My first MIG

[kiml3]

Hi,

I am new to MIG welding - I have done some arc welding before but from what I can see, this is quite a bit more complex...

I've had a good look through this website, however, I'm still not 100% sure what I need... My first project will be to create a custom exhaust system - this involves welding 2mm thick stainless steel (304) pipes together; and stainless steel (304) to steel (the pipe off the back of the catalytic converter).

This is my shopping list so far:

• Clarke PRO90 MIG welder (25-90A) (Would this be sufficient for what I want to do? - Have a budget of around £200 for the welder)
• Ar/Co2 disposable canister (86% Ar, 14% Co2) x3 (I figured one for testing and trying to get it right and 2x for the actual project, but not sure how long one of these canisters lasts)
• Welding wire (308L for stainless steel to stainless steel + 309L for the stainless steel to steel) (0.7Kg reels of each)
• Auto dimming helmet mask (eBay)

I'm not entirely sure whether I have made the right choices for the equipment for the intended project, so if I've suggested something stupid or have gone for an insufficient welder, please say! Is there anything else that I would need or that would be useful?

Any useful tips for a beginner to MIG welding would also be greatly appreciated :-)

If you would like me to provide any more info, please let me know.

Many thanks in advance,

Kim

 

[shenion]

The Ar/Co2 disposables last about 6-8 minutes of use. Figure at least an hours use to even begin to get proficient. So you are looking at a dozen cans.

Add to that, there is too much CO2 for doing stainless. You want 5% or less.

You can use the straight CO2 disposables for practice on mild steel. They last about 40 min or so.

You will want to get a refillable bottle of argoshield light. Not the best for stainless, but will work.

The Pro90 should work ok for the job though.

 

[kiml3]

Thanks for your response. Do you think practicing with CO2 bottles and mild steel before embarking on the actual project with disposable Ar & CO2 bottles would be an idea - just that Argoshield light seems pretty expensive (will look to invest eventually, but for now this is not too feasible); or is stainless steel very different to work with when compared to mild steel?

Also, have will I be ordering enough wire? 0.7Kg sounds like plenty, however, I have no experience as far as this is concerned.

Thanks,

Kim

 

[shenion]

Stainless is a bit different in how it absorbs heat. The process is sthe same.

You will need to get the feel of using the torch. Pipe welding will take positional experience. Even on a bench, you will not be able to always do them in the same position. That takes a lot of practice.

CO2/mild steel will work for practice. You could do some welds on the stainless tubes to practice with CO2, it will look like crap and probably be brittle.

Price the disposable bottles. About £12 each. As I said the Ar/CO2 ones have too much CO2 for stainless welds. You could use the pure argon ones for stainless. Welds will be a bit cold though.

In the sheilding gas section look for the Volkszone offer. If I remember right about £68 to start. About the price of 5 disposables and much more gas.

The 0.7kg rolls of wire should do. Pick up a mild steel one to practice with. I think you can use the 309L for both stainless and stainless/mild welds.

 

[Ragnarok]

argoshield or a rent free equivalent is the only way to go, when you are starting out/learning you are going to need a decent amount of gas, and disposables are insanely expensive, look for adams gas or similar rent free, or possibly the volkszone BOC deal which i just switched to from a 20L rent free, the adams gas type rent free 9L at 137bar has 1233L of gas in it, disposables are 110L usually so you get about 11 disposables worth in a 9L rent free.

cost of 1 rent free 9L 137bar cylinder fill (1233L of gas) £36
cost of 11 disposable canisters (1210L of gas) £158.29 (from machine mart)

while there is usually a refundable £50 deposit on the adams and similar cylinders i wouldn't factor that in to the cost as you can get it back when you have finished with the bottle so even if you only got 2-3 disposables you'd be better off with a rent free 9L.

 

[Ragnarok]

In the sheilding gas section look for the Volkszone offer. If I remember right about £68 to start. About the price of 5 disposables and much more gas.

if you only use about 1 adams or similar bottle a year they work out quite a bit cheaper, much more than that and the volkszone deal makes sense!

edit, little extra info, the volkszone deal is £34.15+vat a year rent £23.38+vat per fill, no collection charge, 20L at 230bar (4600L of gas)