whats the best way to clean a rusty tank?

[brokedowngeorge]

I have used phospheric acid, available at Home Depot, with great results and absolutely no harm to paint. The acid will disolve the existing rust and leave a rust resistant "etch" on the inside of the tank. Expanding on the directions on the bottle: Pour the bottle of acid full strength into the tank and fill the rest of the tank with water (up to 2 gallons water with 1 quart of acid). The severity of the rust will determine the "soak" time. Usually overnight is sufficiant. Don't worry, you will not oversoak and damage the metal but you want to soak long enough to disolve the rust. I pour the dilluted acid into gallon milk jugs to save for later use. Allow the tank to air dry. The rusted areas will turn black and the rest of the surface will look chalky white. If the black areas are scaley, I will drop in a small handful of steel washers and agitate to break it loose. Remove the washers (magnet) and blow the dust out with compressed air. I do a final water rinse to neutralize the acid and flush out any remaining trash. I prefer to force dry the tank (air nozzle) to be sure that all the water is removed.
I have used this method many times and the most difficult part is being patient while the acid does it's job. I have done severely rusted tanks that required the acid full strength and I would rotate the tank every couple of hours for several days. Once the scale is removed and the tanks are water rinsed and dried, the the tanks can be put in service.
I pressure test tanks that were severely rusted because of the possibility of pin holes. If neccessary, repair & seal (another catagory)

[pan957]

I would go over all the welds,mounts, tank tabs etc. to make sure they are sturdy and mig or tig any that are shaky. Next Fit your tank to the frame. Shim a gap with a washer or spacer , Never try to draw a gap closed by overtightening a bolt and nut. Send it to North Cintry radiator in Queensbury, NY. ph# 800-244-1788 for their RENU gas tank sealing service. It last Forever as long as you don't apply heat to the tank. We send all our Taiwanese/aftermarket tanks to them before installing them. I haven't had one leak yet.

[Trichop]

I went to a "Triumph" friends house in KY to visit one day and buy some parts
I saw something strange in his back yard
His RIDING MOWER was on jack stands RUNNING!!! in low gear
attatched to the wheel with bungee cords was a Gas Tank slowly spinning
I asked "What you doing?
"Cleaning my tank" he said
"with sharp gravel inside"
I had to look inside
WOW!!!
No rust
kinda of a "Redneck" way to do it
But it sure works!!

[La Cisne]

I uses electrolysis. Works great.

[Thebigguy0811]

I'm with Le Cisne. Electrolysis is the way to go. A battery charger, baking powder and stainless steel in a plastic shop vac can will take it off. Not really paint friendly, but Great for rusted parts.

[Bryan83]

I just used some apple cider vinegar and some smooth garden rocks. Let us sit for a few days and shook it up. Then used Red Kote to seal it. Came out great! Pic is pre and post apple cider vinegar.





The red kote just made everything nice and red inside!

[stroker]

i filled mine with 3 lbs of 1/4 inch nuts and some diesel then wrapped it in a painters drop cloth put it in my cement mixer for 1 hour came out like new