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Primer adhesion
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ifly4fun2(at)sbcglobal.ne
Guest

Posted: Sun Jul 01, 2007 8:00 am Post subject: Primer adhesion

Hi All,

  Yesterday I finished priming my 701 rudder skeleton with PTI Zinc Oxide and I've experienced poor adhesion results.  I need some advise on where to go from here. 

  The only spray painting I've ever been exposed to is the type that comes out of a spray can.  I used an HVLP sprayer with the reducer proportions as advised by PTI.  The conditions in the shop was 70 deg with 72% humidity. The primer is suppose dry tack free in 5 minutes and it did but the fully cured in 30 minutes hasn't quite happened yet.  I've allowed it to cure overnight and the surface can be chipped down to the chem-film with a fingernail.  Any ideas what may have caused this and what I should do now?

   

  AJ

   

 [quote][b]

naumuk(at)alltel.net
Guest

Posted: Sun Jul 01, 2007 8:08 am Post subject: Primer adhesion

72% humidity might have something to do with it.  Try a dehumidifier in your shop.

                                 do  not archive

 Bill Naumuk

HDS Fuse/Corvair

Townville, Pa

 [quote]   ---

Kevin Bonds

Joined: 09 Jan 2006
Posts: 171
Location: Nashville, Tn

Posted: Sun Jul 01, 2007 9:28 am Post subject: Primer adhesion

Are you scuffing the surface or chemical etching at all? I like Alumiprep. Also I am using Zinc Oxide in the rattle cans instead of Chromate. Think it is a little safer. Adhesion seems pretty good to me, and I live in Nashville, Tn. High humidity is just a fact of life here in summer.    

     

Kevin Bonds  

Nashville TN  

601XL Plans building.  

http://home.comcast.net/~kevinbonds  

   

do not archive DO NOT ARCHIVE   

     

   

    

   

  

  

       [quote][b]

_________________
KevinBonds
Nashville, TN
Plans-building Zenith CH601XL w/Corvair Power
http://home.comcast.net/~kevinbonds

Kevin Bonds

Joined: 09 Jan 2006
Posts: 171
Location: Nashville, Tn

Posted: Sun Jul 01, 2007 9:39 am Post subject: Primer adhesion

Also, a thin coating will adhere better than a thick one.   

     

Kevin Bonds  

Nashville TN  

601XL Plans building.  

http://home.comcast.net/~kevinbonds  

   

do not archive DO NOT ARCHIVE   

     

   

  

  

       [quote][b]

_________________
KevinBonds
Nashville, TN
Plans-building Zenith CH601XL w/Corvair Power
http://home.comcast.net/~kevinbonds

stol701(at)yahoo.com
Guest

Posted: Sun Jul 01, 2007 2:22 pm Post subject: Primer adhesion

I just zinc chromated the skelaton from my 701 rudder and I live in the very dry Southern New Mexico. We do not measure humidity because we have none (joke).  I too can scratch off the primer with my finger nail. Prior to spraying I cleaned up the metal with laquer thinner.

 see at: http://websites.expercraft.com/rhansen/

 Rob Hansen

 ---

dredmoody(at)cox.net
Guest

Posted: Sun Jul 01, 2007 3:05 pm Post subject: Primer adhesion

I'm not a paint expert..... in fact, I hate  painting, but I think your problem is that you expected the primer to get hard  much too fast. I have found that using self etching Zinc Oxide from rattle cans,  cleaning the aluminum with laquer thinner (repeatedly until clean and fairly  streak free) then following the directions works well. The primer can be  scatched off pretty easily until it has had a few days to harden. Gradually  it takes much more than a fingernail to get through it. You can etch before  priming..... you can scratch the hell out of the parts with scotchbrite, emery  cloth, a rock from the nearby streambed, whatever. But until the primer itself  is tough, it can be pulled off the surface. Try giving it more time if you  can.

