Gas welding solid rod to tube

[BeezFun]

Need to gas weld 3/8" solid steel rod to 1-5/8" 20ga tube, in vertical position. They're parallel to each other, held tightly together by a hose clamp. I've been experimenting, it's tough to keep from burning through tube wall. Any tips on how to do this? I've found that using larger tip and holding torch back further seems to work better than using smaller tip and getting right in close. Problem is heat reflected off side of solid steel rod is melting tubing wall. Thanks for any suggestions.

 

[Reyer Farms]

That's going to be tough! Preheat solid stock and focus heat there and try to roll material to 20 ga. It's all about heat control- it's not impossible but it's not going to be easy. Might try brazing it. Good luck!

 

[BeezFun]

Haven't done much brazing, but I've got a bunch of rod. Maybe I'll give it a try.

 

[Reyer Farms]

The shop I learned to weld in had an old Prince Albert tin that was torch welded. Cutting torch. The fella was 80 yrs old when I met him. He was probably the smartest fella I've ever met. He could do magic with metals.

 

[Reverser]

I think you'll have a mighty hard time doing a good vertical weld with oxy/acet. It is somewhat like tig in working with a filler rod in a pre-heated puddle of molten metal. You won't be having a fast freeze as in using stick or mig. If you can find a way to lay it down, it will be very doable.

You will need to use the suitable welding tip sized accordingly for the thickness of the metal, and be sure to use a neutral flame. This is very important.

Here's the best video I have seen on oxy/acet welding. He is very good at explaining the procedure.

Oxyacetylene welding

 

[Tractor Seabee]

OA welding works fine in all positions. It takes some practice to work with joining heavy stock to thinner stock. Like has been said it is all in controlling the heat to the two pieces. It is always easier if you can get the 3/8 rod in a perpendicular position so you can weld in the flat plane. Always get the heavier piece to the melting point before you direct heat to the thinner, then direct just enough heat to the thin member to keep the puddle intact. Us old pipefitters that first learned to OA weld before arc it is a piece of cake. 55 years ago for me and I can still OA weld better than arc even though I was certified for pressure vessels both ways. Horizontal is the hardest position as the puddle tends to sag on the bottom. Brazing can also be done in all positions also with the same horizontal challenge. Heat control is also an issue same. The tendency is to overheat the thinner part and melt the steel before the heaver piece is hot enough. I think brazing takes more practice on position welding than OA fusion. Its all about practice. The torch does not have a brain, it has to use yours. If you are new to welding you may not understand all this so ask away on your confusion.

Ron

 

[CNC Dan]

Need to gas weld 3/8" solid steel rod to 1-5/8" 20ga tube, in vertical position. They're parallel to each other, held tightly together by a hose clamp. I've been experimenting, it's tough to keep from burning through tube wall. Any tips on how to do this? I've found that using larger tip and holding torch back further seems to work better than using smaller tip and getting right in close. Problem is heat reflected off side of solid steel rod is melting tubing wall. Thanks for any suggestions.

Could you use a blower(hairdryer? air gun?) to blow air through the tube to help keep it cooler?

 

[Gary Fowler]

If you use your torch to preheat the solid rod with the flame directed higher up the rod than next to the tube it should work ok. Get the rod red hot then work down closer to the weld area. After pre-heat is done, adjust your flame lower and proceed with the weld still concentrating the main flame on the solid rod. It should not be that hard to do after getting the solid rod hot say about 3" high from the weld area.

 

[BeezFun]

Thanks for the advice and video, wish I had seen that 30 years ago. My gas welding skill level is pretty high when I'm in position, but have never had reason to do out of position.

Here's what I've learned practicing so far. Preheating very important, as Gary suggested I get rod glowing red before starting to weld. I've deposited a few passes of filler vertically on the tube before attempting to weld solid rod to tube. That gave me more tube material to work with and less chance for burn through. I don't understand why, but using a hotter flame and staying a bit further away from the work gives a better result than a smaller flame getting in close. Don't quiite have the puddle control I'd like, but the overall result is better. I think it's because the reflected heat when I'm in close gets the tube too hot.
I am getting some popping, I presume because the puddle is getting too hot. Base material is clean, so I'm not sure what else could be causing the popping. If I do the same weld in position there's no popping, so it has something to do with how I'm controlling the puddle when vertical.

 

[Arc weld]

Are you turning down a larger size tip? That could cause backfiring. Also is your tip equalized? The best way to do this is with the regulators and to completely ignore what the gauges on the regulator say. Once a pure acetylene flame jumps from the end of the tip is the indication that this is the max. flow that tip can handle. With both torch valves fully open you should have a neutral flame right at the point the acetylene alone would jump the tip. I could explain in more detail but don't have time right now.