GTA
All Springer/NP/PCP Air Gun Discussion General => Machine Shop Talk & AG Parts Machining => Topic started by: grumpy on May 30, 2014, 11:46:38 AM
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I was looking at this but it does not say anything about non expanding http://www.mcmaster.com/#loctite-9340/=s6vq0k (http://www.mcmaster.com/#loctite-9340/=s6vq0k)
Thanks for your help.
David
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Just use thin viscosity "Finish / Laminating" grade epoxy.
Using a slow cure catalyst gives you all sorts of fiddle time before it starts hardening.
Many Hobby Shops sell this grade of epoxy.
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Dave, I'd almost bet you have an adhesives distributer in your area code, who could help.
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Thanks for the tip. Any name brand you could suggest ? Folks who work at the local hobby shops aint the brightest in the book and id like to let my fingers do the shopping first.
David
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Or better yet anything at lowes or homedepot, those are both very close by where as hobby shops not so much. Thanks
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Most of the industrial suppliers are very well versed with the 3M and Devcon products. They'll sell to you at a good price, but might also be able to give you a common brand of their product that you might be able to buy at the box stores.
Edit: Is the fitment tight, with little gap? Or do you have a larger gap to fill?
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A boat shop that stocks fiberglass repair products is a good bet. A thin (low viscosity) slow cure high strength epoxy. Most things you can find in the box stores are way too thick.
Wrap the tube with some tape to form a shoulder to push the sleeve up against and hang it vertically from a string for curing so that everything stays centered.
Lloyd
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Lloyd. That was my question about the gap exactly :)
I mount steel/aluminum/or composite fishing reel seats onto carbon rodblanks for heavy fishing rods. I build up a series of dams using 1/2" masking tape...to center everything up, and hold segments of cement in place. Don't need a bunch of epoxy to do the trick. I personally use Devcon and it is 24hr.
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I would ask Sean Pero.... I believe he uses Acraglas, which is a gunsmithing epoxy....
Bob
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here ya go ... been using this product for over 25 years !!
https://images.search.yahoo.com/yhs/search;_ylt=A86.JyQwwIhT0ioAOm8PxQt.;_ylu=X3oDMTBsOXB2YTRjBHNlYwNzYwRjb2xvA2dxMQR2dGlkAw--?_adv_prop=image&fr=yhs-att-att_001&va=20+minute+finish+cure+epoxy&hspart=att&hsimp=yhs-att_001 (https://images.search.yahoo.com/yhs/search;_ylt=A86.JyQwwIhT0ioAOm8PxQt.;_ylu=X3oDMTBsOXB2YTRjBHNlYwNzYwRjb2xvA2dxMQR2dGlkAw--?_adv_prop=image&fr=yhs-att-att_001&va=20+minute+finish+cure+epoxy&hspart=att&hsimp=yhs-att_001)
It is sold as a 20 min ... but in reality unless 85* + takes far longer to set.
Using in cooler temps take a good 12+ hours to get tacky and 24 to semi harden.
* want it thinner yet ? ... a small splash of acetone thins it further to a thick water viscosity ;)
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Thinning with Acetone, in an application like sleeving a barrel, while allowing the epoxy to move into the small space easier, is NOT a good idea, IMO.... Epoxy cures by a chemical reaction, not evaporation, and in such an application the Acetone can become trapped in the matrix.... This can do two things, 1. increase the curing time or even inhibit the curing process, and 2. reduce the strength of the cured product.... It is possible to use limited thinning when laying up a composite laminate where you have a thin product with a large surface area so that the Acetone can evaporate before/during the curing process.... but I would not do it in an internal gluing operation.... where the Acetone has to travel the length of a small tolerance gap to reach the end to evaporate....
BTW, I spent 30+ years building R/C Racing Yachts using Glass/Kevlar/Carbon composites with Polyester, Vinylester, and Epoxy resins....
Bob
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The best way to thin epoxy is to warm it up. Pick an appropriate slow cure and gently warm to the desired consistency, do not overheat. Don't do this with a fast epoxy, it will never make it out of the pot..
Tom
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There is a slo/thin one called Git-Rot...soaks into wood, then hardens. Have no idea about its strength v. the other stuff. Should perhaps look.
cheers,
Douglas
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Yeah, other than heat and humidity, acetone not gonna change the character...I got off that train a while ago...after fighting pitting and airholes. K.I.S.S it and just adhere (pun), to the time required, and it'll work out.
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You guys are right !! ... My bad for mentioning the Acetone trick not thinking about the confined space and evap issue :P
Tho using the epoxy brand shared ... have thinned it with small amounts of acetone MANY many times with no structural changes what so ever.
I too have built Race Boats ... tho the 80 mph R.C. model kind ;)
Good luck which ever route you take !
