Cleaning aluminium for painting.

[Neville]

hmm, yes i thought you meant put oil on it!

The neoprene rubber that we use is 2 mm thick, and is the high quality type and not the commercial type (they normally offer 2 grades). I have noticed with the cork ones that they can leak after a while, but then if you dont spend quite a bit of time getting the surface clean and applying the sealant correctly anything will leak. Ive first hand experience of that aswell!

Des , the penetrators are the stainless steel bulkhead fittings with the short elbow type pipes on them that go through the housing. There are 6 of these. Each has 2 o rings. When you are removing them be careful not to put any pressure on the pipe as they are easily broken.

[Scary Des]

I haven’t tried to get them out yet, the only one I looked at looked a little bit solid How do you take them out
Des

[Neville]

Take the hose off, take the locknut off - should be easy so far, then remove bulkhead fitting by turning , any direction (not threaded internally), then when you get it moving you can push it out (from the lock nut side).

It should come out, maybe have to apply a bit of heat. I would remove them and replace the seals (o rings) and clean it up and the hole before replacing it. Only takes a few minutes. The whole hose thing, those adapter bulkhead pipes and the pistin bases is what lets these drives down, the rest of the machine is quite sturdy and doesnt really go wrong unless not serviced.

[Scary Des]

Thanks Neville will do
What do you do to earth bond the rams I’m using jubilee clips and braid at the moment but never really happy with it.
Des

[nugent]

my tuppence worth beings as we spray 80 + sheets ali per day..

must be bare metal ali

desouter or hand sand with 180grit

degrese with cellolose thinners. or 05/66 clening solvent.(proper stuff)

zinc chromate yellow etch is the best mixed 50/50 with acid reducer

new chromate free does work but still in early stages of getting it right ive had so many different formulations to try its un real... but thay all work to a fashion.. zinc chromate being best!!!

leave to dry 5 mins max. any longer its getting all the moisture out of the air..

do not touch or sand down.. apply primer filler 2/3 thin coats not a heavy build up in one hit,,
single pack isnt hunky dory yet to be honest, gets a skin on it to quick due to lag of butanol in reducer so gets a skin over it before curing,,

sand down and gloss accordingly

we do this all day long 7 days a week and never fails us..

sorry oif i bored you all.

ps i can send you 1/2 ltr cans of etch, reducer. mixed primer if you want all foc throw loads more than that away every day..
note once mixed 5 hr pot life then bin it,,

[jwalker]

Nugent, what is acid reducer?

[nugent]

acid reducer is what you part mix with etch,
some etch base's are supplied with activators,
chromate has an acid reducer to stop it being so fierce . and speeds the drying time, flash's of in about 30secs in our enviroment,,,
with out adought the best way to ensure good adhesion..

[jwalker]

Ta.

[Scary Des]

Originally Posted by nugent

.... i can send you 1/2 ltr cans of etch, reducer. mixed primer if you want all foc throw loads more than that away every day..
note once mixed 5 hr pot life then bin it,,

Just spotted this , thanks for the offer I might take you up on that
My main concerns are that this processes might be a little difficult to control in my workshop and that I can get the Ali clean enough before hand, there are lots of nooks and crannies that are a nightmare to get too. International paints advise against me using etching primer and I think this is because the tight working parameters, coating thickness, temp, timing and over painting time. Whereas the stuff (interprotect) they are recommending is very open on when and how it can be used What I really need is something like Jenolite or someone to do it for me Des