Carbon fiber tube / sleeves....

[TomLally]

Well members. 

I'm looking for feed back on these carbon fiber tubes !! In particular has any member fitted one to a streamline ?? Is it a difficult or tricky process ? Any special tools required? 

Would one tube be sufficient or slip a second on top of the first for extra support and rigidity. 

Many thanks 

Tom

 

[intenseaty22]

Are you looking to fit one over FX’s drinking staw barrel for rigidity? I used one from Amazon because Ernest didn’t have one available in .177 for my Wildcat. But the fit was very loose. The ones he sells are a bit pricey, but probably have a much better fit and are probably meatier. You’re probably better off buying one of his. Mine did help though. 

 

[TomLally]

Glad to hear it helped your wildcat !! Having further discussed the issue with a buddy of mine his opinion is that a barrel band would suit me better!!

My streamline barrel is fairly solid it's not a thin liner so with the shroud over that and it strapped to the air cylinder with barrel band it should be really steady!!! 

But still no harm to look in to the carbon fibre tubing.

 

[intenseaty22]

Well, I am no expert on all things FX, but from what I read here, lots of folk really like those "Superior" barrels/liners. What barrel do you have? If it's not a Superior it may be worth upgrading to one of those if available for your gun. Throw in the barrel band for good measure. 

If I may ask, why are you looking to do this? Does your point of impact migrate by any chance? Just curious as my WC suffered from accuracy and poi issues. 

 

[nervoustrig]

What is the issue you’re trying to solve or the thing you’re hoping to improve? 

If you’re dealing with a wandering POI from day to day, or when it sustains a little bump or that sort of thing, a barrel band is probably what you want to try.

If instead you are looking to make some improvement to group size, stiffening the barrel with carbon fiber to reduce vibration may be beneficial. For best results, you want to seat the carbon fiber into the receiver if possible but it looks like many folks are seeing improvements by just sleeving the exposed portion.

To bond it, Loctite 638 bearing compound works great if the gap is less than 0.010” (0.020” difference on the diameter), or a 2-part epoxy if the gap is larger.

 

[Rj]

Your streamline has the original solid smooth twist barrel. No need to sleeve it. 

 

[TomLally]

Your streamline has the original solid smooth twist barrel. No need to sleeve it.

May be no need at !! Just gathering some info on the CF tubing and if its beneficial!! 

I'm going to install a huma reg next week and want to fire jsb 18gr at 880fps and I'm exploring all options to help squeeze that bit more accuracy 

I will of course see how I get on with my tune first and fire some groups I may just get a barrel band anyway and try it after all is done to see if it aids in finding a little more accuracy but from what I'm reading maybe the CF tubing is more suited to liners over the likes of my barrel!! 

 

[qball]

It absolutely helps, depends on the size you get it could be some what tricky to get the internal diameter correct. My suggestion is error on the looser side and let epoxy do the work. 

 

[TomLally]

If instead you are looking to make some improvement to group size, stiffening the barrel with carbon fiber to reduce vibration may be beneficial. For best results, you want to seat the carbon fiber into the receiver if possible but it looks like many folks are seeing improvements by just sleeving the exposed portion.

yep that's it!!! squeeze as much accuracy as I can from the streamline . I'm just looking for feed back from members who have tried this or indeed done it to sreamline ...it may not even be required but no harm asking all the same!! 

 

[jps2486]

The idea of stiffening the barrel has a lot of merit. My concern is that the coefficient of thermal expansion is different between the steel barrel and the carbon fiber tube. As temporature changes, they will fight each other and POI will change.

 

[TomLally]

The idea of stiffening the barrel has a lot of merit. My concern is that the coefficient of thermal expansion is different between the steel barrel and the carbon fiber tube. As temporature changes, they will fight each other and POI will change.

Very very good point!!!thanks 

 

[Centercut]

IMHO, totally unnecessary if you retain the ST barrel and just shoot the JSB pellets. Gun should be a laser beam as is.

 

[Khornet]

Wish I hadn't done it to my Impact. I should have experimented with the O-rings: number, placement. Can't undo the CF sleeve. POI shift decreased but not gone, groups a lot worse. Tried different tunes but never got it back. On the bright side, it led to me buying a Superior standard liner which is proving to be excellent and will never see carbon fiber.

 

[nervoustrig]

Yeah if you have a barrel with a reasonably heavy wall*, any difference from sleeving it will probably be buried in the noise floor. However if you’re on the fence, it’s also true that the materials have gotten so inexpensive that it’s not a big commitment.

Regarding the concern about the difference in coefficient of linear expansion, bear in mind carbon fiber has been in use on centerfire rifles for quite a long time. In that application, the temperature swings are vastly higher than anything an airgun barrel will ever see.

* In the ballpark of at least 1/2" for .177 , 9/16” for .22, or 5/8” for .25

 

[AirSupply]

My opinion slipping on a cf tube especially if not bonded is a waste of time. The tube needs to be a good fit. The surfaces that are to be bonded must be keyed correctly for the epoxy. It’s a bit of work to do it properly. The liners don’t have parallel sides. If you not careful you still get movement within the cf tube. 
Here is a “solid barrel” I did for a mate. Shoots beautifully! No shift in poi. I’m now doing more solid cf barrels. Have a solid cf Impact bench rest barrel on the way. 
https://www.airgunnation.com/topic/wildcat-mk1-700mm-superior-liner/

 

[AirSupply]

Also not all carbon fibre tubes are the same. That add above is for a pultruded tube. For a barrel you would be better off with a roll wrapped tube as it gives better multi directional strength.

 

[qball]

My opinion slipping on a cf tube especially if not bonded is a waste of time. The tube needs to be a good fit. The surfaces that are to be bonded must be keyed correctly for the epoxy. It’s a bit of work to do it properly. The liners don’t have parallel sides. If you not careful you still get movement within the cf tube. 
Here is a “solid barrel” I did for a mate. Shoots beautifully! No shift in poi. I’m now doing more solid cf barrels. Have a solid cf Impact bench rest barrel on the way. 
https://www.airgunnation.com/topic/wildcat-mk1-700mm-superior-liner/

wow I missed that thread and just wow! Now you got me thinking.....this is bad! Hahaha