View Full Version : gas tank cleaner?

06-26-2007, 07:17 PM
Thanks for all the help everyone on my gas tank problems. At this point I have sand blasted my gas tank, used epoxy primer, and finished it off with semi-flat enamel. After pulling everything apart, I am glad that I did with the various problems I found. I am waiting on parts from TRF before I put everything back together. In the mean time can someone recommend any type of solution to clean a gas tank once it has been pulled? There does not appear to be any rust, just some crud. Even though I had it plugged while I blasted it, I still managed to get some "sand" inside the tank. I was thinking of just filling it up and agitating it with something like Simple Green, followed up by slushing it around with alcohol before installing it. Any suggestions would greatly be appreciated?

Thanks, Kevin

06-26-2007, 07:43 PM
I would have cleaned the inside before painting the outside but if you're careful and don't have any pin hole leaks you should be OK.

When there is heavy varnish I start with a liquid (not gel) type paint stripper poured in the tank followed by a handful of gravel or old nuts & bolts. Slosh that around several times and wait a while between shakes. Following that I dump the contents into a bucket and rinse with a strong cleaner. Simple Green is OK but I prefer Marine Clean from POR-15 as it is stronger. However, once you've used the paint stripper to get the fuel varnish out I think Simple Green would work just fine. Follow that with several rinsings with clean water.

06-26-2007, 08:53 PM
Dear ichthos: I just did my tank (an upgraded aluminum) and would highly recommend the 3 step system sold by Moss Motors. They have a cleaner, an etcher and an epoxy-type sealer all designed specifically for gas tanks to prevent future leaks and corrosion. It's a multi-day process to do it right (lots of draining, rinsing and drying required between steps) but it seems to have delivered a solid product. Good luck!

06-26-2007, 09:47 PM
I was going to clean the inside first, but there was only rust on the bottom outside of the tank. My concern was it rusing from the ouside, and I needed to see if there were any holes on the outside first. It has pitting, but there is still plenty of metal. I filled it up with water and could find no leaks. I also knew I would probably get some dust or sand inside when I sandblasted anyway. I am glad to hear about the Moss kit. I was considering that option. The only thing that stopped me from using it was the cost. I do not see any rust on the inside of my tank, so do you think I would benefit from this process?

06-26-2007, 10:03 PM
no,...ever look inside a beer can. One place gas tanks rust is the top,usually surface only,but a simple muratic solution will clean that up. The moss product is a gamble, especially on a sound tank.

06-26-2007, 11:19 PM
I used kreem on my bike's tank. It worked really well. It has some cleaner, etcher and sealer.
I think they make a size big enough for our tanks.

06-26-2007, 11:37 PM
Kevin- i think rad shops do it too.

06-27-2007, 07:31 AM
I didn't think this thread was going to migrate into the subject of tank coatings. However, now that the door is opened, I encourage everyone to use the search function of this board (beyond just the Triumph pages) for "gas tank sealers" as the topic comes up frequently.

To summarize succinctly here: The main kit products used for tank linings are Kreem, Red Kote, and POR-15. I have used Kreem and POR-15. Everyone I know who has used Red Kote loves it but I have no experience with it. All kits use the same basic process: clean the inside of the tank with caustics, acid etch the inside of the tank with phosphoric (not muriatic) acid, slosh the coating around the inside of the tank. As mentioned, it's a lengthy process to do correctly. Of the two products I've used, I much prefer the POR product. This is NOT their rusty metal paint you'll hear discussed. The POR kit uses friendlier chemicals than Kreem, and leaves a nicer surface coating behind which is metallic in appearance. Kreem looks OK when new but its bright white appearance quickly picks up an orange tint from the fuel. All the products work.

Some radiator shops will coat tanks for you. Like most professional work, it's not cheap. However, if you're uncomfortable doing this yourself it's always an option.

06-27-2007, 08:05 AM
Gunk is usually dried gasoline residues. Solvents clean them nicely. Unfortunately, they will also clean the paint on the outside of the tank just as nicely.

Rust, if you've got it, is easily removed with vinegar. Other acid solutions work as well.

