responding to
http://www.rittercnc.com/metalworkin...ts-487279-.htm
DA wrote:
Don Foreman wrote:

A phosphoric acid wash never hurts either - like Aluma-Prep-33 (or
simple water softener resin cleaner - virtually the same stuff)
(Phosphoric acid and ethyl polyol)

This stuff makes a huge difference with aluminum. It completely
degreases, and leaves a surface that really holds paint. It makes any
paint wet better and flow out nice and level. Aluma-Prep 33 is made
by PPG or Ditzler and is found at places that sell paint and supplies
for auto body work.

Thank you for the reference. Yes, I would much prefer something that works
yet makes no fumes (or less than paint thinners, anyway).

However, I was looking for sources for the cleaner and found this page at
Henkel http://bit.ly/dFiEMk that describes a product called Turco
ALUMIPREP 33 'Cleaner and Conditioner for Aluminum' - judging by
similarities in the name and that they do mention phosphoric acid, I think
it's the same product.
It looks like they do NOT recommend it for castings:

"Turco Alumiprep 33 should not be used on high copper bearing aluminum
alloys or aluminum castings."

Not on castings? Can someone who worked with phosphoric acid cleaner
comment on that please?

Or, and I do get Rich's comment about this not having to be
hospital-clean. Indeed it probably shouldn't be. But to paint these parts
properly is just a part of the fun for me - it is, after all, a hobby
project. That's why I keep bugging people with questions

--
DA in PA