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I got a take off battery box last month for my M37. The old one was rusted through all around the bottom.

I had to cut out portions of the floor under the box and weld in patches. I killed the rust with phosphoric acid and now it is primed and ready to go.

I am in the process of striping, killing rust and getting the new battery box ready to paint. I am going to prime it and the paint it OD.

My question is, should I undercoat it like it was or just leave it OD green?

What have you other guys done with this and what did you use?

Alan

sturmtyger380 wrote:I got a take off battery box last month for my M37. The old one was rusted through all around the bottom.

I had to cut out portions of the floor under the box and weld in patches. I killed the rust with phosphoric acid and now it is primed and ready to go.

I am in the process of striping, killing rust and getting the new battery box ready to paint. I am going to prime it and the paint it OD.

My question is, should I undercoat it like it was or just leave it OD green?

What have you other guys done with this and what did you use?

Alan

We don't use undercoat on anything, the problem is it eventually starts to turn loose in spots, once this starts to happen water is allowed between layers causing rust to start forming underneath the coating. By the time you are able to realize this is going on, in most cases a real big mess is already well underway. Much better off to paint well & clean frequently.

just paint is ok ,just try to keep it clean inside once your batts are in an going dont let corrosion built up an did you put back a drain hole?

Here are some pictures of the floor under the battery box.

I wish I could weld like that, what a beautiful job. It's taking me quite a while now to get the hang of it with my Hobart Handler. I wish you were my neighbor!
Greencom

It looks plenty good from here! Nice job!

sturmtyger380,
Nice job! I also agree, no undercoating, maybe a battery pad?

Ahh, the pics remind me of when I too had to weld in some new metal in that area. Your welds look much better than mine did. I was just getting used ot my Lincoln welder at the time and figured an out of the way spot like that would be forgiving of a few mistakes.

I had my battery box and tray shot blasted then powder coated for corossion protection

Powder coating works great, especially if powder coated with epoxy primer underneath, super tough.

The key to the sheet metal welding is to fiddle around and find the right amps for the gauge and place you are going to weld. Get a good ground (I like the magnetic ground clamp) as close to where you are welding and listen for the light bacon frying sound. You need some copper heat sinks to back up the weld area otherwise your mig wire will jump through or you will blow a hole (I did this in one place and had to build back up the area.) I am not a pro and still make mistakes.

Yes, I've learned a great deal about welding sheet metal(well at least from my standpoint) since welding under the batt box. When I got to the point of welding the cowl under the windshield I had learned that low amps actually produces better welds, especially with the thin sheet. You can't always go by what the chart on the welder's door says. Now I usually take the chart info and reduce the amperage setting by one letter, and have had good results with this. All the welding I did o nthe cowl was done on letter A and I got enough penetration and hardly any burn through.....

I always try to stick a piece of conveyor belting under the batteries, curl it up on the edges if possible. Tom

Hey Tom,
I'm guessing that the belting is something thats around from loading & unloading hops and the other good stuff?

Hello all. When i got my truck, the battery box and the floor underneeth it were both trashed. I removed the box, and cut away the rotten floor. Since I hate welding, I installed a new piece of sheet metal where the old floor was, with enough weld points to hold it together only. Then I used black silicone to close the gaps around it. Not trusting my welding results, I mooved my batteries under the driver's seat, where I enclosed them in plywood. Prior to this I painted the healthy sheetmetal with Herculiner, and to this day it is holding quite good. The upside of this was that now I have lots of storage room under my passenger seat.