  

 Dred

 [quote]   ---

dbortol

Joined: 02 Sep 2006
Posts: 46

Posted: Sun Jul 01, 2007 3:35 pm Post subject: Primer adhesion

I'm no expert on this, but it sounds like a surface preparation problem to me. I just zinc chromated the inside of my rudder trim tab yesterday. I scuffed the surface with a Scotchbrite pad, washed it with warm water and lemon-scented dish soap, and rinsed it with hot water. Didn't use any solvents. Let it air dry and brushed the chromate on with a disposable sponge brush. Then attempted to mow the lawn (realized I didn't have gas, didn't feel like going out to buy any!) and came back 30 minutes later. At that point it was dry enough that I was able to clamp the piece in my brake and form the trim tab without any coming off the surface.  



Dino Bortolin

601XL plans/Corvair 



On 7/1/07, Arthur Olechowski <ifly4fun2(at)sbcglobal.net (ifly4fun2(at)sbcglobal.net)> wrote: [quote]Hi All,

  Yesterday I finished priming my 701 rudder skeleton with PTI Zinc Oxide and I've experienced poor adhesion results.  I need some advise on where to go from here.  

  The only spray painting I've ever been exposed to is the type that comes out of a spray can.  I used an HVLP sprayer with the reducer proportions as advised by PTI.  The conditions in the shop was 70 deg with 72% humidity. The primer is suppose dry tack free in 5 minutes and it did but the fully cured in 30 minutes hasn't quite happened yet.  I've allowed it to cure overnight and the surface can be chipped down to the chem-film with a fingernail.  Any ideas what may have caused this and what I should do now? 

   

  AJ

   

 [quote][b]  http://www.matronics.com/Navigator?Zenith-List http://forums.matronics.com  [quote][b]

ifly4fun2(at)sbcglobal.ne
Guest

Posted: Sun Jul 01, 2007 3:37 pm Post subject: Primer adhesion

Kevin,

  I've scuffed everything with 3M scotchbrite, degreased, alumiprep'd, alodined, rinsed and allowed it to dry overnight and then primed.  I think I may have too thick of a coating.

   

  do not archive

  AJ



kevinbonds <kevinbonds(at)comcast.net> wrote:

  [quote]  <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />    st1\:*{behavior:url(#default#ieooui) }                 Are you  scuffing the surface or chemical etching at all? I like Alumiprep. Also I am using Zinc Oxide in the rattle cans instead of Chromate. Think it is a little safer. Adhesion seems pretty good to me, and I live in <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" />Nashville, Tn. High humidity is just a fact of life here in summer.  

   

    Kevin Bonds

  Nashville TN

  601XL Plans building.

  http://home.comcast.net/~kevinbonds

   

  do not archive DO NOT ARCHIVE

ifly4fun2(at)sbcglobal.ne
Guest

Posted: Sun Jul 01, 2007 3:37 pm Post subject: Primer adhesion

I believe that may be my problem.

   

  do not archive

  AJ



kevinbonds <kevinbonds(at)comcast.net> wrote:

  [quote]  <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />    st1\:*{behavior:url(#default#ieooui) }                Also, a thin coating will adhere better than a thick one. 

   

    Kevin Bonds

  <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" />Nashville TN

  601XL Plans building.

  http://home.comcast.net/~kevinbonds

ifly4fun2(at)sbcglobal.ne
Guest

Posted: Sun Jul 01, 2007 3:41 pm Post subject: Primer adhesion

Rob,

  I like your nifty plans storage desk on your site, not to mention your actual dedicated shop.

   

  do not archive

  AJ



Robert Hansen <stol701(at)yahoo.com> wrote:

  [quote]        I just zinc chromated the skelaton from my 701 rudder and I live in the very dry Southern New Mexico. We do not measure humidity because we have none (joke).  I too can scratch off the primer with my finger nail. Prior to spraying I cleaned up the metal with laquer thinner.

  see at: http://websites.expercraft.com/rhansen/

  Rob Hansen

  ---

ifly4fun2(at)sbcglobal.ne
Guest

Posted: Sun Jul 01, 2007 3:47 pm Post subject: Primer adhesion

Dred,

  I agree, more cure time is necessary prior to assembly.  Dryer weather would nice its been raining all week long.  I think I should of cranked the AC on for awhile prior to priming to remove some of the humidity.