Blasting grit comes out well with a garden hose and a good bit of shaking. Then blow air into the tank for a while, or use the shop vac.

Note on tanks, they come rusted from the factory. Always did, probably always will. Flash rust and such is not an issue. Big flakes are. So don't store your car with the tank half empty.

Kreeme and several others made me a lot of money as a motorcycle mechanic. The money was in removing them. They flake nicely, plugging up the filter and lines, and sometimes the carburetors. Many people paid me a lot of money to remove this stuff. There isn't a single redeeming quality to them, imo.

06-27-2007, 08:41 AM
foxtrapper,...exactly. You spelled out what I was implying. I have done many tanks,and they were RUSTY. The metal etch products that use phosphoric acid leave a phosphoris residue behind.All well and good on metal that you can get at with your hand,because you have to rinse/wipe it off after application for best paint adhesion.To much residue on the bare metal and you will get poor paint bond.Call your PPG tech line and ask them. A few years ago,on this forum,I went thru my process of crap gas tank repair.I am not saying I have the last word on the subject,I don't but I have never had one fail. I have stripped out tanks who had the misfortune to use that gas tank renue stuff. Its LATEX paint. I use muratic acid AFTER a thourgh solvent cleaning,then a thourgh detergent cleaning. The muratic acid must be neutralized with baking soda after rinsing.If you must coat your tank,coat it on the outside,preferably with a fiberglass resin,mixed with the finely ground fiberglass powder.Any coatings on the inside of a tank are a weak link waiting to happen.Bottom line here,the materials needed to do this job aren't expensive,but the time involved is a lot,the fastest,quickest way is a new tank.

06-27-2007, 09:41 AM
I would recommend that you take your tank to a good rad shop and have the cleaning and coating done by a professional The 100 to 150 buck investment is worth it for peace of mind as well as the personal hazard and risk factors alone

John Loftus
06-27-2007, 10:28 AM
Fuel tank sealers are used on some aircraft fuel tanks (a good source for obtaining small quantities is a small airport maintenance shop) so really doubt that the sealers they use are inherently bad.


06-27-2007, 11:28 AM
A trick I used to get all the rust and acumulated gunk out of my gas tank was to drop in a couple of lengths of heavy-ish chain into the empty tank and rattle and shake it about for a while. Shake and rattle till you're good and tired, then take a break and do it a couple times more. Amazing what you will knock loose. Then use the etcher and sealant.


06-27-2007, 11:48 AM
Boxorocks, sorry you've had such bad experience with the phosphoric acid. I've never heard about too much phosphate coating being bad for paint adhesion. I know that a secondary, loose, fluffy and useless phosphate coating can develop if you allow the acid to dry on the surface. If you keep the steel wet with the acid until it develops a uniform matte grey appearance and then rinse off the phosphoric acid you should develop the beneficial surface. I'd be interested in hearing what PPG told you about phosphate coatings.

As John said, tank coatings have been used on aircraft for quite a long time. It's my understanding that the aircraft market is the primary place that Red Kote is used.

I would not describe Kreem or the other tank coatings as Latex paint. The solvent system in Kreem is MEK which is in no way compatible with Latex paints. POR uses a solvent system similar to what's in lacquer... but POR is not in any way like a lacquer paint.

I expected a discussion of tank coatings would bring about differing opinions. Repeating what I said earlier, I've used both Kreem and the POR product and I found the POR easier to work with, more appropriate in appearance, and it developed a tenacious, uniform coating. Applying any of these coatings correctly involves a lot of work and I agree that if you can find a radiator shop to do the job for you... there's nothing wrong with that route.

06-27-2007, 12:17 PM
Just some random comments :

Av gas is quite a bit different than what we put in our cars. For one thing, no MTBE or alcohol. So, what works well in aircraft may not work well in your car.

Aviation tanks are coated with access to the inside of the tank so the surface can be properly prepared; not by just dumping things in and swishing them around. And corroded tanks are simply replaced.

My local radiator shop re-creates this access, by cutting a hole in the tank, so the interior surface can be properly prepared.

On my TR3A, I've gotten by just fine for some 20 years by soldering the leaks from the outside and leaving the inside surfaces alone. It continues to rust, I get some fine flakes in the sediment bowl every time I clean it, but I haven't had any new leaks since 1985.

