Hi Charlie;
        The stuff I got from Van's 4-5 years ago was made by "Packaging Systems, Inc.). I used the capacitive probes on all of my tanks, so I couldn't see the need to install the access plate so I omitted it, eliminating the need for the cork gasket. I figured that if I ever needed in there I could cut the holes and install the access plates at that time. That time may now be near at hand.
        I had a couple of pinhole leaks in the past, but I successfully sealed them with green "self wicking" Locktite. It is impervious to fuel and worked easily and quickly and has so far been a permanent fix. But I think the size of this leak is beyond any chance of this working, so a pourable sealant will definitely be in order. I think I'll start with the FlameMaster brand to begin with.  Do you recall the part # of the stuff you used? I just went to their web site and they have a large selection with 4 types specifically made for various fuel usage and several others that are more multi-purpose but still list fuel compatibility.

  If my other tanks are still fine, then it may not be until next winter that I remove this tank for repairs. Thanks.

Todd


1st step would be to check the datasheet on whatever sealant you used in
the tanks. The Flamemaster brand stuff Van's sells now is supposed to be
immune to avgas and mogas. It seems unlikely that a few minutes of
exposure would cause such a major leak, even with the old
mogas-vulnerable sealant. Did you use access covers on the aux tank like
the mains? If so, did you use the cork gaskets? A LOT of people have
leaks around the cork gaskets after months or years of flying.

I'm just about finished with my RV-7 tanks (remember my aux tank
questions about a year ago?) & I had to seal a few leaks. I called
Flamemaster to ask about a compatible, pourable sealant & they
recommended cs 3600, a 1 part pourable compound. I swapped a few emails
with their help person because some of the datasheets indicate use as a
pourable 'slosh' type sealant, other (later) datasheets omit that use in
the product description. In emails, they maintained its suitability for
use on top of  the 2 part paste that Van's sells. This stuff is not the
same as the milky white stuff that caused so much grief in the past.
It's a translucent red color & acts about like pourable contact cement.
In fact, the datasheet describes it's primary use similar to contact
cement application.

I was able to 'inject' it to the problem areas by sucking it into some
nylon tubing & routing the tube toward the problem seam before releasing
the fluid & then pushing it out of the tube with very low pressure air.
I was trying to minimize the unneeded sheeting over large areas of the
tank where no holes existed. The tanks now hold air, but it will
obviously be a while before I can vouch for long term reliability.