   

  do not archive

  AJ



Edward Moody II <dredmoody(at)cox.net> wrote:

  [quote]        I'm not a paint expert..... in fact, I hate painting, but I think your problem is that you expected the primer to get hard much too fast. I have found that using self etching Zinc Oxide from rattle cans, cleaning the aluminum with laquer thinner (repeatedly until clean and fairly streak free) then following the directions works well. The primer can be scatched off pretty easily until it  has had a few days to harden. Gradually it takes much more than a fingernail to get through it. You can etch before priming..... you can scratch the hell out of the parts with scotchbrite, emery cloth, a rock from the nearby streambed, whatever. But until the primer itself is tough, it can be pulled off the surface. Try giving it more time if you can.

   

  Dred

  [quote]  ---

ifly4fun2(at)sbcglobal.ne
Guest

Posted: Sun Jul 01, 2007 4:03 pm Post subject: Primer adhesion

Dino,

  I scuffed with 3M scotchbrite, degreased, rinsed then alumiprep'd and rinsed again then alodined and rinsed again allowed to dry overnight and then primed.  I think the problem was the amount of primer applied was to thick with high humidity. 

   

  do not archive

  AJ

 

Dino Bortolin <dbortol(at)gmail.com> wrote:

  [quote]I'm no expert on this, but it sounds like a surface preparation problem to me. I just zinc chromated the inside of my rudder trim tab yesterday. I scuffed the surface with a Scotchbrite pad, washed it with warm water and lemon-scented dish soap, and rinsed it with hot water. Didn't use any solvents. Let it air dry and brushed the chromate on with a disposable sponge brush. Then attempted to mow the lawn (realized I didn't have gas, didn't feel  like going out to buy any!) and came back 30 minutes later. At that point it was dry enough that I was able to clamp the piece in my brake and form the trim tab without any coming off the surface. 



Dino Bortolin

601XL plans/Corvair 



  On 7/1/07, Arthur Olechowski <ifly4fun2(at)sbcglobal.net (ifly4fun2(at)sbcglobal.net)> wrote:   [quote]  Hi All,

  Yesterday I finished priming my 701 rudder skeleton with PTI Zinc Oxide and I've experienced poor adhesion results.  I need some advise on where to go from here.  

  The only spray painting I've ever been exposed to is the type that comes out of a spray can.  I used an HVLP sprayer with the reducer proportions as advised by PTI.  The [quote][b]

p.mulwitz(at)worldnet.att
Guest

Posted: Sun Jul 01, 2007 6:43 pm Post subject: Primer adhesion

Hi AJ,



I have spent a lot of time and not a small amount of money 

researching what paints will work on aluminum that I can get locally 

and don't cost the earth to buy.  The problem with aluminum is the 

oxide that forms almost instantly prevents paint from sticking.



I have two different solutions - one for the interior paint and one 

for exterior.



For the interior I wanted flat grey paint.  This wound up being self 

etching primer from SEM.  I prep the surface with fairly coarse sand 

paper (100 or 150 grit?) and clean it with lacquer thinner before 

painting.  This sticks like glue.  For contrast on the interior 

paint, I like flat black enamel in rattle cans.  To get this to work 

well with the self etching primer, I need to use an additional primer 

in between the self etching primer and top coat.  Without the 

intermediate primer, the top coat nearly lifts the self etching 

primer right off the aluminum.



For the exterior I am using the same self etching primer along with 

epoxy primer and finally acrylic enamel.  The last two products are 

from PPG.   This is less expensive than the popular urethane enamel 

and is less toxic too.



Pricing for the self etching primer at my local professional paint 

store runs about $12 for a rattle can and $22 for a quart.  The PPG 

epoxy primer and acrylic enamel run an average of around $100 per 

gallon when you include the required hardeners and thinners.



For aircraft steel parts, the epoxy primer works incredibly well 

directly on the steel.  I don't think it needs a top coat if the 

appearance isn't important like on the flap torque tubes.



Good luck,



Paul

XL fuselage

At 08:58 AM 7/1/2007, you wrote:

 	  Quote: 	
		  Hi All,

Yesterday I finished priming my 701 rudder skeleton with PTI Zinc 

Oxide and I've experienced poor adhesion results.  I need some 

advise on where to go from here.

