Rusty gas tanks

[surfdude]

I'm sure this is at least the 84th time someone has asked this. I have some 1940's Harley gas tanks that have surface rust and varnish inside them. I want to remove the rust and then - yes - I am going to use a tank sealer. (Let's not go there - I just want to focus on the rust please!) Is there a rust remover that I can use that will not allow the tanks to flash rust inside afterwards and also not damage paint? I may not be able to clean, remove rust and seal all in one day so looking for something that will keep them in good shape without me having to spray WD40 in them. Thank you in advance.

[Lyle Manheimer]

First to remove varnish, lacquer thinner works well. Second I like Metal Rescue or Evapo Rust. There are home remedies but I have never found anything that works as well as these products. Metal Rescue has a spray available to coat the cleaned parts to prevent flash rust, I have not used it. I won't go there but there is one coating that says you can use it over light rust and I have done so successfully.

[chuckthebeatertruck]

My prep for internal rust is white vinegar for 3-5 days, hard, fast rinse with lots of hot water, three or four handfuls of fresh, new drywall screws, shake like crazy, acetone to dry it out, and finally caswell sealer.

So long as you move from vinegar to sealer rapidly, there is little flash rust.

i don't care for evapo rust if I'm sealing after. If I am not sealing, it works great. It does, however, gel in fuel if you don't get the tank super clean afterwards.

Dont try to neutralize the vinegar if you try this method. Just flush the tank with a copious amount of very hot water and dry fast. The very tiny amount of flash will be taken off by the screws, which are needed to tooth the surface for the sealer. And, epoxy sealers care far less about tiny amounts of surface rust than others.

I also like vinegar because it is cheap, easy to access, easy to dispose of, and works very well.

good luck.

[exeric]

I also like vinegar because it is cheap, easy to access, easy to dispose of, and works very well.

good luck.

I agree with the above. I have used vinegar with a lot of success, and I was very skeptical before I tried it. I also use fish tank gravel to abrade deeper rust, and I do use baking soda to neutralize the vinegar, followed by a steady flow of running water through the tank. MEK, and acetone work great to displace water, and will rapidly evaporate. I use Red Kote sealer and they say it can be used over light, flash rust.

I only use a tank sealer on tanks that were originally soldered together, and tanks that I have had to do invasive surgery on. "36 and later H-D tanks can be repaired on the outside, or surgically cut the weld seam on the back plate and do repairs with full access to the inside.

[rickgeo]

Brethren,
Another Option , Might Be Elizabeth Radiator, I have Used Them With Good Results, They Have A Website

Rick Stambaugh
#2472

[T. Cotten]

You could always try the search function, SurfDude!

Here's some...

https://forum.antiquemotorcycle.org/...g-with-acetone

https://forum.antiquemotorcycle.org/bboard/forum/general-amca-forum/vendor-services-and-supplier-information/20639-gas-tank-cleaning-and-sealing-recommended-vendors

....Cotten

[exeric]

Surfdude, your post got me to thinking about the inside of my '51 tanks and sure enough, there is some flaky rust, and 'cling-ons that I can't abide. So I'm now in the same situation as you I'm going to use the same routine I suggested in my previous post, but I'm not going to seal the tanks. I know the metal is good so once they're clean (?) I'm going to slosh some oil in them to frustrate the rust.

[surfdude]

Thanks everyone.

Cotten! I know it but it's fun to get the latest opinions, too! But thanks!

I did throw 40 sheet metal screws in one tank the other night, covered it in blankets and ran it in the dryer for an hour or so. Did not do much!

[jug]

Now that I got rid of the hard rust how do I get rid of the flash rust that is two days old? If I don't will it come off with gas and plug up the screen? Thanks much guys.