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AKZO priming questions

Palamedes

Palamedes

Well Known Member
With regards to AKZO I'm assuming its this you're using; http://www.aircraftspruce.com/catalog/cspages/akzoprimer.php

but that says interior. Can you use it on exterior surfaces knowing full well it will be primed or painted over later?

The reason I ask is I have a lot of little scratches all over the surfaces of the parts that I didn't think to leave the vinyl on and I want those to disappear =)

Also, can someone give me the scoop on how to prime with AKZO?
What equipment do I need?
 
Akzo is a two-part epoxy primer and you shoot it with a primer gun. I used it extensively on my plane and it's very tough. IIRC, it's a 1:1 mix, but don't take that as gospel. You don't need a forced air respirator to shoot it, but you do want an appropriately rated activated charcoal filtered mask. I liked it because it dried fast and was really tough.
 
Thanks for the fast response. I have never done this before, how big of a cup do I need on the primer gun? How fast does it go I guess is the better question?
 
Palamedes said:
Thanks for the fast response. I have never done this before, how big of a cup do I need on the primer gun? How fast does it go I guess is the better question?
Click to expand...

I had a Devilbiss primer gun. Almost any gun with a 1.4mm tip will do fine with this. I'd recommend one of the guns with the disposable cup systems just because it's less trouble. A lot of people have had good luck with the Harbor Freight spray gun, but you do get what you pay for. As for how fast it all goes, it goes quickly if you have your parts prepped and ready to prime. As in all things, I'd practice on some scrap first.
 
Truth is it is a very forgiving product. Your best bet is to just mix some up and see how it goes on some scrap. I have some thoughts for you from my experience:

1. Get one of the $70 spray guns from Rockler or someplace like that. You have to have a plastic cup because it sticks to metal. HF has one some people use - I find their stuff inferior but your mileage may vary. Online is a AKZO spec sheet that tells you the nozzle size to use - the guns usually ship with that size so nothing special.

2. I use a pneumatic shaker to mix the can. It is an HF shaker about $100. In my opinion the stuff is too sludgy to mix by hand; but your mileage may vary. This is a place where HF has the best thing around at that price point. It generates a ton of moisture to run the shaker; I think it will die of corrosion eventually. But I like shaking paint.

3. There are good videos online about spraying primer; coat once in one direction, then repeat going 90 degrees from the first. Watch the edges; they get missed. Watch the things that are bent at angles, they get missed too.

4. Don't goop it on; if it is wrinkly you put on too much. If it is metal showing a lot you put on too little. If it is rough and powdery it was too much air for the paint flow. You gotta play with your setup to get it right.

5. Buy the 3M PPS cups. You mix the material in them, spray with them, then throw the liner away. Can't tell you how much time they save. They go in the mixer too with a little ingenuity. They will also spill all over your mixer if your cunning isn't up to speed (like mine at first). I have the big ones and the small ones. I couldn't get the little primer pistol to work for me so the small cups on the regular gun are awesome for touchup. The big cups can't really get the last half ounce to the nozzle so the small cups get that done for small jobs. You will need an adapter to make the 3M cups fit your gun. 3M has an online list with all the particulars for all the types of guns.

6. I draw up the epoxy with a turkey baster and squirt it into the cup. I used a second baster for the hardener. Never mix them. You can clean both with MEK or something before it dries. Or you can just let them dry and reuse until it plugs up then get a new one. Up to you.

It's a little thought and effort and online purchasing research to get it right when you know nothing about it at the start. But I'm really happy now and I get so much more satisfaction than the spray-can primers gave. It is a better product engineered for this application and it works awesome.
 
I'd always just prep up a big pile of parts, and get them all primed in one session. Akzo is tough enough that you can work with the parts and not worry about knocking the primer off later. In fact, once it's fully cured, it's a bear to remove even with MEK.
 
Not to deviate too far from the original question, but if I was building another plane, I'd do things a little differently:

1. I'd choose an epoxy primer with a color close to what I wanted in my interior (like a nice light gray)

2. I'd only prime parts that were not already alclad, or were on lapping joints or were interior skins. That way my interior would be ready to go, with minor touching up. The plane would be lighter as well. I probably over-primed on my current project.
 
Good advice above, but I see that you are asking about priming the exterior. Personally, unless you discuss and plan this with your painter first, I wouldn't do it. The painter will want a primer that is compatible with his paint, and if AKZO isn't what he wants, he will strip it all off anyways. AKZO is $$$ I wouldn't want it to be wasted.

I primed the inside of my wings and empennage with AKZO. It is certainly tough, but I got tired of the fumes and the hassle. Switched to water-based, 1-part eko-prime for the fuselage, and it is plenty tough for me.

I wouldn't worry too much about what the aesthetics at this point. Even if you don't paint for a while, you can buff and polish it up real nice later, if you want.

Chris
 
Palamedes said:
With regards to AKZO I'm assuming its this you're using; http://www.aircraftspruce.com/catalog/cspages/akzoprimer.php

but that says interior. Can you use it on exterior surfaces knowing full well it will be primed or painted over later?

The reason I ask is I have a lot of little scratches all over the surfaces of the parts that I didn't think to leave the vinyl on and I want those to disappear =)

Also, can someone give me the scoop on how to prime with AKZO?
What equipment do I need?
Click to expand...


For the exterior, most painters will scuff and re-prime (depending on the brand of paint they use) or totally remove the primer. So you a basically adding weight and spending extra time and money.

Trust me, don't worry about all the minor scratches. You won't be able to see them after painting.

I ended up using a primer pistol that I either got from Van's or Cleaveland to do the priming. It works pretty well. It uses a 35mm film canister to hold the paint. It's a little hassle for large jobs, but it sure made clean up significant less effort. You throw the canister in the trash. :)

Also, with most primers, don't overspray. You want a transparent covering, not a solid color. Priming to a solid color can add another 10lbs. Ask me how I know.
 
I have two things to add to this discussion.

All major airframe manufacturers epoxy prime the inside and outside of the aircraft. They do not strip off the exterior epoxy primer prior to applying top coat paint.

A correct application of primer is .8-1.2 mils. A mil is equal to .001". You cannot see through a 1 mil application of primer. If you can see through the primer it is not thick enough and it will not prevent corrosion. Do the research in the product data sheet for application weight per square foot. This will give you real world application weight after the primer is cured. If you determine that that the extra 4 or 5 pounds is too much then I suggest you simply skip the priming process instead of misting on a see through primer coat that will accomplish nothing.
 
To the OP: Do a search on AKZO here on VAF. There are several threads on it that are quite recent and I think you'll find quite a wealth of info.

Bottom line: I wish everything about building was as easy as using and shooting Akzo.....! :)
 
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