Welding Help?

[madman]

I have some Wheelchairs im trying to repair for the local old folks home. Lots of welding required. Hows the best way to reweld these chrome plated tubes that breal? Is it tig mig?? Should the chrome be sanded of prior to welding??? Thanx Fellows. Mike

[Your Old Dog]

I wish I had the skills to help out like that....

[Swarf&Sparks]

I'd certainly be using TIG. Done a lot of thin-wall 316, but I dunno about the chrome. maybe use 316L wire? High chrome/nickel anyway.
I'd be interested in hearing more on the subject myself.
Rgds, Lin.

[torker]

Mike...This depends which material the chair frames are made of. I doubt that they are chromoly but they COULD be. Any idea of the wall thickness?
I've actually welded thinwall chrome (covered) ms tubing with mig, .023 wire(S-6)/75/25 mix gas. Very carefully grind the chrome off before welding. Need about 1/8" on each side. This method will produce the least discoloration of the parent chrome.
Tig is the best for this but does discolor the chrome a bit more.
If you use ER80S-D2 or 70S-2 you'd still want to grind a bit of the chrome off(I use thin lil' cutoff wheels in an air powered cut off tool). This will give you the most ductile weld. You could also use ER70S-6 (like your mig wire) but it won't be quite as strong...although it'd prolly be acceptable.
SS filler? I'd only use 310 or 312 as most other SS fillers will be brittle.
You'd only need a few rods to do this. You''l find that tig fillers will break you. $200 to $300 for a tube of filler rods that may sit for years.
If you can back purge this you'll get the best welds...you almost have to when using SS fillers.
Russ (up before the chikkins )

[speedsport]

I wonder why nobody ever considers O/A welding anymore.

[JCHannum]

O/A is as easy as TIG, it will add a bit more heat though.

With thin walled tubing such as this where the repair will be stressed, turning up a plug to fit inside the tube and brazing is another approach that will reinforce the repaired area.

Definitely remove any chrome plating from the weld area. Torker's advice is excellent as usual.

[torker]

I wonder why nobody ever considers O/A welding anymore.

Ha...ya it'd work...but the discoloration/scaling would be horrid. FWIW...I'm teaching my helper how to gas weld right now. She was having trouble grabbing the concept of tig but after some gas welding...her tig has improved 100%.
JC...good call on the plug!

[Gator]

Torker,
Could he use some of the Brownell's Heat Paste to control the heat and keep the chrome from discoloring?

[Dawai]

A good ox-actylene rig, A flapper wheel to peel the chrome back. Chromium is known to cause cancer, no joke.

I personally like the Henrob DHC2000... but it is pricy. Not sure it is any better than the smaller torches. It has a tiny flame, easy to control and the only advantage I can really see is that it is so close to your hand you have less shakes. The tiny flame means you have more time between proper penetration and falling out in a puddle-hole.

Welding with it, bring the metal up to orange state, when it sparkles add rod or move on cause it is fixin to drop out.. other than that it is just like brazing.

Henrob=$369 american.. probably a grand Canadian. http://www.cut-like-plasma.com/
there is a comparable regular pencil type torch, my younger brother has one, $150.. and it comes with regulators. Henrob does not, there is a lot in that henrob box that never gets used.. put in there to jack up the price.

Tig rig? bigger learning curve. It works too.

[pntrbl]

News to me on removing the chrome. I just "altered" a chrome exhaust pipe to fit up on my Grandson's quad. 2 cuts, mig'd them with .035 and CO2, and they seem fine. Wall thickness was .060.

Obviously it'll develop 2 rust bands over time but we live in the desert ....

What happens when you don't remove the chrome?

SP