But if I was going to "seal" it, I'd take it to :
In addition to the hype on the website (and the lifetime guarantee), my friend at Mac's Radiator says it works great and I believe him. I've dealt with Kurt for almost 30 years now, and he's never steered me wrong.

I've seen a car where the classic "slushing" compound looked like paint after you apply paint stripper; it wasn't a pretty picture. At least the stuff he used was attacked by something in the fuel. (Sorry, don't know the brand name.)

06-27-2007, 01:00 PM
Yup dklawson, thats exactly what happened to me. I figured if a little was good,more was better.I shot the metal twice,let it dry and scotch padded it off. Shot my primers/paint. Looked fab,for a few months(engine compartment) then blistered. Called PPG, they said basicaly what you said. It was not the first time I used the stuff,just wanted to have it be a good and sound finish. My question tho is why use it at all,or any sealer. The latex stuff is what the re-nue coatings were,if they still are,I dont know. You use the term MEK, that the catalyst for fiberglass resin,my choice for the OUTSIDE coating.

06-27-2007, 01:38 PM
There's a world of difference between glopping Kreem in an old gas tank and the lining process of an aviation fuel tank.

06-27-2007, 02:04 PM
laquer thinner will eat thru the varnish left by dead gas, let it soak a few days...flush with lots of water...repeat as required. You can etch with phosphoric acid which is readily available at mant hardware stores. I have used the POR 15 tank kit several times and have had excellent results with it.

06-27-2007, 02:23 PM
Yup dklawson, thats exactly what happened to me. I figured if a little was good,more was better.I shot the metal twice,let it dry and scotch padded it off. Shot my primers/paint. Looked fab,for a few months(engine compartment) then blistered. Called PPG, they said basicaly what you said. It was not the first time I used the stuff,just wanted to have it be a good and sound finish. My question tho is why use it at all,or any sealer. The latex stuff is what the re-nue coatings were,if they still are,I dont know. You use the term MEK, that the catalyst for fiberglass resin,my choice for the OUTSIDE coating.

Metal treated with phosphoric acid, even when properly applied and prepared for painting is not always compatible with all primers. Picklex20, a phosphoric acid product, warns not to use self etching primers. I have also read on auto painting forums where they advise the same for acid etched metal.

Best to check the primer product specs before prep work and application.

06-27-2007, 07:47 PM
Ray, I agree that you certainly should follow the paint maker's instructions. When I buy paint products, I buy all of the components from one supplier and only ones that are supposed to work together. In the case of PPG mentioned earlier, the last car I painted used PPG's DCU paint system which does include etch primer among its compatible components. I've had good luck acid washing panels, applying the PPG etch primer, followed by their high-build primers and top coats. Beyond the issue of phosphoric acid... I consider it very important to choose your paint components wisely and follow the directions carefully.

Boxorocks, the catalyst for fiberglass is not MEK (exactly), it's MEK-P which has peroxide, lots of peroxide. MEK is just a very strong (and dangerous) chemical solvent. I think you can still get it at hardware stores which is VERY surprising because OSHA (and probably the EPA) have all but removed it from industry. I believe it's linked to liver cancer.

As was mentioned on the previous page of posts, you can always solder pin holes if you don't want to line the tank. I've lined three tanks over the years and I don't regret the decision(s). However, Foxtrapper's choice of the phrase "glopping" to how kit type tank liners are applied is sadly appropriate. You really do feel like you're creating a big mess when you undertake this process at home.

Why coat at all? Well as an example consider the RH tank in my Mini. I can buy a new reproduction tank from the U.K. for over $400, I can buy a used one in the U.S. for about the same (with it's own potential rust holes), or I can line the tank I've got, seal its pin holes, and eliminate rust and scale. The $40 or so investment in the liner kit just made fiscal sense.

06-27-2007, 10:43 PM
If you decide to go the Kreme route, make sure you have a VERY well ventilated area and are prepared for a mess. I tried it, and while it is too soon to really tell it hasn't make anything worse. To get a good coat you are going to have to use quite a bit and twirl the tank around for coating.