Caswell sealer failures? Please report

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I used the caswell sealer on my tank back in 2008.

The tank had been empty, without cap or petcocks for at least 15 years. I thoroughly cleaned the inside of the tank, following caswell's directions, but did not cut the tank open as some here have done. I carefully mixed the product and applied it - twice. The tank then sat empty for another three months while I finished the rest of the bike and painted the tank.

The sealer lasted almost through the SECOND DAY before I noticed something wrong. Mike Caswell said he'd send me another batch, but never did.

The sealer, when wet with gasohol, looked like old latex, and was soft and very flexible. When peeled out of the tank and allowed to dry out for a day or two, it became very hard, but would still flex when pushed on. I doubt it would crack under normal use, but I am certain it is not ethanol-proof.

Here in Florida, there are very few places where one can get ethanol-free gas.

I replaced the fiberglass tank with one of those Pakistani ones, which needed a little seam welding to be leak-proof, and bondo to remove some wrinkles.

I didn't realize at the time that the tank and side covers would not have been original to the bike anyway, as it is an 850, and probably started life as a Hi-rider rather than the Roadster it is now.
 
What good would another batch have done now that the tank was ruined? Maybe you should have asked for money back which wouldn't even have paid for shipping on the Pakistani tank? I'm sticking with avgas until I can afford a metal one or someone comes up with another option, most likely another metal one or the politicians quit getting money from ethanol.

Dave
69S
 
Ron L said:
I applaud your efforts, Hobot, but a survey will always be inconclusive. If there is a failure, how can you be certain it wasn't a failure in application?

35+ years in polymer chemistry including some experience with both Bisphenol A and Novalac Epoxy (Bisphenol F) gives me a little insight to their properties. Carbonfiber makes some good points in theory, but the scientist in me wants to see hard data. There are factors that influence how flexible vs brittle the cured (crosslinked) polymer will be. One is the molecular weight range of the epoxy. The higher, the more flexible and less brittle and vice versa. These are very viscous polymers, so to get something that flows without the addition of solvent, I expect Caswell's is a pretty low molecular weight, which would tend to corroborate CF's theory.

As I have said before, the process of "slosh" coating a tank is risky. Cutting out the bottom, thoroughly cleaning it , and brushing on a sealer is a much better way.

Novolac epoxies are quite solvent resistant, so I would not expect any alcohol (ethanol or methanol) would soften a properly cured system. Any failure with gummy residue in the carbs is either the polyester of the tank or a poorly mixed, poorly cured epoxy. These systems can take days to completely cure, and you should wait at least a week before putting gas in them. These systems are used to coat steel storage tanks that store petroleum products and years ago we made novolac epoxy coatings for storage tanks for distilleries.

As to liquor stored in plastic bottles, next time you get one of those plastic beer bottles, cut it in half. Carefully peel away the layers. You will find at least four layers of different plastic! (but none are epoxy)
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Ron,

I have a FG interstate tank that hasn't been used for 30+ years, but in great shape internally. With much help from Carbon Fibre, I feel I'm headed down the right direction. (Novolac Resin). And your above quote talks about your experience with Novolac resins...the problem is, is I can't buy them anywhere! I've emailed numerous companies even as far as major Chemical corporations like DOW just to be shut down after asking for small quantities. All I want is to save some money on a new steel tank but I can't find any viable options. Do you have any suggestions as to where I might be able to find a Novolac resin that can be sold to me in the correct quantities for my Interstate tank?

Thanks,
Matt
 
The problem may be not so much the ethanol attacking the liner but more of a problem of the liner not adhering to the fiberglass. I treated my Triumph steel tank with POR15 six years ago and it has had 10% ethanol in it continuously since. I have seen absolutely no evidence of any deterioration of the liner. It looks absolutely the same as the day I did it. The POR15 kit has an etching cleaner and I spent a long time with a hair dryer making sure it was perfectly dry.
I also let it set for several months before I put any fuel in it. I currently have two fg commando tanks and I bought a Hirsh kit and a Caswell. But now I'm wondering if any liner, even if it stands up to the alcohol, attaches to the fg well enough to last.
 
htown16 said:
The problem may be not so much the ethanol attacking the liner but more of a problem of the liner not adhering to the fiberglass. I treated my Triumph steel tank with POR15 six years ago and it has had 10% ethanol in it continuously since. I have seen absolutely no evidence of any deterioration of the liner. It looks absolutely the same as the day I did it. The POR15 kit has an etching cleaner and I spent a long time with a hair dryer making sure it was perfectly dry.
I also let it set for several months before I put any fuel in it. I currently have two fg commando tanks and I bought a Hirsh kit and a Caswell. But now I'm wondering if any liner, even if it stands up to the alcohol, attaches to the fg well enough to last.
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If you are attempting to seal a rusty steel tank (internal surfaces on anything but a brand new steel tank will all be rusty), then after the loose rust particles have been removed, the rust will provide a very good surface for any one of the snake oil "sealers" to adhere to, so chances of long term success are probably around 50% greater than with GRP, which tends to have a very hard smooth skin of oxidised fuel residues covering all internal surfaces, which is pretty much impossible to remove and key using any of the methods suggested by the snake oilers.


