On Thu, 12 Jan 2006 19:10:04 -0800, Jerry Springer
wrote:

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.

That has been a problem in the RV's, When I built my tanks in 1988 it
was common practice in manufacturing to use Pro Seal on the seams and
rivets and then Slosh the complete tank. Many builders had the slosh
come loose and had to remove the tanks and and clean out all of the old
slosh. Some builders just junked the tanks and built new tanks as that
was the easier way to go in some cases. It seems that any chemicals that
you use to remove the old slosh just gums it up and makes a complete
mess. I have slosh in my tanks and and am reaching the 17 year mark with
no signs of it coming loose but am keeping my fingers crossed. Van's
have found that the tanks seal just was well just using Pro Seal with
out the slosh.

Jerry

The tanks need to be clean and etched before sloshing so the slosh
can bite.No oxide layer. Won't guarantee it will never peel, but if
you get a good bite you won't get corrosion between the metal and the
slosh, which lifts the slosh.Most slosh kits come with an etchant for
steel. Use aluma-prep (Phosphoric acir IIRC) on aluminum tanks.