I don't think Randolph made the alcohol resistant sealer 18 years ago.
It is part # 912 I think. If it the old stuff and you ran auto fuel in
it that was a mixture of gas/alcohol the blistering is what usually
happens. I have a Zenith 801 and I would dread to have to unzip my
wings to get at the tanks. We all feal your pain....

Ben
N801BH
www.haaspowerair.com

Tim Hickey wrote:
I guess that it has been at least 18 years since I build the fuel
tanks for my CH-300. They are of welded aluminum construction, and
were sloshed with Randolph's sloshing sealer. The Alcohol resistant
type, if I remember correctly.
Today I drained the tanks so I can replace the fuel selector valve,
which is enjoying a small leak around the selector shaft, when I
noticed that there is a small flake of sealer that has cracked loose
from the rest. Further examination shows that there are areas that
look like small blisters are forming under the sealer. I suspect that
this is not an unusual problem, as I seem to recall that others have
had this problem also. The question I have, is what to do. It seems to
me that the tanks need to be removed, (big job), and the sealer
flushed out of there. I seem to recall that some were using MEK to cut
and remove the sealer. Does this seem like the thing to do?
Advice welcomed.





Zenith CH-300 Driver.