Carbon fiber sleeved barrel, some questions?

[rkr]

It seems that my .357 Evanix barrel is as rigid as all dente spaghetti, so I started thinking about putting a CF sleeve on it. As I understand it the principle is to use a CF tube and slow epoxy for the operation. Now some questions:

In the wonderful world of ebay I can find either 18mmID-22mmOD tube or alternatively 19mmID-22mmOD tube while the barrel has 18.0mm OD - which one should I choose?

If 18mm ID pipe is too tight can I sand off some from the inside or will that destroy the pipe?

Is there an optimal tightness for a pipe, i.e. can it be too tight or too loose?

Could I double sleeve the barrel, i.e. glue one 22mm OD pipe around the barrel and then 25mm OD pipe around that making the sleeve match the original shroud diameter?

[Motorhead]

You want the 18mm .... Wood dowel and some 80/120 grit worked back and forth to get a scratchy snug fit if to tight is the best.
Doing so won't hurt the tube, especially when wetting the I.D bore with thin lamination grade epoxy 
I do the same thing on 16mm ( .630" ) LW barrels using the Ebay / China 16/18mm tubes.

[Anthropy]

you can check with Goodwinds for carbon fiber tubes.  They have a large selection of carbon fiber and fiberglass tubing

goodwinds.com


Regards,



Tom

[rkr]

Thanks guys, I ordered the 18-22mm pipe. It will be interesting to see how much difference it makes.

[rsterne]

2mm wall should make a big difference.... Is the CF running mostly lengthwise, that gives the maximum stiffness.... The tube I use is unidirectional CF with just a thin twill layer on the outside for appearance....

Bob

[Sfttailrdr46]

  I am glad to see that all my time reading so many diverse threads has helped a fellow member with "skills" and the wherewithal to utilize my suggestion

[rkr]

I am glad to see that all my time reading so many diverse threads has helped a fellow member with "skills" and the wherewithal to utilize my suggestion

Yes, it was your suggestion that got me thinking. If reducing the barrel motion with barrel bands is good, then sleeve and bands should be even better. Those e-bay cf tubes won't brake the bank and I should be able to open up those bands for 22mm pipe - so why not try it?

[Sfttailrdr46]

  I think it may have one of Rsterne's posts and it stuck in my mind

[rkr]

2mm wall should make a big difference.... Is the CF running mostly lengthwise, that gives the maximum stiffness.... The tube I use is unidirectional CF with just a thin twill layer on the outside for appearance....

Bob

It's rolled twill type so it should be only 65% of the rigidity of unidirectional pipe. On the other hand, who knows how the barrel actually moves? There could be twist as well in which case twill could be better than unidirectional. Actually twisting motion should be there or the groups should be close to vertical.

[Motorhead]

With a semi resilient epoxy bond connecting the two together ... It's not moving much if at all   

[rkr]

With a semi resilient epoxy bond connecting the two together ... It's not moving much if at all   

Which brings me to my next question, what brand and type is recommended? I'm in Europe so I may not find the same brand but I can probably find something with similar properties.

[Motorhead]

With a semi resilient epoxy bond connecting the two together ... It's not moving much if at all   

Which brings me to my next question, what brand and type is recommended? I'm in Europe so I may not find the same brand but I can probably find something with similar properties.

Had Great success using "LAMINATING" grade & viscosity epoxy.
This grade of epoxy once mixed generally is fairly thin flowing like pancake syrup or even thinner yet   
Cure time like all epoxies is temp sensitive ... but these grades at modest temps take well over an hour to tack up and a full 24 hr too cure.  There Minimal shrinkage and semi resilient by design.
Sometimes called a Finish Cure grade

[PakProtector]

I have sleeved a few. There is some prep involved. Acetone to clean up with is quite useful. Fit the tube; dowel and sandpaper to smooth the inside, and give it some scratches. some electrical tape to give you a solid stop to push down to, and seal up the liquid before it hardens. wet the barrel and the inside of the tube. plug up the bore and the crown; modeling clay will be fine for this job...a hemispherical blob, stuck well into the bore will be quite enough. Before the glue is fully hard, remove the clay and clean the crown if need be with the acetone. Q-tip will be useful. Acetone in a wee shot glass is quite enough. With he sleeve wet, there will be a bit that comes out the end when the sleeve slides past the muzzle...be ready to clean this up. Mix and measure the epoxy with a boolit scale. 200 grams should be enough. leave standing vertical to cure. With the sleeve seated on the electrical tape stop, wrap one more layer over the joint( the stop should be tube OD match ), to keep it from running out as it waits to cure.
cheers,
Douglas