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acetone not gonna change the character
I disagree, I have had Epoxy refuse to cure for over a month when thinned with Acetone and left in a sealed pot.... When it did cure, you could crumble it with your fingers.... YMMV of course, depending on the type of Epoxy and concentration of Acetone, but that was my experience.... once!
Bob
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Don't know your brand, condition, concentration, etc. etx. Doesn't matter. Probably did crumble, as it didn't get a good chance to bind to itself with the acetone keeping separating it in a closed condition.
I think we all agree that it's best not to use acetone, and that's what matters. ;)
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This probably sounds crazy but I used Gorilla Glue to put on my homemade barrel shroud . The shroud is made from a piece of steel plumbers pipe that i ground down with my dremel. I dont think i will ever get it off.
Tommy
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This is not a shroud but a barrel wrap. These aint cheap and would be an expensive lesson if the wrong products use.
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That is why it sounded crazy.
Tommy
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I think the strength of the adhesive is secondary to complete coverage. No glue will come close to the stiffness of the CF, it real job is to fill the empty space.
Tom
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This is not a shroud but a barrel wrap. These aint cheap and would be an expensive lesson if the wrong products use.
I'll admit that I don't know what you're looking at Dave. If it's a solid, carbon "arbor" sleeve, then a good epoxy blend will secure it. If you're looking at physically wrapping carbon cloth, over the barrel, then you should get resin, and then the clearcoat for the final appearance coat.
Forgive that I'm probly slow on the uptake here ;)
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I have to admit that I have only bonded a CF sleeve to one barrel, but the results were good. I have a fair amount of experience from previous years at my "paying job" dealing with epoxies in critical applications.
Here is a look at some deflection testing I tried with a pseudo before and after with the CF sleeved barrel. The CF sleeve does indeed greatly increase the stiffness of the barrel.
I used Emerson and Cuming 24LV catalyst and 2651-40 resin to bond the sleeve. This has excellent gap-filling properties, especially when the components to be bonded are heated slightly, which I did. I suspended the barrel from a string to eliminate any side loading. The barrel was .496 dia and the tube was .501 I.D. The tube was heavily scuffed with 60 grit paper which raised enough of a burr to help center the barrel in the tube. I brushed the epoxy onto the warm barrel and carefully "threaded" the barrel into the sleeve. The heavy burrs left from the 60 grit seemed to hold the epoxy to the barrel and help prevent it all from just being pushed off the barrel by the sleeve.
The EC epoxy is a high quality material I had on-hand that has characteristics suitable for the sleeving operation.
There are probably more readily available epoxies that are just as good, or better, but I haven't researched it.
Here are the results of the deflection test.
Basically the plain barrel deflected 64% more than the sleeved one.
Lloyd-ss
(http://i226.photobucket.com/albums/dd79/loyd500/Carbon%20Fiber%20sleeve/setup_zps26756843.jpg) (http://s226.photobucket.com/user/loyd500/media/Carbon%20Fiber%20sleeve/setup_zps26756843.jpg.html)
(http://i226.photobucket.com/albums/dd79/loyd500/Carbon%20Fiber%20sleeve/deflectiontest-2_zpsa114a5a3.jpg) (http://s226.photobucket.com/user/loyd500/media/Carbon%20Fiber%20sleeve/deflectiontest-2_zpsa114a5a3.jpg.html)
(http://i226.photobucket.com/albums/dd79/loyd500/deflectiontest-3a_zps06b7e4e2.jpg) (http://s226.photobucket.com/user/loyd500/media/deflectiontest-3a_zps06b7e4e2.jpg.html)
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Great post Lloyd. How did you keep the epoxy from getting in the barrel ?
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for about 2' of joint overlap I can't escape the feeling that having both pieces wet will result in a better joint. it should be no issue to pour a bit into the liner and then push it onto the barrel( also painted ). This process *WILL* require some means of protecting the bore from glue. greased and or waxed patches crammed in the muzzle end should do the trick. That and a bit of a mushroom over the crown to keep all the important bits clean( well, clean-able anyway ).
cheers,
Douglas
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Modeling clay is a good solution for plugging the bore. Also, your local anodizing house will have silicone plugs for plugging holes that seal great.
Tom
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Great idea, I have a shop right around the corner that sells it, and its cheap too :)
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Great post Lloyd. How did you keep the epoxy from getting in the barrel ?
I only applied the epoxy tot he barrel, not to the inside of the sleeve, so that wasn't an issue.
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for about 2' of joint overlap I can't escape the feeling that having both pieces wet will result in a better joint. it should be no issue to pour a bit into the liner and then push it onto the barrel( also painted ). This process *WILL* require some means of protecting the bore from glue. greased and or waxed patches crammed in the muzzle end should do the trick. That and a bit of a mushroom over the crown to keep all the important bits clean( well, clean-able anyway ).
cheers,
Douglas
Doug, you are probably right that a light wetting of the I.D. of the sleeve wouldn't hurt. A rubber cork from a hobby shop ought to keep the goo out of the bore.
