Gas Tank Sealers

[indianut]

let's put the nasty rumor that increased alcohol content leads to increased water or moisture in the fuel or the tank to rest. This is just modern marketing hype that preys on peoples lack of knowledge to sell them products they don't need and that probably don't do much. Water in your gas is almost a thing of the past because of the alcohol. Remember something that removed water from fuel called dry-gas? It was nothing more than denatured alchohol.

absolutely untrue!

[bmh]

From Wikipedia;
"Dry gas is an alcohol-based additive used in automobiles to prevent any water in the fuel from freezing, or to restore combustive power to gasoline spoiled by water. The name Drygas is actually a brand name, owned by Cristy. It is a liquid that is added in to the fuel tank, that absorbs the water and keeps it in solution."

Seems to contradict the dept of commerce. I also did not see the term hygroscopic used in the physical description of alcohol, though many products seem to claim that it is so and for a fee they will sell you the cure ( for a problem that doesn't really exist). We use alcohol as a mild cleaning solvent at work, and my observation is that an open container of alcohol will evaporate faster than it pulls water out of the air, even in the most humid conditions. Chemically speaking when you add water to alcohol you get a solution, no mater the proportions of the two. The resulting solution is still alcohol, just a lower "proof". Distilleries add water to alcohol all the time to adjust the proof for bottling. Ever see a bottle of Jack Daniels separate? Once the proof of the alcohol gets low enough it will behave more like water and freeze more easily, be more reluctant to burn, etc. But that would require a great deal of water. When I was involved in road-racing years back, we used to add 10% racing alcohol to our proprietary fuel blend to help keep the other 4 ingredients from separating.

The water that winds up in fuel tanks, if not let in by a leaky cap , is usually formed from condensation in the air space in the tank. That process happens whether or not the fuel contains alcohol or not. Hence the advice to keep your tank full. This is not to say that alcohol is harmless to our old machines. To the contrary, it poses plenty of hazards such as dry rotting rubber lines for one. But i don't believe it is a serious contributor to "tank rot". To the contrary it is probably helping to eliminate the problem.

[dommi7]

From the Minnesota Department of Commerce at:
http://www.state.mn.us/portal/mn/jsp...htsandmeasures

"A gasoline/ethanol blend can absorb a certain amount of water. In general, the greater the percentage of ethanol in the blend, the larger the amount of water the blend will hold. Also, the higher the temperature, the greater amount of water the blend will hold. A blend that contains the maximum amount of water it can absorb for that temperature and percentage of ethanol is saturated. If a saturated blend drops in either temperature or percentage of ethanol, the water will start to precipitate (fall) out of the solution and settle at the bottom of the tank"

You used products such as Dry-gas to absorb water into solution. Without the alcohol, the water doesn't mix into the gas. Once the alcohol is introduced, the fuel will absorb moisture from the atmosphere. If the fuel is saturated and temperature drops enough, the water will separate from the gas. In the dead of winter, adding Dry-gas or its equivalent to prevent fuel line freezing is no problem, because the atmosphere holds very little water, and the temperature will not drop much farther.

I don't think we can discount this as a nasty rumor.

[bmh]

With higher ethanol content, there may be more water in a tank, maybe that's what Eric is observing?

Let's put the nasty rumor that increased alcohol content leads to increased water or moisture in the fuel or the tank to rest. This is just modern marketing hype that preys on peoples lack of knowledge to sell them products they don't need and that probably don't do much. Water in your gas is almost a thing of the past because of the alcohol. Remember something that removed water from fuel called Dry-gas? It was nothing more than denatured alchohol.

[dommi7]

With higher ethanol content, there may be more water in a tank, maybe that's what Eric is observing?
Regarding sealers - we have absolutely no control over future formulations of fuel. To place some plastic coating inside a tank seems pretty risky to me. Just think about the guy that has that bike some 40 or 50 years from now. What kind of headache will you give to him? Heck, he probably won't be able to get MEK or any of the nasty stuff we have on hand. Give me bare steel - spray some oil inside during storage to preserve it.
I've got 70 year old tanks that are almost like new on the inside - I think the secret is to keep the tanks full and don't let it go stale, burn it up and fill it up.

Not so sure about Eric's thoughts on the gas being destructive to the tanks. If that were the case would it not also eat away at the heads , intake valves, piston rings and the like?

[bmh]

Add a double handful of wood screws and shake.

