D

Dancer

Member
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
 
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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.
 
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.
 
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
 
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 :)
 
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.
 
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
 
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?
 
jcoloccia said:
I'm curious...did you find that the Yellow went on a lot better too, Paul, or is it just me?
Click to expand...

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

Paul
 
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...
 
Are you guys also cleaning the metal with Alumiprep or something comparable? Before using the self etching rattle can?

Lance
 
More than you ever wanted to know about Zinc Oxide

Warning! Long!!!

I've used green Tempo Zinc Oxide from Aircraft Spruce on my empennage, wings and fuselage. I didn't want to destroy the alclad, so here is my procedure:

1. Clean each piece with Dawn dish soap, applied with a sponge.

2. Etch each piece with Alumiprep. I soak small pieces in a plastic container filled with Alumiprep. I use a spray bottle and sponge to apply the Alumiprep to large pieces like skins.

3. Rinse off the Alumiprep with water and dry each piece.

4. Spray the Tempo Zinc Oxide and let it dry at least overnight. If you can let it dry even longer, it seems to get harder with time.

After using something like 30 cans of the stuff, here are my impressions:

1. Tempo zinc oxide is a complete hassle to use because the cans have a strong tendancy to clog. I never use it below 70 degrees and I try to have an extra spray nozzle on hand when I use it. During the winter, I keep the cans in the house the night before I spray them.

2. I usually get my best results if I can use an entire can during a single session. After using a can, I turn it upside down and spray until just the propellant comes out to try to clean the nozzle and tube. Sometimes this allows me to use the remainder of the can at a later session, and sometimes it doesn't.

3. The longer you can let it dry, the harder it gets and the better it sticks. I always let it dry at least overnight before riveting, and if you can wait a couple of days, that's even better. I realize the stuff might stick better if I roughed up the surface with a scotchbrite pad, but I haven't wanted to destroy the alclad.

4. If the temperature is too hot, say 90 degrees, the stuff will have a rough texture when it dries. I think what is happening is that it partially dries before it hits the metal. It seems to stick OK, but I don't like the bumpy texture.

5. I get my best results from the first part of the can. As the can runs out of propellant, the spray pattern isn't nearly as nice, and it goes on a little blotchy. Fortunately, this stuff is going on the inside of the plane, not the outside, so I don't worry too much about how it looks.

So, the big question... Would I use it again? Maybe. I think I'd try the self-etching yellow stuff mentioned by Ironflight that you get at West Marine and see if that works better. At least you wouldn't have to hassle with the Alumiprep. I have one large skin left to go on my project, and some interior parts, so I'll use the four cans of Tempo Zinc Oxide I have in my garage, but after that I think I'll try the self-etching yellow stuff from West Marine.

Edit: According to the West Marine Web site, the self-etching stuff isn't available in California, so it looks like I will continue to use the non self-etching Zinc Oxide from Aircraft Spruce. The self-etching stuff on the West Marine web site is $15.99. The Aircraft Spruce web site shows Tempo Zinc Oxide at $7.00 per can.
 
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Re: things being available in California

I'm not saying nothing....all I'm saying is I happen to live in California and somehow some parts of my plane where primed with this stuff. Ya' fallah? :cool:

Also in this thread somewhere is a link I posted that I've bought products from in the past.

YMMV
 
Top Coat over Tempo 5606

I have a specific question on using a particular product in my research for an interior* primer. (So I don't start yet another primer war). I haven't decided on which primer yet, it's more of a "if I use this one, and I did this, what sealer product/brand should I use?", kinda question.

Since I live near salt water, I understand that it would be beneficial to add a "top coat" or sealer over a rattle-can Zinc Chromate or Oxide primer for added corrosion protection. This sounds reasonable. Assuming I use Tempo 5606 self-etching primer on interior parts, what kind of top coat or sealer would I use? Specific brand names would be helpful.

Also, is there any harm (to the alclad layer) with applying just a very light coat of self-etching (or non-etching) primer and maybe even sealer over the alclad surfaces? I agree it's probably not needed, but it would make it look consistent and potentially help with resale.

John Edwards
RV-9A Empennage

* This is only for interior protection; I will probably use a different product for painted surfaces.
 
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