Thermal Conductivity of Carbon Fiber Barrels

[mensajd]

In theory, exotic carbon fiber matrices can have pretty good thermal conductivity. But given the price constraints on [relatively inexpensive compared to formula 1 brake gear] carbon fiber wrapped barrels, do commercially available carbon fiber wrapped barrels actually have similar life-cycle characteristics to quality [SS or chrome moly] steel barrels? Or POI stability? If the thermal conductivity is poor, then one might be cooking the steel part of the barrel. Inquiring minds want to know...

 

[Totoro]

Depends on application IMO.

If you're a high volume unsponsored PRS shooter or shooting heavy p-dogs, it doesn't seem cost effective to me. A carbon barrel is almost double the cost of a fluted cut-barrel from any of respected tube doctors.

On my own rifles, that majority are big game LR-type so I run a carbon to save weight and help with balance.

And of those carbon rifles, I dump 1-2 boxes a season to verify zero and trajectory. So I will hardly get chance to really test barrel longevity.

 

[jcmullis2]

IMO Absolutely. They have such poor conductivity that the cf actually acts more like an insulator holding the heat in. Not an issue with barrels that you shoot once or twice and are allowed to cool such as a hunting rifle. It’s been over 35 years since I studied thermodynamics and I have nothing to substantiate this but the top competitors don’t use them on their competition rifles.

 

[Frank Green]

There are two basic types of CF. One that insulates the heat and one that helps wick the heat away.

That being said what you do to the outside of the barrel in my opinion doesn't do anything to help the barrel life per say. Every time you light that round off the flame temp. in the throat area of the chamber is around 2200 to 4000F depending on caliber and type of powder being used etc...

So rate of fire (how hot you get it), type of load and how often you clean it etc.. are going to be bigger factors in barrel life then it being cf wrapped.

Also I'll say the all steel barrels take longer to heat up where as the cf wrap because of less steel in the blank is going to heat up faster. The proper cf barrels do cool a little faster/quicker but I don't think it's enough to offset anything at all. Again I don't see any gain by it.

We have two CF barrels in accuracy gun set ups for testing ammunition and bullets at some ammo/bullet makers. One is in 6.5CM so it will be interesting to see if they really do get any extra barrel life out of them vs. a solid steel barrel. The guns/testing is done in controlled conditions and clean at set intervals etc...so very few variables. They don't see any accuracy difference in our cf barrels and our all steel barrels. The one accuracy set up is in a barrel clamp mounting block. I was also curious if that would cause any accuracy issues by clamping on the cf and so far no issues. So that was cool.

Later, Frank
Bartlein Barrels

 

[jcmullis2]

There are two basic types of CF. One that insulates the heat and one that helps wick the heat away.

That being said what you do to the outside of the barrel in my opinion doesn't do anything to help the barrel life per say. Every time you light that round off the flame temp. in the throat area of the chamber is around 2200 to 4000F depending on caliber and type of powder being used etc...

So rate of fire (how hot you get it), type of load and how often you clean it etc.. are going to be bigger factors in barrel life then it being cf wrapped.

Also I'll say the all steel barrels take longer to heat up. The proper cf barrels do cool a little faster but I don't think it's enough to offset anything at all. Again I don't see any gain by it.

We have two CF barrels in accuracy gun set ups for testing ammunition and bullets at some ammo/bullet makers. One is in 6.5CM so it will be interesting to see if they really do get any extra barrel life out of them vs. a solid steel barrel. The guns/testing is done in controlled conditions and clean at set intervals etc...so very few variables. They don't see any accuracy difference in our cf barrels and our all steel barrels. The one accuracy set up is in a barrel clamp mounting block. I was also curious if that would cause any accuracy issues by clamping on the cf and so far no issues. So that was cool.

