primer: rattle can Zinc Oxide

[Dancer]

I've read the hundreds of posts regarding primers. I still need some help.
I want to take the middle ground between no priming at all and the 3 step (cleanser, alodine, primer or epoxy).

Does the rattle can of Zinc Oxide actually provide any corrosion protection or is it just an adhesive for people wanting to add a top coat?

Also, I haven't seen any posts regarding Sanchem's SafeGard 6100 (safe alodine replacement) since January of this year. Why did this product seem to drop off the map?

Thanks,
Lance

[N674P]

Zinc Oxide should provide at least as much corrosion protection as any other single stage product. Something else you might look at is SEM self etching primer. It comes in rattle cans, and in quarts. It goes on real nice, and is fairly durable, but wipes right off with MEK.
The nice thing about bulk single stage is when you're done spraying, you can pour the excess primer back in the can.

[Kyle Boatright]

One thing that doesn't get differentiated enough is the issue of corrosion prevention vs primers. Some products do both well, but the easy to apply products are more of an either/or proposition.

Zinc Oxide (and zinc chromate) are both excellent and lightweight corrosion preventatives. They will give you much more corrosion protection than any of the grey rattle can primers. They will give you poorer paint adhesion than the grey rattle can primers.

So, your best compromise will be to use zinc oxide on interior structure that won't get painted. Use it on faying surfaces inside the cockpit too.

Later, you can shoot a better *primer* on the stuff that will get painted.

[Dancer]

Thanks guys that's pretty much what I'm looking for (some corrosion protecton on internal parts that wont get painted) and is quick and easy to apply.

I see Aircraft Spruce sells Tempo Zinc Oxide in rattle cans, it doesn't appear to be self etching though.
How does SEM self etching primer differ from that? Same corrosion protection as Tempo Zinc Oxide but with self etching?

Do I need to use a cleanser like alumiprep?

Thanks for all your advice.

Lance

[jcoloccia]

I believe on Spruce's Tempo Zinc Chromate is non-etching. Tempo does manufacture a VERY complete line of primers - Zinc Phosphate/Oxide/Chromate in etching and none etching. Also in different colors. The Tempo Yellow Zinc Chromate seems to go on MUCH smoother than the green, for example...I believe yellow is it's natural color and green was later mandated by the airforce to cut down on cockpit glair (hence "chromate green"). Maybe the pigment screws up the delivery...I dunno...

www.reddenmarine.com

Or any other marine supply house. In this case, Spruce actually has pretty decent prices but their selection stinks. Also, you're going to have to get over little boat on the label instead of an airplane

[Kyle Boatright]

Self etching means it sticks better. That isn't very important in a non-wear area such as interior structure, but it is important for areas you plan to paint.

The SEM and other rattle can primers are self etching. That means they stick well and will hold paint well. BUT, they don't offer the corrosion protection of any of the Zinc Chromate (ZC) or Zinc Oxide (ZO).

Why are the ZC and ZO products better at corrosion prevention? Because zinc is a sacrificial element and will corrode before the aluminum *and* leave an oxidized layer on top which will protect the aluminum. ZC was the standard corrosion protection product for many years, and is still an outstanding product for that purpose.

Make sure you check the safety instructions on all of these products. While your exposure isn't going to be like that of someone who worked for (say) Grumman in the '40's, the stuff still isn't good for you.

[Ironflight]

When I got started on my tail kit a few years back, I also wanted a primer for interior stuff that would never see top coat. I went to our aviation supply house, and bought a can of the Tempco green stuff, then to West Marine and bought a can of the Tempco yellow self-etching. I think I also went to the auto parts store and bought a can of green non-self etching that, after research on the internet, I discovered was also made by Tempco. The bottom line was that after some basic spray and scratch tests, the stuff from West Marine went on better, stayed on better, and cost half as much.

If you're just getting started, doing a little testing to satisfy your own curiosity won't cost much, and the stuff you don't like, well, use it around the house....

Paul

[jcoloccia]

Paul's spot on, as usual. The Tempo 5606 and 5605 (Yellow and Green self etching zinc chromate designed for boats...under water use) takes a day or two to really fully set (convert, cure, whatever it does), but once it does it's tough as nails....super hard.

The non self-etching (if you don't etch yourself first) scratches off with a fingernail...even this morning, 1 year later.

I'm curious...did you find that the Yellow went on a lot better too, Paul, or is it just me?

[Ironflight]

Originally Posted by jcoloccia

I'm curious...did you find that the Yellow went on a lot better too, Paul, or is it just me?

Definitely, the yellow went on way better - I've got a can or two of green that someone can probably HAVE.....dreadful stuff!

Paul

[N674P]

Wow. Sounds like what I'm really after is that zinc oxide self etch yellow. All I have left on the wings are the ailerons and flaps, but that could take a can or two...