Removing Varnish from gas tank

HalcyonDays

HalcyonDays

Senior Member
I am in the process of removing 35 year old gas, that has lined my tank with varnish, from the gas tank. I am using denatured alcohol, very carefully. It is a slow process and wondering if there is a better way or better product to use. When I first opened the tank, the gas cap had what appeared to be coffee grinds on it and the aluminum strainer had disintegrated I will try to post photos if it would help
Z
 
The process and what it looks like now.
Z
 

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I use vinegar and let it sit for 6 weeks. some guys spend the money for evaporust and similar and swear by it. That seems to work faster.

Vinegar has always worked well for me and Im never in a hurry........

I also use vinegar in my radiator as well.
 
How do you guys know that the Alcohol, Vinegar, or Thinner has actually removed all of the varnish? How do you know if the Acetic Acid found in Vinegar has started forming rust inside the tank??
 
Brent, I'm helping a friend clean his tank that has a lot of varnish residue - it's almost the consistency of tar. We've started off by using lacquer thinner and it seems to be working very well in dissolving the varnish. What do you recommend?
 
The key word is all. The denatured alcohol is removing large chucks of a granular substance. So far I would say I have removed about 50-60% of this stuff. A lot more needs to be removed before even a filter would allow the car to run. This car was a "Henry" award before being stored in an enclosed trailer, in a barn, for thirty five years. The craftsmanship in the restoration work is phenomenal. The best solution would be to remove the tank and send it off to Brent to have it taken apart and properly cleaned. I was hoping for a less traumatic alternative, but it may not be possible.
 
HalcyonDays said:
The key word is all. The denatured alcohol is removing large chucks of a granular substance. So far I would say I have removed about 50-60% of this stuff. A lot more needs to be removed before even a filter would allow the car to run. This car was a "Henry" award before being stored in an enclosed trailer, in a barn, for thirty five years. The craftsmanship in the restoration work is phenomenal. The best solution would be to remove the tank and send it off to Brent to have it taken apart and properly cleaned. I was hoping for a less traumatic alternative, but it may not be possible.
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Not sure just how "less traumatic" it will be since PPG's Concept is being phased-out, and matching the existing paint in texture and hue is likely going to be a bear.

As many likely know, PPG has finally stopped manufacturing the DCC (Concept single-stage) paint. PPG's Delfleet Essential line is an alternative but ironically, a quart of it weighs about a 1/3rd less than a quart of Concept which means the pigments are likely not as good. Matching has been a nightmare thus far too. If you can preserve what you have for the near future, I am going to suggest that to you.
 
mcgarrett said:
Brent, I'm helping a friend clean his tank that has a lot of varnish residue - it's almost the consistency of tar. We've started off by using lacquer thinner and it seems to be working very well in dissolving the varnish. What do you recommend?
Click to expand...

Not exactly sure what to tell you. The issue that we are seeing is that it softens it but does not dissolve it. We get tanks in that still have chunks, and many times they tried to coat over the top of it which really made a mess.


I want to chase another rabbit here a tad. I am curious what this new phenomenon of Artificial Intelligence is going to get its information on Model-A restoration. I am going to start another post and we will comment on it there.
 
I haven't used it a model A tank yet but I still use it in a lot of other tanks and that is a lye solution. My favorite was good old Drano crystals with aluminum bits to really get a good hot reaction. It has also been discontinued since I have to substitute Black Swan crystals now. I have to mix it first and then get it in the tank without spilling it or severely burning myself. It works over night on a moderately crusted up tank. If it's real bad then it would take more to clean out the crud. It doesn't affect the corrosion though. It may also play hell with any lead that might still be in there.

In aviation we used MEK to dissolve fuel related varnish but the stuff is expensive now days. It will play hell with your lungs if you breath too much of it. Acetone will also desolve fuel varnish but it takes longer than MEK.
 
How do you know if the Acetic Acid found in Vinegar has started forming rust inside the tank??
__________________good point Brent. after using the vinegar, I then neutralize the tank
by flushing it out. I then ad a pencil filter and a small filter right before the carb. Never had a problem therein...........
if something works for you, use it. if not, then change your approach till you get it right.
there is more then one way to .............
 
ronn said:
How do you know if the Acetic Acid found in Vinegar has started forming rust inside the tank??
__________________good point Brent. after using the vinegar, I then neutralize the tank
by flushing it out. I then ad a pencil filter and a small filter right before the carb. Never had a problem therein...........
if something works for you, use it. if not, then change your approach till you get it right.
there is more then one way to .............
Click to expand...

Ronn, I kinda wanted to stay out of this but I'd bet we have seen at least a dozen tanks over the last 6 months or so where they customers told us they tried to use Vinegar inside their tank and now they are rusting way more than they ever had a problem with before. It used to be Muriatic Acid that was hard on Model-A tanks. Now we are adding Vinegar to that list. The misinformation that is passed around on those Social Media Model-A pages is so rampant that I no longer even try to be the 'savior'. Now I just move on and bite my tongue. If Vinegar works successfully for you, then by all means use it.
 
This is what was left of filler screen when I first opened tank after 35 years
 

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I appreciate your input Brent. I have been using vinegar for 20 yrs now and have had no problem.
Is it that the customers arent flushing the tanks after? I then immediately dry them out.

as I stated it has worked fine for me and Ive also flushed blocks and rads in the same manner. I also always add MMO on a regular basis as well. Admittedly, I dont drive far.
my tanks look fine and I dont see any rust coming into the filters either.
 
We used to do a lot of gas tank welding repair.
The first thing we did was take the tank to one of the local chrome shops and have it "pickled". It cleaned it to bare metal and did not touch the solder if there was any.
 
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