[wirejock]

How long did you allow fuel tanks to cure before testing?

The tanks will be done (finally) tomorrow. I don't want to compromise the seal by testing too soon. After the z-brackets are installed, my plan was to put wax paper on the spar and mount them for a few days to allow them to fit before the proseal fully hardens.
When they go on the spar tomorrow it will be 50 till I remove them in the shop. Up to this point they have been inside at 70.
I can move them to the heater control room after but it runs low 90s.
I know temperature, mixing rates, etc. apply. I figure a week after they are removed from the spar should be fine but prefer to hear from others.

 

[paul mosher]

cure

As long as you're not using B72 (it does exist) a week at above 50f should be OK.

 

[bruceh]

I would give it at least several days. As long as the sealant is no longer tacky, the 1psi put into the tank shouldn't blow any of it out.

Don't bother with the balloon. Get some clear vinyl tubing and make a simple manometer "U" shape with some water in the tubing to show that you have positive pressure in the tank. The water will rise and fall with barometric pressure and temp changes. As long as it doesn't go level on each side of the "U", your tanks will be leak free.

 

[longranger]

Keep a sample of your last batch of sealant in the same environment as the finished tank. When the sample is good and firm, you're good to go.

 

[wirejock]

Idea

Keep a sample of your last batch of sealant in the same environment as the finished tank. When the sample is good and firm, you're good to go.

Great idea.
I just finished the baffle and z-brackets and mounted them on the wax paper covered spar.
They fit perfect.
Thanks for all the advise. Much appreciated.

 

[Larco]

How long did you allow fuel tanks to cure before testing?

The tanks will be done (finally) tomorrow. I don't want to compromise the seal by testing too soon. After the z-brackets are installed, my plan was to put wax paper on the spar and mount them for a few days to allow them to fit before the proseal fully hardens.
When they go on the spar tomorrow it will be 50 till I remove them in the shop. Up to this point they have been inside at 70.
I can move them to the heater control room after but it runs low 90s.
I know temperature, mixing rates, etc. apply. I figure a week after they are removed from the spar should be fine but prefer to hear from others.

The manufacture of the tank sealant told me some years ago that when you can touch it and not leave a finger print, you are good to go. worked for me. Larry

 

[wirejock]

Fingerprint

The manufacture of the tank sealant told me some years ago that when you can touch it and not leave a finger print, you are good to go. worked for me. Larry

Thanks Larry
I will double check with the fingerprint.