Early model battery box repair

[Rugbyfan]

I have an early model e30 with the battery box rust. My plan is to cut out the damaged part, grind to bare metal, make a cardboard template and weld in a replacement part. It doesn't have to be pretty, just functional. I've never welded but a friend is willing to help with his wire feed. What type of metal do I buy? I planned on seam sealer and bed liner. Any suggestions or tips?

[jonnywadster]

I'm doing this right now myself

I got sheet metal from home depot or lowes, made a template using the section I cut out and tac welded it in.

Make sure your buddy does the piggy back type of welding weld a little go over two inches welded a little go over to your next tac so and so fourth so you don't burn through and create major issues.

So far I've spent a lot of time on this griding/sanding and now I'm to the point where I've primered, seam sealed, and painted everything.
The final step is I'm putting some herculiner over the batter tray area real clean like, my buddy did this on his car after a similar repair and it looks great.

It's not that hard, just took me wayyyy more time then I wanted and I'm kind of a perfectionist so.
I'll eventually relocate the battery to the trunk.

[AndrewBird]

Whatever you get, make sure it isn't galvanized! Welding it creates toxic fumes.

20-22ga sheet is what you want. Either that, or get someone to cut out what you need off a parts car.

[meanEG]

I have an early model e30 with the battery box rust. My plan is to cut out the damaged part, grind to bare metal, make a cardboard template and weld in a replacement part. It doesn't have to be pretty, just functional. I've never welded but a friend is willing to help with his wire feed. What type of metal do I buy? I planned on seam sealer and bed liner. Any suggestions or tips?

Cereal boxes and beer case cardboard work the best. thinner wire in the MIG work the best. 16ga is pretty hard to bend. 20is good. any metal will work. galvanized is ok, just use a fan to help blow the fumes away before it gets in your mask. if you se galvanized just drink a glass of milk after you weld. you can get seam sealer form Autozone believe it or not $$$, but there is a Sherwin Williams on Montgomery crossroads. I prefer the FinishMaster on 17. They gave me the best prices and more knowledge. Amazon can be a great asset as well. best to treat the weld afterwards before you seal it up

[allen_t]

ECS tuning has battery holder for sale online. I was thinking of purchasing that instead of having to weld

[PKile]

I would re-think the Herculiner idea for coating the new battery box metal...the truck bed coatings are not acid proof. I had the same situation with a vert where the battery leaked and the residue was never cleaned up. I neutralized the acid with baking soda solution and cleaned the incipient rust with a cup brush and sandpaper. I put 3 coats of epoxy primer (Spray Maxx aerosol can) followed by Randolph #345 Acid-Proof Aircraft Battery Box Paint from Aircraft Spruce.