Zinc Chromate Priming Safety

[Jarrett]

So after using self-etching primer I have decided to change over to Zinc Chromate primer (rattle can) and this has been giving me way more consistent results. Once I move onto the wings I'll be changing over to an Epoxy primer or something similar. I'm wondering what safety precautions I should take as this stuff is pretty toxic. Obviously, when I prime I where a respirator, gloves and safety glasses as when enhaled this stuff can cause cancer(would a paint suit also be a good idea?) After the part has been primed, should I still be wearing a respirator around the parts? I'm assuming I should be fine, as it's not in its gaseous phase, but I just want to double check. Furthermore, should I be wearing gloves when I touch these primed parts? Lastly how long do most people wait to start working these parts (dimpling, riveting, etc.)? From what I've read online, I see that 3 days should be okay. Thanks!

[mike newall]

STOP - Now !

There are better products without chromate in.

Change and you will be healthier for it

[Jarrett]

Hey Mike, thanks for the input. I think that's probably a good idea (if I have to ask those questions it might be a good idea to stop). Luckily I only did two parts with the stuff and it's all been removed for consistency (I'm doing the tail cone, so I want all the primer to be the same). What rattle can primers would everyone suggest? I'm currently using the duplicolor self-etching primer and it has given me okay results. I'm thinking I could maybe change my surface prep? I clean with lacquer thinner before priming. I'm thinking of maybe using acetone and walking with water beforehand? Thanks!

[wirejock]

Originally Posted by Jarrett

Hey Mike, thanks for the input. I think that's probably a good idea (if I have to ask those questions it might be a good idea to stop). Luckily I only did two parts with the stuff and it's all been removed for consistency (I'm doing the tail cone, so I want all the primer to be the same). What rattle can primers would everyone suggest? I'm currently using the duplicolor self-etching primer and it has given me okay results. I'm thinking I could maybe change my surface prep? I clean with lacquer thinner before priming. I'm thinking of maybe using acetone and walking with water beforehand? Thanks!

Tons of threads on primers, priming and prep. Almost as many as us.
Prep is a pet peave. Personally, I believe, and I spent a huge amount of research, surface must be hydrophillic. Aka, water break free. That means removing aluminum oxide and spraying paint before it reforms because it's hydrophobic.

Scuff with scotchbrite.
Debur and dimple
Scrub thoroughly with gray scotchbrite and Bon Ami cleanser. No worries about solvents getting on your skin or in the environment.
Rinse
Dry
Shoot within 2 hours.

Backing down off my soapbox.

[Steve Iacoviello]

I suggest reading Van’s opinion on primers. Not using any primer is OK or alodine and epoxy on the other extreme, your choice. Not sure anyone will notice if you change primers during your build. Everything is toxic but it typically depends on concentration and time. Spraying a few cans of zinc chromate would not worry me. Breathing it 8 hours a day for 20 years would. Let’s face it, the gasoline we pump in our cars is carcinogenic. For my build I used self etching rattle can for the small parts and a two part wash primer for the bigger parts. I cleaned with water followed by acetone which dries quickly. My opinion is to keep building and not over think the small things.

[David Paule]

Remove blue film,
Scrub surface with maroon Scotchbrite,
Wipe clean with lacquer thinner or denatured alcohol,
Spray with rattle-can SEM.

Consistently good results.

Dave

[wirejock]

Oh yea. I forgot about PPE.
Consider a HobbyAir. Pretty awesome. Positive pressure respirator. Blows filtered air into your mask. Pkus you look cool!
If not, buy good filters. 3M #60926. Store the respirator in a zip bag with a dessicant pack. The filters are designed to absorb organic compounds so leaving it out reduces the effective life. Label the cartridges with a date and replace annually or sooner depending o usage. I retire mine to a second mask and use it for dust or yard work.

[BillL]

Originally Posted by mike newall

STOP - Now !

There are better products without chromate in.

Change and you will be healthier for it

Please provide references for genuine corrosion testing that included 2024 to justify this statement.

[mike newall]

2024 as we use has a flash coat of pure aluminium which gives it excellent corrosion protection.

Vans don't normally prime their interiors.

Now - primers.

4 basic types

Zinc Chromate - has a chemical affinity to the aluminium, usually has an acid etch component to aid adhesion and creates a good protection, but as it is a heavy metal, is rather damaging to us humans...

Non Chromate etch - uses an acid to etch the surface and uses a good film thickness to provide a great protection of the substrate.

Epoxy - still has an acid element to etch the surface but uses a much thicker film of paint to protect the substrate.

Alodine etc - Chromic conversion of the surface layer to provide a very robust corrosion protection but very nasty chemistry.

Choice is yours......

I won't go anywhere near chromate thanks - my Father was poisoned with chromium in a laboratory fire many years ago at the University he worked at and suffered for the rest of his life.

[lr172]

Originally Posted by mike newall

2024 as we use has a flash coat of pure aluminium which gives it excellent corrosion protection.

Vans don't normally prime their interiors.

Now - primers.

4 basic types

Zinc Chromate - has a chemical affinity to the aluminium, usually has an acid etch component to aid adhesion and creates a good protection, but as it is a heavy metal, is rather damaging to us humans...

Non Chromate etch - uses an acid to etch the surface and uses a good film thickness to provide a great protection of the substrate.

Epoxy - still has an acid element to etch the surface but uses a much thicker film of paint to protect the substrate.

Alodine etc - Chromic conversion of the surface layer to provide a very robust corrosion protection but very nasty chemistry.

Choice is yours......

I won't go anywhere near chromate thanks - my Father was poisoned with chromium in a laboratory fire many years ago at the University he worked at and suffered for the rest of his life.

While I am only familiar with a few epoxy primers, I don't believe any of them have an acid for etch in their formula. In fact, at least one recommends against applying to a surface that received an acid etched treatment (suspect this is due to the possibility that the user will not fully rinse the surface, preventing proper adhesion). Most all require mechanical etching (i.e. sanding or scuffing) prior to application for proper adhesion to aluminum.

Larry