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Welding Round Tube - Any Tips?
John P - 12/6/11 at 08:05 PM

I have so far welded my chassis using an old ESAB Mig welder with 0.8mm wire which seems fine although as it's all square section tube I guess it's relatively easy.

I would like to make my own wishbones and to see how difficult this might be have tonight welded up some basic T joints from an odd piece of 20mm dia x 16 swg round tube simply because I had a piece. (I appreciate this isn't the actual matetial used in a wishbone).

The results seem very strong but are also fairly untidy as I found it very difficult to weld around the curvature without constantly stopping. The weld looks too big and is verly lumpy but I couldn't break it with a club hammer, the tube simply bending first).

Are there any techniques which would help? I know I probably should get them done by a professionsl welder but would still like to try myself first.

John.


Chippy - 12/6/11 at 10:03 PM

You could try increasing the amps, or reducing the wire speed. HTH Ray


nick205 - 12/6/11 at 10:07 PM

Just a thought, but how are you holding the workpiece? Might be easier to weld in a different orientation.

A welder I used to work with had a heavy steel turntable which he rotated with one hand whilst MIGing with the other. Somewhat dependent on being able to hold the workpiece ina suitable position, but usuallly achieved with various clamps/magnets.


austin man - 12/6/11 at 10:14 PM

Cant You tack on side turn it over then weld half turn it back over and weld the rest ? sounds like you need a bit more power if the weld is lumpy.

The wishbones are probably the most critical part I pesonally wouldn't leave it to chance if I wasn't confident of my welding.


907 - 12/6/11 at 10:16 PM

Comfort is the key to good welding.


Get comfortable where you intend to finish, then move back to the start.
Start welding and as the weld progresses it gets easier.

IMHO this is better than a comfortable start, then tying yourself in a knot trying to get round.


( The same thing applies to clay pigeon shooting )

Paul G

edit to corect speeling

[Edited on 13/6/11 by 907]


Theshed - 13/6/11 at 08:29 AM

That's a good tip "907" - thanks. I have been struggling with the same thing with TIG. I launched into welding wishbones having forgotten that I had enjoyed a 15 year rest from (occasional) professional welding - what a mess! I have vowed to practice and practice - welds are now looking ok. It is a fiddle on smallish tubes. I did my steering column in the lathe getting my partner to wind it round by hand as I welded - that worked.


David Jenkins - 13/6/11 at 08:46 AM

I always hated doing the round tube on my chassis - I just couldn't get the torch action right.

Got there in the end though...


ashg - 13/6/11 at 12:46 PM

funny you should say that. personally i prefer welding round tube rather than square. if space and position permits i tend to start on the flattest part then work round into the fillet part and end up back on the flat, then turn it over and do the other side. if your not confident then get someone that is competent to do it but at the end of the day your still just welding two bits of metal together and practice makes perfect.

my welding is usually pretty good but last weekend i helped one of the neighbours weld up his old busted trailer. the thing was so old and rotten it was a pig to weld and had me thinking is it me or the welder. did a few runs on some nice metal and it was obvious it was the crappy metal the trailer was made out of.

get everything nice and clean, set it all up in a nice position to be welded. sit down and get comfortable then go for it. the best thing i ever did to improve my welding was to buy a very nice esab auto mask that i could actually see through easily .


blakep82 - 13/6/11 at 03:29 PM

on the very rare occasion i weld round tube, and i'm far from a pro welder, i have it all tacked, i'd do 4, this then stops you getting carried away, because you weld from one tack to the next, reposition to weld the opposite side, then reposition to another one, and so on. stops you trying to weld the whole way round in one go if you have markers