http://www.mtfca.com/discus/messages/257047/328855.html?1356114016

I finally had some time to play with my oval tank. I removed the cap rather easily and with out a boom. A few taps in the right direction and off it came. Maybe the 15 degree temperature in the garage helped. Looking inside I can see a baffle that goes the full width and height of the tank. There are small allowances at the edges for the fuel to flow. No way anything courser than sand is going to pass. It would be a night mare to get it all back out! Luckily the rust is minimal and I will be flushing it with muriatic acid as a rust remover.

Don't use muriatic acid.......it'll eat up the galvanizing like nobodies business.......

Thank Craig, didn't know that. What can I use, It's not all that bad.

Get a gallon of phosphoric acid and give it a good rinse. Actually muriatic dilluted at 10:1 is about the same Ph. Rinse well with water and backing soda. Now for a treat; turn the volume down if you have sensitve ears!
Does wonders on blackened wood eh? troop

http://www.youtube.com/watch?v=IGxss0B6yyE

http://www.youtube.com/watch?v=fbTv06lUlM8

I bought a refinishing kit from Lang's. Came with a cleaner, etcher and POR sealant. Instructions were clear and it took me a couple of days between cleaning and etching and they recommend a full 4 days for the sealant to fully cure. I notice that nobody seems to go that route and I am afraid to ask why. The inside of my tank came out great and so far I have seen no negative effects. I used a plastic threaded plug for the bottom hole after removing the sediment bowl and used a cheap replacement gas cap. You just have to make sure that none of the POR remains in the the threads of the filler hole or sediment bowl hole.

John, a number of years ago there was a sealant on the market that would melt as some newer gasoline was introduced. Made quite a mess I heard.
The current sealer works with the current fuel on the market. Langs and other vendors should have these answers.

I use hydrochloric (muriatic) acid to strip zinc from bolts and other parts that need re-plated. It takes about 20-30 seconds to strip the zinc from a brand new bolt, right down to the steel.

Just thought you might want to know how much time you'll have to pour it in, swish it around, dump it out and neutralize it before you start getting pin-holes in your tank.

Acids, as far as laymen are concerned come in various strengths. Judiscious use is always warranted. Always try it on a sample part for results. Realistically they are in order of strength:
Hydroflouric
Hydrochloric,
Sulphuric
muriatic
phosphoric
citric
and good ol' coca cola with some phosphate

Your "order of strength" is flawed. While hydrofluoric acid will dissolve glass, it has little effect on many metals except their oxides. I use it frequently in plating to remove metal oxides. It's actually classified as a weak acid even though it can be deadly to humans.

Also, muriatic acid IS hydrochloric acid. They have the same chemical formula--HCL.

If it's no worse than that, I would not bother with any more cleaning. I would use one of these screens http://www.modeltford.com/item/2903BSC.aspx stuck into the top side of your sediment bowl. Nothing large enough to cause you a problem downstream can pass through it, yet it offers no resistance to flow. If a bunch of crud were to clog the lower part of it, the fuel just flows from a little higher up. There would have to be 2" of crud in the bottom of the tank before this thing would quit working. I used to play with antique outboard motors. I would make something similar to this and solder to the tank fitting of every one of them. Screens like this are the greatest thing since sliced bread for gravity flow fuel systems. They are simple. work great, and the price is right.

Once again thank you for all the ideas. I'm thinking of doing very little. I'll flush it with water and throw a couple of cans of coke into it just for sh*ts and giggles. Will use a screen and keep after the bowl for a while.