View inside Fuel tank, previous coating?

[charliekwin]

My tank looked a lot like siteunseen's, and I did much the same: sloshed/rinsed with water and 88 large nuts, rinsed with muriatic and then phosphoric acid, more water, then acetone, and finally used Red Kote.  Materials were probably ~$100, but it was quite a bit of effort and no small amount of misery sloshing a fuel tank around in 95 degree weather wearing blue jeans, a long-sleeved shirt and a mask.  The end results were good, though.  I did have pink fuel for a bit, which apparently is common with California's gas formulation, and is also apparently not something to be concerned about.

[siteunseen]

I read this a few times,http://atlanticz.ca/zclub/techtips/fuel/gastank/index.htm

Then this,  http://www.damonq.com/techsheets/red-kote.pdf

Made a list and order of the steps, the acid and the liner are time sensitive, beforehand.  If you have everything lined up and ready to use it's pretty easy.  The first one I did, I had know idea what to expect and wound up getting a little flustered.  The 2nd one was kinda fun. 

Just playing, it's not fun using acid in the heat of the summer. 

[Captain Obvious]

Sloshing around dangerous chemicals while wearing masks. In the middle of summer.

Sounds like a scene from Breaking Bad!

[charliekwin]

No tighty-whities here!

[bartsscooterservice]

It's not that bad looking at the pictures. I would clean up the feed and return lines, and have them re-soldered. ( would not cost much ) 

The inside I would put alot of nuts and bolts in there together with some cleaning vinegar. Shake it for a while, leave it a day, then shake again, then drain the tank and see how it looks. If it's clean  use por15 fuel tank coating ( 3 steps ). The first time I would fill it up with gas, and slush it around for a while, and then drain it again, then put new gas again, when it's under the car,  Put a new fuel filter and you are ready to go.

- Soldering = cheap

- Cleaning vinegar and nuts and bolts = cheap

- Por 15 fuel tank coating .. $ ?

Another option would be sandblasting the outside ( cheap option.. drill and wire wheel ) of the fuel tank, then have it soldered, and then repaint it. Steps for the inside the same.

 

 

[siteunseen]

Vinegar's a good idea. You can also use a short section of chain instead of nuts, whichever you may have.

I used a brass wire wheel on a cordless drill on the outside of mine. Painted it black then did the bottom with undercoating. I wish I had used truck bed liner though, it's much tougher.

[Mark Maras]

 PO of my 260 used 1/2"(no minus) clean crushed rock and phosphoric acid. Said it was a PITA but it turned out good. Too bad he left it that way. No coating. Some visible rust inside now.

[DaveR]

So i got some prices, and I talked to the local radiator shop guy. Also talked to sandblaster, who would charge $100 to do the outside.

Local rad guy will charge $300, apparently will clean it up via thermo chemical flush, braze it up, leak test it, coat the outside, and 2x red kote the inside.  He says its warrantied for 5 years. This SHOULD be the direction I go, but I am having a really hard time being comfortable doing it.  For one the guy is old school, so he's not the best at answering questions and instilling confidence.  He just kind of maintains that I have nothing to worry about and he never has an issue.  Because of this I can't get a good read for how well he will prep the outside of the tank, although I assume it has to be sandblasted.  Finally, and most importantly... the red kote instructions say this

Boilout is not recommended because the high alkalinity removes the tin from terne plate making the plating flake off. Red-Kote will not stick if the plating is coming off. Some tanks do not have this plating.

But again, he still maintains that whatever process he does he doesn't have issues.

Because of all this, I considered doing it myself... but the order of operations gets incredibly complicated and time consuming. Here is the sequence I believe I have to follow.

1) Re-braze the return port (currently this means bringing it to a shop, probably the rad shop)
2) Cleaning the inside out. Do it myself, crushed rock, muriatic acid, etc.
(I suppose I could jam something into the return port to do the cleaning.  Still not sure how I will seal up the fuel sender hole, as my fuel sender works and i don't want it in there with the acid)
3) Pressure/leak test.  Probably need to have it cleaned out before doing this, so as to make sure to expose any small leaks.
4) Have it sandblasted on the outside.  I've cleaned it up a bit myself with the wire wheel but its a big job no doubt. Guy would charge $100 for an hour in the booth to do this.  (Hopefully this doesn't expose any more leaks)
5) Coat the inside myself
6) Coat the outside myself.

