R

R Eleew

Member
I am trying to gather as much information about primers before I get my tail kit. What is the primer of choice in the RV community? I plan on priming all inner surfaces of the Emp. and Wings and the contact points in the Fuse.

I would like a self etching primer that does not need to be activated. Something you can pour and shoot in small amounts. I may be asking for too much???? Oh ya....I want it to be the most durable too....I live in the deep South...Katrinaville!

Any suggestions?

Thanks!:cool:
 
Hi,

Welcome to the forum. There are several different options here. I use a self-etching primer made by SEM. I mostly just use the rattle cans so I don't have to go through so much setup and cleanup for just a small batch of parts. However, when I did have larger number of parts or large surface areas that needed priming I used a Harbor Freight el-cheapo HVLP gun and PPG self-etching primer. HVLP is great for keeping the overspray down. You can usually find either or both of these at auto paint stores.

Some folks use a self etching primer from NAPA. They often put it on sale for half price (around $3.50 a can). I bought a bunch and then found out I didn't like it. It seemed to go on much thicker than what I was used to. However, other people seem to like it. Maybe I was doing something wrong.

Use the search feature of this forum and you will find a ton of hits on this subject.

BTW, I started building in "Katrinaville" (actually, Slidell). I moved to middle Georgia about the same time that Katrina hit. Where are you?
 
Oh yes...the primer wars

I"m a less is more guy and frankly I'm only doing primer for resale. There's a bazillion '46 model aircraft still flying corrosion free with no primer at all.

I'm using the NAPA 7220 with good results, it's easy to shoot, tolerant of extreme temps when applying (humiditity is a different story) and is very durable for rattle can. I love epoxy prime and I plan on using it on my interior, but I'm not patient enough to breakout the paint gun for a couple of small parts plus the epoxy primer seems heavy to me.
 
Here is a short story on spray self-etch primers. We sell them all except the NAPA product. Lots and I do mean LOTS of info in the archive files.

NAPA 7220 is packaged by Sherwin-Williams company. Sherwin-Williams 988 is the same blend but slightly lighter in color. SW can has a special nozzle that spays a little nicer pattern. Both dry quickly, not real hard, and neither has any corrosion protection at all. I like the SW988 better. SEM also makes a self etch that is nice and works OK as well.

Dupont makes a product 4115S which is a self-etch that actually has a little corrosion protection (but not much). Also with special nozzle and nice pattern, drys quick and seems more durable to me than any of the other products. This is the one I prefer by far. Probably $10 a can but it goes a long way. Normally two light coats is plenty. Does smell stronger than any of the products above. The 4115S is a sorta olive color and they make a light gray which I think is 4114S.


None of the self etch rattle cans are intended to have any corrosion protection as they are designed to be topcoated. In general, most primers do not provide corrosion protection by themselves and depend on the topcoat to seal out the elements. (a few exceptions) All of Vans QBs come with Sherwin Williams self etch (not the same as SW988) so I doubt you are really adding any protection with the rattle can over what is already there.

All of the rattle can products can be easily wiped back off with a rag and lacquer thinner so that tells you there isn't much there.

The two part epoxy primers are the best from this standpoint and way better than any rattle can product for corrosion protection. If you want corrosion protection this is the better route but more trouble, expensive, and heavier. Spruce has seveal products including some water base stuff.

Attached is a picture of the Dupont rattle can product. FYI, the other is a door jam clearcoat product that is a high gloss clear that will really dry hard and durable over almost any topcoat. I did my panel with the Anodize Grey over the 4115S Dupont and then clearcoated with the high gloss and it looks like a high dollar auto finish. (don't have much panel showing so gloss isn't a problem.)


The SEM 39133 is not a self-etch but is made for flexible stuff like the carb air box or other fiberglass/plastic kinda stuff.



All of these products and more should be avialable at any Automotive Refinish Color store and you should get a lot of good advice as well. Look for someone that sells Dupont, Sherwin Williams Automtive, or PPG Ditzler products as these will typically be specialty suppliers and know the products well.

