Fuel tank/ Proseal curing

I finished closing up my tanks today, now waiting on Proseal to cure so I can leak check
A few questions.

1. Plans call for countersinking, then prosealing remaining rivet holes in rear baffle. This step is to be done after Proseal has cured..... how long should I wait? Clecos with blue tape.




2. Most folks say to wait a week or two to allow Proseal to cure before leak checking. Is there any guidance on how I can tell when the Proseal is fully cured? I planned on waiting at least a week.

3. Can I countersink, Proseal and rivet these 14 or so holes in the baffle when the Proseal has cured enough not to show a fingerprint

I waited 3 days before riveting, and 1 week before leak-testing. No need to countersink the skin for the baffle (unless you want to); I and many others simply dimpled the skins and baffle flanges. (edit - I now see the pic, and that you're only talking about the last few countersunk holes; still 3 days in that case; I found 2 days still squeezed out some proseal when riveting)

_Alex

Whatever the material spec sheet says?

There are an awful lot of A320s out there where I or my former colleagues have done tank entries during overnight servicings, slapped a heat lamp onto the area after closing up and leak tested a few hours later in the early morning, immediately prior to departure, all done in accordance with material specs and the maintenance manual with complete confidence that 1000 odd passengers (and crew) would be safe during that day's combined flying.

Fast forward to a few tank entries I did on an RV9A this year where I left them to cure 24 hours before filling up and static leak testing a further 24 hours. All good.

Jskyking said:

2. Most folks say to wait a week or two to allow Proseal to cure before leak checking. Is there any guidance on how I can tell when the Proseal is fully cured? I planned on waiting at least a week.

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FWIW what I did when I mixed up the tank sealant was to wipe the remainders from the batch onto something in the workshop (like an unwanted edge of the workbench). When that was hard to the touch I knew I was good to go.

Cure

GeoffP said:

FWIW what I did when I mixed up the tank sealant was to wipe the remainders from the batch onto something in the workshop (like an unwanted edge of the workbench). When that was hard to the touch I knew I was good to go.

Click to expand...

What he said. ^^^
Every batch and every location is unique. Best to know by checking the control.
Up here, I can point a heater and still have a stone cold part. I waited 2 weeks.

I actually called and talked to a support person at the manufacture of the stuff we call pro seal (what Vans sells) and was told this. When you can touch it and doesn't leave a fingerprint it is good to go. From my experience, in cold weather it probably can use or will need a heat lamp to help the cure.

Thanks for the inputs-
I’ve got a sample run from the last process used in sealing the tanks. In my case the left wing baffle. Since there were many different “ batches of Proseal that were mixed in the baffle assembly, there might have been slight variations in the Proseal composition.
On previous steps the “ fingerprint check”;was a pretty good litmus test...so I’ll include that in the measure.
Since I’m in no big hurry, I’ll wait at least a week while I work on something else. Plus we have plenty of heat - the consistent high OAT’s don’t seem to be tapering off.