Zinc Chromate
Zinc Chromate
Hi all,
I am using zinc chromate from A/C Spruce in a spray can to prime some small parts.
Before spraying, I rough up the surface with a Scotch bright pad and then clean it with MEK or alcohol.
I've noticed however, that the after the primer dries, it's pretty delicate. I can take my fingernail and scratch it right off.
Is there anything I can do to make the primer 'stick' better? Should I alodyne the parts first?
I am using zinc chromate from A/C Spruce in a spray can to prime some small parts.
Before spraying, I rough up the surface with a Scotch bright pad and then clean it with MEK or alcohol.
I've noticed however, that the after the primer dries, it's pretty delicate. I can take my fingernail and scratch it right off.
Is there anything I can do to make the primer 'stick' better? Should I alodyne the parts first?
- Wicked Stick
- Class B
- Posts: 1000
- Joined: Wed Feb 09, 2005 10:00 pm
- Location: KEWB
How long are you waiting before you do the scratch test ?
In colder weather, the primer may not be fully cured enough to be scratch resistant even though it feels dry to the touch.
It really needs like 24 to 48 hours in a 60 plus temp zone to fully cure.
If that doesn't work, try a self etching primer or a two part epoxy primer that is design for bare metal.
In colder weather, the primer may not be fully cured enough to be scratch resistant even though it feels dry to the touch.
It really needs like 24 to 48 hours in a 60 plus temp zone to fully cure.
If that doesn't work, try a self etching primer or a two part epoxy primer that is design for bare metal.
Dave "WS" Rogers
RV-8 (125 hrs & counting)
N173DR
RV-8 (125 hrs & counting)
N173DR
-
- Class C
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- Location: Sartell MN
- Wicked Stick
- Class B
- Posts: 1000
- Joined: Wed Feb 09, 2005 10:00 pm
- Location: KEWB
yes. Clean with alcohol or lacquer thinner. rough it up with Scotchbrite, clean again with thinner. It is ready for paint.
I liked to shoot parts in the evening then let them sit overnight or longer. I heat my shop with wood stove, so would leave the parts hanging over or near the stove.
I liked to shoot parts in the evening then let them sit overnight or longer. I heat my shop with wood stove, so would leave the parts hanging over or near the stove.
Brian
Townsend, MT
Townsend, MT
- painterjohn
- Class G
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Like Brian, I've used SEM throughout my project. It's very good. And for cleaning, you can save some money and get excellent results using naptha, commonly known as Coleman fuel. Just as good but much cheaper than mineral spirits, MEK, etc. The last gallon I bought cost me less than $5.00 at the local sporting goods dept. store.
- painterjohn
- Class G
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- Joined: Mon Feb 27, 2012 9:03 am
- Location: Giddings Texas
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