If i could find a way to get it brazed without a shop, and then pressure tested without a shop... it would certainly simplify things greatly.

But honestly this is so much time I have to invest when there is plenty of other stuff I need to sort out on the car to get it running this summer.

Or I shell out $200 more, and do the "Gas tank renu" process for $500 with lifetime warranty.  It's definitely the overkill route, but the DIY path is so time consuming and I'm having a hard time being comfortable with the local guy.

[Patcon]

Don't blast the outside! The metal is thin, you will either warp it or cut more holes into it. There is no reason to pressure test the fuel tank. The tank coating will take care of any pins holes, if you see a lot of coating appear on the outside of the tank while lining it you will be able to figure out where it's coming from. Use paint stripper on the outside of the tank or sand paper. If you slick it up good with paper , it doesn't have to be perfectly clean, then you can spray it with what ever you want. Put some rock in the tank or a section of chain, fill it with acid. Hang it with some chains or a some rope or put it in a swing so it is easier to slosh back and forth. Presto, all clean. Seal it and be done. Don't over work this. Lot's of people have done it before you, it's not really that hard. As for the sender hole, cut a piece of sheet metal (metal can, flashing, etc) the same size as the sender and lock it in with the sender ring to seal up the hole. Do not leave the sender in the tank with the aggregate and the acid...

[DaveR]

Oh right, I've had it apart for so long I forgot that the sender ring closed it up, perfect.

Thanks for all the advice, i'm really trying not to over complicate it, but I have a tendency to take things overboard. 

 

[Dave WM]

I hope this works out for you. One mine it had big sheets of red coating peeling off, then breaking up into smaller parts. I took it to a rad shop, they said "red coat" and told me they could not help. Next I tried putting a 2000 watt heat gun in it, wrapping it up with blankets, cooking it for hours. After melting down my cheap heat gun and nearly starting a fire (the blankets began to char, and the paint on the outside began to melt/burn) I put a bunch of hex nuts in it and sloshed it around with acetone till my arms ached. That broke up a lot of the (now black and charred looking) coating but still a mess. At that point I threw in the towel and took it to the renew guy. He told me there was a messed up filter plastic filter on the pickup (guess I melted that, duh). If I had to do it all over again I would prob take it to a custom shop and get a quote on having one fabricated. I hear you about going overboard. Guess I could have done nothing and drive around with a big arse pre filter on it.

Edited April 25, 2016 by Dave WM

[Zed Head]

The instructions for RED-KOTE say it's solvent-based, and they recommend MEK or similar for clean-up.  In the solvents world, gasoline would be considered a "non-polar" solvent, and MEK "polar".  They're different ends of the spectrum.  Just some trivia to explain why it might work to pour a gallon of MEK in to the tank and slosh it around.  If it doesn't dissolve it completely, it might swell and soften it enough to break in to chunks.  It might be an air cure material, like linseed oil, which would stop it from dissolving but still leave its susceptibility to MEK.

They even talk about using MEK to remove other coatings.

Edit - looks like RED-KOTE is not a cross-linked or cured material (see MSDS below).  So it should dissolve completely in MEK.  Sorry Dave, that you spent all that time with the heat gun and blackened char, although yours might not have been RED-KOTE, maybe one of the others.  Anyway, were it my problem I'd scrape a chunk out and see how it handled some MEK before throwing a gallon in the tank.  p.s.  2-Butanone is another name for MEK.  So, about 50-50 acetone-MEK is what they dissolve 27% RED-KOTE in.

Edit 2 - on second look it does have a crosslinking agent, at low concentration.  So it would probably swell a lot, like gelatin, in MEK.  Still an improvement in getting it out.  But maybe why the rad guys wouldn't touch it.

"Red-Kote is a solvent-based polymer coating "

"15. For clean-up use methyl ethyl ketone, acetone or a quality lacquer thinner with no alcohol in it. "

"Remove old coatings completely first, using MEK, acetone or other solvent "

http://www.damonq.com/techsheets/red-kote.pdf

http://damonq.com/MSDSSheets/DMN0142.pdf

Edited April 25, 2016 by Zed Head