Tank Sealant

chasesa · Feb 27, 2011

I just had my steel tank sealed with aircraft fuel tank sealant. It's very effective in sealing seams in airplane so they don't fall out of the sky. Should be OK for a Commando, if it stays on the ground.

The job was no muss & fuss, Just had to have it dry & clean.

I am thinking of doing the same thing to my fibreglass tank. Any opinions out there?
Stephen

Webby03 · Feb 27, 2011

I don't see any reason why not. The sealant should not react with the fiberglass.
Just make sure you use the thinnest one with a longer drying time, if I remember correctly (it's been a long time since I've been on the tools) choose a sealant with a part number ending in "A", this is the thinner brush on stuff, the last digit is normally 1/2, 1, 2 etc. this is the drying time, choose one with a long enough drying time to give you plenty of time to completely seal your tank.

Once you have mixed the sealant, you can stop it from drying and going off by keeping it in the freezer.

I hope this helps

Webby

norbsa48503 · Feb 27, 2011

Not talking directly with the maker of the sealant would be a mistake.

batrider · Feb 27, 2011

Our local Avgas doesn't contain any ethanol. It is the ethanol and other additives that negatively affect fiberglass tanks and some current tank sealers. So it would be good to check with the sealer manufacturer and ask whether it is affected by ethanol. Also you could ask about use on fiberglass and any recommended prep for the used fiberglass tank.

Russ

AltaNorton · Feb 27, 2011

Stephen, I have a fiberglass tank and would love to save money by not buying a steel one. Could you tell me where you got the tank sealant, an how well it works with your fibreglass tank when you get it in there.
Thanks,
Matt

Carbonfibre · Feb 27, 2011

chasesa said:
I just had my steel tank sealed with aircraft fuel tank sealant. It's very effective in sealing seams in airplane so they don't fall out of the sky. Should be OK for a Commando, if it stays on the ground.

The job was no muss & fuss, Just had to have it dry & clean.

I am thinking of doing the same thing to my fibreglass tank. Any opinions out there?
Stephen

The commonly used polysulphide aircraft sealers used for wing tanks amongst other things, are not resistant to alcohol bearing fuels, and failure is pretty likely.

There are industrial polysulphides which are resistant to alcohol type fuels though, and these use an alternative catalyst material.

bwolfie · Feb 27, 2011

I have lots of experience with aircraft sealants. The sealant you speak of is commonly refered to in the trade as "b" seal, usually b 1/2 is common. there are a, b and c grades of it, a is the thinnest and sprayable, b is in the middle and is brushable and c is the thickest. the number at the end represents working time in hours. Once mixed it can be frozen to stop the process. It can be thinned out with MEK, makes it cure very fast and spread well. I experimented with it and modern fuels, it failed after a week. Unfortunatly Not a soulution. I also tried Hysol EA9309, an aircraft epoxy, also failed. And EA 9396, too failed. All of which I had access too. I have some caswell for my tank, but have yet to use it.

Jeandr · Feb 27, 2011

It is always easier to pour stuff down the filler neck than to open up the tank and fix it for good. While I would like to believe the poured in products work, I would also like to believe I have a chance of winning the lottery. Cutting open the tank and relining it with a layer of fibreglass and either vinyl ester or epoxy resins and then painting on a good sealer while the tank is open and then doing it again after it has been closed again is MY way of insuring a fibreglass tank remains sound with modern fuels. It is a lot of work, but it is doable at home by anyone, no special tools required.

Jean

bwolfie · Feb 28, 2011

I've been looking at the bottom seam on my NOS Dunstall tank. I'm trying to build up the courage to cut into a piece of history. I also need to find a 100 Ohm fuel sending unit that will work. That is becoming the biggest problem.

Carbonfibre · Feb 28, 2011

Getting hold of some Novalac epoxy, and mixing in some chopped GRP fibres, will result in a tank sealer thats an awful lot better than the Caswell stuff, and is far less likely to crack and fall off, which is the major reason for slosh coat epoxy sealers failing.

You need a resin which is relatively low viscosity, and that is not solvent based.............the Caswell stuff can be used, but this is very costly in comparison to industrial products, and needs to be warmed up to reduce viscosity if you are using a filler material to increase film strength when cured.

boz · Feb 28, 2011

If you are going to use aviation sealer then plan on using aviation gas. As it has been pointed out it is the ethanol in modern road gas that is eating up the older fiberglass. Then you have the problem if you can get av-gas you are not supposed to run it in a vehicle that goes down the road because you are not paying the road use taxes that you do when you buy pump gas.

