Post Posted: Sun Dec 25, 2011 6:54 pm
 Subject: Review of the Caswell Epoxy Gas Tank Sealer

I had bought a 2001 Ninja 250 with 203 miles on it, and had been sitting indoors/outdoors for a decade. The gas tank was extremely rusted, and needed to be replaced or re-coated. I grabbed the Caswell 2 part epoxy thanks to the guidance of those on this forum.

I am not a chemicals expert but this stuff seems to be nothing more than 2 part fiberglass resin. I am not sure if there?s anything more special about it. I?m almost wondering if some bucks can be saved by just going to a local marine shop and buying some of that?.

I followed the directions to the T for prepping the tank. When it came time to pour the stuff in my tank was still coated with rust. I emailed Coswell and asked them if this is as intended or if I should do something like the acid wash to remove the rust. They said just stick to the directions so that?s what I did.

The directions say that the kit is good for 2 coatings of a 5 gal tank. The ninja 250 tank being a bit less than 5 I planned on doing 2 applications. After mixing the first half batch and pouring it into the tank, it became apparent that the stuff was way too thick to get good coverage inside the tank. Even though the temperature was what the directions call for, in my opinion it was still too thick. After moving the tank on all axis?s for 20 min there were still large portions uncoated when I looked inside. I decided to add the other half of the mix. So I pretty much added the full kit in 1 application. There was a lot of waste when I let the excess spill out, but I feel like I got the entire inside of the tank coated when I added the 2nd half. If I were to do it again I would add the thinner like the directions call for if working in warmer temperatures, even though I was still within the working temp range. I think having the stuff being more watery would have better coated the tank and allowed me to do the 2 coatings. But when I did this I did not have the thinner on hand.

I let it dry for 2 days. The stuff dried exactly like fiberglass resin does. I really think that?s all it is. Looking inside the fill cap, everything I can see is coated. Hopefully most everything else is. I have a clear inline fuel filter after the petcock and it is very clean after the first tank. No visible rust particles at all, and that?s even with the petcock filter being pretty bad, if not worthless at this point. My only gripe about this is that it?s clear. So when looking in the tank it still looks like it?s covered in rust. If trying to sell the bike that may become an issue.

In summation: good product. Next time I would thin it for application.
Post Posted: Sun Dec 25, 2011 7:07 pm
 Subject: I suspect you may have gotten a touch too much activator...

on the first mix, which made it thicker. You really need to weigh out the 2 parts (I used my postal scale and 2 paint-mix cups). I also did 1/2 batch on a CBR600 tank and while it was thick, it easily coated the interior as I rotated it around. I made the mistake of sitting the tank in the sun, which prematurely started the hardening process.

Where it Excelled was in sealing over .5~1 inch holes when the exterior was sealed with tape. It turned my swiss-cheese tank into a useful item that had no leaks and functioned perfectly.

Post Posted: Sun Dec 25, 2011 7:12 pm
 Subject: Ahh a scale would of been a good idea.

I DO have a scale but it didn't occurred to me to use it. Thant's a great idea.

I was using small paint mixing buckets and just going by the OZ markers. I filled it pretty much exactly to the half oz marker (whatever it was, I forget) So if I was off it wasn't by much... that is if the OZ marker on the paint can is true.

A scale is a much better method though.
Post Posted: Sun Dec 25, 2011 11:56 pm
 Subject: You might be mixing up fluid and dry ounces.

Bloody English/American measurement system Stare

Brian's method measures weight. The way you measured it seems to be volume. I don't know what the directions call for, but it is easy to mix those up.

Grams or cc would have been a lot easier Very Happy
Post Posted: Mon Dec 26, 2011 8:04 am
 Subject: Hush with your Metric rant.. :P The US gov dropped that ball.

And it's beyond expensive to change now, especially for an organization who can't be bothered to learn how to balance their checkbook.
Post Posted: Mon Dec 26, 2011 8:45 am
 Subject: not sure if they give weight on the cans.

I knoow they had fl oz on the cans. Not sure about weight though. I've already tossed them. Not sure how you would weigh it out without knowing the initial weight.
Post Posted: Mon Dec 26, 2011 6:31 pm
 Subject: Fiberglass Resin

Whether you could use fiberglass resin depends if it dissolves or softens in gasoline. Whatever you use to coat the tank has to sit in gasoline for the rest of life of the bike. The last thing you want is for something to dissolve out of the coating and gum up the carbs if the bike is not run for a while.

It's perfectly possible that fiberglass resin would be fine. Then again it's possible that it wouldn't be. You'd have to know the exact chemical composition of what you use and it's long term resistance to gasoline.

There's also the factor of adherence to metal and/or rust. Again that would depend on the exact chemical composition of the material.

There are certainly reports out there of fiberglass fuel tanks in boats being partly dissolved by the ethanol in gasoline. Since you pretty much can't buy gas without ethanol these days, whatever you coat the inside of your tank with has to be resistant to ethanol in gas (plus any other additives like MBTE that might be in there).

You can't tell what stuff is just by looking at it (or even smelling it).
Post Posted: Wed Dec 28, 2011 8:25 am
 Subject: temperature

I used the Caswell kit and it worked great. The directions make a big deal about doing it at the right temperature, and following that, it worked fine.
Post Posted: Mon Jan 02, 2012 8:08 pm
 Subject: Epoxy vs polyester.

Just to clarify, when you say "fiberglass resin" most people think polyester resin, which IMHO wouold not be a good choice. Epoxy reisn is very different with much better adhesion, toughness, and chemical reistance -- and higher cost. Unlike polyester, where you can add more activator to get it to kick faster, epoxy needs a more precise balance of resin to hardner, otherwise it just gets weaker.

I've used Gougeon Bros. epoxy (sold in marine supply stores) for over 40 years and never had a failure of the epoxy. Which is not the same as never having a failure... They sell resin and hardner pumps which make the mixing simple, one pump resin to one pump hardner.

Post Posted: Fri Apr 13, 2012 1:31 am
 Subject: Am I dumb?

About to do this process in the next week, but I have some "dumb" questions:

1. The directions call for screws to be added and shaken around the tank to loosen any excess rust from the tank's walls. How do you get the screws out afterward?

2. How do you drain the excess compound?

The problem I foresee is the tank opening opens into the tank about 1-2 inches keeping everything in. I drew a rudimentary picture ill include to show what im talking about.

Thanks in advance.

Post Posted: Fri Apr 13, 2012 8:12 am
 Subject: Re: Am I dumb?

Get the screws out with a magnet. Or use nuts on a string, or a length of chain.

As for pouring it out, I had no trouble pouring Kreem out of the fuel inlet. I can't see this stuff being much different.
Post Posted: Sun Apr 15, 2012 11:24 pm
 Subject: Epoxy allergy

Be careful when working with epoxy. I got by far the worst allergic reaction of my life when helping someone lay up fiberglass on a boat using epoxy resin. You might not be allergic... or you might find out the hard way.
Post Posted: Sun Jun 11, 2017 9:06 pm
 Subject: Am I dumb?

I just found your post with illustration about draining your caswell tank sealer through your gas inlet... I had the same concern, and was thinking about draining through my petcock. How did this turn out for you and do you have any suggestions? Thanks

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