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Discussion Starter · #1 ·
Hi,
I need some help. I am working on a bullpup project and have moved the handguard retainer up by the muzzle brake.
The piece I have is a metal tube, only about 3/4 of an inch long and about 1/16 of an inch thick. The inner dia. fits a tad loose around the barrel and the outer dia. is correct for the handgaurd retainer.
I need to somehow weld the puppy in place and was curious which to use and what gas to use. I am very familiar with flux and soldering being I did jewelry work. But have only brazed a few times using a ox/act torch and the pre brazed brass stuff (had the white stuff on outside)
So hopefully one of you fine gents can help walk me through this.

Many thanks!
 

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Brownells has different solders that melt/flow at different temperatures. They also have 3 1/2% nickel welding rod that supposed to be good. If the handguard retainer is off the barrel it makes it easier because you don't have to worry about damaging the barrel or anything else. One thing to not, silver solder won't take bluing or phoshate, but Brownells has solder black that blackens silver solder.

Your best bet is using MAPP/Oxygen or Oxy-Acetylene depending on how thick the material is. The thicker the material the more heat you will need. You can go to the Brownells web site and look up these P/N's.

1.) 080-547-025, welding rod - not silver solder (there are smaller diameters also)
2.) 080-538-432, 355 Silver solder (melts @1145 degrees, flows @1205 degrees
3.) 322-100-650, Fusion solder (flux is premixed with the solder), melts @1145 degrees
4.) 322-120-650, same as above but melts @1220 degrees
5.) 322-120-750, same as above but non-flowing, melts @1000-1700 degrees

They also have softer solders but I don't reccommend them for your application. Hope this helps.
 

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The fusion paste that TK mentioned would be my choice.
It works great for SS muzzle devices, I don't see why it wouldn't work for your application.
 

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Discussion Starter · #4 ·
Thanks so much.That helps a lot.
I just looked up the Brownells site.

Rob
 

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I need some silver solder for some AMD 65 builds but I am confused on which one to get. Which one would I need to use to make the feds happy?
 

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Fal_shooter,

Use the 322-100-650. It has a 1145 degree melt point, Feds require 1100 minimum.
Works great and very easy to use. Make sure you clean both parts thoroughly first.
 

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1100 is RED
So if your torch can't get the metal red then you are wasting your time.
My smith had a MAP torch (single cylinder) and tried to SS on my flash hider on my AMD65 and it didn't take. I let it cook for 10 mins on high and it got a dull red color but would not get any warmer.
 

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I use one of these Mapp/Oxy kits.
You can get them at Lowes or Home Depot for around $50.
Works great, gets much hotter than straight Mapp gas.
 

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Remember that the parts have to be clean! You need to remove all oil, paint, blue,parkarizing,grease and so on or it will fail. Sand blasting is good but hard to do on int. threads of a brake.
 
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