Later, Frank
Bartlein Barrels

I’m glad you joined in.
#1 Do y’all use the CF that wicks heat away from the tube it’s wrapped around?
#2 When you say the cf barrels cool faster, is that on the exterior of the barrel that’s cooler or the interior/bore of the barrel?
#3 Have y’all tested the cf barrels against solid steel barrels to see the difference in barrel life? I know you mentioned 2 being used by an ammunition maker but are they comparing them against solid steel barrels.
This is very interesting and I like that y’all are working to bring us better equipment through the use of new materials. One day we might be able to simply replace a relatively thin tube with rifling in it instead of the complete barrel. Like a sleeve.
Thanks for making great barrels and all y’all contribute to this sport.

 

[Frank Green]

I’m glad you joined in.
#1 Do y’all use the CF that wicks heat away from the tube it’s wrapped around?
#2 When you say the cf barrels cool faster, is that on the exterior of the barrel that’s cooler or the interior/bore of the barrel?
#3 Have y’all tested the cf barrels against solid steel barrels to see the difference in barrel life? I know you mentioned 2 being used by an ammunition maker but are they comparing them against solid steel barrels.
This is very interesting and I like that y’all are working to bring us better equipment through the use of new materials. One day we might be able to simply replace a relatively thin tube with rifling in it instead of the complete barrel. Like a sleeve.
Thanks for making great barrels and all y’all contribute to this sport.

Welcome on joining in!

1.) We use the cf that does wick the heat faster.
2.) It's very difficult to measure the inside of the barrel while shooting but because you have less steel material there it will cool a little faster but if I had to put numbers on it your only talking like 10-20 minutes or something like that (I forget the numbers and comparisons that have been made) from when being really hot and both at the same temp. Again the all steel barrel with more material will take longer to heat up.
3.) Again I say no difference in barrel life between standard steel and cf barrels. The ones being tested right now will give us the best numbers as they are being shot in controlled conditions like I stated earlier.

The biggest thing that is going to help barrel life is a better/different grade of material and nothing to do with cf. Maybe if you ran the barrel in a water jacket like in water cooled machineguns would be the best option but no practical for a bolt gun or a normal semi auto rifle. LOL! Some guys in short range benchrest have had some type of a water cooling system set up so right after a relay they cycle cold water thru the bore of the barrel to cool it down quick but that's all I've seen.

A replacement sleeve or liner would be cool.....just don't know of a easy way to do that myself. We've made liners for guys restoring an old rifle and want to bore out the old blank but us it because of all the factory lettering engraving etc....but it is time consuming to do.

Later, Frank

 

[jcmullis2]

Welcome on joining in!

1.) We use the cf that does wick the heat faster.
2.) It's very difficult to measure the inside of the barrel while shooting but because you have less steel material there it will cool a little faster but if I had to put numbers on it your only talking like 10-20 minutes or something like that (I forget the numbers and comparisons that have been made) from when being really hot and both at the same temp. Again the all steel barrel with more material will take longer to heat up.
3.) Again I say no difference in barrel life between standard steel and cf barrels. The ones being tested right now will give us the best numbers as they are being shot in controlled conditions like I stated earlier.

The biggest thing that is going to help barrel life is a better/different grade of material and nothing to do with cf. Maybe if you ran the barrel in a water jacket like in water cooled machineguns would be the best option but no practical for a bolt gun or a normal semi auto rifle. LOL! Some guys in short range benchrest have had some type of a water cooling system set up so right after a relay they cycle cold water thru the bore of the barrel to cool it down quick but that's all I've seen.

A replacement sleeve or liner would be cool.....just don't know of a easy way to do that myself. We've made liners for guys restoring an old rifle and want to bore out the old blank but us it because of all the factory lettering engraving etc....but it is time consuming to do.

Later, Frank

Great information. I’m definitely gonna get a cf barrel for my 308 win. I’m sure it’ll last me a long time if not a lifetime in that chambering. I appreciate you giving us the straight dope on this. I know you’ve alleviated many of my concerns and hopefully it’ll help others decide which barrel is best for them. Thank you and have a good day

 

[E. Bryant]

The thermal resistance of the interface between the barrel surface and the surrounding air is going to dominate the heat transfer performance, particularly if there is no active airflow.

