Mystery problem with Alodine

Kevin McGreevy · #1 04-14-2008, 05:29 PM

Hi all,

This is my first post, and my mentor in MT said that I should contact y'all for this question- so he is to blame! I am not even building an RV even tho I really like the aircraft and am totally inspired by all that have taken on a project. I fly (train) in one of those glass diamonds- but I digress.
I am repairing my sailboat (home) that was damaged in Katrina and just got around to refinishing the mast. Stripped it down, sanded washed, prepsol, then a nice wash of Dupont 225s, wash and dry, conversion coat with 226s. Waited for the magic to happen. When I rinsed the 226s after about 5 min, there was no gold coloration to the aluminum. If you looked carefully, you could see a slight "rainbow effect" . The aluminum is T6061 and I do not know if that has any bearing on the problem.
So, in light of the "no-gold", went into a hold on applying the Corlar epoxy primer. Can any shed light on where I may have screwed up the process. I'm pretty anal about following directions, and I had a nice sheeting on the 225 rinse so I am just stymed.
I know you folks have treated more aluminum parts than I ever will, so I really respect your collective wisdoms. Thanks to all

All the best,
Kevin

Mike S · #2 04-14-2008, 06:34 PM

Kevin-------welcome aboard-----yep, pun intended.

Hopefully the moderators----and I am one---will let this post stay------even though we are supposed to remove non RV stuff, I really dont see this as a problem.

Besides, Alodine is aircraft related.

Anyway, in my experience, the Alodine is pretty consistent in causing a color change.

But, we are working on alclad material for the most part, and I really doubt that there is any 6061 in our planes.

Hopefully you will get a successful answer.
And after you are through with the training in the diamond, go find a ride in an RV-------but be warned, it could cost you lots of $$$$-----the grin is not without consequence.

TSwezey · #3 04-14-2008, 06:58 PM

The only times I have seen alodine not change the color was when the alodine had been exposed to air for a long time or it been contaminated with something. Every single piece of Al on my plane has been alodined.

jsharkey · #4 04-14-2008, 07:01 PM

Alodine loses it's strength after a while. The yellow dye is an indicator that it is still effective. No color change on the metal surface means that it is past its sell by date. There is a "clear" variant without a dye for cosmetic applications - don't know how you know whether it works or not.

Jim Sharkey

lorne green · #5 04-14-2008, 08:16 PM

Isn't alodine photo (light) sensitive as well? I keep mine in an old photo negative developing cylinder. Too much light...the product becomes ineffective?

chaskuss · #6 04-14-2008, 10:56 PM

Quote:

Originally Posted by Kevin McGreevy

Hi all,

This is my first post, and my mentor in MT said that I should contact y'all for this question- so he is to blame! I am not even building an RV even tho I really like the aircraft and am totally inspired by all that have taken on a project. I fly (train) in one of those glass diamonds- but I digress.
I am repairing my sailboat (home) that was damaged in Katrina and just got around to refinishing the mast. Stripped it down, sanded washed, prepsol, then a nice wash of Dupont 225s, wash and dry, conversion coat with 226s. Waited for the magic to happen. When I rinsed the 226s after about 5 min, there was no gold coloration to the aluminum. If you looked carefully, you could see a slight "rainbow effect" . The aluminum is T6061 and I do not know if that has any bearing on the problem.
So, in light of the "no-gold", went into a hold on applying the Corlar epoxy primer. Can any shed light on where I may have screwed up the process. I'm pretty anal about following directions, and I had a nice sheeting on the 225 rinse so I am just stymed.
I know you folks have treated more aluminum parts than I ever will, so I really respect your collective wisdoms. Thanks to all

All the best,

Kevin

Kevin
Glad you mentioned that you are using 6061. It takes 3 times as long for Alodine to "convert" 6061 compared to 2024-T3 Lorne's comment about Alodine, Iridite (and others) being photo sensitive (affected by the sun) is true. However, that is more of a problem for those of us who set up dipping tanks (bathing the parts in the Alodine) while out in the sun. The first day everything works great. It's the NEXT time you try to use the Alodine that it won't work (due to sun exposure).
Either try to leave the 226 (aka Alodine) on 3 times longer OR make the Alodine stronger, which is only possible if you started with powdered Alodine, as opposed to liquid Alodine (or in your case 226) I should also mention here that powdered Alodine costs about 10% of the price of the liquid. I suspect that with shipping prices going up due to fuel costs, that price differential will increase.
Another tip is to NOT let the part dry after rinsing off the 225 (aka AlumiPrep cleaner) The part will actually start to oxidize while it dries. This prevents the conversion from taking place. Once the item oxidizes, you have to start from scratch. This is one time where the instructions give you a bum steer. Rinse off the 225 and apply the 226 while the part is still wet with rinse water.
Click on my user name to get my email address. You can contact me off list for more info.
Charlie Kuss

Kevin McGreevy · #7 04-15-2008, 11:27 AM

Well, everyone thanks for the insight on this issue. Mike, my wife was standing over my shoulder reading your post and all she said was, "Oh, no. Another place to hemmorage money."

Yes, I would like to build one someday, and I will definitely get a ride- but I take your warning to heart!

All the best,
Kevin

az_gila · #8 04-15-2008, 02:59 PM

Quote:

Originally Posted by Mike S

......
But, we are working on alclad material for the most part, and I really doubt that there is any 6061 in our planes.

......

Mike.... most of the non-sheet stuff on our RVs is 6061-T6. All of the angles and bars, and some tubing.... and even the instrument panel (at least in the -6)

http://www.vansaircraft.com/cgi-bin/...&product=angle

http://www.vansaircraft.com/cgi-bin/...product=altube

..and I've been alodining it....

gil A

DrHolling · #9 04-15-2008, 04:07 PM

I have found that if you treat 6061 parts after a while the Alodine will impart a 'blue' colored finish instead of the normal gold. I assume it is from copper contamination from the 6061. I now have 2 seperate bottles of Alodine; one for 2024 and the other for 6061. Normally I try to 'dip' most pieces and pour the Alodine back into it's container between batches.
This is the first I've heard about the photo sensitivity of Alodine. Mine came in translucent white (almost clear) plastic bottles. I would have expected it to be packaged in a darker container. Live and learn.

Dave

Mike S · #10 04-15-2008, 04:38 PM

Quote:

Originally Posted by az_gila

Mike.... most of the non-sheet stuff on our RVs is 6061-T6. All of the angles and bars, and some tubing.... and even the instrument panel (at least in the -6)

http://www.vansaircraft.com/cgi-bin/...&product=angle

http://www.vansaircraft.com/cgi-bin/...product=altube

..and I've been alodining it....

gil A

Gil, thanks for the education, I stand corrected