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Alodine and Zinc Chromate, Part II

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messydeer

Joined: 13 Feb 2006
Posts: 214
Location: Bellingham, WA

Posted: Mon Jul 03, 2006 11:46 am Post subject: Alodine and Zinc Chromate, Part II

Hi!



I spent most of yesterday etching my VS parts with Alumiprep. I draped a vinyl shower curtain across my table w/ 2x4's underneath around the edges. Things went pretty well. Aluminum fizzed and turned sorta white. 



After draining and rinsing the drape well, I put in Alodine, 1:2 w/ water as suggested in their literature. Used cheesecloth to drape over areas that stuck out above the bath and kept it pretty moist. I was dissappointed with the results. Even after leaving parts in their for 15 minutes, there was little color change.



I tackled it again today and added straight Alodine 1201 to the old bath, making the solution maybe 1:1. That seemed to do the trick. Only took 5 minutes for the desired color change. But I did notice the 2nd batch of parts took longer to change. I might also mention the original 1:2 bath was recycled from my first session a month ago. Although Henkel says you can re-use the solution, it seems fresh Alodine does a much better job. 



But even with the fresh concentrated solution, I still got some patchiness. I did prep well: dish soap solution sprayed on and scoured w/ scotchbrite; rinse w/ water; wipe w/ lacquer thinner; kept fingerprints off parts.



Right now I've sprayed all with the first coat of zinc chromate (tempo cans). Alodine is supposed to help promote adhesion of the primer. Given the patchiness of its coat and the hassle with its application, I'm considering just acid etching and then zinc chromate without Alodine. How does this sound to you zinc chromaters? 



Thanks,

Dan[/b]

_________________
Dan

admin(at)arachnidrobotics
Guest

Posted: Mon Jul 03, 2006 12:38 pm Post subject: Alodine and Zinc Chromate, Part II

    I live in the wet jungles of Oregon, and very few builders here are going to the trouble of Etching, Alodine, and Zinc.  Nearly everyone is using Zinc Chromate on mating surfaces, but many of those builders are just using a scotchbrite pad to rough the surface prior to spraying.  With more rainy and wet days than sunny, the aircraft are still exhibiting very good corrosion resistance when using 6061-T6.  Note that the important part of that sentence is the "T6-6061" part. 

    If you're using a less corrosion resistant type of aluminum (2024-T3 is common) you'll want to do all you can to prolong the life of the aircraft.  6061-T6 will still benefit from the Etch, Alodine, Zinc process, but already exhibits excellent corrosion resistance (due in part to being artificially aged during the production porocess).



messydeer <messydeer(at)yahoo.com> wrote:[quote] --> Zenith-List message posted by: "messydeer" 



Hi!



I spent most of yesterday etching my VS parts with Alumiprep. I draped a vinyl shower curtain across my table w/ 2x4's underneath around the edges. Things went pretty well. Aluminum fizzed and turned sorta white. 



After draining and rinsing the drape well, I put in Alodine, 1:2 w/ water as suggested in their literature. Used cheesecloth to drape over areas that stuck out above the bath and kept it pretty moist. I was dissappointed with the results. Even after leaving parts in their for 15 minutes, there was little color change.



I tackled it again today and added straight Alodine 1201 to the old bath, making the solution maybe 1:1. That seemed to do the trick. Only took 5 minutes for the desired color change. But I did notice the 2nd batch of parts took longer to change. I might also mention the original

NYTerminat(at)aol.com
Guest

Posted: Mon Jul 03, 2006 1:13 pm Post subject: Alodine and Zinc Chromate, Part II

Dan,

  

 Not to get another scotchbrite and primer debate going, I just used  the scotchbrite and cleaned with lacquer thinner and sprayed with self etching  primer and have had great results.

  

 Bob Spudis

 N701ZX  701/912S

  

 do not archive

  

  

  

  

  

  

 In a message dated 7/3/2006 3:49:03 P.M. Eastern Daylight Time,  messydeer(at)yahoo.com writes:

  	  Quote: 	
		  Hi!



I spent most of yesterday etching my VS parts with    Alumiprep. I draped a vinyl shower curtain across my table w/ 2x4's underneath    around the edges. Things went pretty well. Aluminum fizzed and turned sorta    white. 



