Looking for Insight/Advise on Weld-On Fittings

[Gordon Gould]

I had a hard line rust out down in the bowels of the dozer so I need to replace two lines. Where they have to go and connect in there is no room for hose or compression fittings which I have managed to make work in the past. So this is my first try at weld/braze-on fittings and I am on shaky ground. The lines are 1/2" with JIC males and the hydraulic relief pressure is 2000 psi.

Just to get a feel I drilled out some 1/2" nuts and made a bronze braze, silver solder, and O/A weld with a piece of tubing. None of them were perfect but I think I can make any of them work but don't know which one would be best. One concern is the recess for the tubing in the fittings I got is only 3/16" - seems skimpy but I really don't have a clue.

On the Bronze Braze I used flux coated rod. I am pretty OK with it but only got about 75% wicking all the way to the bottom. I am thinking that if I fluxed the joint before assembly wicking to the bottom all around would happen and probably got more than 3/16" with flux coated rod alone.

The Silver Solder( braze ) was with 45% silver wire and Stay-Silv flux. I fluxed the joint before assembly. This was the first time I silver soldered anything in my life. The filler wicked down nicely and filled the joint. Then I spoiled it by trying to get a fillet on top. Filler would not flow and I probably got it to hot trying. I am thinking it would be fine to just fill the joint and quit. I should not try to make a fillet.

The O/A weld is OK but after I wire brushed it off I could see some under cut. I need to avoid that or go back and fill it.

Here they are







So now I need to pick a method. I am most comfortable with the Bronze Braze but there are a lot of things I don't know so any advice would be appreciated.

gg

 

[Tractor Seabee]

Bronze is a little more forgiving with excess heat. Get the temp right through the whole and it will suck down in the joint like silver. I have done all three processes and have the materials to do all. My preference is 45% silver as I have done a lot of it spending time in the refrigeration trade. For what you are doing O/A weld would be my last choice. If you are working in a tight space the bronze might be you best bet. With silver a fillet on top does not add anything. It is the capillary action into the joint that does the job.

For all 3 processes the most common problem with novices is they use too large a tip. You do not want instant heat. That may have been you problem on the O/A undercutting. For ypou job I would use either a #0 or max of #1 tip, maybe even a 00. Try some test joints first to determine the optimum heat.

Worked a job once installing HP air piping for ship diesel engines, triple heavy brass pipe with insert ring fittings. Required a coast guard certification test. The alloy rings come out; you clean them, the pipe and the fitting cavity. Heat it up and when you see the silver alloy come out of the joint you are done. No filler rod aloud. Lesson learned here is that with silver everything has to be clean and don't burn the flux.

Ron

 

[mrmikey]

Agree with TB above, silver solder. Clean and not over hot, once it gets oxidized from too much heat, you're done and have to clean it up again.Melt the solder with the material, not the torch............Mike

 

[Gordon Gould]

Thank you gentlemen - that is exactly the kind of guidance I need. I will practice with the silver solder to get some consistency befor I do the real deal. You did not mention my concern that the 3/16" deep recess for the tubing seemed small for silver solder joint so I assume that is a non issue ??

gg

 

[Tractor Seabee]

Agree with TB above, silver solder. Clean and not over hot, once it gets oxidized from too much heat, you're done and have to clean it up again.Melt the solder with the material, not the torch............Mike

Yeah, that's the problem trying to lay a bead, it can be done but you really have to watch the temp and keep the flame out of the puddle. I worked jobs where the spec called for a small bead on top.

Ron

 

[Gordon Gould]

Thanks for the advise on Silver Solder. This is how they turned out.





gg

 

[Tractor Seabee]

Looks like you got it right. Good job. Actually SS is almost as easy as soft solder, same principals apply, clean, flux, do not overheat, and let the material melt rather than the flame.

Ron