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Old 10 November 2010, 12:00   #1
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Welding stainless

All I've ever welded was mild/hard steel with a stick, from 10 mm down to about exhaust type thickness, whereafter I switch to gas, ... never having welded stainless, a fareing on the RIB needs a couple of straps re attached, can I just gas weld it like I'm used to doing with some gash stainless lying about, or will I need to gets me some funny rods and do it with the stick ? The straps are only about 3 mm thick going back onto some tube

ps will I get heat discolouration etc ?
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Old 10 November 2010, 12:10   #2
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How thick is the tube?
The last thing you want is to blow holes in it with the arc welder!
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Old 10 November 2010, 12:52   #3
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You can stick (arc) weld stainless with ordinary rods but the weld will rust. Best to get some proper rods. It would help to know the composition of the stainless you are welding, 316, 304 etc, as you can buy rods specific for type. You can get general purpose stainless rods that will do the job ok. You will get heat marks, you will need to pickle the welds with pickling paste to clean them up & this will get rid of the heat marks. Beware of the pickling paste, it's evil stuff if you get it on your skin. I find stainless easier to weld than ferrous.
TIG's best if you can do it
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Old 10 November 2010, 16:14   #4
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Quote:
Originally Posted by Anchorhandler View Post
How thick is the tube?
The last thing you want is to blow holes in it with the arc welder!
I'd imagine about 1.5 , its only 15 mm OD or so



Quote:
Originally Posted by Pikey Dave View Post
It would help to know the composition of the stainless you are welding, 316, 304
By eck .. its shiny .. thats my limit I'm afraid


Because of the anticipated tube thickness,.. I'd prefer to use gas, but Ive never attemped with either, and just wondered if it was possible with gas, is there any difference in melting point for example over mild steel ?
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Old 10 November 2010, 16:24   #5
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Quote:
Originally Posted by Bigmuz7 View Post
I'd imagine about 1.5 , its only 15 mm OD or so



By eck .. its shiny .. thats my limit I'm afraid


Because of the anticipated tube thickness,.. I'd prefer to use gas, but Ive never attemped with either, and just wondered if it was possible with gas, is there any difference in melting point for example over mild steel ?
I'm more than willing to stand corrected, but I don't think you can gas weld stainless in the traditional way. I know for a fact you can't cut it with gas like you can with mild steel. It doesn't melt & pool, it just sags & blobs. If I could, I would take it to someone who could TIG it, a much better job.
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Old 10 November 2010, 16:26   #6
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I'm not going to advocate gas welding stainless, it'll make a mess with discolouration etc that will be a bugger to clean up but more importantly there'll be a lot of heat going into what is probably fairly thin gauge tube, distortion could be a issue.

But if you must use a carborizing flame (excess acetylene) and a flux like Solar Flux, get the torch as close in to the joint as poss.

If you can't get hold of any filler rod without buying a kilo for couple hundred quid I've got some thin gauge 316 rods, could chop a couple in half and post 'em

Get an inverter down on your Xmas list, they're pretty cheap these days
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Old 10 November 2010, 17:05   #7
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Get an inverter down on your Xmas list, they're pretty cheap these days
I have a couple going cheapish.
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Old 10 November 2010, 17:09   #8
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I have a couple going cheapish.
Do you now? How much?
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Old 10 November 2010, 17:12   #9
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I have a couple going cheapISH.
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Old 10 November 2010, 17:18   #10
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Do you now? How much?
I have two Thermal Arc Thermadyne ?model. The lads at work are saving-up to buy them. Should have more next week. I'll let ya know.
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