 

[hereinaz]

You can find probably dozens of other threads on it. Along with opinions of all stripes.

All I know is my Proof barrels perform the same as steel in typical range and hunting scenarios. The steel barrel in still a steel barrel. Stiffness per weight goes to CF, so by weight the CF I have walk less when heated than sporter barrels.

Cost and weight is the reason you don't see them in competition and do see them in hunting.

 

[Richie Rich]

In theory, exotic carbon fiber matrices can have pretty good thermal conductivity. But given the price constraints on [relatively inexpensive compared to formula 1 brake gear] carbon fiber wrapped barrels, do commercially available carbon fiber wrapped barrels actually have similar life-cycle characteristics to quality [SS or chrome moly] steel barrels? Or POI stability? If the thermal conductivity is poor, then one might be cooking the steel part of the barrel. Inquiring minds want to know...

Yes you are right, carbon fiber captures heat and does not let the heat dissipate nearly fast enough before cooking the lands and grooves buy a superheat build up from friction. Ultimate Arms is about to revolutionize the rifle barrel industry with a new heat sinking metal that will dissipate heat at a super fast rate of speed from a new heat sink process. It almost can cool as fast as it can be heated. There’s life after friction!!
Will let you know more about this later. We also unlike Proof research have used thermal heat testing for the proof we need. It’s also light weight .

 

[Wannashootit]

Some guys in short range benchrest have had some type of a water cooling system set up so right after a relay they cycle cold water thru the bore of the barrel to cool it down quick but that's all I've seen.

That's so counterintuitive to me...
Pumping air down the bore makes sense to me (I do it all the time when I'm in a hurry to cool down a Cerakoted barreled action for assembly) as it's very gradual heat dissipation- but pushing cold water into a steaming hot bore seems like a really bad idea...

 

[b6graham]

Yes you are right, carbon fiber captures heat and does not let the heat dissipate nearly fast enough before cooking the lands and grooves buy a superheat build up from friction. Ultimate Arms is about to revolutionize the rifle barrel industry with a new heat sinking metal that will dissipate heat at a super fast rate of speed from a new heat sink process. It almost can cool as fast as it can be heated. There’s life after friction!!
Will let you know more about this later. We also unlike Proof research have used thermal heat testing for the proof we need. It’s also light weight .

you work for Ultimate Arms? the same one with the $7k R700 in 308 Warbird?

 

[rtB]

Digging up an old thread is always a great way to launch a new product.

 

[b6graham]

Digging up an old thread is always a great way to launch a new product.

especially as a non site sponsor

 

[Frank Green]

That's so counterintuitive to me...
Pumping air down the bore makes sense to me (I do it all the time when I'm in a hurry to cool down a Cerakoted barreled action for assembly) as it's very gradual heat dissipation- but pushing cold water into a steaming hot bore seems like a really bad idea...

Some do it! All I can tell ya!

 

[Wannashootit]

Digging up an old thread is always a great way to launch a new product.

Damn...missed that

 

[Richie Rich]

Yes you are right, carbon fiber captures heat and does not let the heat dissipate nearly fast enough before cooking the lands and grooves buy a superheat build up from friction. Ultimate Arms is about to revolutionize the rifle barrel industry with a new heat sinking metal that will dissipate heat at a super fast rate of speed from a new heat sink process. It almost can cool as fast as it can be heated. There’s life after friction!!
Will let you know more about this later. We also unlike Proof research have used thermal heat testing for the proof we need. It’s also light weight .

you work for Ultimate Arms? the same one with the $7k R700 in 308 Warbird?

