I think I'm trying to clean the rust out of my tank incorrectly. Please help.

[DumbGenius49]

So I'll start out with the fact that I've done this same thing two times in a row. For some reason I expected different results the second time but that obviously didn't happen. So first I empty the fuel out of the tank, and I completely fill the tank with white vinegar (5% acidity). I let that sit for about three says and the inside of the tank looks so beautifully clean when I peek in the gas cap hole (while the vinegar is still in the tank). As soon as I empty the vinegar out, a thin layer of rust (not uniform, but in a wave-like pattern) forms all around the tank. After that I would fill the tank with ice and slosh it all around the tank and when I would empty that water out it would be completely brown with rust. Right after that dumps out, another layer of rust forms and when I put fuel in there the fuel comes out of the petcock brown. What am I doing wrong? What is the correct process, and I'm open to suggestions about other ways to get rust out of the tank.

 

[fastbysuzuki]

It's called flash rust, as soon as you have finished derusting pour some alcohol in the tank rinse it out fill with petrol immediately or spray WD-40 to ward off flash rusting.

 

[Guest]

What he said

 

[DumbGenius49]

So as soon as I pour the vinegar out? So I don't rinse the tank out with water after dumping the vinegar? That makes sense, I'm just making sure.

 

[Nessism]

The vinegar must we washed out with water before applying the WD-40 and alcohol.

 

[hampshirehog]

The way I do it is to stick a hose pipe in the tank filler, turn on the water and pull off whatever I've been blocking the fuel outlet with. Flush through with water for a good few minutes until all the vinegar has gone then pull the hose out and start spraying WD40 in through the filler cap hole until the water has gone.

 

[herm744]

Here is a link to my other forum with good advice on cleaning tanks http://www.2strokeworld.com/forum/index.php?topic=31338.0

 

[Nessism]

Here is a link to my other forum with good advice on cleaning tanks http://www.2strokeworld.com/forum/index.php?topic=31338.0

If you look through the archives here you will find at least 25 different threads on how to derust a tank. And inside those threads you will find about a dozen different methods, some good and some bad.

Personally, I'd recommend against extreme methods involving muriatic (hydrochloric - HCl) acid. That stuff is nasty and should be neutralized using a base solution after use. If you are concern about flash rust don't use HCl. Toilet bowl cleaners typically have HCl in them.

Phosphoric acid is the stuff used in industry to derust steel. If you purchase a Por-15 or Kreem tank sealing kit they include a bottle of phosphoric acid to remove the rust with. When in doubt use what the pros use.

 

[limeex2]

I used vinegar and ended up with more rust than I started with.

 

[Guest]

The key to using vinegar is once you're ready to pour out the vinegar you must use a Baking soda/water mix to flush out the tank after the vinegar is poured out or it will flash rust. You then either fill it with gas or coat it with oil etc. if you're leaving it to sit.

 

[Chip]

I had a radiator shop owner suggest using clean gravel to develop rust my tank. He said to put clean gravel in the tank and shake it around. In theory it sounds feasible however I have not tried yet.