Caswell Coating New Tank/Removing Old Tank Questions....

[OrangeDragon]

Hello,

I have read every post on DMF for Caswell Coating a tank but I still have a few questions.

There are many good tips and lessons learned in the posts I have read but I am going to use Ducatiz's step by step process found in this thread:    http://www.ducatimonsterforum.org/index.php?topic=64897.0

FYI, I bought a new tank off of ebay and will coat that one and remove my old tank(i will clean and coat this one sometime later)

1. Ducatiz, in your step by step process are you state to mix the caswell.  is this mixing the entire kit or half of it?  I am assuming the entire kit. 

2.  Related to the question above... Of the amount of caswell poured into the tank, what kind of percentage of the caswell should come out on the final step?  Should it be very low and the point is to retain as much of what was poured into the tank and use it all to coat the inside?

3. I tried to find xylene but could not find it.  It was suggest to use this product which states to use whenever xylene is required:   http://www.lowes.com/pd_13446-78-GKIM24630_0__?productId=3396066   Does anyone have any experience with this product?  Not good?  Or should I use acetone instead if I can't find xylene.

4. If all is a success above,  I plan on taking the old parts(fuel filter, gas cap etc) off of my current tank and put them on the newly coated tank.  Will I need any new parts?  Ie replace an O-ring, etc or will it be easy to use all of the old parts.

5. This last question is more of a curious question and it relates with question 2... I know the benefits of a coated tank outweigh the con of an expanding tank but what kind of fuel capacity reduction is expected after coating the tank?  is it insignificant?

Thanks in advance for answering my questions.

[ducpainter]

My experience...

Half a kit will do a tank if reduced enough.

I've never been able to get much out due to the shape of the tank flange and the filler flange.

I'd get a new o-ring in case your old one swells...they will do that sometimes

Your capacity will be reduced by the amount of material you put in...ie: if you add the whole kit you'll lose a little over a quart capacity. That's another reason I try to use a half kit. The idea is to form a barrier between the nylon and fuel. It doesn't have to be thick...just consistent.

[OrangeDragon]

Another question...

6.  The hole where the fuel pump goes, do I need to coat the edge of the round hole or if there is caswell on the edge of that hole will I not be able to reinstall the fuel pump(meaning the added thickness of the caswell will reduce the diameter of the hole opening)?

[ducpainter]

I believe that edge should be covered, as well as the surface where the o-ring sits.

You can do that after you remove the sealing plate, with a brush,  if you're careful to keep the coating out of the threaded inserts.

[uclabiker06]

Take your time to prep the bike.  The whole process is really not that bad; you'll be fine.  Just make sure that you get none of it on the tank from your fingers while you're rolling the tank around.

[OrangeDragon]

Well, the coating project came out only ok.  I definitely missed some spots on the "shelf" about the size of a quarter.

I am not sure if the thinner that I used was all that good.  It seemed that the coating mix set a lot quicker than I expected. 

Following Ducatiz' instructions, I poured in half the caswell mix into the tank.  But when I went to put in the other half, it had already set and I couldn't go for second coat nor could I brush in any more coating mix at the hard to reach spots like the "shelf".

I wish I had a second caswell kit on hand as the instruction state to add a second coat when the first coat is still tacky.

I am not sure why the other half set so quickly as the mix I was swirling in the tank was still honey like.  The room temp was in the 70s.

Other than this problem everything else went fine.  Overall not a difficult process but if I was to do this again I think I have a better handle on what do do better.  When my old tank shrinks back, I will coat that one.

Lessons learned:

1. I used the clear caswell.  I am going to try the dragon blood next time. But overall it is the areas that you can't visually see that the color will not help.  The areas that I could see the coating definitely got coverage.
2. Either have a second caswell kit on hand or mix half first and then the second half when the first coat in the tank is tacky.  The second option is obviously cheaper.
3. I could not get my hand in deep enough to put a stopper on the inside of the filler neck at the top.  So I used a #8 stopper from the outside of the filler neck at the top.  This worked fine for me.  I screwed in a metal eyelet for a handle to pull the stopper out.
4. My plexiglass bottom cover was also ok.  I got some cracks in the plexiglass while sawing the shape and drilling the holes.   I am going to try and get another one made with laser cutter.  I got a minor leak through the rtv silicone.  I will use an old O-ring on the next attempt.
5. I got lucky and did not damage the paint on the tank.  I changed gloves frequently whenever I made a minor change in task.  I blew through the gloves but better safe than sorry. 
6. Xylene isn't available over the counter in California.  It can be bought at Grainger but you need a business account.  I am not sure if the thinner that I used caused the rapid setting of the second batch or it reacted with the mixing container. The hardened mix was hot to touch and weakened the mixing container like it was melting it.

