Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > 998 / 996 / 916 / 748 > Chromatic primer

[Jon]

Anyone know of a place to get my mag wheels re- chromatic primed.( not sure of spellng)

[Edited on 19-4-2005 by Jon]

[AK]

Jon - try Andy @ Pitstop Paint

http://pages.eidosnet.co.uk/pitstopm...cle/page8.html

did all the work on AK's tricolour & does many different types of paint finishes, on all sorts of bikes.
Lovely bloke, so lovely in fact, he is going to take a day out of the paintshop to ride our bike at Cadwell!

Say we said to call

Charlotte

[rob748b]

You can try Belmont Metal finishing, they were on about it when i picked up my wheel, really nice blokes. They painted my Mag and they charge £35 per wheel, did a really good job on it to

http://www.belmontmetalfinishing.co.uk/

Cheers

Rob

[Felix]

I don't there is such a thing as a chromatic primer. The process I think you're referring to is called chromatic conversion coating. It's a chemical process, not a paint application.

Presumably, you're asking this because of magnesium. As far as I know, Dymag will do it. Don't know if they'll only do the conversion coating without the painting afterwards.

You can also try Surface Engineering Association, which list a number of companies that perform this process. I remember speaking to Ingram&Glass about this a couple years back. The bloke I spoke to was Micheal Glass (MD) at 01483 415 262.

[RickyX]

The stuff you want is Alodine 1200 - speak to a friendly person in the aircraft industry and they might be able to get hold of some.
It's not usually sprayed on, it is applied with cloths and then the excess wiped off.
It is a substitute for chromic acid anodising - this is done in a chromate tank and you'll need somebody special to do this.

R X

[skidlids]

Oxford Industrial Finishers (OIF) In Eynsham do it, they do all my powder coating for me.

[Felix]

So, Ricky, can you use Alodine on magnesium? Does it accomplish the same as the proper process, i.e. from a corrosion barrier? Can you then use any ordinary paint process as a top coat?

An amazing amount of knowledge floating around these parts.

[Jon]

Thanks for the replys all. I'm spoilt for choice now. I think I'm going to have a word with Yeti, he's ex RAF and might know of a source

[RickyX]

Felix,
I was wrong...Alodine 1200 is not listed in my source manual for magnesium alloy. The process still involves chromic acid conversion but appears to be slightly different
Here is how to do it:

All magnesium alloy surfaces that have been reworked must be cleaned and treated with a
conversion coating.

Materials Required:
(1) Chromic Acid
(2) Calcium Sulfate
(3) Cheesecloth
(4) Solvent - General Cleaning of Metal (Series 88)
(5) Sodium Hydroxide
(6) Sulfuric Acid

Prepare the Solution
NOTE: The solution must be prepared and stored in polyethylene or glass container.
(1) Fill a clean polyethylene or glass container to the 9/10 level with distilled water.
(2) Slowly add 1-1/3 fluid ounce (39.5 milliliters) of chromic acid per gallon of final solution.
(3) Add 1 fluid ounce (29.6 milliliters) of calcium sulfate per gallon of final solution.
(4) Fill to final solution level with distilled water.
(5) Stir vigorously for 15 minutes to ensure that the solution is saturated with calcium sulfate.
(6) Let solution stand for 15 minutes to allow undissolved calcium sulfate to settle to the
bottom of the container.
(7) Decant to another polyethylene or glass container without transferring undissolved calcium
sulfate.
(8) Adjust pH with additions of Sodium Hydroxide or Sulfuric Acid to bring within a range of 1.2 to 1.6.

Prepare the surface for conversion coating.
(1) Mask all surfaces likely to be affected by running, dripping, or splashing of the solution.
(2) Seal or plug all holes, gaps, and inlets to assemblies containing honeycomb or foam
plastic with suitable sealing or caulking material or rubber plugs to prevent entry of any
solution.
(3) Wipe treatment area with dry clean cheesecloth to remove loose particles and residue.
(4) Wipe with cheesecloth dampened (not saturated) with solvent, Series 88. Repeat using clean cheesecloth until no visible residue transfers to the cheescloth.
(5) Allow to dry to a minimum of 15 minutes.

Apply the conversion coating
CAUTION: SEVERE RUBBING OF WET SURFACE CAN CAUSE COATING DAMAGE.
(1) Apply solution by swabbing with brush, swab, swatches, cellulose sponge, or white blotting
paper. Maintain a continuous wet film until metal surface becomes dull golden or dark
brown in color. Discard used solution.
(2) Rinse with cold clean water.
CAUTION: DO NOT DIRECT HIGH PRESSURE AIR TO SURFACE WHILE DRYING
AS COATING IS STILL SOFT.
(3) Allow to dry at ambient temperature. If possible, use low pressure air to dry the surface.
(4) Restore the original finish as soon as possible after drying. Handle parts with clean gloves
and keep parts clean and dry to avoid surface contamination.

[Jon]

Thats brilliant Ricky. I've got some cheese cloth, plastic bag and water. Just got to get the rest of the stuff now