LocostBuilders - powered by XMB

Welding Questions

DorsetStrider - 24/1/10 at 12:52 AM

Hiya all.

I've got a SIP handymate gasless mig welder... I've been offered a cheap CO2 bottle so am thinking of modifying it to gas. Is this possible? and if so what is involved?

Also I have a TIG welder... I was under the impression that with TIG welding you could only use pure argon or helium... but now I'm asking myself why? Is it possible to use CO2 when TIG welding?

As always any help/advise gratefully received.

MikeR - 24/1/10 at 01:16 AM

gas and gassless use different polarity, if you want to convert you need the polarity switching along with some way of delivering the gas, via a restriction so you can controll how much, to surround the welding wire.

argon is used to tig weld ali. co2 can be used to (mig) weld steel with co2 / argon mix being the 'best' for steel (this is debatable as it affects the weld slightly differently to just co2). I'm guessing its the same for tig.

skinned knuckles - 24/1/10 at 09:22 AM

for mig welding with gas, you need to reverse the polarity compared to gassless.

for tig welding, only pure argon will do. (for me at least) wether you are welding ali (welding in AC if your machine can) or steel.

IMHO i would choose Tig every time. I have a tig, a mig (gas type) and a stick welder. the latter 2 are just gathering dust.

NigeEss - 24/1/10 at 09:27 AM

If you use Co2 with a TIG the tungsten electrode will disintegrate.

Co2/Ar mix give best results for mild steel with MIG but good can be achieved
with pub Co2.

MakeEverything - 24/1/10 at 09:43 AM

My SIP welder is a No-Gas welder, but has all the connections for plugging in a small bottle.
Ive used CO2 for TIG, but it does run a bit hot, and the welds finish off black, rather than bright. Not sure on the strength of the weld in comparison to using Argon, but ive cut a few open and they seem to be strong enough. It may be that by using CO2 the weld becomes more brittle.

As said, i can use my welder with or without gas, and i dont need to change the polarity.

Peteff - 24/1/10 at 11:14 AM

quote:
Originally posted by DorsetStrider
Also I have a TIG welder... I was under the impression that with TIG welding you could only use pure argon or helium... but now I'm asking myself why? Is it possible to use CO2 when TIG welding?

As always any help/advise gratefully received.

Tig needs an inert gas, co2 is not inert. The carbon in the gas will be included in the weld and cause brittleness as well as the tungsten problems.

I just read this again and thought about it, you are asking yourself why industry buys more expensive pure argon instead of using much cheaper co2 ? I would ask someone else other than yourself. It might just be a fad or it might be that it is the only thing that works properly. Mr MakeEverything, remind me not to go near your car if you weld parts using tig + co2. It seems to be strong enough, what do you base that observation on. It seemed strong enough till I hit that pothole then it just fell off

[Edited on 24/1/10 by Peteff]

MakeEverything - 24/1/10 at 11:42 AM

quote:
Originally posted by Peteff
Mr MakeEverything, remind me not to go near your car if you weld parts using tig + co2. It seems to be strong enough, what do you base that observation on. It seemed strong enough till I hit that pothole then it just fell off

[Edited on 24/1/10 by Peteff]

Mr PeteFF, i never said i TIG welded my car, and i based it on some 'Garage' tests, on a piece of test metal that i had welded. Beating the crap out of it with a 4lb hammer to try and shear the weld, and cutting it open told me that it was doing the job i wanted, though as i also said, "It may be that by using CO2 the weld becomes more brittle".

You said "I just read this again ", but i suggest you get your eyes checked.

Peteff - 24/1/10 at 02:16 PM

quote:
Originally posted by MakeEverything

You said "I just read this again ", but i suggest you get your eyes checked.

If you look at the post I quoted it was from DorsetStrider, should have gone to Specsavers mate

It says "if you welded"

MakeEverything - 24/1/10 at 02:37 PM

quote:
Originally posted by Peteff

quote:
Originally posted by MakeEverything

You said "I just read this again ", but i suggest you get your eyes checked.

If you look at the post I quoted it was from DorsetStrider, should have gone to Specsavers mate It says "if you welded"

So when you say "Mr MakeEverything, remind me not to go near your car if you weld parts using tig + co2" you actually mean that your talking to someone else, and referring to a completely different statement?? twat.

Peteff - 24/1/10 at 03:42 PM

quote:
Originally posted by MakeEverything

quote:
Originally posted by Peteff

quote:
Originally posted by MakeEverything

You said "I just read this again ", but i suggest you get your eyes checked.

If you look at the post I quoted it was from DorsetStrider, should have gone to Specsavers mate It says "if you welded"

So when you say "Mr MakeEverything, remind me not to go near your car if you weld parts using tig + co2" you actually mean that your talking to someone else, and referring to a completely different statement?? twat.

Way to go mate, let's start name calling

Read through that again then go get the dictionary and find "if"

gazza285 - 24/1/10 at 04:44 PM

Guess somebody's a little touchy today.

DorsetStrider - 24/1/10 at 06:06 PM

Calm down guys I didn't want to provoke an arguement with this I was just hoping against hope to find a lo(er)cost solution.

Guess it'll be an argon bottle after payday and a gas mig when funds allow. ho hum

one last question... if I tack weld using my gasless mig that wouldn't cause a problem when fully welding with either gas mig or tig would it?

[Edited on 24/1/10 by DorsetStrider]

Peteff - 24/1/10 at 06:56 PM

If you knock the slag off the tacks you should be fine to run over them with tig or mig. There are lower deposit options for the gas if you shop around like this on ebay. I think the cylinders are a lower pressure than the mainstream suppliers but for DIY it should be a decent alternative.

MakeEverything - 24/1/10 at 07:18 PM

There was a supplier on Ebay called Adams gas that was selling argon cylinders and delivering. I think they have an external site as well, but the 'domestic' stuff seems to have disappeared from it. Might be worth a ring though?