape. It has more force than i expected in multiple layers. The temperature has always been my concern. I got high temp resin to fix that so we'll see how it performs. Out to the shop to finish these

 

[25WSM]

Seems like your having way too much fun with this. I used to work in a fiberglass layup shop building boat parts. Just the smell of ppe and resin makes me want to puke now. The mask we had were not the best and it definitely let the smell through. I've never had issues with chips or fibers getting infected like others have stated. But getting burned by those huge blue chips sure sucked when I worked as a machinist. I ran a larger lathe turning rolls and was taking off 1/4 inch cuts. 1/2 in on the of per pass. Those chips were bastards to be sure. This has been a fun thread keep up with the project I like what your doing. Got to wonder what NASA would come up with if they had to design a rifle barrel. Or the kids at MIT.
Shep

 

[bdlesh]

Since you are experiencing. How about machining the barrel down to allow a cf tube to seat at the camber end and thread the muzzle to accept a battle nut or brake to preload the tension on the barrel? Kinda like the Dan Wesson revolver.

 

[Mram10us]

Since you are experiencing. How about machining the barrel down to allow a cf tube to seat at the camber end and thread the muzzle to accept a battle nut or brake to preload the tension on the barrel? Kinda like the Dan Wesson revolver.

Like this? They have an interesting idea here. Wonder how it differs with regard to accuracy from PR.

 

[bdlesh]

Like this? They have an interesting idea here. Wonder how it differs with regard to accuracy from PR.

I should have known if I thought of this someone else already had. I have a Dan Wesson and have always thought their barrel set up was really well thought out. Maybe the system would would to switch barrels like remage.

 

[Mram10us]

I should have known if I thought of this someone else already had. I have a Dan Wesson and have always thought their barrel set up was really well thought out. Maybe the system would would to switch barrels like remage.

I hear ya. When I started this thread, I thought i was the only one who had thought of wrapping a barrel in carbon fiber

 

[bdlesh]

I hear ya. When I started this thread, I thought i was the only one who had thought of wrapping a barrel in carbon fiber

I think most of us are " what if I....". This hobby is kinda based on that thought line. We are always tinkering with loads, barrel lengths, optics or cartridge choice. There are so many ways to improve......or make worse any part of this.

 

[birdiemc]

I hear ya. When I started this thread, I thought i was the only one who had thought of wrapping a barrel in carbon fiber

Not a chance, you're in good company around here, lots of maniacs with great ideas...however you seem to be the best at jumping on an idea and testing immediately. I think and think, then save and save money before I jump in lol

 

[XSIVSPD]

Not a chance, you're in good company around here, lots of maniacs with great ideas...however you seem to be the best at jumping on an idea and testing immediately. I think and think, then save and save money before I jump in lol

I take it one further and usually never actually jump... Lol

 

[Mram10us]

The 28 nosler that started life as a #5 brux weighed 79.9oz with barrel, receiver and lug. Just finished the CF part tonight and just need to add a different brake tomorrow. It weighs 69.8oz with the sacrificial brake full of epoxy It will be more than 10oz of savings which is huge in my book. It is the bottom one in the picture. 3 down, one or two to go.

 

[birdiemc]

The 28 nosler that started life as a #5 brux weighed 79.9oz with barrel, receiver and lug. Just finished the CF part tonight and just need to add a different brake tomorrow. It weighs 69.8oz with the sacrificial brake full of epoxy It will be more than 10oz of savings which is huge in my book. It is the bottom one in the picture. 3 down, one or two to go.
View attachment 225863

You're killing me...I'm really wanting to go try this now, but I cant...I got too many other projects in line, finally about to build my reloading press. Gotta stay focused.