Brazing help

[Mutant_Xj]

What did I do wrong! I'm building a roof rack for a scaler out of 1/8" rod and was almost finished. I was brazing a cross rail on the bottom that went side to side, It was under three cross rails that went front to back. When I brazed two joints together the front to back rails warped and took an s curve shape. I built all of the rack except I needed two more cross rails and some bolts to mount it, before it was finished. I didn't have anything else warp on me like this did.

I'm kinda POed right now because I spent 2 weeks working on this and now I have to cut a bunch of it out and replace it or start new. I don't think I had too much heat on it because I didn't do anything different then any other joint.

[Mr.Joshua]

That's sucks man. I can't offer any help, I haven't had that happen to me....yet.
I can only offer sympathy---that sucks

[SMR 510RR]

Some info on the process you are using and maybe some pictures of the parts may help us determine where you are going wrong.

Right now the only information we have is that you warped some metal...

[Mutant_Xj]

I'm using a MAPP/OXY micro torch I got from Tractor supply. Brazing rod I got from Lowes. Ive been trying to get the torch with about a 1/8-1/4"blue cone in the flame with as short of a flame coming out of the torch. It's hard to get a consistent flame each time because the valves are cheap on the torch and hard to get it set right. I probably have between a 3" to 6" flame while I'm brazing. If it's a longer flame I'll hold the torch further away.

I've been heating the steel trying to get everything heated evenly. When the steel just starts to get red I touch the joint with the brazing rod and focus the heat on the brazing rod until some melts. If the puddle just sits on top I'll use the torch to move it around and fill in the joint. Usually if there's enough brass on the top of the joint I'll flip it over and get the brass to move around to fill in the other side. If I need to I'll add more brass to fill in the joint. After I'm finished I'll submerge the joint in water to cool and move on to the next joint. The two joints on the cross rails didn't even make it to the water before they warped.

[transambill]

I don't ever quench my joints in water, I let them cool down by themselves. Using gravity to move the solder around helps to but the solder follows heat and if the joint has enough heat in it the solder will go after that heat and the joint will fill itself. If you have enough heat in the joint it will pull the solder around it so you shouldn't have to manipulate it very much by turning it.

[Duuuuuuuude]

Originally Posted by transambill

I don't ever quench my joints in water, I let them cool down by themselves. Using gravity to move the solder around helps to but the solder follows heat and if the joint has enough heat in it the solder will go after that heat and the joint will fill itself. If you have enough heat in the joint it will pull the solder around it so you shouldn't have to manipulate it very much by turning it.

Exactly. I've screwed up some perfectly good parts by dunking them in water. Now they just sit and cool until I can handle them.

Also remember that the longer you heat a part, the greater your chances of either warping it or getting it hot enough to weaken a nearby joint.

[Mr.Joshua]

X2 on not quenching the joint. Even when you think you have dried everything off water will surface at the next joint and trash the braze.

Also if you flux the entire joint you should have enough heat for the solder to travel around the while joint and not have to reheat it.

The more you heat up a piece, the weaker it will become. Keep the heat focused at the area to be brazed

[spookyseven]

Another suggestion is use the tried and tested Harris safety siv brazing rod. It needs a lower heat to melt, which means less chance to warp, and it flows better which means less chance of moving when handling to braze the other side. Also when you heat metal red hot it can pull impurities out which can cause problems with the joint.

[Mutant_Xj]

I'm using the flux coated brazing rod and if there's not much flux on the rod i have a jar of the powder flux I've been using as well. Should I put flux on the steel rather then the braze rod?
I dunk the part in water because that's what I was taught in high-school when I was taught Oxy/Acetylene welding. I know it's not the best but when I first started brazing I'd let it cool, but it too to long to move on to the next joint. Most of what I've been building is small enough that I cant wear gloves because they get in the way.
Thanks for the replies. I think I've been heating up too much around the joint. The brass flows better when I do that but I guess that's where I screwed up.

I can't find the harris safty silver anywhere local. The closest welding supply is about 30 minutes from me and I never get there when they are open.

[SMR 510RR]

Originally Posted by Mutant_Xj

I'm using the flux coated brazing rod and if there's not much flux on the rod i have a jar of the powder flux I've been using as well. Should I put flux on the steel rather then the braze rod?
I dunk the part in water because that's what I was taught in high-school when I was taught Oxy/Acetylene welding. I know it's not the best but when I first started brazing I'd let it cool, but it too to long to move on to the next joint. Most of what I've been building is small enough that I cant wear gloves because they get in the way.
Thanks for the replies. I think I've been heating up too much around the joint. The brass flows better when I do that but I guess that's where I screwed up.

I can't find the harris safty silver anywhere local. The closest welding supply is about 30 minutes from me and I never get there when they are open.

I actually do cool my joints in water but I wait a good 10 min first until they have cooled most of the way slowly...Call me impatient! I think the difference is that the 1/8 rod is small compared to the 3/16 I normally use.

You can usually find decent deals on SafteySilv on ebay in a kit that has both the correct flux and the actual wire.