Rust hole - sheet metal sizes

[Percent]

I have a E36 328i coupe which has a small rust hole under the body at the front sill.

I intent to buy a MIG welder and repair it myself but what thickness metal should I buy for the replacement patch?

[Martin350]

I usually use 1.0mm (18 gauge).

[E-bmw]

As above, 1.0mm generally for non-structural steel.

If you haven't migged before practice first will make it easier & make sure the area is well prepped to good metal, cardboard helps when making a template to cut the metal to shape/size.

All might sound obvious, as I say don't know if you have done it before.

Also consider renting if it a first time, generally £40 - 50 gets a good machine with consumables for the weekend.

http://thetoolhireshop.com/category/power-equipmen...

[Martin350]

E-bmw said:

cardboard helps when making a template to cut the metal to shape/size.

Can't beat a bit of C.A.D.



Cardboard aided design.

[E-bmw]

[Percent]

Thanks for the replies.

I'm looking at buying a fairly 'cheap' MIG now. Any recommendations?. It will be only used for car repair/fabrication.

Thoughts on this?

https://www.amazon.co.uk/Sealey-MIGHTYMIG100-Profe...

[E-bmw]

Don't buy no gas!

Simples!

You DO want a gassed mig.

Unfortunately that nearly doubles your price, but no gas migs aren't worth the money.

If is just for occasional use you are probably better renting.

[Percent]

Would a secondhand [ebay] gas/mig be advisable?

[E-bmw]

Totally dependant on what it is.

I stumbled upon a brand new half price, un-bid-on small "hobby-mig" 5 years ago & it is still going strong.

I only use it 5 or so times a year, so "job's a good 'un" the experience could have been very different.

[E-bmw]

In real terms just rent for the first few times & then you will know what you can & can't do & what you want & also (most importantly) what you think it is worth to you.

[E-bmw]

Realistically, this is probably you ABSOLUTE MINIMUM & please do not take this as a recommendation!

https://www.ebay.co.uk/itm/150AMP-welder-gas-no-ga...

It seems to be a Sealey under another brand & on top of that you will need a mask & consumables.

[sassanach0]

1.0 is 18gauge now???

[TooMany2cvs]

sassanach0 said:

1.0 is 18gauge now???

No, 18 gauge is now 1.0mm. (Well, 1.2mm - 20 gauge is 0.9mm)

https://www.metalsupermarkets.co.uk/sheet-metal-ga...

OP - have you ever welded anything in your life before? MIG isn't terribly hard - but a bit of grotty car floor is not the best place to start. Will you be going from the underside, or from the top? Welding upside-down is FAR harder than the right way up. And don't, ffs, forget to remove everything vaguely flammable from the vicinity... Sparks from both welding and grinding travel surprisingly far - and make a mess of glass.

Edited by TooMany2cvs on Tuesday 27th March 19:26

[Percent]

Never welded before

This what I want to sort. It's only a little larger than a pound coin behind the right front wheel of my E36.

[TooMany2cvs]

Percent said:

Never welded before

This what I want to sort. It's only a little larger than a pound coin behind the right front wheel of my E36.

There's a LOT more going to need cutting out.

Let's see a wider pic.

[227bhp]

Good luck welding a small patch on that

What you find is that big expensive welders are easy to use, small cheap ones are hard work and working upside down is even worse, expect to blow plenty more holes in that cill.

[tapkaJohnD]

Per Cent.
Take an awl, or other sharp-pointed tool, and jab the metal around the hole, hard!
Once it will not go through, cut back to at least 20mm all round.
Your hole will now be much bigger! But you will have a fighting chance that you can weld to the remaining metal.

No argument with the above advice on going for a gas welder; I'd add not a cheap one that lacks a cooling fan - they over heat and stop working.

The secret of success will be practice. And more practice! And, it looks as if you will be welding this patch overhead, which is the most difficult poisition to do so. Hiring a welder will need a long lease to get you enough experience. Unless you intend to take up car restoration as a hobby - in which case go for it! - taking your car to a welder may be cheaper, and certainly easier.

Look for businesses that sell welding products in your area, which can point you to their customers, or else for fabricator businesses. Perhaps someone in their workshop could take this on for beer money (Many beers!)

Good luck!
John

[Mignon]

The biggest mistake most novices make when trying to fix rust patches is not cutting far enough back to good metal. You can't weld to rust - end of. That whole panel in your pic looks too far gone to weld anything to. You need clean bright steel to weld to and if there is none then the only cure is a complete panel.