If you can find a store that sells Nobel or USAir (aircraft specialty paints) they have a couple of rattle can products as well.

Hope this helps and remember,.... it's just one opinion,...lots more out there.

Bill S
7a finishing
 
Primer choice depends on how much corrosion protection you want, how much you are willing to spend and how much hassle you want to go thru.

A couple years ago Van's reported on a primer test they ran. Hung some parts under an outdoor stairway, one with no protection, another with a 2 part, probably epoxy, and a third had a self etch primer, I believe--I think it is what they use in the QB kits. Left the parts in the weather for quite awhile and it rains about 45-50 inches a year in western Oregon, cloudy and damp from November 1 thru April; this year all thru May.

At the end of the test, only the unprotected piece had any sign of corrosion.

Napa self etch primer is easiest to get, easy to use. 2 part epoxy is a hassle, you need to estimate how much you will need to use and mix that amount and will sometimes find you mixed too much & the excess gets tossed or you mix too little and have to mix more, you then mix too much and the excess gets tossed. Consider at least 10% toss loss when you compare costs. Middle ground in hassle and protection is zinc chromate if you can find it & you shoot it with that little gun Van's sells for about $25 that uses a film can as a paint cup.
 
If you don't like the self etch...

...just wipe it with acetone and/or MEK and it's instantly gone....:)

The 2-part epoxies are far more durable and chemical resistant...

Akzo from AC Spruce is one of the easiest to use... 1:1 mix and easy to spray. Use it in a thinner coat that described above... it should be almost transparent when correctly applied (0.8 to 1.0 mill thick) - No top coat needed on this one.
 
I use Stewart Systems primers

R Eleew said:
I am trying to gather as much information about primers before I get my tail kit. What is the primer of choice in the RV community? I plan on priming all inner surfaces of the Emp. and Wings and the contact points in the Fuse.

I would like a self etching primer that does not need to be activated. Something you can pour and shoot in small amounts. I may be asking for too much???? Oh ya....I want it to be the most durable too....I live in the deep South...Katrinaville!

Any suggestions?

Thanks!:cool:
Click to expand...

Stewart systems bought the old "Aircraft Finishing Systems" primers and paint. What is cool about this stuff is it's water based and isn't going to poison you.

It is also light. I use the EcoEtch to clean and etch the aluminum wash off with water and let dry and then shoot the primer. It can't be easier except if you use a self etching primer.

It will wipe off with MEK if you rub it enough but I don't plan on dumping MEK in the innards of my plane!

Check it out.
 
primer

I use the self-etching rattle cans from Aircraft Spruce. I can't remember the particular name and I'm not at home. I am only putting primer where two surfaces mate during construction. Later I will switch up to something with a little more Umph for the interior and exterior paint.
 
A brief lesson:

A primer is for helping finish paint adhere.

A product designed for corrosion protection is something else entirely.

Some products (two part epoxies) offer both properties, at a cost in money and time.

If I was doing another RV, I'd use zinc chromate for corrosion prevention on the internal surfaces. It is cheap, dries fast, and can be purchased in bulk (for big spraying jobs) or in rattle cans. It is a proven corrosion preventative. I would not use it as a primer for finish paint, because it doesn't stick as aggresively as other products.

But that's me.

What I would not do would be shoot a coat of automotive primer over the inside surfaces of the airplane. It doesn't offer much, if any, corrosion protection, which is the only reason you'd prime the insides anyway. On the other hand, it does add weight, time, and cost. So (again, in my analysis), there is little benefit to these products.
 
I have used Zinc Oxide. It is supposed to be a safer alternative to Zinc Chromate. Comes in rattle cans and applies nicely in two light coats. Not very "tough" but as said before you should not expect to beat up the inside of your wings/emp and such.

Anyone else use this? Bought mine from spruce

Ryan
 
You must log in or register to reply here.