The only spray painting I've ever been exposed to is the type that 

comes out of a spray can.  I used an HVLP sprayer with the reducer 

proportions as advised by PTI.  The conditions in the shop was 70 

deg with 72% humidity. The primer is suppose dry tack free in 5 

minutes and it did but the fully cured in 30 minutes hasn't quite 

happened yet.  I've allowed it to cure overnight and the surface can 

be chipped down to the chem-film with a fingernail.  Any ideas what 

may have caused this and what I should do now?



AJ

stol701(at)yahoo.com
Guest

Posted: Mon Jul 02, 2007 2:10 am Post subject: Primer adhesion

Thank You AJ,

 My shop is nothing more then a metal building w/ a dirt floor. I posted my reply on the primer before waiting a couple days to see how it set up. I will be back at the "airplane factory" tonight, so I will see how it is doing.

  

 Rob

 ---

naumuk(at)alltel.net
Guest

Posted: Mon Jul 02, 2007 6:34 am Post subject: Primer adhesion

All-

     We may be talking apples and  oranges here, because I'm using Zinc Oxide rather than Chromate. 

     This spring when we had high  humidity from all the snow melting off it would take two days for parts to tack  dry. It hasn't rained in a week and yesterday I shot a couple of parts and they  were dry as a bone in an hour. Just an observation, not a hard and fast  recommendation.

 Bill Naumuk

HDS Fuse/Corvair

Townville, Pa

 [quote]   ---

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Mon Jul 02, 2007 7:28 pm Post subject: Primer adhesion

What colour Scotch Brite... Only kidding.... Let's not go there!



I read one post that said the builder alumipreped and then alodyned the

parts.  I think that alumiprep with a water brake test is more than enough.

When you rinse the part if the water doesn't sheet off evenly then back to

scrubbing with the alumiprep, rinsing etc. etc..



Noel

 	  Quote: 	
		   Time: 04:35:01 PM PST US

 From: "Dino Bortolin" <dbortol(at)gmail.com>

 Subject: Re: Primer adhesion

 

 I'm no expert on this, but it sounds like a surface 

 preparation problem to

 me. I just zinc chromated the inside of my rudder trim tab 

 yesterday. I

 scuffed the surface with a Scotchbrite pad, washed it with 

 warm water and

 lemon-scented dish soap, and rinsed it with hot water. Didn't use any

 solvents. Let it air dry and brushed the chromate on with a disposable

 sponge brush. Then attempted to mow the lawn (realized I 

 didn't have gas,

 didn't feel like going out to buy any!) and came back 30 

 minutes later. At

 that point it was dry enough that I was able to clamp the 

 piece in my brake

 and form the trim tab without any coming off the surface.

 

 Dino Bortolin

 601XL plans/Corvair

 

 On 7/1/07, Arthur Olechowski <ifly4fun2(at)sbcglobal.net> wrote:

 >

 > Hi All,

 > Yesterday I finished priming my 701 rudder skeleton with 

 PTI Zinc Oxide

 > and I've experienced poor adhesion results.  I need some 

 advise on where to

 > go from here.

 > The only spray painting I've ever been exposed to is the 

 type that comes

 > out of a spray can.  I used an HVLP sprayer with the 

 reducer proportions

 > as advised by PTI.  The conditions in the shop was 70 deg 

 with 72% humidity.

 > The primer is suppose dry tack free in 5 minutes and it did 

 but the fully

 > cured in 30 minutes hasn't quite happened yet.  I've 

 allowed it to cure

 > overnight and the surface can be chipped down to the 

 chem-film with a

 > fingernail.  Any ideas what may have caused this and what I 

 should do now?

 >

 > AJ

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

ifly4fun2(at)sbcglobal.ne
Guest

Posted: Mon Jul 02, 2007 7:45 pm Post subject: Primer adhesion

Rob,

  I've placed a 1000W heat lamp (not facing any parts) with a circulating fan in the shop and have seen a substantial difference in the feel of the primer, at 93 deg and 53% humidity it is definitely curing now. 

