More testing on my Barrels

[Mike Franzen]

Today I took my barrles that I had previously mentioned in the thread "Barrel Inclusion", to TSI for some testing. TSI tests metal parts for the Aerospace industry looking for flaws, weaknesses, etc. They spent 4 hours with the barrels and were fascinated by them. About 10 different specialists looked them over. Both barrels were ultrasonically measured for thickness at the breech, 6", 12" 18", 24" and the muzzle. Then the area in question was painted with penetrating dye and viewed under ultraviolet light. Next, they were put under a high resolution microscope. Finally the area was xrayed to try and determine extent of the damaged area. I've included a few pics from what was a very interesting day.

[Frank Cronin]

Great stuff! What was the verdict?

[Rick Losey]

and what was the result of the physical??

[Dave Suponski]

Come on Mike you got us on the edge of our seats here. Spill the beans...:)

[Mike Franzen]

After all their testing they believe it is a gouge caused by something hitting the barrel. There was no evidence of the weld seam separating. The barrel thickness at that spot is 60 thousandths. Here's how the barrels measured in thickness starting at the breech:
right barrel left barrel
.197 .194
6"- .099 .107
12"-.064 .054
18"-.046 .039
24"-.041 .039
32"-.049 .050

That "gouge is about 13'' from the breech.

They referred me to a guy that tig welds for Aerospace industry if I want to do a "Cosmetic" repair. They wouldn't say whether or not it was definately ok to shoot but the Xray tech said he would do the first test firing if I allowed him to.

[Dave Suponski]

Interesting Mike. Thanks for the report.

[Steve Huffman]

What did the bores measure please ?

[Gary Carmichael Sr]

I need one of those machines! what did they charge you? Gary

[Mike Franzen]

Due to my good looks and charming personality (and the fact they were having a fun diversion...) they didn't charge me a thing! They usually see the high tech, run of the mill parts, like fuel pump impellers for the space shuttle. They were kids in a candy store with 135 year old twist steel Parker barrels, lol. But, I did pick up on one interesting thing that really grabbed my attention. They have an etching solution in a tank they dip metal parts into that brings out the contrast of differing metals. The guy told me it would show a stark contrast between the iron and the steel. It would plainly bring out the weld lines. So, I'm thinking I'm going to take a section of ribless, 10 gage wrecked barrels, polish them up and give them a dip. Might be interesting. He told me he dipped an old damascus bbl flintlock pistol and it came out beautiful.

[Mike Franzen]

BTW Gary, the ultrasonic measuring device was a Krautkramer USN 160. They said that was as good as it gets.

[wayne goerres]

If I may ask what kind of chemical solution was in the tank. Hope it isn't top secret.

[paul stafford jr]

the old barrel makers used to dip the barrels in a etching solution to match the barrels before they were assembled. i belive it was diluted hydrocloric acid. but that process did not last it was only for matching the tubes. i would like to know who first figured out how to do the black and white finish. very cool stuff at the testing lab. thanks for the look in.

[Mike Franzen]

I don't know the name of the solution. I asked and was told something that didn't make sense. He did say it was heated. I'll find out more and when I do I'll post it.

[Eldon Goddard]

I knew ultrasonic would be great for barrel wall measurement. Just waiting for the technology to get a little cheaper.

[Mike Franzen]

Just for everyone's information lest you think I was smart enough to come up with this idea for getting my barrels tested on my own. The idea came from Edgar Spencer who passed it on to Jim Dispagno who relayed it to me. I want to thank both of those gents :)

[edgarspencer]

Mike, I had all that testing capability in-house at my steel foundry. It was one of the reasons why I enjoyed staying after work; that and the machine shop. I had a Panametrics UT machine and 2 K-Bs. One of which would pay for a fairly decent A1-S. I Got certified in every NDT discipline, first as a level II, to do it, then as a Level III to teach it. "I liked it so much I bought the company" (Actually I hated the business, I just loved making steel and stainless steel)

[Mike Franzen]

Edgar, one test they wanted to run was to determine the composition of the barrels. Unfortunately that machine was down. I thought that would have been very interesting. Tomorrow morning I'm going to another aerospace company and have the separation welded by tig. I'll let you know how that goes if you're interested.

[edgarspencer]

Mike, I would be interested in how you make out. The machine they would have used would have been either an optical-emission spectrometer, or an x-ray florescence spectrometer. The optical emission unit will leave a small (5/16" diameter) 'burned' area where a high energy source causes and arc, the emitted light is then broken down by a diffraction prism, then measured to determine each % quantity of each element the machine is set up for. You need to know this so they don't set it up to leave the arc mark in an exposed area. The x-ray florescence machine will not leave a mark. Not all labs have that machine, because of it's cost.
I'd want to know the chemistry before you have a welder pick his own filler material, so that you get a good weld, with regard to metallurgy, mechanical properties and cosmetics.

[Mike Franzen]

Thanks Edgar. Not being familiar with these things I would have never thought about that. I'll keep you posted.

[Mike Franzen]

Just got my barrela back from the TIG welder. Looks like they did a great job. Hopefully the next pic I post will be of the finished product!