how to weld with weak welder

[andreyyyk]

hello, i have a project im going to be doing soon so i decided to make sure my welder will be capable.i need to weld 7ga steel plate to the strut towers of my car and my welder is only capable of welding 12ga. i have the lincoln sp-125(old welder). with .030 wire

i can make "acceptable" or "good" welds but i am not technical at all.



is it possible to make a nice weld with my welder and strong? i have a few same sized 7ga peices but but it seems like its burning the metal too much, and i have to make swirl motions, or "U" motions to get enough material, but it overlaps each motion too much, and leaves "waves" and the welded metal sticks out too much.

at work we have a more powerful welder and i only had to drag it straight and it made a nice weld that didnt have much deformation and didnt burn the edges of the base metals, and had enough material.

so i need to know if there is a correct way of using my welder for my project?



thanks in advance

 

[Lawnmowerboy]

Depends how thicker metal you want to weld. you won't manage a full pen weld on anything more than 2mm it will weld 4 at a push but not for anything structural.

 

[andreyyyk]

im sorry, what are you trying to say?

by paper work my welder is only capable of welding 12ga (2.8mm) metal, but i have a 7ga(4.7mm) plate i need welded.

the strut towers of the car are thinner.




and again, sorry i am trying to learn!

 

[Robotstar5]

Hi Andreyyyk, welcome to the forum.

It is possible to weld material thicker than the "paper" maximum of your welder by grinding an angle on the edges.

Have you looked at the tutorials? (at top of page) it will give you an idea of processes and terminology used.

 

[piman]

Hello Andreyyyk,

why are you using such heavy material on a car? Isn't it better to go for thinner material without sacrificing strength by good design? What are you trying to do?

Alec

 

[andreyyyk]

this is what im trying to do.
yes i watched the tutorials, i just need to know if it will be strong enough. this is going to be a track car so i cant have it break off.

or what would you reccommend? i could hire someone who can come with their own welder, i just wouldnt prefer it

 

[LuckyXie]

7ga(4.7mm) plate ? ---- I think you should use bigger Amp output model !

 

[andreyyyk]

I know that... but i dont have another welder... that is why im here

 

[Lawnmowerboy]

There's no chance of getting a weld penetrating as well as that with a little 120a welder.

 

[andreyyyk]

ok, i guess i will make a 220v outlet in my garage and borrow the welder from work.

 

[BrokenBiker]

as this is going to be a track car I would go for a much bigger welder with enough power to get a full penetration weld in one pass. you don't want it cracking off on a tight bend.

 

[zardoz]

ok, i guess i will make a 220v outlet in my garage and borrow the welder from work.

Thats by far the best option. these little 110v welders havent got the umph for anything much over 3mm.

 

[andreyyyk]

So how would you guys recommend me weld this? Any techniques or tips or advice? Anything will help. Maybe setting up the welder and tip positioning?

 

[Bede]

You could multi-pass it. A slight sideways weave to create a slightly wider weld and involve more parent metal. Do a standard weld all around as a root, then offset your start points for your second run, welding half on the base parent metal and half over your first run, thus creating a nice step for your third and final capping run to bridge across from the top of your second run to the remaining edge of the circular plate. Weld it in a following method - as in say run right to left, then your next run, rotate the workpiece to the right then start your weld to the right, moving left to finish over the start point of your previous welds. This maintains even penetration at your weakest points - the start points of your welds. If you stagger the start points on your capping welds an inch or so further around from your other start points it will mean your weak points are at least sitting over other penetrative welds or will be covered by penetrative capping welds.

It's possible to achieve stronger welds than your machine is built for if you understand the strengths and weaknesses of welds.

And make sure all parts are as clean as you can get them. Give yourself the best chance of maximum penetration. Use a wire brush to clean each weld prior to running upto it with your next run or over it with your two capping runs.

Your own competence will dictate whether or not you will achieve the desired results for a track car.

 

[Bede]

In the photograph, I can see four runs around that plate. To explain, the third run from the right is started on top of the end of the second run. You need to do the opposite. Start at an unwelded point and end on top of a previous start of a run. Only your final weld will start on the end of a run as it's the last run to lay down. If you're trying to squeeze every last bit of possible penetration out of an inadequate welder then little things will help. Overlap very slightly the start of the run you end on rather than stopping just short as in the two welds at the forefront of the photograph. If that was some kind of liquid vessel it would be leaking like a seive... sieve... collander.

 

[Lawnmowerboy]

Another option would be to arc weld it with a multi pass weld. As strong as MIG if not stronger.

 

[Drains]

There's some good advice above on technique and on size of welder etc, but honestly, the best advice surely is to get someone who knows what they're doing, with the right plant, to weld this?

The OP has already stated he's not experienced in welding (that's obvious), and the weld is for a suspension mounting on a track car. Get it wrong and risk death to yourself and others.

I've just done a little risk assessment in my head for this one, and can you guess the result?

 

[Bede]

That's certainly the obvious answer. The question is, how many other areas carry potential hazards where inexperienced folks decide to build themselves a track car? It's not just some ropey welding. If folk are gonna undertake something that's really out of their depth then that's their call. At least with some sound advice they can minimise the risk. But yeah, if it's a serious stress point then you'd be silly to have a stab unless fully competent.

Each to their own and all that.