After draining and rinsing the drape well, I put in Alodine,    1:2 w/ water as suggested in their literature. Used cheesecloth to drape over    areas that stuck out above the bath and kept it pretty moist. I was    dissappointed with the results. Even after leaving parts in their for 15    minutes, there was little color change.



I tackled it again today and    added straight Alodine 1201 to the old bath, making the solution maybe 1:1.    That seemed to do the trick. Only took 5 minutes for the desired color change.    But I did notice the 2nd batch of parts took longer to change. I might also    mention the original 1:2 bath was recycled from my first session a month ago.    Although Henkel says you can re-use the solution, it seems fresh Alodine does    a much better job. 



But even with the fresh concentrated solution, I    still got some patchiness. I did prep well: dish soap solution sprayed on and    scoured w/ scotchbrite; rinse w/ water; wipe w/ lacquer thinner; kept    fingerprints off parts.



Right now I've sprayed all with the first coat    of zinc chromate (tempo cans). Alodine is supposed to help promote adhesion of    the primer. Given the patchiness of its coat and the hassle with its    application, I'm considering just acid etching and then zinc chromate without    Alodine. How does this sound to you zinc chromaters?    



Thanks,

Dan[/b]



--------

Dan

Crvsecretary(at)aol.com
Guest

Posted: Mon Jul 03, 2006 1:49 pm Post subject: Alodine and Zinc Chromate, Part II

Hello Bob and Listers:

  

 I used the scotchbrite/lacquer thinner/rattle can approach for the  horizontal stabilizer, elevator, flaps, and ailerons with acceptable  results.  I have two questions for everyone:

  

 1) The scotchbrite pad thing seems to take forever by hand.   I'm using a plain old scotchbrite pad (number and color to remain nameless so as  not to incite another Scotchbrite debate) and rubbing the parts to take the  shine off them.  Is there an easier way?  A wheel or something to make  the job move along?

  

 2) I've just started priming the wing ribs using a  scotchbrite/lacquer thinner/two-part epoxy primer.  WOW - this stuff REALLY  sticks !!!!  I like it - but it's a lot of work.  Is anyone else using  a two-part epoxy primer?

  

  Tracy  Smith

Naugatuck, CT

601xl N458XL (reserved)

do not  archive



  

  

  

 In a message dated 7/3/2006 5:14:29 PM Eastern Standard Time,  NYTerminat(at)aol.com writes:

  	  Quote: 	
		        Dan,

    

   Not to get another scotchbrite and primer debate going, I just used    the scotchbrite and cleaned with lacquer thinner and sprayed with self etching    primer and have had great results.

    

   Bob Spudis

   N701ZX  701/912S

    

   do not archive

    

    

    

    

    

    

   In a message dated 7/3/2006 3:49:03 P.M. Eastern Daylight Time,    messydeer(at)yahoo.com writes:

    	  Quote: 	
		  Hi!



I spent most of yesterday etching my VS parts with      Alumiprep. I draped a vinyl shower curtain across my table w/ 2x4's      underneath around the edges. Things went pretty well. Aluminum fizzed and      turned sorta white. 



After draining and rinsing the drape well, I put      in Alodine, 1:2 w/ water as suggested in their literature. Used cheesecloth      to drape over areas that stuck out above the bath and kept it pretty moist.      I was dissappointed with the results. Even after leaving parts in their for      15 minutes, there was little color change.



I tackled it again today      and added straight Alodine 1201 to the old bath, making the solution maybe      1:1. That seemed to do the trick. Only took 5 minutes for the desired color      change. But I did notice the 2nd batch of parts took longer to change. I      might also mention the original 1:2 bath was recycled from my first session      a month ago. Although Henkel says you can re-use the solution, it seems      fresh Alodine does a much better job. 



But even with the fresh      concentrated solution, I still got some patchiness. I did prep well: dish      soap solution sprayed on and scoured w/ scotchbrite; rinse w/ water; wipe w/      lacquer thinner; kept fingerprints off parts.



Right now I've sprayed      all with the first coat of zinc chromate (tempo cans). Alodine is supposed      to help promote adhesion of the primer. Given the patchiness of its coat and      the hassle with its application, I'm considering just acid etching and then      zinc chromate without Alodine. How does this sound to you zinc chromaters?      



Thanks,

Dan[/b]



--------

Dan

admin(at)arachnidrobotics
Guest

Posted: Mon Jul 03, 2006 2:14 pm Post subject: Alodine and Zinc Chromate, Part II

3M makes a Roloc disk for use with a 90-degree die grinder.  You can get it in any flavor of standard scotch-brite pad.  Be carefull with your RPMS.  It will eat right through your .020 skins if you're too high!



