So, if i only would get a shurflo, what screws would that be that would
need replacing?
I still have some titanium rod round here that i might get machined, or
buy titanium screws....
thanks
ST
>
> No probs, I'm glad to help someone else avoid having to go through all
> the trial and error I did. I found two main brands of 12V "on demand"
> diaphragm pumps for water supply in caravans. Diaphragm pumps are more
> efficient, and more suited to high pressure/low volume than centrifugal
> impeller pumps. This means for our "small" sized pumps a diaphragm type
> is a better choice. The two brands are Shurflo, and Flojet.
> Unfortunately all the Shurflo's are built the same and are not FeCl3
> resistant only because they use stainless steel screws to hold the
> little plastic pistons on the diaphragm. The Flojet apparently does not
> have this drawback with all materials are resistant. Here is a copy of
> the reply I got from Flojet customer support when asking about chemical
> compatibility.
>
> "The wetted materials are:
>
> - Polypro/galss plastic for the housing and check valve assembly
> - Poly/glass inner piston
> - Santoprene diaphragm
> - EPDM check valves
> - EPDM switch diaphragm
> - Santoprene seal ferrules
>
> Rgds,
> Roy"
>
>
> I bought a Shurflo pump over the Flojet because at the time I didn't
> know better and they had more details on the datasheet. Considering the
> Shurflo flaw, it lasted a good 3 months before the SS screws finally
> gave way in the CuCl2. Luckily for me, only the ball bearing was
> damaged, so I was able to remove the last remaining threads of the SS
> screws and replace them with plastic coated machine screws. I managed
> to save my Shurflo pump and its been in operation for a few months now.
> The Flojet should be ok.
>
> http://www.flojet.com/prodInfo/overview/81000-233_ds.pdf
>
> There are more powerful models than this one but the price doubles
> because they are considered "industrial". I can't see any major
> differences between them that would justify the price jump. In any case,
> you have to choose the right nozzles to get the best performance from
> your pump. Mine is operating at 200 kPa (2.0 Bar) , which was chosen for
> maximum power transfer without overloading the pump motor. Electrical
> power = 12.5V @ 6.5A. Running time approximately 1/2 hour before case
> temperature rise reaches 60°C. Etching time normally is only a few
> minutes however.
>
> For your nozzles, see http://www.spray.com Considering I'm in Australia
> it only took two weeks to order three nozzles via their Australian
> representative ( A$10/nozzle). I was surprised to learn that the spray
> nozzle business is setup for selling small quantities. The factory had
> to especially make my nozzles because they didn't have them in stock,
> anywhere.
>
> Adam