Its a very good idea to leave the tank to cure for as long as possible before introducing fuel, as this will greatly increase the chemical resistance of the sealing material, which in some cases where the cure exotherm temperature has been low, will make up for the fact that the snake oilers do not suggest proper post cure processing is required. For those who cannot wait for several months before using a tank, then 8 or 10 hours post cure at elevated RT will be very worthwhile doing.
 
htown16 said:
The problem may be not so much the ethanol attacking the liner but more of a problem of the liner not adhering to the fiberglass. I treated my Triumph steel tank with POR15 six years ago and it has had 10% ethanol in it continuously since. I have seen absolutely no evidence of any deterioration of the liner. It looks absolutely the same as the day I did it. The POR15 kit has an etching cleaner and I spent a long time with a hair dryer making sure it was perfectly dry.
I also let it set for several months before I put any fuel in it. I currently have two fg commando tanks and I bought a Hirsh kit and a Caswell. But now I'm wondering if any liner, even if it stands up to the alcohol, attaches to the fg well enough to last.
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I can't speak for all failures of course, but my failure was clearly one of the coating not adhering well to the tank surface.

I used the Caswell tank sealer on a brand-new fiberglass Fastback tank. I followed all of the instructions to the letter. After a couple of months of use, I found that the carburetor slide was sticking. I traced the sticking slide to gunk coming out of the tank. A close inspection of the tank showed that sections of the sealant had bubbled from the inside surface of the tank allowing the fuel to directly contact the fiberglass.

I did not blame the Caswell as I never saw any claim that it was suitable for fiberglass. All of the advertisement and directions seemed to be for steel. So I just chalked it up to being my mistake. I still have a nice set of red Fastback bodywork on the shelf with peeling/bubbling liner in it though.
 
The technical "expertise" of those selling Caswell products is made very clear in the current advertising by the Caswell UK operation. This clown seems to think problems with GRP tanks are due to the MTBE in current fuel, as well as ethanol! Makes you wonder if those who are actually selling this stuff dont have a clue, what chance is there of them being able to develop a flexible tank sealer, suitable for use in GRP tanks?

This same person was formerly selling a solvent based epoxy product (Tapox) as a tank sealer, which was even less likely to work than the stuff on offer currently, as solvent needed to be removed from tank during the cure process with an airline, to ensure that the resin actually cured! If tank sealant buyers are forced to deal with buffoons such as this, as well as those who make all sorts of ridiculous claims about whatever it is they are peddling, I am not sure there is much chance of successfully dealing with a problem GRP tank!

Maybe if buyers of these products started to ask to see test results before buying blind, then the snake oilers would be forced to either come up with products that worked, or simply stop selling current offerings that dont work?
 
Carbonfibre said:
This clown seems to think problems with GRP tanks are due to the MTBE in current fuel, as well as ethanol! Makes you wonder if those who are actually selling this stuff dont have a clue,
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If I am not mistaken MTBE has been outlawed in US fuel for quit a few years.
 
Quite right Bill...........also in most of Europe around about the same time scale. The point being that if the idiots selling the snake oil, are seemingly clueless as to whats the cause of the problems with modern fuels, it would appear that providing effective products that actually work isnt of that much interest to them.
 
hobot said:
Anonymous Carbonfiber has been educating us on the details of diluted Caswell Novalac tanks sealer vs best industrial strength resins to save old school fiber tanks from new school ethanol fuel. I surveyed Brit Iron list last month to get 2 reports of Caswell failure, one 2 wks later another 2 yr later in Calif. Question is, were these failures of application or innate fault with Caswell sealer sold?

Over last decade have read a over a dozen surprise carb clog to engine seizure from un-coated tanks and about as many of finding flaked and dissolved POR15 and Kream. There was a rash of Caswell coating done about 7-8 yr ago but I'm not hearing of rash of Caswell failures. So confused if no one is testing with ethanol or Caswell applied well is up to the task. Me and my buddy Wes had committed to Caswell before we heard of its possible worthlessness. So we are part of the on going testing, sorta of.