   

  do not archive

   

  Art



Robert Hansen <stol701(at)yahoo.com> wrote:

  [quote]        Thank You AJ,

  My shop is nothing more then a metal building w/ a dirt floor. I posted my reply on the primer before waiting a couple days to see how it set up. I will be  back at the "airplane factory" tonight, so I will see how it is doing.

   

  Rob

  ---

ifly4fun2(at)sbcglobal.ne
Guest

Posted: Mon Jul 02, 2007 8:02 pm Post subject: Primer adhesion

Noel,

  Well the wife picked up these multipurpose scotchbrite pads in bulk at Sam's there kind of nice cause they have a sponge on the opposing side too wipe the oxidation off with......just kidding.  They were the real deal and water beading was non-existent when rinsing.

  I believe the culprit is myself. Lack of spraying technique which resulted in a thicker than necessary coating in high humid conditions.  The worst that can happen now is my CG shifts a tenth of an inch aft.

  Art

Noel Loveys <noelloveys(at)yahoo.ca> wrote:

  [quote]--> Zenith-List message posted by: "Noel Loveys" 

What colour Scotch Brite... Only kidding.... Let's not go there!

I read one post that said the builder alumipreped and then alodyned  the

parts. I think that alumiprep with a water brake test is more than enough.

When you rinse the part if the water doesn't sheet off evenly then back to

scrubbing with the alumiprep, rinsing etc. etc..

Noel

[quote] Time: 04:35:01 PM PST US

 From: "Dino Bortolin" 

 Subject: Re: Primer adhesion

 I'm no expert on this, but it sounds like a surface 

 preparation problem to

 me. I just zinc chromated the inside of my rudder trim tab 

 yesterday. I

 scuffed the surface with a Scotchbrite pad, washed it with 

 warm water and

 lemon-scented dish soap, and rinsed it with hot water. Didn't use any

 solvents. Let it air dry and brushed the chromate on with a disposable

 sponge brush. Then attempted to mow the lawn (realized I 

 didn't have gas,

 didn't feel like going out to buy any!) and came back 30 

 minutes later.  At

 that point it was dry enough that I was able to clamp the 

 piece in my brake

 and form the trim tab without any coming off the surface.

 Dino Bortolin

 601XL plans/Corvair

 On 7/1/07, Arthur Olechowski wrote:

 >

 > Hi All,

 > Yesterday I finished priming my 701 rudder skeleton with 

 PTI Zinc Oxide

 > and I've experienced poor adhesion results. I need some 

 advise on where to

 > go from here.

 > The only spray painting I've ever been exposed to is the 

 type that comes

 > out of a spray can. I used an HVLP sprayer with the 

 reducer proportions

 > as advised by PTI. The conditions in the shop was 70 deg 

 with 72% humidity.

 > The primer is suppose dry tack free in 5 minutes and it did 

 but the fully

 > cured in 30 minutes hasn't quite [quote][b]

barcusc(at)comcast.net
Guest

Posted: Wed Jul 04, 2007 4:57 am Post subject: Primer adhesion

I had the same problem with adhesion, I went to the  House of Color and explained my problem and they recommended DuPont Etch Primer  A-4115S. It works much better than anything I have used in the  past.

  

  

 Clyde Barcus

601 XL, Continental Powered

Wings, Tail & Engine  Complete

Working on Fuselage



 [quote]   ---

ifly4fun2(at)sbcglobal.ne
Guest

Posted: Wed Jul 04, 2007 6:29 am Post subject: Primer adhesion

Thanks Clyde, I appreciate your input.  I think I've looked into DuPont primer once before but was disgusted with the $200/gal price tag that came with it.  How much does this stuff cost now and days?  



Clyde Barcus <barcusc(at)comcast.net> wrote:   [quote]    I had the same problem with adhesion, I went to the House of Color and explained my problem and they recommended DuPont Etch Primer A-4115S. It works much better than anything I have used in the past.

   

   

  Clyde Barcus

601 XL, Continental Powered

Wings, Tail & Engine Complete

Working on Fuselage



  [quote]  ---

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