DogT · Feb 28, 2011

I'm using avgas to avoid the F/G problem. Seems to run fine in the bike. Some people will say it's not good, it is leaded gas albeit low lead. I still don't leave any gas in the tank for any length of time, it's just too easy to drain.

Dave
69S

Carbonfibre · Feb 28, 2011

Industrial polysulphide sealers are seemingly impervious to alcohol bearing fuels, but use of a filled novalac sealer, with proper prior preparation, and sticking to the use of super unleaded fuels (which have only 5% ethanol) will work perfectly well in most instances. For bikes that are only used occasionally then avgas is certainly an option, but obviously not feasible for bikes that are ridden and used on a regular basis.

chasesa · Feb 28, 2011

Folks,
Thanks for the comments.

First, I applied the sealant to control corrosion inside my steel tank (850 Mk. lll). It's very clean & original, so the sealant will hopefully keep it that way.

Secondly, I am not worried about ethanol on my fibreglass tank ('68 750), at this point, anyway, as it's not in fuel sold in Canada. Unless the conservative lobby gets its way, there's no sign that ethanol is likely to be sold here either. I have had my negative experience on this tank following a fill-up in Maine. Took a lot of effort to sort out the immediate bleeding of resin (with help from this forum).

Rather, I was just thinking of sealing the glass tank against other leakage issues (I am checking on possible adverse impact of the sealant on glass).

Good to see a topice fully explored!!
Stephen

Carbonfibre · Feb 28, 2011

I would be extremely surprised if ethanol stays out of Canadian fuels for very long...............here in the UK levels have now been increased to 15%, and resistance to alcohol fuels by those representing owners of older vehicles, which in many cases are likely to be damaged by this fuel, has been pretty much non-existent!

mikegray660 · Feb 28, 2011

humm - ethanol, sealants, and fiberglass tanks

http://www.youtube.com/watch?v=7IU1bzZheWk

Jeandr · Feb 28, 2011

chasesa said:
Folks,
Thanks for the comments.

First, I applied the sealant to control corrosion inside my steel tank (850 Mk. lll). It's very clean & original, so the sealant will hopefully keep it that way.

Secondly, I am not worried about ethanol on my fibreglass tank ('68 750), at this point, anyway, as it's not in fuel sold in Canada. Unless the conservative lobby gets its way, there's no sign that ethanol is likely to be sold here either. I have had my negative experience on this tank following a fill-up in Maine. Took a lot of effort to sort out the immediate bleeding of resin (with help from this forum).

Rather, I was just thinking of sealing the glass tank against other leakage issues (I am checking on possible adverse impact of the sealant on glass).

Good to see a topice fully explored!!
Stephen

Although they don't say anything, Petro Canada was the gas that ruined my Fastback's gas tank, Esso on the other hand has always been OK so far.

Jean

Jeandr · Feb 28, 2011

mikegray660 said:
humm - ethanol, sealants, and fiberglass tanks

http://www.youtube.com/watch?v=7IU1bzZheWk

:lol: good one

Jean

Carbonfibre · Mar 1, 2011

mikegray660 said:
humm - ethanol, sealants, and fiberglass tanks

http://www.youtube.com/watch?v=7IU1bzZheWk

The one and only reason there are at the moment no off the shelf sealers likely to work properly long term with GRP tanks, has to do with the greed of those who are selling unsuitable re-packaged industrial products, and are making something like 400-500% profit!

None of these people have carried out any sort of proper testing related to these products, and generally the only choice is between the differing advertising blurb (which is about 90% nonsense in most cases!). There is certainly a big market for a sealing product that actually worked, but i would guess this has now been reduced by 50% or more due to the crap being sold by the snake oil people!

Gary · Mar 1, 2011

I inquired as to whether there was any DEFINATIVE sealer to protect a fiberglass tank from modern fuel attacking it. ANY barrier coat at all. This is what I got back, his title says it all? I mean, they carry some hellacious chemicals and sealants and barrier coats, oh my!

"I do not have a material for your application. Sorry."

Thank you for your interest in our products. Please contact me with your
questions.

Epoxy Systems, Inc.
Norm Lambert
President &
Director of Technical Support

Epoxy Systems, Inc
Florida & Vermont USA
Available by Phone M-F 9AM-4PM Eastern Time (6 AM - 1 PM Pacific Time)
352-533-2167 (Voice)

Tank Sealant

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