There always seems to be a pattern that emerges from this occasionally
repeated debate.
Those who actually have a pump think they're brilliant.
Those who don't, aren't so sure;
hence the fuel for debate!.
Duncan McF.
----- Original Message -----
From: "Rowland Carson" <rowil@clara.net>
Subject: RE: Europa-List: 1st Stupid Question
>
>
> >I had the usual pump that comes from Michaels Engineering/Rook Metering
and
> >had horrendous problems
>
> Not everyone has had these sort of problems with resin pumps. I
> wouldn't be without mine, which is the same Michael Engineering
> model, and has already built at least one Europa before I started
> using it.
>
> It's far from perfect - I can think of several improvements I would
> make if I was going to make & market such a device. Switch from mild
> steel pistons to stainless, for instance. And modify the geometry to
> allow re-calibration without so much trial & error. I already changed
> the moveable cylinder clamping arrangement which improved things
> considerably. And I turned up a couple of little fruitwood caps for
> the outlet pipes so they wouldn't clag up from exposure to the air
> when left idle for too long. Another downside of the pump is that if
> you want to switch from regular to slow (or fast) hardener, you need
> to recalibrate as they are different densities.
>
> The accuracy of pumps versus digital scales has been mentioned. You
> should consider the absolute accuracy (dependent on linearity and
> other things) as well as the resoluton of any digital scale. Work out
> the possible error in measuring the mass of hardener and see if it
> will achieve the required accuracy of ratio for small batches to give
> the specified strength when cured. This has been discussed previously
> on the list, so you should be able to find references to it - but I
> can dig out the sums I did for my Ohaus digital scale if anyone wants
> to see them.
>
> regards
>
> Rowland
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