Well, I hope the spots I missed aren't going to cause the tank to swell. But I'm sure the coating is only as good as its weakest point. 

I wish I could go back in and hit those spots with a brush but caswell says to only apply a second coat when the first coat is tacky.  I am beyond that point. 

I only hope that this tank doesn't expand because of those exposed spots.

[ducpainter]

Regarding the setting of the other half of the kit...

Epoxies create heat as they cure. The larger the volume of material, the more heat it creates. That excess heat is what sped up the cure of the material in the mixing container.

You are correct in that you should have mixed each half separately.

[OrangeDragon]

Just thinking out loud...  what if I get some more caswell and strategically hit those spots I missed.  I think I can reach them without actually putting a layer of caswell over the cured caswell.  there would be a tiny overlap or joint between the two but at least the nylon part of the tank will not be exposed.

Would putting the new caswell in strategically now be worse than just leaving the exposed spots of nylon?

[ducpainter]

I would do it as opposed to leaving bare spots.

Also thinking out loud...if you could somehow abrade the Caswell coating you could put another coat over all of it. You might contact Caswell and ask about a suitable method.

[OrangeDragon]

I spoke with caswell tech support(very nice guy and helpful).

I told him I missed a few spots and that the caswell coating was already cured.
He said to put some acetone in the tank. Slosh it around for 3 to 5 minutes. Drain excess and wait 10 to 15 minutes for the acetone to evaporate. Then add the caswell to the tank for the new coat.

He said the acetone will make the cured coat tacky to accept the new caswell coat.

[ducpainter]

I'd test that method before I re-coated just to make sure.

If it works it will save lots of people a bunch of aggravation.

Can you buy acetone in Cali?

[OrangeDragon]

I'd test that method before I re-coated just to make sure.

If it works it will save lots of people a bunch of aggravation.

Can you buy acetone in Cali?

I called caswell tech support three times triple checking I understood the info and the same guy was very confident with the information he provided me. 

I will do a test on the Plexiglas cover which has the caswell coating residue.  I was using this to verify cure as I tossed out the cured stuff that hardened in the mixing container immediately after my "I am a complete dumb#ss" moment .

If the cured stuff on the Plexiglas gets tacky then I should be good to hit the tank.

I am debating whether to apply the acetone around the spots I missed and hit those locations with the caswell when it is in its honey like stage where I can control its flow.  One reason I am thinking of doing this versus recoating the entire tank is to preserve as much fuel capacity as possible.  The other reason is it concentrates the repair work in a few locations instead of the whole tank in case this repair method doesn't turn out great.  In other words the condition will for better or worse be closer to how it is now. 

If this tank ends up expanding because of my coating job, I have the old one as back up and will do a better job(maybe) coating that tank.... or just getting a motowheels aluminum tank.

Yes, acetone is still available in California.  I will try and test tonight and provide an update.

[OrangeDragon]

I put acetone on the Plexiglas with the casewell already cured on it.  The cured caswell did not turn tacky at all. 

Acetone evaporates quite quickly.  I only tried surface application of the acetone.  I swirled some on it and it evaporated.  I then doused a rag with acetone and let it sit on top for a few minutes but that didn't work.  I then poured a small pool of acetone on the glass.  I let is stand on the glass and it also evaporated before creating any difference with the cured caswell.

I didn't try submerging the plexiglass in acetone as I didn't think that would mimic surface swirling the acetone in the tank.

My next step is to mix a little caswell(I know the instructions say not to mix less than half) and apply over and next to the cured casewell on the plexiglass and see how it bonds with it.

Most likely I am going to strategically hit the missed spots in the tank right now.  I think it is the better option than not trying to cover them or trying to re-coat the entire tank again.

I think I can be more accurate spreading the honey caswell on the spots with my finger.  Am I going to have to worry about excessive heat from the curing process.  I can double triple up on gloves if so.  I have a about 4 exposed spots to hit and that is it.

[ducpainter]

If you can get the job done in a few minutes you'll beat the heat.

[OrangeDragon]

Results of testing new caswell coating on cured coating on the plexiglass:

I mixed a small batch of the caswell. 1oz part A and 1/2oz of part B.  I didn't use any reducer.

I prepped the glass by cleaning it with acetone.

I swirled the caswell in the Tupperware and at the 30minute mark. The caswell was at a good honey point where I could apply it to the cured caswell with my bare finger. I think because the ca swell mix was so small it did not generate a lot of heat.

I applied next to cured caswell and on top of cured caswell to mimic what I will attempt in my tank.

I can barely see a seam line between the old and new. It is almost fully cured and I put some stress on the new work to separate the old and new caswell but nothing happened. I tried to peel it off with my finger nail and nothin happened. I will try again in 24 hrs.

I know caswell says not to mix less than half of what is supplied but I haven't noticed any difference in performance with the small mix and the full mix I did.