We used about 2 cups worth of brand new 1/4-20 nuts. Still crap hanging on in some sections. Yet the parts that softened in the gas came right off. the parts that didn't seem to be on really good. I'll have him call a radiator shop like Chris mentioned, maybe they can cook it out. The paint's already gone.

Not so sure about Eric's thoughts on the gas being destructive to the tanks. If that were the case would it not also eat away at the heads , intake valves, piston rings and the like?

[rwm]

can't you make some kind of bladder.i don't know from what or how.something like a tin box plumbed to your fill and outlet.i know it's alot of work. just throwing my 2 cents in

[silentgreyfello]

Eric, I had a similar situation on a 1914 HD tank... hundreds of pinholes. After cleaning the tank out with diluted muratic acid to get it clean, I used POR 15. On the outside of the tank, I taped up the entire tank to temporarily keep the POR 15 from running out. Two coats to the inside. After 10 years, the tank still hasn't developed a leak!

[Chris Haynes]

The two part red stuff from the rad shop worked on my '65 FLH. A friend had the same thing by the same shop, and his pealed off. Heck if I know what goes on with this stuff. Gas tank sealer is about the most confusing thing there is. Do people really want something to stop or prevent leaks, or do they just think that the inside will go to heck if it isn't coated? Isn't it possible that a tank in good shape, with just gas in it, and when drained and properly stored when not ridden wouldn't need a sealer? I wish we could just get one solid answer on this.
Mike

Every radiator shop has some kind of sealer. RENU actually works and stays in place.

[exeric]

I agree with you Mike, about leaving a good tank alone, although I am going to check out Chris' suggestion about a professional coating for modern tanks. In my case, my tank had about 30 pinholes and areas that are rust laced. There is no replacing a 1916 Excelsior tank with a reproduction because they don't exist, so I'm faced with fixing what I have. I'm doing what Brian mentioned and that is leading up the leaks and pressure testing as I go. I am convinced that modern gas with it's devil's brew of chemicals and high content of ethenol is what is attacking the bare steel gas tanks so I believe it's critical to use some kind of sealer. I've had good luck with 'Redcoat' but like I said, it turns the gas red so it must be breaking down. Whether that is a permenant condition or just part of the curing process is unknown to me. That's why I wanted some first hand accounts before I use it again.

[portagepan]

The two part red stuff from the rad shop worked on my '65 FLH. A friend had the same thing by the same shop, and his pealed off. Heck if I know what goes on with this stuff. Gas tank sealer is about the most confusing thing there is. Do people really want something to stop or prevent leaks, or do they just think that the inside will go to heck if it isn't coated? Isn't it possible that a tank in good shape, with just gas in it, and when drained and properly stored when not ridden wouldn't need a sealer? I wish we could just get one solid answer on this.
Mike

[Chris Haynes]

The absolute best gas tank sealer is a process called RENU. Look in yer yellow pages under radiator repair. Find the shop that has the RENU logo in their ad. Here is the link to their website. For cars they coat both inside and outside of the tank. Obviously for bikes you only have the inside done.
http://www.gastankrenu.com/index.htm

[darrylri]

Kreem recommended acetone, that seems to temporarily soften the coating but how do you get inside to scrape it off?

Add a double handful of wood screws and shake.

I used POR-15 on the tank of my 1953 BMW R51/3. I was very careful to follow the directions, and the tank then went out for painting. I've been running it for three years now with California's reformulated gas and 10% ethanol, with no problems.

[bmh]

After seeing all that Kreem stuff everyone used for so long starting to come undone by modern fuel blends, not to mention the problems associated with trying to remove what the gas doesn't, I will no longer use sealants of any kind. Not worth the risk and eventual hassle in my opinion. We have been trying to get whats left of the failed sealer out of a friends pair of 66 tanks for 6 months now without much success. Filled them with MEK. Stuff leaked out at the pin holes that were originally sealed with sealer, ruining the paint and preventing the tank from being filled enough to try to soften the leftover sealer. It's been a real mess. Kreem recommended acetone, that seems to temporarily soften the coating but how do you get inside to scrape it off? Not going to take a chance on playing this game again. From now on all my tanks will be pressure tested with all leaky welds re-done and any pin holes soldered as Eric mentioned. I'm even considering re-parkerizing the tanks after that.

[Robert Luland]

Great Stuff!