process for painting an aluminum porta (outboard) bracket

by **Admin - Shine** Tue May 31, 2016 8:04 pm

Questions from an email. Customer i painting an aluminum outboard bracket.......

Preparation
1. Porta Bracket has been sandblasted to remove all coatings.
2. Tape off areas of bracket that will not receive paint (i.e, the polyethylene
bearing).
3. Coat all aluminum surfaces with Alumiprep 33 solution (one part Alumiprep, two
parts water). Let stand for 2-5 minutes, ensuring the surface stays wet the entire
time. Scrub with scotch brite pad to enhance cleaning.

Yes, to scrub with scotchbrite but not copper or steal wool

4. Rinse thoroughly.
5. Coat all aluminum surfaces with Alodine 1201 (undiluted). Let stand for 2-5
minutes, ensuring the surface stays wet the entire time.
6. Rinse thoroughly.
7. Dry completely.
Priming
1. Mix equal amounts of surfacing primer base and activator.
2. Let stand for 30 minutes.

20 minutes is fine when it this hot.

3. Add 10-20% reducer by volume.

you can reduce more if you want, i would start with 20% and go up from there if you want more

4. Apply 3 coats of primer, waiting 1-3 hours between coats.
Question: The product data sheet says the pot life is 8 hours @ 72F. Does this
mean I should mix enough to spray all 3 coats and let it sit in the gun until I finish
the 3 rd coat? Or mix enough for each coat, and clean the gun between coats?

I like to mix what I will use for each application. When your done spraying, empty primer from gun (if there is any left) then run some reducer through the gun. You dont have to clean the gun, just run reducer through it while its sitting

5. Let final coat cure for 16 hours and then sand with 220 grit.

220 is good, it powders up the primer easy and the scratch marks are not too deep

Painting
1. Mix equal amounts of topcoat base and spray activator.
2. Add 10-15% reducer by volume.

10% is good,

3. Apply 2 coats of topcoat, waiting 45 – 90 minutes between coats.
Question: The product data sheet says the pot life is 4 hours @ 72F. It also
says best results are achieved if the product is used within 2 hours of mixing, and
a fresh mix is recommended for final coat. Is it ok to let it sit in the gun until I
finish the 2nd coat? Or mix enough for the first 2 coats, but only add enough to
the gun for each coat, and clean the gun between coats?

same as with the primer, I would not clean the gun completely, just run some reducer through it

4. Apply final coat.

pretty simple.

Have a test piece of something to spray first so you can dial in your gun pattern