    



Crvsecretary(at)aol.com wrote: 	  Quote: 	
		        Hello Bob and Listers:

  

 I used the scotchbrite/lacquer thinner/rattle can approach for the  horizontal stabilizer, elevator, flaps, and ailerons with acceptable  results.  I have two questions for everyone:

  

 1) The scotchbrite pad  thing seems to take forever by hand.   I'm using a plain old scotchbrite pad (number and color to remain nameless so as  not to incite another Scotchbrite debate) and rubbing the parts to take the  shine off them.  Is there an easier way?  A wheel or something to make  the job move along?

  

 2) I've just started priming the wing ribs using a  scotchbrite/lacquer thinner/two-part epoxy primer.  WOW - this stuff REALLY  sticks !!!!  I like it - but it's a lot of work.  Is anyone else using  a two-part epoxy primer?

  

  Tracy  Smith

Naugatuck, CT

601xl N458XL (reserved)

do not  archive



  

  

  

 In a message dated 7/3/2006  5:14:29 PM Eastern Standard Time,  NYTerminat(at)aol.com writes:

  	  Quote: 	
		        Dan,

    

   Not to get another scotchbrite and primer debate going, I just used    the scotchbrite and cleaned with lacquer thinner and sprayed with self etching    primer and have had great results.

    

   Bob Spudis

   N701ZX  701/912S

    

   do not archive

    

    

    

    

    

    

   In a message dated 7/3/2006 3:49:03 P.M. Eastern Daylight Time,    messydeer(at)yahoo.com writes:

    	  Quote: 	
		  Hi!



I spent most of yesterday etching my VS parts with      Alumiprep. I draped a vinyl shower curtain across my table w/ 2x4's      underneath around the edges. Things went pretty well. Aluminum fizzed and      turned sorta white. 



After draining and rinsing the drape well, I put      in Alodine, 1:2 w/ water as suggested in their literature. Used cheesecloth      to drape over areas that stuck out above the bath and kept it pretty moist.      I was dissappointed with the results. Even after leaving parts in their for      15 minutes, there was little color change.



I tackled it again today      and added straight Alodine 1201 to the old bath, making the solution maybe      1:1. That seemed to do the trick. Only took 5 minutes for the desired color      change. But I did notice the 2nd batch of parts took longer to change. I      might also mention the original 1:2 bath was  recycled from my first session      a month ago. Although Henkel says you can re-use the solution, it seems      fresh Alodine does a much better job. 



But even with the fresh      concentrated solution, I still got some patchiness. I did prep well: dish      soap solution sprayed on and scoured w/ scotchbrite; rinse w/ water; wipe w/      lacquer thinner; kept fingerprints off parts.



Right now I've sprayed      all with the first coat of zinc chromate (tempo cans). Alodine is supposed      to help promote adhesion of the primer. Given the patchiness of its coat and      the hassle with its application, I'm considering just acid etching and then      zinc chromate without Alodine. How does this sound to you zinc chromaters?      



Thanks,

Dan[/b]



--------

Dan

randy(at)shadycreekoutlaw
Guest

Posted: Mon Jul 03, 2006 2:54 pm Post subject: Alodine and Zinc Chromate, Part II

Afix the scotchbrite pad to a vibrating or random orbital sander...   This will should help.

  

 Randy

 XL Wings - Plans Only

 http://www.n344rb.com

 Do Not Archive

  

 [quote]   ---

noelloveys(at)yahoo.ca
Guest

Posted: Mon Jul 03, 2006 4:31 pm Post subject: Alodine and Zinc Chromate, Part II

Did you do a water break test?  Spray a little clean water on the prepared

aluminium and it should coat the aluminium without any breaks in the

water... Then it's ready for the Alodine.  I've used Alodine several times

without the splochyness you describe.