Any bad Caswell reports among forum?
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Doing a search on this forum about Caswell sealer I came across this thread. I am working on a 55 Triumph that sometime in its past had what I think was Caswell's sealer installed. The BPO must have let is sit and pool inside the tank as there is a lump of epoxy in there that has broken free. Moving the tank around it sounds like there is a brick inside. Of course it is to big to get out the neck! Is there anything that can dissolve the Caswell sealer? Could have the bottom cut out but if I can I would rather not. Did talk to a guy at a radiator shop and he said nothing they had would touch it.
Ideas?

John Ebert
Texas
 
Sure,
"Berryman Chem-Dip Carburetor and Parts Cleaner" softens it right up - or maybe I should say the stuff they sold several years ago did. It may have been reduced to dishwashing detergent by now... jim
 
I'd give acetone a try. Not sure if it will work or not but it doesn't cost much and can't hurt anything.
 
I have done two fiberglass roadster tanks with caswell double coating. One started bubbling after two years. Caswell seems to be a temporary fix. Have upgraded one to steel tank.

George
 
If its the old Caswell, some ethanol/gas mix should work. My Caswell failed after a couple days with E10 gas back in '08. Turns the liner into what looks like old latex - kinda transparent brown and very flexible. Should be able to pull the junk out with a hook or long-handled hemostat when it's soft.


I only put ethanol-free gas in my bikes now.

http://www.pure-gas.org lists ethanol free gas stations throughout the US
 
mschmitz57 said:
I've seen this stuff called Attack Epoxy Dissolver online for dissolving epoxy resin.
I've never used this product so it's a bit of a gamble. A half gallon is around $70.
http://www.esslinger.com/attack-epoxy-r ... r-cleaner/

Otherwise I'd ship the tank to Ross Thompson and let him open the tank up and clean it out properly.
Ross does amazing work.
http://www.execulink.com/~rosst/
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This stuff is dichloromethane. Pretty nasty stuff. It will probably dissolve the polyester resin in a fiberglass tank. I'd only use it on a metal tank.

I second the Ross Thompson recommendation for metal work. Exellent work, but not cheap.
 
mschmitz57 said:
So how do you know the failed sealer is Caswell? Did the P.O.tell you?
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I am making an assumption as to what the sealer is or was! Not sure. I have chipped out a small bit by the filler neck and put it into some paint stripper. No effect at all.
I have been slowly and I mean very slowly cutting up the block of sealant through the filler neck. Holding on to it with a pair of long nose vice grips and cutting it with a hack saw blade. Got about half of it out and hope to have the rest out later today.
Once the big chunk is out I will pour in some MEK and hope it dissolves the rest of it. I will keep you posted on my progress if there is any!
It is always something. The bike had a solo Bates style seat on it when I got it. Bought the correct seat and went to fit it and no go! Called a friend in Arizona who had a similar model for advise. Sent him a picture and he sent one back with the "correct" set up. Again, someone had brazed in a filler piece into the back of the tank where the nose of the seat goes. Got out my cut off wheel and gently removed the filler. Had the paint matched and then went to strip the paint off, that was easy. But the steel plate that the mounting bolts screw into were stripped out so I am making replacement ones using thinker metal. When I tapped the original mounting plates back to flat is when the chunk of sealer broke loose. It is always something isn't it?

John Ebert
Texas
 
I was wrong in that I thought paint stripper wouldn't remove epoxy tank liners. I had put a bit of the liner I had removed into a jar with some paint stripper. Looking through the side I thought it hadn't been affected. Took the top off the jar and touched it with a screw driver and it just fell apart.
I put a piece of the liner into another jar and added MEK and as of 24 hours later it hasn't been affected in the least.
It took me 5 hours to get all the lump of epoxy out. Holding it with a pair of vice grips and cutting it with a hacksaw blade. Not a fun time but the tank has been saved.
John Ebert
Texas
 
I have cleaned out Caswell from a couple of tanks now.

You need dichloromethane - this used to be the active ingredient in paint stripper, but because it is so hazardous, most domestic paint strippers hardly contain any these day.

I buy dichloromethane in 5 litre containers from chemical companies at a really low cost.

Swish it around with a handful of drywall screws, and it will get all the sealer out in no time at all
Make sure you count how many drywall screws you put in the tank, so you can ensure you get the same number out again!!!!

Wash it out with lots of fresh water (I use a hose pipe and my airline so that the bubbles agitate the water to make sure there are no loose crusty bits of old sealer lurking inside).

Then, if you are going to re-seal the tank, give it a good swish with acetone - this will leave the tank clean, pollution free (to accept your new coating) and will also make sure there is no water left.
 
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