how long for dry tank to shrink back?

[BK_856er]

Ducpainter, after my one experience I'm with you.  However, I'm reluctant to deviate from the Caswell max 5% thinner instruction in order to get better flow.

Good to hear that it's normal for the Caswell "leftovers" to cure rapidly/differently than what's in the tank.

For anyone planning this in the future, be prepared to improvise and expect the unexpected + don't take the tutorial too literally.

I removed the silicone stopper (from the inside) and finally had a chance to inspect with a mirror and light.  Actually from what I can see I'm very impressed with the coverage uniformity and leveling!  I did fully clear the overflow holes of the partially cured epoxy - the pic is how they looked after I peeled the tape off.

Using a different image server and hope the attachments work...

BK

[ducatiz]

Yeah, my setup isn't two coats separated by hours, it is an inital pour and then fill up to paint the innards with a chipping brush. 

It starts to gel pretty fast.

[BK_856er]

ducatiz, by my math your tutorial spaces out the two additions by 40min, and your General area last summary post describes two coats allowing the first one to get tacky.  My recent experience was that the second portion gelled in about 20min.  Granted I used a ROUND container to mix, not a square Tupperware with more surface area - should have followed more closely!

With a mirror I found some spots near the pump attachment that didn't get coated.  That location will always be submerged in fluid and is the lowest point of the tank.  My OCD won't let it be, so I have another Caswells kit on hand for touchup!

(A) I only need an ounce or so and hate to waste a whole kit.  If anyone local (94303) is ready to coat let me know ASAP and I'll share what I have.  I also have Marine Clean, Xylene, stoppers, fuel pump opening plate, 1x recent experience, etc.

(B) What fun science experiment can I do with 1.5 pints of Caswells?

BK

[BK_856er]

All buttoned up!  The black rubber bumpers (original type pn 86610401A) are asymmetrical and have a tall and short side.  Does the tall side go on the inside of the frame?  Seems this way from the parts diagram.  I looked at old pics of my bike and Ducati installed each side differently. 

BK

[ducpainter]

Yes...tall side inside the frame.

[BK_856er]

Yes...tall side inside the frame.

BK

[ducatiz]

ducatiz, by my math your tutorial spaces out the two additions by 40min, and your General area last summary post describes two coats allowing the first one to get tacky.  My recent experience was that the second portion gelled in about 20min.  Granted I used a ROUND container to mix, not a square Tupperware with more surface area - should have followed more closely!

With a mirror I found some spots near the pump attachment that didn't get coated.  That location will always be submerged in fluid and is the lowest point of the tank.  My OCD won't let it be, so I have another Caswells kit on hand for touchup!

(A) I only need an ounce or so and hate to waste a whole kit.  If anyone local (94303) is ready to coat let me know ASAP and I'll share what I have.  I also have Marine Clean, Xylene, stoppers, fuel pump opening plate, 1x recent experience, etc.

(B) What fun science experiment can I do with 1.5 pints of Caswells?

BK

I try to let it get tacky, but it's really a play-by-ear.

I have found that after adding the first batch to splash a bit more xylene in the remaining batch keeps it from getting too thick before use.

I used a chipping brush to move stuff around inside to make sure areas were coated.  For the opening, I covered it with the lucite and sealed it with an oring, then inverted the tank to make sure the bottom is covered. 

I never put a mirror in to inspect that area, but I have look in thru the filler hole with a FO camera and found it was covered well.

[BK_856er]

Tank is on and bike is restored to proper running condition after several years hibernation.  I elongated the slots in the undertank bracket to give a few more mm clearance to the ignition cylinder.  Bumpers seemed to fit best with the long part on the outside.  Primed the pump with a bunch of key cycles - obvious by ear when all is good.  Fired right up.

First ride today over the hills to the coast and back.  Everything works perfectly - just need to regain all my riding skills!

BK

[Syscrush]

I don't know how to explain what happened and why the stuff in the tank kept flowing, but the portion in the mixing beaker took off like a rocket and hardened.

I think that this is pretty common for epoxy and for polyester resins - they cure faster with heat, and the curing process is exothermic AND they're thermal insulators. When they're spread out thin, they can reject the heat associated with the curing process, so they cure more slowly. The stuff in the mixing bowl can't reject heat as efficiently - in a tall, thin, round mixer it will cure faster/hotter than in something like a square cake pan. The shape of the container definitely matters. I once had a mixing container of epoxy resin start hissing, popping, and smoking - on the verge of spontaneous combustion - while the same batch applied to my mold was able to flow and be manipulated with a brush. I put on welding gloves and dropped it in a bucket of water outside and ordered more resin.

.

[BK_856er]

I think that this is pretty common for epoxy and for polyester resins - they cure faster with heat, and the curing process is exothermic AND they're thermal insulators. When they're spread out thin, they can reject the heat associated with the curing process, so they cure more slowly. The stuff in the mixing bowl can't reject heat as efficiently - in a tall, thin, round mixer it will cure faster/hotter than in something like a square cake pan. The shape of the container definitely matters. I once had a mixing container of epoxy resin start hissing, popping, and smoking - on the verge of spontaneous combustion - while the same batch applied to my mold was able to flow and be manipulated with a brush. I put on welding gloves and dropped it in a bucket of water outside and ordered more resin.

.

You are 100% correct.  I came to the same conclusion after thinking it through.  My flawed expectation was that the "stuff left in the container" would be representative of what was going on in the tank and a gauge of the cure status.  Your technical description is spot on.

BK

[BK_856er]

One year and 2 sets of tires later:  the treated tank has held its shape and the coating is still intact as far as I can tell.   

BK

[GK]

Well done, glad everything is AOK!

So glad my tank is metal.

[koko64]

Great to hear its holding up.