Noel



[quote] --

msherman95632(at)yahoo.co
Guest

Posted: Mon Jul 03, 2006 4:55 pm Post subject: Alodine and Zinc Chromate, Part II

--- Crvsecretary(at)aol.com wrote:



 	  Quote: 	
		    

 Hello Bob and Listers:

  

 I used the scotchbrite/lacquer thinner/rattle can

 approach for the  

 horizontal stabilizer, elevator, flaps, and ailerons

 with acceptable  results.  I have 

 two questions for everyone:

  

 1) The scotchbrite pad thing seems to take forever

 by hand.   I'm using a 

 plain old scotchbrite pad (number and color to

 remain nameless so as  not to 

 incite another Scotchbrite debate) and rubbing the

 parts to take the  shine off 

 them.  Is there an easier way?  A wheel or something

 to make  the job move along?

  

 2) I've just started priming the wing ribs using a 

 scotchbrite/lacquer 

 thinner/two-part epoxy primer.  WOW - this stuff

 REALLY  sticks !!!!  I like it - 

 but it's a lot of work.  Is anyone else using  a

 two-part epoxy primer?

  

  

 Tracy  Smith

 Naugatuck, CT

 601xl N458XL (reserved)

 do not  archive

 

  

  

 

Tracy.
	




I used the two part epoxy on the entire airplane

inside.  Alumaprep/alodine then prime.  Yes it was a

lot of work.  I let the alumaprep do all the work of

dulling the surface. I mixed some 409 cleaner in with

the full strength alumaprep to do two steps in one. I

cleaned it with thinner first to get off the ink, then

let the alumaprep do its thing.  



I know a lot of people say there is no need to go to

all this work, that 6061 will outlast all of us. 

Maybe so, but I had a 1964 C-150 that was paper thin

because of corrosion after thirty years and never by

the ocean. Yeah I know it was 2024 not 6061.  But the

2024 they use has an almost pure aluminum layer clad

on it, this is way more corrosion resistant than 6061.

Where did all that pure aluminum go?



I figure that some new owner of my plane thirty years

from now will look inside at no corrosion and say WOW

did this guy really know how to build an airplane.

Worth every extra hour I put into it.



  Although I must confess that I found a place called

Pacific Coast Anodizing that did what the industry

calls Chem-film, (alumaprep/alodine)that did all of

both wing parts (ribs,skins,spars all little parts)

for $75.00 and the entire fuse and tail parts for

another $125.00 for me.  I got them back individually

wrapped in paper, picked up and delivered to my door. 

Not bad if you live in the central valley of

California.



Keep up the good work I think it is worth it.



Mark S.

701/912S

Paint booth built

painting



__________________________________________________

messydeer

Joined: 13 Feb 2006
Posts: 214
Location: Bellingham, WA

Posted: Mon Jul 03, 2006 6:52 pm Post subject: Re: Alodine and Zinc Chromate, Part II

Thanks everybody for the feedback :=)



 	  Quote: 	
		  The scotchbrite pad thing seems to take forever by hand.? I'm using a plain old scotchbrite pad 	




Ditto w/ the dual action scotchbrite, especially w/ skins, since the pad is ~6" across. I have a weanie compressor so it's not time efficient for me.



 	  Quote: 	
		  Did you do a water break test? 	




Well...uh...no...Knew about it but didn't do it. I did notice the water ran off easily in sheets, but should have thoroughly tested. 



 	  Quote: 	
		  jungles of Oregon 	




I'm in similar jungles of the former Oregon Territory. Before that the city was named by George Vancouver after the controller of the storekeeper's account of the Royal Navy. Juding from that, I presume it to have been one of the last things he named.



Cheers,

Dan

_________________
Dan

NYTerminat(at)aol.com
Guest

Posted: Mon Jul 03, 2006 7:56 pm Post subject: Alodine and Zinc Chromate, Part II

Tracy,

 I found that it was not bad using the pad by hand. I know that there are  scotchbrite wheels that are available but I did not use them. I found that when  the pad took longer to use I got rid of it and used a new one. They weren't all  that expensive and the new one worked much faster.

  

 In a message dated 7/3/2006 5:50:25 P.M. Eastern Daylight Time,  Crvsecretary(at)aol.com writes:

  	  Quote: 	
		  The scotchbrite pad thing seems to take forever by hand.     I'm using a plain old scotchbrite pad (number and color to remain nameless so    as not to incite another Scotchbrite debate) and rubbing the parts to take the    shine off them.  Is there an easier way?  A wheel or something to    make the job move along?

messydeer

Joined: 13 Feb 2006
Posts: 214
Location: Bellingham, WA

Posted: Mon Jul 03, 2006 8:13 pm Post subject: Re: Alodine and Zinc Chromate, Part II

Enco sells the maroon 7447 scotchbrite for $.59 per pad. I don't use one, but they also have on sale scotchbrite wheels. Order more than $50 and you can get shipping free if you use the code WEBRN76 Their site is www.use-enco.com. They ship fast, are fairly cheap and have excellent customer service.

