Gas Tank Internal Coating

[cyaker]

Years ago I cleaned and coated the inside of my gas tank using TRF's slushing compound. The car went back to storage had a couple of gallons of fuel in it. Can't even blame the DPO. Now I have cleared out the gas residue using muriatic acid. Found areas of slushing compound sealer had failed and was peeling away from the tank. I was able to clean it out using Dupont paint thinner.
There is limited surface rust on the inside. Any recommendations on what to do now to protect? Have seen mixed comments in other places about sealers (Kreem) that I suspect were like TRF's slushing compound. Has anyone tried POR tank coating?

 

[macino62]

i have done the POR coating, and it's worked for 6 years now. I did an acid etch of the inside of the tank (it's the red nasty stuff), and then I did the rubberized coating stuff. this stuff is very very very volatile. if the fumes get in your eyes, it will knock you on your butt. in fact, when i was spreading the coating around the tank, i made the mistake of looking down into the fuel sender hole. ....the fumes hit my eyes, and it felt like i had been stabbed in the eyes.

my overall impression of the stuff is extremely positive. i did it on my TR4 6 years ago, and did it on my Porsche 912 back in 2003 with perfect results, as well.

 

[Guest]

If you get a chance, snag the latest (Nov.) copy of Hemmings Sports & Exotic Car magazine from the bookstore (or just go to Barnes and Noble and read it there like almost everyone else). They have an informative article highlighting a company (Empire Auto Radiator, Albany, NY) doing a complete rehab on an old Volvo gas tank. A process called Gas Tank Renu. Kinda interesting. Renu has their own line of gas tank liner coatings it seems. Often a phone call to some of these companies will bring new information into your life that opens doors.

PS, an old trick to help clean the inside of a gas tank is to drop a length of heavy steel chain down in to the empty tank (the key word here is empty) and roll the tank around until your arms want to drop off, then do it some more. Kindof a tumbler effect.



Bill

 

[cyaker]

Interesting, I had gotten a flyer on Gas Tank Renu when I went to a local radiator shop. I had hoped they would steam out the tank, but they had quit because of EPA rules. He advised Gas Tank Renu had done a demo for his staff a couple of months ago. They actually split the tank coat it and then reassemble.
Actually I finished final rinse on tank tonight. Used a rust converter (Right Stuff) for the final rinse. Looks so good, I am now questioning the need to coat.

 

[dklawson]

I also use Right-Stuff rust remover a lot. It's a quality product for the right price.

I've used Kreme tank coatings and POR's product. I'm at a bit of a loss concerning Macino62's description above. Perhaps POR has changed their formulation over the past few years. What he's describing sounds like Red-Kote which I understand is used by aircraft maintenance people. Like Kreme, it appears to use MEK as a solvent and it's just as nasty as Macino62 describes.

POR's current product offering is MUCH nicer to work with and has much gentler fumes. ALL of these coatings require multiple cleaning steps. You start with a strong caustic degreaser to remove varnish and gum. The next step is an acid etch to remove rust and roughen the sheet metal. Each kit maker has their own formula but they're all phosphoric acids like the Right-Stuff mentioned earlier.

Having used two of the above mentioned systems I much prefer POR. Their kit was easier to use, has less fumes, and most importantly to me... it leaves a metallic looking rubbery liner in the tank. To a casual observer the tank won't look coated. Kreme goes on white but turns orange shortly after exposure to gas.

One additional note. I believe POR also offers a (different and separate) gas tank prep kit specifically targeted to remove other, previously applied tank coatings.

 

[foxtrapper]

If tank coatings were so important, they'd be oem. Yet the makers of tanks still make them from uncoated mild steel. Might be a clue there.

Might also be a clue in the failure you ran into with the slushing compound. Personally, as a motorcycle mechanic, I made a lot of money cleaning out Kreeme from the inside of gas tanks.

Clean the tank out with vinegar or such. Ignore the flash rusting, and don't store it empty in a damp area that heat cycles. Do that, and the tank will last a good half century or more without incident.

 

[Guest]

[ QUOTE ]
If tank coatings were so important, they'd be oem. Yet the makers of tanks still make them from uncoated mild steel. Might be a clue there.



[/ QUOTE ]

Excellent point......



Bill

 

[dklawson]

I never thought tank coatings were there to protect the tank from rust... I have only used them to repair pin hole and seam leaks in tanks that would otherwise be scrap.

The point that the coating isn't needed because it isn't OEM is technically correct. Yes, properly filled with fuel or kept in a dry place a tank won't rust, therefore, tank coatings aren't necessary. They also add weight and expense... neither of which is desirable to market new vehicle. However, tank coatings aren't inherently bad just because the factory chose not to use them.

If the coating will save your otherwise leaky tank, you have nothing to loose. Take your time, follow the product's instructions, take no shortcuts, and you'll have reasonable results.

 

[Don Elliott]

I had a hole in my gas tank back in 1990. I had it slushed but a radiator and gas tank shop. It cost me $100.00 back then. I store my car for 5 months every winter. I leave about a gallon of gas in the tank and store the car in my heated garage. Because the tank was coated inside, I never have to worry about condensation or rust inside the tank during winter storage. Every spring, I fill up the tank with fresh gas and this way, I don't need to concern myself about gas stabilizer.

 

[Dave Russell]

[ QUOTE ]

The point that the coating isn't needed because it isn't OEM is technically correct. Yes, properly filled with fuel or kept in a dry place a tank won't rust, therefore, tank coatings aren't necessary.

[/ QUOTE ]
Another take on the situation. As was said above, an uncoated steel tank will flash rust when new. The rust appears to form as a light rust powder coating on fresh metal. Once the rust has formed, it stays fairly stable but if disturbed will come loose as microscopically fine powder, which it appears to be.

The powder will pass through the fuel system without too much bother, unless, a very fine filter is present, & if so, it will clog the filter. I had a couple of clogged filters until the rust in the brand new tank stabilized. Notice that the older LBC's only had a coarse screen for a filter.

I remember very old, 1940's to 1950's tanks being galvanized inside. Don't know what is being used in new cars, if anything. It's likely that the newer sealed & charcoal filtered fuel system vents prevent a lot of moisture entry & reduce the alcohol/water problem.

I think this problem is becoming more common in older externally vented cars as the newer alcohol containing fuels are being used. Alcohol is very hygroscopic & attracts/absorbs a lot of water.

The old trick of keeping the tank filled to reduce moisture doesn't appear to help much anymore on older cars that are using alcohol laced fuels.

I personally would use an aluminum tank if it was available, which it wasn't at the time.
D

 

[CinneaghTR]

I had my TR4A tank "gas renu"-ed at the local franchise in Maryland this summer. It was mucho expensive /ubbthreads/images/graemlins/eek.gif (multiply the price of the POR-15 kit by four or get a quote on a new tank and you get my drift), but the tank looks great and is as good as new.

Having said that, dear old Dad's TR4 needs the tank refurbished and we're going with the POR-15 kit. We will have more time for system restoration whereas I wanted to get the 4A on the road in a shorter period of time.

 

[jessebogan]

Many, if not all new cars feature plastic fuel tanks. No rust, no muss, no bother. They used metal tanks because that is what was available,and they were cheap (The driving force behind most decisions in the car business).
I have used the Gas Tank Renu a couple of times. A triumph tank was $$$, an XJS tank was many $$$, more than double. I was not amused.I have yet to try the POR15 tank repair kit, but I have used a lot of their products, and so far I am pleased.I have a friend that has a decent sized motorcycle collection, and he has had great success with the product sold by Casewells, who I think are a sponsor of this site.