attaching gauge

attaching gauge

Joined: March 9th, 2010, 1:28 am

August 28th, 2012, 5:11 pm #1

Well I've been practicing soldering on my broken 392 brass body tube so hopefully when my gauge comes, it'll go smoothly. I've found that removing the thicker parts of the fittings and leaving just the threaded tube the gauge will screw into makes soldering much better. I assume this is because the threaded tube is considerably thinner metal than the rest of the fitting, and heats up quicker with the torch. I cut the bottom off of a nut for a 1/4" compression fitting and soldered the remaining threaded piece onto the body tube with flux, plumbers' copper-sweating type solder, and high heat from a cheapo LP torch. This I cannot break off with my bare hands at all, only a heavy strike of a hammer would break it off. I noticed when soldering thicker couplers or reducers on, if not heavily pre-heated, they would easily break off with a jerk of the hand. I also noticed that tinning the body tube or nut before-hand was actually detrimental to adhesion??? I would have thought vise-versa....but roughing up both surfaces, applying plenty of flux, clamping with a "c" clamp, and heavily pre-heating before trying to apply solder resulted in the strongest bond I could get out of regular solder. I know that it's a lot of air pressure, but do you guys think that sounds like a bond that will hold? I really don't want to have to go to my dad's work and try brazing or silver-soldering it, as my dad's right arm is in a sling, and I'm inexperienced with those techniques.
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Joined: April 28th, 2010, 12:23 am

August 28th, 2012, 6:56 pm #2

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Joined: March 9th, 2010, 1:28 am

August 28th, 2012, 7:44 pm #3

no...I skeletonized the valve. I'm soldering a nut onto the body tube where the wall of the valve used to be, the pressure now being contained between the o-rings on the two halves of the skeletonized valve and the wall of the body tube. So soldering on the nut, drilling a small hole through the body tube there, and screwing the pressure gauge into the nut. I'm not sure about 1000 PSI, probably 1200 or a little higher...1500PSI gauge. uhh, I've read that copper-sweated pipe fittings soldered in this fashion can withstand ~1500PSI without blowing off, and that's soft-copper alloy, this is all solid brass. Idk. I think I'll try it this way and pump the gun up with the gauge facing away lol in case it randomly decides to shoot off the body tube.
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Joined: April 28th, 2010, 12:23 am

August 28th, 2012, 8:02 pm #4

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Joined: March 9th, 2010, 1:28 am

August 28th, 2012, 8:54 pm #5

I have to take the valve out to solder on anything anyways, I'll take pics of everything when I get my gauge.
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Joined: June 25th, 2002, 1:34 pm

August 29th, 2012, 10:30 am #6

Well I've been practicing soldering on my broken 392 brass body tube so hopefully when my gauge comes, it'll go smoothly. I've found that removing the thicker parts of the fittings and leaving just the threaded tube the gauge will screw into makes soldering much better. I assume this is because the threaded tube is considerably thinner metal than the rest of the fitting, and heats up quicker with the torch. I cut the bottom off of a nut for a 1/4" compression fitting and soldered the remaining threaded piece onto the body tube with flux, plumbers' copper-sweating type solder, and high heat from a cheapo LP torch. This I cannot break off with my bare hands at all, only a heavy strike of a hammer would break it off. I noticed when soldering thicker couplers or reducers on, if not heavily pre-heated, they would easily break off with a jerk of the hand. I also noticed that tinning the body tube or nut before-hand was actually detrimental to adhesion??? I would have thought vise-versa....but roughing up both surfaces, applying plenty of flux, clamping with a "c" clamp, and heavily pre-heating before trying to apply solder resulted in the strongest bond I could get out of regular solder. I know that it's a lot of air pressure, but do you guys think that sounds like a bond that will hold? I really don't want to have to go to my dad's work and try brazing or silver-soldering it, as my dad's right arm is in a sling, and I'm inexperienced with those techniques.
piece of brass "inside" the valve body to screw the gauge into. I turn a piece on the lathe to match the id. of the valve, then mill it to thickness.
Last edited by jpsaxnc on August 29th, 2012, 10:33 am, edited 1 time in total.
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Joined: November 28th, 2002, 6:26 pm

August 29th, 2012, 5:24 pm #7

Worked great! Still is working great, actually..



Steve
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Joined: March 9th, 2010, 1:28 am

August 29th, 2012, 6:51 pm #8

That's what I'm doing, just instead of a hunk of threaded metal, and actual brass fitting. I'm fully confident now. I found a pumice stone attachment for my die grinder that's a cylinder exactly the same diameter as the body tube, so I can grind my fitting to perfectly contour the curvature of the tube. I tested it out on my broken body tube and took a hammer to it to see what it'd take to break off. I hammered several times, and the soldered on nut didn't break off until after the hammer actually dented the crap out of the brass. I had to hit it HARD to break it. I'm pretty sure this is going to be a success! I wish my gauge would hurry up and get here!!
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Joined: November 28th, 2002, 6:26 pm

August 29th, 2012, 8:38 pm #9

...are...

1. The area of the solder joint.
2. Its quality.

By using a large brass block - which has excellent solderability - James got a very large area of contact and a strong bond.

Steve
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