This was reply that I sent to Lee:
I didn't respond because I don't know what I'm talking about.
Both of my wing tanks were sloshed with Sealpak CS3600
which my mechanic recommended (and I do trust him). He
reassured me that in the unlikely event that some came loose
it would fall to the bottom out of reach of the uptake. Assuming
it did make it to the uptake it would get stopped by the screen
and my wing tank would still have fuel when the header tank
started getting empty.
Sure cheaper and quicker than sending tanks off to be rebuilt.
Dan
Anyone out there familiar with Sealpak CS 3600? Should I start
worrying now or wait awhile?
On Apr 18, 2009, at 1:40 PM, William R. Bayne wrote:
Hi Lee,
Ercoupe Service Memorandum No. 33 issued in 1947, acknowledges that
tanks of riveted construction had
evidenced seam leakage and/or seepage in the field. Sloshing was
the ERCO-recommended method of
repair to the then-new aluminum fuel tanks. Only the seam areas
were to be sloshed. "It is not necessary
or desirable to cover the remaining surfaces..."
On January 15, 1954, ESM 33A changed the recommendation from 3M
EC-570 to EC 776. Done in the
prescribed manner by a professional, these sloshes served the
intended purpose well.
By the late eighties the formulation of autogas had changed to
"unleaded" and to achieve the higher octane
necessary for modern autos now had much in common with generic
paint thinners. The phaseout of 80/87
avgas and introduction of ethanol to auto fuels caused slosh
compounds applied in the past (and previously
serving their intended purpose satisfactorily) to dissolve or come
loose in pieces of varying size.
Randolph came out with various compounds, at least one of which was
supposedly safe to use with auto fuel.
Unfortunately, gasoline has never been a "blend" of compounds that
is stable in formulation. The very process
of refining petroleum produces gasoline as a by-product, the volume
and consistency of which can be varied to
a considerable degree but never eliminated; which was further
blended as necessary to meet (rather broad)
specifications. Some of us are old enough to remember "gas wars"
when too much gasoline filled storage tanks.
I believe our tank expert, John Wright (and probably the people
that make their living sealing Cherokee tanks)
uses Pro Seal in tank seams before re-riveting. Terneplate and
stainless steel tanks have soldered seams that
should be repaired by soldering. Some aluminum tanks have welded
seams that should be repaired by welding.
Perhaps it would be more accurate to state that there is no
"sloshing compound" in current production that
the manufacturer or Univair has approved for use in Ercoupe tank
seams. That said, I find it hard to believe
that in all these many years of "better living through
chemistry" ;<) there are no space-age compounds suitable
and safe to use today for simple seam sealing...seemingly a "minor
repair".
A final point worth making. Wing tank finger strainers exist (or
should). These are describe on page 48 of the
Ercoupe Service Manual, and actually illustrated on page 46, Fig.
31. Unfortunately the same cannot be said of
fig. 32, 33 or 34. These should be removed before sloshing; then
cleaned/replaced as appropriate.
Best regards,
William R. Bayne
.____|-(o)-|____.
(Copyright 2009)
--
On Apr 18, 2009, at 11:57, [email protected] wrote:
In as much as no one responded to my question as to what use
sloshing compounds are, I assume there is no good use for sloshing
compounds..
Lee
