Tank Sealant Working Time

briand · #1 04-26-2006, 03:57 PM

I was talking to the paint/sealant expert at work today and he informed me that the B1/2 has a 1/2 hour working time and the B2 has a 2 hour working time. I see many builders express frustration with how much to mix that can be used at a sitting. I would like to get some thoughts on this from you guys to see if the B2 is really workable for 2 hours.

While I'm here I'll also ask if there is anything wrong with starting my wing kit with the fuel tanks(can't wait to get at that sealant)? I see you can buy them pre-fabbed from Van's so I figure it should be alright but would like to know if there is anything I should look out for doing it this way?

TShort · #2 04-26-2006, 04:27 PM

Dunno about the working time - will be interested in the answers, too.

As far as the tanks, you could do them first, but then you couldn't do the z-brackets the "easy" (i.e. Dan Checkoway) way:

http://www.rvproject.com/20020605.html

You can do lots of stuff up to there - I went ahead and fabbed all the components for the tanks (brackets, etc), cut and deburred the stiffeners, etc. but am waiting to drill anything else until I get them tested on the wing (few more days, I hope!)

Thomas
-8 wings

FlyerJumper · #3 04-26-2006, 05:10 PM

Haven't used the 2 hour, but the 1/2 lasted right at 30-35 minutes for us before it was completely unworkable.

Sealing the rudder trailing edge

JimWoo50 · #4 04-26-2006, 05:30 PM

I don't see anything wrong with building the tanks first. A friend of mine is doing it that way. You're going to drill it to the spar anyway and to a strip at the outboard end. Don't scrimp on the sealant especially at the bottom of the rear baffle. If I had to do it again I would build both wings at once also.

Kyle Boatright · #5 04-26-2006, 08:05 PM

Working time on proseal is extremely temperature and humidity dependant. If your shop is cool and dry, you can expect longer than "book" working times.

If the shop is hot and damp, you can expect shorter than "book" times.

Can you do the tanks first? I don't see why not.

Davepar · #6 04-26-2006, 09:48 PM

I used the 1/2 hour tubes and they really harden up fast. Someone suggested dunking the sealant gun in a bucket of ice water occasionally while working. That helped extend the working time quite a bit for me.

ptrotter · #7 04-27-2006, 08:13 AM

Keeping the saelant cool will significantly increase the working time. The working time specified by the 1/2 or 2 part number is based on 77 deg. F. and 50% humidity. Higher temps or humidity will reduce the working time. Be careful about dipping the gun in ice water as getting the sealant wet will speed up curing, make sure the water doesn't touch the end of the tube.

Also, you should store any unused sealant in cool place if possible, it will increase the shelf life.