Welding on deeply pitted rusty metal

[/pine]

Have you considered a cheapo sand blasting gun (from Harbor Freight etc.)?...I've seen them from $15 and a bag of media from TSC is less than $10...if there are not really large areas they work well...8 PC Air Sandblaster Gun Kit Gun Tubes Pick Up Sand Blaster 1 4" Air Nozzles | eBay

Good Luck...

 

[ThomasH]

It depends on how small in diameter the pits are, but in general you can do pretty well with a knotted wire wheel on an angle grinder. You should be able to get it to the point where it can be stick welded anyway. Afterwards, wire brush it all and put some iron eating paint on it, and follow that with some enamel and you should be good.

 

[stuckmotor]

A mixture of 1 part molasses to 8-10 parts water does a very nice job of cleaning rust off to bare metal. You need to submerge it for about 10 days or so but it works. No harsh chemicals to deal with after either. Just wash off with water and dry and paint or weld or whatever you want to do.

Now that's a chemical I can live with. I'll have to try it.

 

[SPYDERLK]

If you have a stick welder you can just use 6011 rod. Rust is decomposed in a weld puddle and impurities are displaced. 6011 is quite effective at getting to the metal.

 

[BWSwede]

That's weird, I replied yesterday but it didn't take. I'll try again.

Thank you all very much for your suggestions. In response:

The molasses method is great, and seems to work well but what I am working on is way too big for any tank that I have or want to purchase.
I have tried a knotted wire wheel and a cup and they didn't get to the bottom of the pits.
I am welding with a 220v mig welder. If flux core will work I'll try my 110v using the flux core wire in it.
The mini sand blaster idea is great has some potential. I'll need to look into that since I have no more than 4 sf to do.

Lots of great ideas. I'll try the navel jelly approach first. I read on another site that it is important not to let it dry on the metal as that is when the iron phosphate is left behind. I'll keep it in solution and hopefully with a wire brush (tooth brush size) I can work it into the pits to eat away the rust.

Thanks again,
BWSwede

 

[pmsmechanic]

The molasses method is great, and seems to work well but what I am working on is way too big for any tank that I have or want to purchase. BWSwede

I haven't seen it done but I've read of people digging a large enough hole in the ground to set a vehicle cab into. The hole is lined with plastic and the cab and molasses mix are added and two weeks later no rust. I can't say I would go this far but it's a cheap way to get a big enough container.

 

[Oldpath05]

Best way for rusted steel, 3/32-1/8 E6011 then sand blast/walnut shell blast or the other way around, cheaper way is E6011 then wire brush-ish then Hammerite paint

 

[SPYDERLK]

Best way for rusted steel, 3/32-1/8 E6011 then sand blast/walnut shell blast or the other way around, cheaper way is E6011 then wire brush-ish then Hammerite paint

Exactly ... High 90s result with no fuss. ........ But OP doesnt have stick. Only has MIG.

 

[Ryansweatt2004]

If the OP has access to a decent air compressor then I would vote for using one of the small sand blasters to clean out the rust pits.

 

[Oldpath05]

Exactly ... High 90s result with no fuss. ........ But OP doesnt have stick. Only has MIG.

I use to have a stick welder, it's on my wish list, come's in handy on rusty steel. I find that's one of the draw-backs with mig, it like's shinny metal.