View Full Version : fuel tank restore,coating

12-29-2010, 02:51 PM
has anyone used fuel tank services in fl for fuel tank cleaning and coating ? looking for some feedback...thanks chris

01-01-2011, 10:01 AM
Not them specifically, but most of the bigger shops have the right processes and chemicals to do the job properly. There are some 'home' kits, but to really do it right, this is an industrial-strangth process, especially in these days of ethanol.

Cheers, Sirhr.

Bill Pedalino
01-16-2011, 08:36 AM
I have now taken the position that, if your tank doesn't leak, clean it and don't do anything more.

T. Cotten
01-16-2011, 09:13 AM
Here's my favorite tank sealer.


01-16-2011, 10:17 PM
Hey Cotten,

Do you know what brand of tank sealer that is? I take it that it was attacked by some evil Midwest gas blend?

AMCA 9757

01-16-2011, 10:48 PM
The picture Cotten posted is precisely why I will painstakingly clean my tanks and avoid sealers!!!

Tom Lovejoy
01-16-2011, 11:23 PM
I have done three tanks at home, I used a tank sealler the model T guys recomended. I dont remember the name of it, But that was 20 years ago and so far no problems. I have seen folks, dont know what they used who had lot's of problems though. Two of my tanks were in pretty bad shape and I was affraid not to use sealler. I agree, better not to if you can help it - but I have had good luck, knock on wood :-)

01-16-2011, 11:35 PM
Good to hear you've had luck Tom! That picture above does haunt me though...:D

T. Cotten
01-17-2011, 08:34 AM

I do not know what brand the red sealer was,
but it had been in service without problems for more than half a decade, passing hands through two local customers, before it suddenly decomposed.
2006 was a peak year for digestive P4gas, eating even quality powdercoating. But somehow, the Kreem in my wife's '65 remained un-touched. Yet Kreem is a sealer most commonly cited for failure!

So the variables are many.
It may well be that a combination of different additives from different fuel providers created a mix more digestive than any one brand alone.
Or it may even be a result of illegal dumping into isolated station tanks: When disposal of some solvents exceeds $1500 a barrel, it becomes tempting to mix it into thousands of gallons of fuel, and sell it at $3 a gallon.
(Illinois' EPA only tests for octane rating, not contaminants.)

The only way to absolutely avoid the problem is to avoid soft sealers.


01-17-2011, 09:23 AM
We do a lot of gas tank sealing at the shop. At this point, 100 percent of the prewar cars that come in (with unsealed tanks) are suffering from issues due to ethanol. On these cars, there are no plastic or rubber fittings. Everything is brass, steel, bronze, etc.

What is happening is that the ethanol is dissolving all the old varnish (and captive rust and crud) that has lived happily in the tank for decades, as long as the tank contained only 'pure' fuel. Ethanol dissolves the varnish very effectively (like Gumout), puts it in solution and then it comes out of solution in the carbs and intakes where it gums up the jets, extra air valves, intake ports, etc. with a treacley mixture that I refer to as 'candy apple coating.' It comes off with laquer thinner and elbow grease. It bakes on with heat. Lovely.

On these tanks, we send them to Canada where they are chemically and abrasively cleaned (often having 'windows' cut in the tank and re-welded to access around baffles.) Pin holes are repaired and then the tanks are coated inside *and* outside (though we can request to have the outside coating left off. Though it is a paintable epoxy coating, it can cover details like rivets, etc. that need to be left exposed.) The coatings are tough, but you must NOT move metal (ie do your bodywork first) or you can loosen it.

The scale of the cleaning job pretty much mandates large tanks, aggressive solvents, etc, especially when you are talking some pretty huge (25 gallon minimum) tanks up to the 40+ gallon LeMans tanks. And these can cost $3 - 8K to replace. Cost to clean and coat one of these big prewar car tanks ranges from $400 - 800 (depending on how much metal repair is needed.) We could not touch that cost if we did them in-house.

The coating part, however, is not the hard part. It's the cleaning. And while Kreem gets a bad rap... there is nothing wrong with it. As long as the person using it gets the tank dead nuts clean, spotless, perfect. Anything left behind will cause adhesion problems for any sealer.

FYI, in the days before there were big companies doing this, we had some creative methods of cleaning. One was to fill the tank with gravel and sand slurry, wrap it in blankets and put it in a small cement mixer for hours on end. I once did a motorcycle tank (c. 1989) in a sleeping bag in a Dryer. Sealed up and filled with water and Black Beauty. It came out spotless. I don't recommend those sort of things today... But necessity is the mother of invention. And punching quarters into a Laundromat dryer is cheap!

So not to discourage anyone from trying home sealing products. Just be aware that w.out very, very close attention to cleaning, you will have trouble.

My $0.02 having done upwards of 100 car tanks in the last 8 years.

Here are some pictures

From left-to-right: 1 Bottom/inside of a carburetter that had been running with varnished gas. 2 This is 'new' gas after just a few days in a tank that had bad varnish inside (see picture 5) The car's running was steadily deteriorating as it all gummed up. 3. Jet needle from the carb in picture 1. 4. Inside throttle body of carburetter showing the 'candy apple coating' and treacle I was referring to. 5. Inside of the tank from which the gas in picture 2 came. The varnish was being steadily dissolved out of the tank and put into solution. You can see how hard it would be to clean that.





Chris Haynes
01-17-2011, 12:20 PM
I send my tanks to a radiator shop that uses the RENU process. I have never had a problem. I skip the outside coating on motorcycles.

01-17-2011, 03:04 PM
Me and a friend had ours done by the same shop, using that 2 part process. Mine is good years later, his looks like Cotten's sack glob. I do agree with no coating, unless there is a problem beforehand. I mean, it is just common sense to me. It is about like that ripoff undercoating some car manufacturers sell, to supposedly extend car life. Just a moneymaker, and wishful thinking by the buyers. Still a ripoff to me.

01-17-2011, 05:30 PM
Mike: you are right that in many cases, sealing is not needed.

But on some of these old vehicles (bikes as well as cars), the tanks are getting thin. Weld lines (often tinned or lead sealed) can be starting to crack. And rust blooms can appear quickly after aggressive cleaning, adding debris to the fuel and eating away even more metal. In a new/modern tank with good, thick sheetmetal and seams... there is no need. In vintage tanks and in rare or difficult-to-replace tanks that otherwise may not survive... sealing does serve a need.

Of note, I put a set of repro tanks on my '64 FLF when I was restoring it. The 'instructions' with the new tanks required sealing. The seller said it must be done. Assuming they were just trying to sell Kreem... I filled the tanks with wood alcohol to see if they really needed sealing... and the brand new tanks wept in several spots along the weld lines. Pinholed in the seams. I asked to return the tanks, and Customer Service said that 'they all leak, this is why we require sealing.' Needless to say, I'll never buy another set of their tanks...

But you are right. Tank sealing is not needed on tanks that are otherwise good and clean.

On cars, we use the RENU process that Chris Haynes referenced. Our franchisee is across the border. It is a first rate process but on bikes, request "Inside" coating only.