Just a suggestion to those using pumps in the UK:
The hardener can react slowly with air to make a gooey lump at the end of the
spout.
Putting a self-tapping screw up the hardener spout after use, or wrapping
a bit of cling-film over the end will minimise this.
David Cripps
GBWJH
(SP Systems)
-----Original Message-----
Sent: Friday, May 03, 2002 8:24 PM
Subject: Re: Resin pumps
>Has anyone else had a problem with their Michael Engineering
>Ltd./Rook Metering
>Equipment Inc. resin pump where it pumps a black contaminant (believed to be
>fine aluminium particles) with the resin?
Jeremy - my pump is the one previously owned by Duncan. I calibrated
it initially at my storage cupboard temperature and then was unable
to use it for a few weeks. When I came to use it nothing came out of
the hardener spout! I found that the valve in the bottom of the
reservoir had corroded slightly and stuck closed. I drained the whole
thing without pumping (as the old maths books used to say, it is left
as an exercise for the student to figure out how to empty 2 rigidly
connected reservoirs without cross-contamination or waste of the
expensive contents!). After all that I found that I could have freed
the valve by poking it, without draining. I cleaned the whole thing
out (the acetone didn't appear to affect the pump seals) including
removing some brown rust off the top of the hardener piston, and
re-ground the poppet valve. Things worked OK after that, but if I
don't use the pump for more than a few weeks the valve still tends to
stick. Sometimes after freeing the valve I got some darkish traces in
the hardener (small tank) spout for the first few strokes, but as
that was usually for dry micro (ie no real strength required) I was
happy to use it. Doesn't seem to be doing it much now - or maybe I'm
exercising the valve more frequently now and not giving corrosion a
chance to take hold. The only remaining irritation is that the
hardener tends to solidify at the mouth of the spout and (partly)
obstruct the flow of the first stroke. This can even result in a jet
of hardener that misses the mixing cup entirely! Now I always poke
the hardener side with a piece of wire to dislodge any crust before
starting a layup session. Again, any slight portioning error caused
by removal of the amount of hardener in the crust will be confined to
the first stroke. I discard it unless it's being used for dry micro.
I'm puzzled as to why they didn't use stainless instead of mild steel
for various immersed parts and so avoid these corrosion problems.
(Although, having tried myself to work and machine stainless, maybe
it's not such a mystery!)
Not really answering your query at all, sorry!
regards
Rowland
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