JB weld in "Four Winds" shotgun

[johnwilliamson062]

http://thefiringline.com/forums/showthread.php?p=3956200
I ran a google search and that thread came up. I am thinking of replacing the wood dowel spacer on a "four winds" shotgun with a JB weld spacer. In order to easily adjust the firing pin I will need to remove the large tube from the end cap, so I will be trying to coat most of the other parts in a release agent. Kiwi shoe polish is available to me for free, so that is what I was planning to try.
My plan is to
1. coat the entire endcap, firing pin bolt, and end of 1 inch tube barrel with release agent
2. Install firing pin bolt
3.Mix JB weld
4.Fill endcap with JB weld
5. Install 1 inch tube in endcap.

Once the epoxy sets I whould be able to remove the 1 inh tube, firing pin and with minimal difficulty possibly even the plug. I will then make adjustments to the plug so it is flush with the end cap and file the firing pin bolt so it extends the correct amount.

The problem I foresee is that while screwing in the threaded components some release agent will be removed. I can re-coat the exposed portion of the firing pin, but not the 1 inch tube.

My main concern is mentioned in the previous thread. The max temp is 600* for JB Weld. Now, in this case none of the metal is heat treated, so I imagine this is of no concern.

To beat some obvious off topic replies:
1. This will be tested at a remote location using the "long string" method with a number of barriers between myself and the gun and one overhead for falling debris should there be a catastrophic failure. I will likely never fire it from my hand or anyone else's.
2.I know the laws in my area concerning a short barreled shotgun and will be using a 3/4 inch pipe that far exceeds the minimum length requirements. I may take it to an open carry event though.
3. The article has a lot of stupidity involving conjecture of how the shotgun will be used. I posted the link for the graphic only as it is the best I have found.

 

[Dixie Gunsmithing]

I would never recommend you build this. Pipe (even sched. 80), and conduit can't stand up to the pressure generated by the shell. It may fire a couple of times, and the next, the pipe might burst, and that is bad, as shot will fly everywhere.

I watched a Remington 870 barrel rupture, on YouTube, while a guy was turkey hunting in a blind. It was not pretty. I don't think the guy ever did find out why it did that, but most likely there was something lodged in the barrel. He was lucky.

I wanted to add this for a comparison. The working chamber pressure for a 2-3/4", 12 gauge round is around 11,500 PSI, and the working pressure for a piece of schedule 80, 3/4" pipe is 3,500 PSI, with a bursting pressure of 17,600 PSI. Barrels are proof tested at double load, so they will handle 23,000 PSI, or a 2:1 safety factor. Also, barrels are honed smooth for the shot, and wadding to have minimum resistance, and pipe can have a ridge from the welding inside them, and are rough at that. That will make the pressure go up a good bit, and since you're all ready close to bursting pressure, it would be dangerous.

 

[johnwilliamson062]

I understand your concern and generally agree these are not safe for normal use.
"The working chamber pressure for a 2-3/4", 12 gauge round is around 11,500 PSI"
As I understand it that is the max set by SAAMI. Actually 11,800 psi I believe. The actual pressure of sporting loads, which is all these guns are reputed to be able to fire for any period of time, is a bit lower. I have a number of very light loads available for my use. There is some speculation that the lack of seal between the two pipes also reduces pressure. I am not sure this is true as I would think such a situation would result in a burn similar to that caused by the cylinder gap on a revolver.

I have designed a number of safety measures to be used while "testing" this and other variants. I will have more between me and the shotgun than the round fired from a production gun could penetrate. I will be reasonably safe.