UA/ARMS/ manufacturer designs all of our Actions for bolt rifles and In all L.A. calibers. We also build all Lazzeroni calibers including the 7.82/308 Warrior Mountain lite Rifle by Ultimate Arms LLC.

 

[Aftermath]

Yes you are right, carbon fiber captures heat and does not let the heat dissipate nearly fast enough before cooking the lands and grooves buy a superheat build up from friction. Ultimate Arms is about to revolutionize the rifle barrel industry with a new heat sinking metal that will dissipate heat at a super fast rate of speed from a new heat sink process. It almost can cool as fast as it can be heated. There’s life after friction!!
Will let you know more about this later. We also unlike Proof research have used thermal heat testing for the proof we need. It’s also light weight .

 

[Mech Eng]

Well since this thread is back from the dead I have a question for @Frank Green. Did you develop a custom resin to increase the heat transfer or did you find a company that already produced one. Mainly because I'm looking for a resin with high thermal conductivity, but most I have found that most are pretty low.

 

[Frank Green]

Well since this thread is back from the dead I have a question for @Frank Green. Did you develop a custom resin to increase the heat transfer or did you find a company that already produced one. Mainly because I'm looking for a resin with high thermal conductivity, but most I have found that most are pretty low.

Define high thermal temperature? 300F could be considered a high temp. With that being said...you get the barrel that hot...regardless if it's solid steel or CFW your killing the barrel. Your not stopping what's happening inside the bore at the throat. The carbon fiber isn't going to do crap to stop or help that. The average flame temp. from the powder and depending on the load, type of powder, cartridge etc...the flame temp is around 2200 to 4000F. 2200 is around the temperature of lava. Yes it only happens for milliseconds when you pull the trigger but rate of fire, number of rounds in between cleanings, type of powder, type of bullet are going to effect barrel life more than what the carbon fiber is going to do for yo.

We are using a company that makes the resin.

Later, Frank

 

[Mrindecisive]

@Frank Green did there end up being a difference in barrel life between the CF and steel test barrels? Would you be able to elaborate on the fire rate these test barrels see?

 

[Frank Green]

@Frank Green did there end up being a difference in barrel life between the CF and steel test barrels? Would you be able to elaborate on the fire rate these test barrels see?

Nothing conclusive that I can tell you at all.

We made a few accuracy test barrels for a couple of ammo/bullet makers and they haven't seen a difference per say. Small sample lot of only 4pcs.

Again I don't expect a difference to begin with. Your not stopping what is happening inside the bore of the barrel. The type of steel will have a bigger impact on barrel life then cfw the barrel.

 

[Richie Rich]

In theory, exotic carbon fiber matrices can have pretty good thermal conductivity. But given the price constraints on [relatively inexpensive compared to formula 1 brake gear] carbon fiber wrapped barrels, do commercially available carbon fiber wrapped barrels actually have similar life-cycle characteristics to quality [SS or chrome moly] steel barrels? Or POI stability? If the thermal conductivity is poor, then one might be cooking the steel part of the barrel. Inquiring minds want to know...

Like over cooking lands & groves ?

 

[Ape_Factory]

CF conductivity depends on the arrangement of the carbon strands in relation to one and other. Has nothing to do with the resin per se but can have a small effect. Carbon strands in parallel are exceptional at thermal transfer where chopped carbon, short strands loosely arranged and compressed in a mold, isn't as good (stated simplistically). The methodology of creating strands in parallel is a critical factor. There are "techniques" out there, organic in process, which lend towards the ability to conduct heat.

Either is better than say iron, and will generally remain more stable with lower temp spikes vs. a metallic. They'll also recover, shed heat more quickly than heavier metallics like stainless or iron but less so than say aluminum or copper. No one is making copper barrels so it's sort of a moot point.

Ceramics can be designed either way as a conductor or insulator and can outperform any other material but is often fragile and lacks the dimensional stability component carbon fiber can bring when arranged accordingly. Now mix the two and you may really have a big advancement in thermal management.