During the prep of the barrel before the bonding, I put a coarse 60 grit cross hatch on the barrel which raised enough of a burr on the barrel to provide areas to trap the adhesive on the barrel as I slowly inserted and twisted the barrel into the sleeve. I clamped a plastic stop on the barrel to positively locate the end of the sleeve so that when the barrel was suspended vertically for curing, the adhesive did not have a way to run out the bottom. Also, the warming of the barrel before applying the adhesive, and doing the initial curing at over 100 deg F greatly improves the flowability and gap filling of the epoxy. (With a slow cure epoxy.) The epoxy I used is a potting compound designed for good flow, wicking, and gap filling. The job seemed to turn out ok.
Lloyd-ss
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for about 2' of joint overlap I can't escape the feeling that having both pieces wet will result in a better joint. it should be no issue to pour a bit into the liner and then push it onto the barrel( also painted ). This process *WILL* require some means of protecting the bore from glue. greased and or waxed patches crammed in the muzzle end should do the trick. That and a bit of a mushroom over the crown to keep all the important bits clean( well, clean-able anyway ).
cheers,
Douglas
Doug, you are probably right that a light wetting of the I.D. of the sleeve wouldn't hurt. A rubber cork from a hobby shop ought to keep the goo out of the bore.
During the prep of the barrel before the bonding, I put a coarse 60 grit cross hatch on the barrel which raised enough of a burr on the barrel to provide areas to trap the adhesive on the barrel as I slowly inserted and twisted the barrel into the sleeve. I clamped a plastic stop on the barrel to positively locate the end of the sleeve so that when the barrel was suspended vertically for curing, the adhesive did not have a way to run out the bottom. Also, the warming of the barrel before applying the adhesive, and doing the initial curing at over 100 deg F greatly improves the flowability and gap filling of the epoxy. (With a slow cure epoxy.) The epoxy I used is a potting compound designed for good flow, wicking, and gap filling. The job seemed to turn out ok.
Lloyd-ss
"An engineer by nature. The affliction is knowing that everything can be made better."
it seems you are already familiar with the issues involved...LOL
cheers,
Douglas
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Douglas,
I was lucky enough to work with a lot of very smart people during my career, so if I didn't learn something new every day, it was my fault. Its the same way here on the GTA. A lot of smart people exchanging their ideas and experiences. The next time I do one of these, I will try your suggestion and swap the I.D. with some of the epoxy before inserting the wetted barrel. That is a good suggestion.
Thanks, Lloyd
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To plug the barrel all you need to do is squirt some rtv silicone in the end. A little solvent down the other end and it will come out when done.
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To plug the barrel all you need to do is squirt some rtv silicone in the end. A little solvent down the other end and it will come out when done.
Good tip. Thanks!
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Is this just a carbon fiber wrap? Or is this a vinyl wrap I have used the self adhesive ones with good success. I've also used the 3M spray adhesive with good results. Spray, let get tacky and apply. Great stuff. If real epoxy I've used the two part epoxy from HD/Lowes. I've used that to apply accent wood to stocks but have not used on CF. Let us know what worked or not for you.
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Is this just a carbon fiber wrap? Or is this a vinyl wrap I have used the self adhesive ones with good success. I've also used the 3M spray adhesive with good results. Spray, let get tacky and apply. Great stuff. If real epoxy I've used the two part epoxy from HD/Lowes. I've used that to apply accent wood to stocks but have not used on CF. Let us know what worked or not for you.
These are carbon fiber tubes, usually with about a 1/16" wall thickness that add substantial stiffness to the barrel and change the vibration characteristics..... and usually improve the accuracy too.
Lloyd
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Sean is now using CF tubes with a 1/8" wall bonded to the barrel.... 1/2" ID x 3/4" OD.... Stiffer than a steel barrel of 3/4" OD and a fraction of the weight....
Bob
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Wow, 1/8" wall sounds really nice for performance!
Added benefit: Fat barrels always look a whole lot cooler, too, IMHO.
Lloyd-ss
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Is this just a carbon fiber wrap? Or is this a vinyl wrap I have used the self adhesive ones with good success. I've also used the 3M spray adhesive with good results. Spray, let get tacky and apply. Great stuff. If real epoxy I've used the two part epoxy from HD/Lowes. I've used that to apply accent wood to stocks but have not used on CF. Let us know what worked or not for you.
These are carbon fiber tubes, usually with about a 1/16" wall thickness that add substantial stiffness to the barrel and change the vibration characteristics..... and usually improve the accuracy too.
Lloyd
Ahh I get what you are doing. Should have read all of your posts. So not so much the bonding but filling the space between them. I see why you needed something viscous.