The Priming Debate
 

Since I originally put these emails below together, I have been using Variprime by Dupont and a Small HVLP gun.  I have been very happy with the results.  The cup holds about 4 oz of paint.  I used about 8 oz on the ailerons and flaps each and about 20 oz on the wing ribs and spar.  You mix the paint and the etching compound one to one.  Then pour it in the gun.  I only prime the mating surfaces of the skins and all of the small parts.  I buff with scotch brite or an angel grinder with a buffing wheel.  These buffing wheels are made by 3m and very useful.  It is kind of like a scotch brite pad on a wheel and come in different grades.  I mostly use the fine. 

I then clean the whole thing with MEK.  You need to be ventilated and use gloves but it works great.  The important thing is to rough up the critical surfaces and to get all of the oil and finger prints off.  I then shoot it with primer.  It dries to the touch in about 5 minutes.  It seems to be working well and has been easy.  It took about 3 hours to clean and shoot the wing ribs and spars.  Clean up with Lacquer thinner and make sure you keep the gun clean.

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Emails about Priming

There is a self etching zinc chromate primer that I think NAPA makes.  I was going to use it and forget etching and alodine.  I am still not convinced that you really need to etch and alodine.  6061 is pretty good as far as corrosion and ZAC doesn't think it is necessary.  As far as a paint booth.  I just wear a respirator and lay out plastic. I will do more when I do the final priming and painting.  The priming isn't near as much trouble as the etch and alodine.  I did that the other day and it was kind of cold playing in the water in the driveway trying to get the rinse done.

Original Message -----
Subject: Re: zodiac

    I will not be able to order the tail until the end of Jan.  Trying to prepare my garage for the winter. My garage is not insulated and it gets really cold! I installed a heater this past weekend but now I need to insulate. all this is taking away from my airplane funds.  Heck, time I get done with my garage it will be spring again! 
    It is becoming very difficult to know what primer and method to use. Thanks for the links.  I just hate the idea of mixing the epoxy together, making a paint booth,  disposing of the waste, cleaning etc. I hit burn-out when painting the Challenger! I guy that has a hanger to my northeast is building an RV, and was using the rattle cans for primer, but am unsure of the kind. I believe a NAPA product.  I thought about just using this for this a/c.?? time will tell.
Thanks for the response.
   
----- Original Message -----
Subject: Re: zodiac
I am using zinc oxide from Airparts out by Mid Cont http://www.airpartsco.com/.  It was only about $5 a can and I am only putting on a light coat.  I only used about a half a can on the rudder.  It is very easy to use.  But I am thinking about changing over to the 2 part epoxy.  I am planning on this for the external primer under the color.  It may be good to get some practice with it.  Talking to some other folks in town they get their stuff from PPG downtown. I am also looking at a self etching 2 part called Variprime by Dupont.  They have it at M&M supply here in Wichita.  It runs about 200 for a gallon of both activator and base.  I have heard of a lot of RV folks using this. http://www.hooverandassociatesinc.com/aviation/RV-9A/priming.htm.  This self etching doesn't need to be prepared like the others. I am a little concerned about using this as an external primer. Not really sure why though.

in a question to ZAC I got the following:
For internal parts,  Chris generally does not recommend alodine on 6061-T6. For external parts, the preferred method is to wait until the aircraft is ready for the top  coat (painting).  At that time, the bare metal will be prepared following the specific paint manufacture instructions for the aluminum.   ......    Not very committal.

My plan for now is to finish the stab with the shaker can of the zinc oxide and alumiprep and alodine for the ribs, spars and parts.  I may stay with the shaker can for the wings, but will use the 2 part for the fuse.
 
For the skins I am just buffing the inside with scotch brite pads and hitting it with the shaker can.  I am leaving the outside clad. I am concerned about using acid etch and alodine on the finished assembly.  I don't like the idea of getting that stuff in the in the rivets or not getting a good rinse.  So when I am ready to start painting the outside I will scuff the clad coat on the skins and treat it with a wash primer like from Sherwin Williams  http://www.sherwin.com/apps/PickPros/display.asp?type=data&id=35 .  I will then use a two part epoxy and final color coat. 

Any way after a lot of research this is the plan.

Have you ordered the kit?
-- Original Message -----
Subject: zodiac

Hi Matt,
    Congrats on the completion of the rudder!  How is the stab coming along?  I was just wanting to know what primer you are using, and were you got it.  After researching the web, I think using the alumiprep and  alodine  is the way to go!  I thought you said you are not using the  two-part epoxy primer?? Seems like a lot of people  use this primer.  With the Alumiprep and alodine process i guess you would not need the self-etching primer in the cans. 
anyways,