_________________
Dan

noelloveys(at)yahoo.ca
Guest

Posted: Tue Jul 04, 2006 4:28 am Post subject: Alodine and Zinc Chromate, Part II

Mark:



I congratulate you on using the Alodine and zinc chromate.  I think the

epoxy base is a bit of overkill if you aren't going to try to stick cloth

over it but as you say it will stick!!  



If you really want pure aluminium and I don't think you really do, its

available in sheets from the folks who make aluminium doors etc.  You will

find pure aluminium isn't nearly as corrosion resistant as alumiclad 6061.

You will also find it has the strength a little greater than wet toilet

paper and rivets won't stay tight in it.



Did you alodine both sides of your skins?  Doing so protects the skins under

the nice urethane paints and primers.



Noel



[quote] --

msherman95632(at)yahoo.co
Guest

Posted: Tue Jul 04, 2006 6:22 am Post subject: Alodine and Zinc Chromate, Part II

Noel.



No where in my post did I say to use pure aluminum.

What I said is that pure aluminum is clad to 2024 to

make it more corrosion resistant. So the pure aluminum

coating is more corrosion resistant than bare 6061 or

2024.  That is why most certified aircraft use 2024

alclad, they get the strength of 2024 and the

corrosion protection of the pure aluminum clad.



Mark S.



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



[quote] 

 <noelloveys(at)yahoo.ca>

 

 Mark:

 

 I congratulate you on using the Alodine and zinc

 chromate.  I think the

 epoxy base is a bit of overkill if you aren't going

 to try to stick cloth

 over it but as you say it will stick!!  

 

 If you really want pure aluminium and I don't think

 you really do, its

 available in sheets from the folks who make

 aluminium doors etc.  You will

 find pure aluminium isn't nearly as corrosion

 resistant as alumiclad 6061.

 You will also find it has the strength a little

 greater than wet toilet

 paper and rivets won't stay tight in it.

 

 Did you alodine both sides of your skins?  Doing so

 protects the skins under

 the nice urethane paints and primers.

 

 Noel

 

 

 

 > --

noelloveys(at)yahoo.ca
Guest

Posted: Tue Jul 04, 2006 6:57 pm Post subject: Alodine and Zinc Chromate, Part II

Sorry I misunderstood you.  



Noel



[quote] --

John Bolding

Joined: 23 May 2006
Posts: 281

Posted: Wed Jul 05, 2006 2:18 pm Post subject: Alodine and Zinc Chromate, Part II

---

admin(at)arachnidrobotics
Guest

Posted: Wed Jul 05, 2006 3:15 pm Post subject: Alodine and Zinc Chromate, Part II

    Your statements are basically correct John.  6061-T6 is 'slightly' less corrosion resistant than 2024 clad in pure aluminum (very slightly so). Keep in mind that the layer of pure aluminum is sometimes only a few atoms thick.  this shouldn't be of any concern if you're painting your aircraft.  If you're going to polish the aluminum and leave it bare, that layer will eventually become thin enough as to warrant corrosion treatment and painting.  I understand that several good products exist specifically to provide extended protection to polished aluminum aircraft, although I've never used any of them.

    If you were able to find 6061-T6 with a layer of pure aluminum, you'd get the best of both worlds.  Good luck on that one.  It's not necessary, so it's not available...



Tom Henderson

601XL Fuse 

A few weeks from completion, FINALLY!



McMinnville,  Oregon

503-474-3882





John Bolding <jnbolding1(at)teleshare.net> wrote:[quote] --> Zenith-List message posted by: "John Bolding" 

---

noelloveys(at)yahoo.ca
Guest

Posted: Wed Jul 05, 2006 6:56 pm Post subject: Alodine and Zinc Chromate, Part II

It is my understanding that for corrosion to occur there are two things

required moisture and a source of oxygen.  Pure aluminium is very porous as

it corrodes this porosity will hold moisture which speeds up the corrosion

process.  Alumiclad, as I understand it, allows a thin layer of oxidation to

occur that  is not thick enough to be porous just thick enough to isolate

the underlying alloys from a source of oxygen.



Noel



[quote] --

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