joedallas

joedallas

Well Known Member
Does any one know where I can by a quart of Flamemaster B4 fuel tank sealant

The top of my fuel tanks have over 140 rivets and
I don't think I can install them in under two hours.


Thanks for any help

Joe Dallas
 
That link is to the faster-setting sealants.

Skygeek might have what you're looking for. They seem to have a wide selection.

Or you can do as I did; goop the tank up and assemble it with clecos and let it cure. When fully cured, rivet it.

I used Wirejock's idea for getting extra clamping force on the clecos, by using #4 nuts as spacers on the inside of the joint. Mine had those lockwashers attached so I put the lockwashers away from the airplane parts, which made them easier to grasp afterwards. They came off without any trouble.

The only downside was that my clecos wouldn't initially fit in my #4 nuts, so I drilled them out with a #40 bit in the drill press. Went pretty quickly and no problem. Still, I'm building an RV-3B, not one of the prepunched kits, so my view of what was no problem might not match everyone's.

Dave
 
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joedallas said:
B2 is two hour working time
B4 Is four hour working time

A is thin viscosity
B is thick viscosity

B4 will give me plenty of time if I can find it

Dave's cleco all may work if I cleco every other one then rivet the open holes then mix a new match and rivet the clecoed holes one by one

can I get some opinions of that idea

Thanks
Joe
Click to expand...

Try this: http://www.aircraftspruce.com/catalog/cspages/ac236b4.php?clickkey=560794

I used this on all four tanks and had plenty of working time. I found it no more or less difficult or messy to seal, cleco, and rivet in one session as compared to seal and cleco, then rivet later. But, using B4 like this is twice the price of the B2 from Van's (you're paying ~$50 for a pint of B4 vs. a quart of B2).
 
4 hours = less stress

Thanks
It is worth the extra $50 to do it all at the same time


rmartingt said:
Try this: http://www.aircraftspruce.com/catalog/cspages/ac236b4.php?clickkey=560794

I used this on all four tanks and had plenty of working time. I found it no more or less difficult or messy to seal, cleco, and rivet in one session as compared to seal and cleco, then rivet later. But, using B4 like this is twice the price of the B2 from Van's (you're paying ~$50 for a pint of B4 vs. a quart of B2).
Click to expand...
 
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I constructed my RV7a tanks with the standard 2hour sealant and I'm a slow worker. I agree with others about using the cleco's....and then mix a fresh batch for the rivets. I found one tiny leak at the rear baffle on one tank. After that was corrected, no leaks. The leak I had at the baffle was not related to rushing or fast sealant cure time.....that area is a balance of putting in enough to seal and not putting so much that it billows when riveting (at least I thought that at the time) and there is no way to get inside and seal without cutting ports (which I didn't do).

Ellis
 
great place to learn

using clecos and a second batch for the rivets may work

I believe that vans wants us to use a hand squeezer ( and squeeze slow ) so that the joint is tighter than you can get with a power rivet puller or clecos.

if the joint is over two hours old then the rivet will not pull the joint as tight.

MY tanks are in the wings and I want to do the best job I can and a little more money is not a Issue.

This venue is a great place to learn

My view

Thanks All

Joe Dallas


EllisMcgaughy said:
I constructed my RV7a tanks with the standard 2hour sealant and I'm a slow worker. I agree with others about using the cleco's....and then mix a fresh batch for the rivets. I found one tiny leak at the rear baffle on one tank. After that was corrected, no leaks. The leak I had at the baffle was not related to rushing or fast sealant cure time.....that area is a balance of putting in enough to seal and not putting so much that it billows when riveting (at least I thought that at the time) and there is no way to get inside and seal without cutting ports (which I didn't do).

Ellis
Click to expand...
 
I was surprised that my sealant remained tacky for almost a week after fabrication. Must be OK: four years, 435 hrs and no leaks.
 
One thing I forgot to mention. Cure rate is affected by temperature. The cooler you keep the shop, the longer the cure time.....temp often has a huge affect on reaction rates. And....make sure you mix the two parts well. Many reports of curing problems have been traced back to inadequate mixing.
 
I found it helpful to make a test blob when I built the tank so I could determine cure status without disturbing the actual tank.
 
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