White Lightnin Installation, shoulder or no?

[Dr. Tim-Boone]

Like Dan says,    shorten WL liner to the thickness of the barrel wall then tighten in with compound. double check to make sure it doesn't protrude into the breech area of the barrel    This always seemed simple to me.......I couldn't do the shoulder thing if I had to...............       

[Dphariss]

I remember the article as well.  Buckskin Report or Blackpowder Report. Same publisher.  Pretty gory looking.  As I remember, it included a part of the tang still attached to the plug. 

Dan, I think I thanked you for all your help with that breech project, but in case i did  not -- thanks for all you did.  I appreciated the pieces you machined and the idea of the spanner wrench for the liners was extreeemly valuable to us.  We made another from a wide bladed screw driver before we were done.  At any rate the help was invaluable.

Regards,
Pletch

I am glad to have helped out if you have any other ideas let me know.
Right now I am remodeling the "back porch" as we call it....
Soon as I started pulling to old windows out the temp went over 90....
But the wife is happy.
Dan

[jerrywh]

Dan.
   Tell us this. How do you thread to the bottom of the hole ? or  do you leave the threads off of the last thread or so? Then--- how do you make the bottom of the hole flat? or -- do you use a tappered shoulder?   As for me, besides using pipe compound on the threads I do not thread all the way to the end of the hole and then just jam the last thread or so. I drill all the way thru but don't thread all the way thru.

[davec2]

Dr.Tim,

I'm glad your not worried about putting in a shoulder...it's sort of like doing a root canal through your navel.

Dan,

Excellent photo of a properly installed breach plug bottomed on the bore.  However, that is in no way a "seal".  In the rocket world, I deal with sealing very hot, very high pressure combustion gasses all the time.  If I put your breach plug assembly on my test bench and apply even 2,000 psi nitrogen pressure, it will leak like a sieve, let alone at the 10,000 to 20,000 being generated upon firing.  I'm not saying that there is anything improper with what you are saying and showing.  It is absolutely the correct way to breach a barrel.  Just don't think it is a complete seal to high pressure gas.  In the absence of applying a thread sealant (like LockTite), it is the fouling itself that forms a seal.  I routinely seal rocket engines operating with gas temperatures of 5,000 F or more with bathtub caulk (silicone).  By rights, it should not seal at all at those temperatures.  However, if the space into which it is applied is small and there is not continuous gas flow (i.e. the initial flow of gas into the seal area is dead headed), the silicone will char and be packed back under pressure into a very effective, high temperature, labyrinth seal made out of carbon.  The same thing is happening in the breach.  But it is not that very irregular surface, thin steel edge interface between the plug and the edge of the bore that is making the text book definition of a seal.  It is a restriction to the flow of high pressure gas rather than a seal.  But a restriction is very good in a gun barrel, because the high pressure is only applied for a very short instant in time.  Before much leakage can pass by the restriction, the barrel is vented back to atmospheric pressure by the exiting of the projectile from the muzzle.

[jerrywh]

 What Dave 2 says explains one thing I have found in restoring  antique guns. When removing the breach plugs from some 18th century guns the plugs were black where the fouling had leaked by for some time but there was no corrosion to speak of. The plugs were extreemly tight and did not appear to have corroded threads at all. Besides that those breach pluge never even had a shoulder or a seal af any kind. They were just a rounded thread with a forced fit. They could have had sealer on them of some kind but it was not detectable. 

[Dphariss]

Dr.Tim,

I'm glad your not worried about putting in a shoulder...it's sort of like doing a root canal through your navel.

Dan,

Excellent photo of a properly installed breach plug bottomed on the bore.  However, that is in no way a "seal".  In the rocket world, I deal with sealing very hot, very high pressure combustion gasses all the time.  If I put your breach plug assembly on my test bench and apply even 2,000 psi nitrogen pressure, it will leak like a sieve, let alone at the 10,000 to 20,000 being generated upon firing.  I'm not saying that there is anything improper with what you are saying and showing.  It is absolutely the correct way to breach a barrel.  Just don't think it is a complete seal to high pressure gas.  In the absence of applying a thread sealant (like LockTite), it is the fouling itself that forms a seal.  I routinely seal rocket engines operating with gas temperatures of 5,000 F or more with bathtub caulk (silicone).  By rights, it should not seal at all at those temperatures.  However, if the space into which it is applied is small and there is not continuous gas flow (i.e. the initial flow of gas into the seal area is dead headed), the silicone will char and be packed back under pressure into a very effective, high temperature, labyrinth seal made out of carbon.  The same thing is happening in the breach.  But it is not that very irregular surface, thin steel edge interface between the plug and the edge of the bore that is making the text book definition of a seal.  It is a restriction to the flow of high pressure gas rather than a seal.  But a restriction is very good in a gun barrel, because the high pressure is only applied for a very short instant in time.  Before much leakage can pass by the restriction, the barrel is vented back to atmospheric pressure by the exiting of the projectile from the muzzle.

ML rifles are not rocket engines and you are ignoring the preload on the threads I think. Its a crush fit its not just screwed in till it touches, there is "clamping force" on the joint. Its a preloaded crush fit joint.
Having disassembled guns with breeches so fitted I can assure you that they don't "leak like a sieve".
If we consider 10000 psi breech pressure in the 50 caliber smoothbore and consider the area that it can push against, .196 square inches. So 10000 times .196 is is 1960 pounds. Will this exceed the clamping force exerted by a 4140 breech plug and a 1137 steel barrel 5/8 x 18 thread with something like 40 ft lbs of torque (guess could easily be more) with oiled threads. If it will not exceed the clamping force how does it leak?
I fit these until the plug will always pull up the same, maybe 6-10 cycles. Thus if the breech is removed it will not turn in farther or re-installation. Something I encountered on a very nice condition, possibly unfired, Belgium 18 bore shotgun I once had and some other old guns in less pristine condition.


Dan

[T*O*F]

When removing the breach plugs from some 18th century guns the plugs were black where the fouling had leaked by for some time but there was no corrosion to speak of.

Jerry,
That may not have been fouling.  I seem to recall a reference where they mixed soot with grease and used it as thread lube for breechplugs.

[jerrywh]

The last plug I installed I put anti seize compound on it.  I think most people put too much emphasis on breach plugs being perfectly sealed. I have taken many a breach plug out of 200 year old guns that were almost impossible to remove and the showed no signs of ever failing from corrosion.  My common sense tells me that the way things are going the human race won't last long enough for your breach plug to fail. Even if the human race lasts another 400 years no ordinary person will own a muzzleloader or any gun for that matter. Bows and arrows will be about the limit.
  PS--- then the argument will be over bow strings failing.

[Dr. Tim-Boone]

Jerry, I hear whale gut makes the best bowstrings.........Oh yeah "save the whales"  

[longcruise]

  I have taken many a breach plug out of 200 year old guns that were almost impossible to remove and the showed no signs of ever failing from corrosion. 

But, Jerry here we are 200 years later looking only at the plugs that did not fail in the last 200 years.