yeah got a can of U-pol Acid #8 and the instructions on the can are rubbish

can I use this on stainless? and once dry just use the red oxide primer as I was orginally going to do? any hints on using it as it's in a stone chip prone place and so I need the paint to bond well

cheers

The datasheet doesn't mention stainless steel, though I suspect it will work ok. It's really designed for materials that form an oxide layer though, you shouldn't really need it on stainless.

Whatever you do, make sure you use it in a very well ventilated area, or use a proper mask! I used #8 to prime the fork legs on my bike recently and I was just using a disposable mask and it made me feel very dizzy for a while, much worse than normal paint aerosols

Aerosol or proper spray?

I have always sprayed etch a little thinner than normal paint, a light flash coat followed by a normal heavier (as in normal) coat, then primer as normal.
Why? I can't really remember, but I think the info was gleaned from a bodywork chap years ago. Never tried it on stainless though, but should work (I think!!)

If you want the paint to bond well, you will have to prep just like you would any steel - the paint needs a proper key to stick.

First prize is sandblasting the part, or else prep with sandpaper

Just today I confirmed a spec of an etch primer to paint stainless in an industrial application and a "sweep blast" was required for prep.

Cheers

Fred W B

[Edited on 18/3/11 by Fred W B]

From U-Pol website:

ACID #8
Ready to Use Etch Primer
ACID #8 is a 1K ready to use etch primer available in
aerosol or 1 litre cans. It is used for priming bare metal
surfaces, this promotes adhesion of paint and
prevents steel from rusting.

ACID #8 is chromate free. Typical applications are over rub through areas prior to painting, on new bare
metal panels or over bare seams before sealant is applied.

Surface preparation and instructions for use ACID #8
can be applied to the following surfaces:-
• Bare steel.
• Aluminium.
• Galvanized and Zinc coated steels.
• Fully cured paint.
• Polyester bodyfillers and G.R.P.
Thoroughly clean and degrease surfaces with a suitable spirit wipe or thinner.
Abrade wet or dry with 280-320 abrasive.
Re-clean, dry and degrease.

Application Shake can thoroughly before use for a minimum of 2 minutes.
Apply 1-2 light even coats.
Allow 3-5 minutes flash off time between coats.

Drying time Allow 10-20 minutes before overcoating.
Drying time is dependent upon film thickness, humidity and temperature.

Over-painting: Under normal circumstances it is not necessary to flat
ACID #8 and should be directly overcoated.
ACID #8 may be overcoated directly with top coat.
However, if the repair requires additional build, primer
filler should be used before topcoat is applied.

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Originally posted by MikeRJ

Whatever you do, make sure you use it in a very well ventilated area, or use a proper mask! I used #8 to prime the fork legs on my bike recently and I was just using a disposable mask and it made me feel very dizzy for a while, much worse than normal paint aerosols

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