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fehdxl

Well Known Member
Hi List,

I'm working on my fuel tanks and everything is going fine. However, I have a couple questions of the group...I'm interested in what others have done.

I bought two viscosities of 'proseal' from Sealpak here in town. One is the viscosity of peanut butter, the other honey.

I'm guessing everyone typically uses the 'peanut butter' version, but has anyone used the 'honey' version between the ribs and the skin; the stiffeners and the skin; etc? On one hand I think the 'honey' would squish out better thus making a tighter fit. But I'm concerned that it may flow out too much and leave voids.

My second question applies to either viscosity. How do I know when I've exceeded the working time of the proseal? For example, it's somewhat cold here in KS now and even 16-hours later, the extra proseal left in the cup will still flow off of the popsicle stick when held vertical. Can I still use this left over?

Thank you for your time.

-Jim
40603

P.S. The 'honey' flows out really nice over the shop head side of the rivets and I believe is its intended purpose.
 
Stick with the "peanut butter"

The thicker viscosity is typically used between faying surfaces to develop a seal. The thinner material is often refered to as "brush sealant" as it is used to paint surfaces. At a previous job, for instance, our engineering drawings specified that assembled AN fittings for the pitot static lines be painted with brush sealant prior to close-out. I believe the thinner material would have difficulty maintaining a seal under/around flutes and other discontinuities. The standard "peanut butter" version is MIL-S-8802, Class B. Follow this link to find excellent data sheets on the various versions of polysulfides:

http://corporateportal.ppg.com/NA/Aerospace/Sealants/Sealants_Products/FuelTank_StdTech.htm[/URL]

Good luck
 
Sealpak refers to their sealant as class A and class B. The B being for gun or spatula use and the class A for brushing. I used the class A for all internal sealing and wet rivet installations. Use the class B for the rear baffle and the tank end ribs, especially in the corners where a big fillet is required. just allow at least 72 hours before testing and if you did the rear baffle properly there should not be any leaks.

Van's only sell the Class B, the Class A is considered a hazardous material for shipping
 
Thanks for the info guys.

John, If I understand you correctly, you used the 'honey' between the inner ribs and the skin; and the 'peanut butter' everywhere on the end ribs and rear baffle, right? Can you describe the 'wet rivet'? I had a little bit of polysulfide that was in the dimpled hole from buttering up the internal side; but I didn't make it a point to make sure there is enough there to squish all around the dimple and thus the rivet. Definitely didn't dip the rivet into anything before installing. Is it destined to leak?

I've attached a few pictures of my progress. Quite a learning curve between the first and the last stiffener...and I have a lot more to go. I really like the way the 'honey' flows out over the shop-head side of the rivets.

BTW, the 'peanut butter' is: CS3204 B4 - AMS-S-8802B; and the 'honey' is: CS3204 A2 - AMS-S-8802B.

Here are some pics.








Thanks again for your time.

-Jim
40603
 
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