Aluminum primer question

[rjrobin2002]

If I clean aluminum with Aluma Bright "Hydrofluric Acid" and then prime with this Zinc Chromate Primer, should I be good to go on painting?


http://www.globalindustrial.com/p/j...=Liquid-Coatings-shop&infoParam.campaignId=WP

 

[rastiss]

what are you working on first of all(besides just calling it aluminum)?

 

[rjrobin2002]

Bumpers, light bars, nerf bars, dash panels, rims, tool boxes.

 

[rjrobin2002]

Here is a dash we cut for my friend.

 

[rjrobin2002]

http://classicbroncos.com/forums/showthread.php?t=214141

 

[TwoDalesDad]

Why use zinc chromate on aluminum...when what you need is an aluminum SEALER FIRST... PPG... Then spray as needed.....WHY NOT POLISH THE BUMPER? ...

 

[allenfahey]

I would use a reputable paint line primer on it. Depending on what is wrong with the aluminum you could do as TwoDalesDad said and spray sealer, let flash then paint. Check the TDS (technical data sheet) on the primer to see if it's compatible with aluminum as a substrate. For instance according to the TDS sheet for PPG's DP40 you can directly spray on aluminum mixed as a primer or sealer. Some paint lines like Spies you spray a 1K or etching prior to primer or sealer.

 

[rjrobin2002]

I hate polished aluminum due to oxidation. I had heard read a bunch times that zinc chromate is the only primer you are suppose to use for aluminum. I also read about needing these 2 steps before priming.
http://pc.dupont.com/dpc/en/US/html/visitor/common/pdfs/b/product/dr/ChromaSystem/H-19290_225S.pdf

http://pc.dupont.com/dpc/en/US/html/visitor/common/pdfs/b/product/dr/ChromaSystem/H-19291_226S.pdf

Then is it saying these are suitable primers when it says :
Undercoats
DuPont 4001S
™
/4004S
™
/4007S
™
2K UltraProductive Primer-Filler
DuPont 4904S
™
2K UltraProductive Primer-Filler
DuPont 1141S
™
/1144S
™
/1147S
™
2K Urethane Primer-Filler
DuPont
™
URO
®
1120S
™
/1140S
™
Primer-Filler
ChromaPremier
®
22860S
™
Etch Primer
VariPrime
®
615S
™
Low VOC Prime ‘N Seal
®
2710S
™
/2740S
™
/2770S

 

[rjrobin2002]

This is from wikipedia: An interesting Ford fact also

"Zinc chromate, ZnCrO4, is a chemical compound containing the chromate anion, appearing as odorless yellow solid powder.[2][3][4] It is used industrially in chromate conversion coatings, having been developed by Ford Motor Company in 1920s.[5] Exposure to zinc chromate can cause tissue ulceration and cancer.[1][3]

Its use as a corrosion resistant agent was applied to aluminium alloy parts first in commercial aircraft, and then in military ones. During the 1940 and 1950s it was typically found as the "paint" in the wheel wells of retractable landing gear on U.S. military aircraft, not because of its glaring yellow-green color symbolizing anything, but to protect the aluminium from corrosion."

 

[rjrobin2002]

This is from the TDS of my epoxy primer I use.

For Aluminum: Wash with detergent, rinse and dry well.
Clean with Nason® 441-05™ (or locally permitted cleaner).
Clean and etch with Alumiprep #33 per label instruct
ions. Allow to dry before applying Nason® 491-16™

 

[bmc69]

zinc chromate primer is generally a good choice and certainly only really works well when applied right after the acid wash.

We have our own chromate conversion tank here at the shop for all the smaller parts (less the 18" long) ...and for the larger ones we use a product from Pro Line (owned by Sherwin Williams now) that has proven superior to zinc chromate primers, a strontium chromate 2-part epoxy primer. Same as with the zinc chromate products, the aluminum needs to have been freshly blasted and/or etched. l

 

[rjrobin2002]

zinc chromate primer is generally a good choice and certainly only really works well when applied right after the acid wash.

We have our own chromate conversion tank here at the shop for all the smaller parts (less the 18" long) ...and for the larger ones we use a product from Pro Line (owned by Sherwin Williams now) that has proven superior to zinc chromate primers, a strontium chromate 2-part epoxy primer. Same as with the zinc chromate products, the aluminum needs to have been freshly blasted and/or etched. l

Do you top coat right over the stronium chromate primer, or use a tie coat primer between? How long do you wait after spraying the primer before top coating?

 

[bmc69]

Do you top coat right over the stronium chromate primer, or use a tie coat primer between? How long do you wait after spraying the primer before top coating?

The strontium chromate epoxy primer we use must be covered with top coat within less than 12 hours. After that ... a major sanding operation is required.