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Storage of Alumaprep or Alodine?

Dbro172

Dbro172

Well Known Member
I just whipped up a couple of big ol' batches of alumaprep (1:3) and Alodine (1:2) to do my wing ribs. I put these in huge flat rubbermaid container that fit my wing ribs. Now that im done, I have a few gallons of each (pre-diluted with water) that I poured into seperate five gallon pails, put the lids on and put em' in the shed.

I assume this will be good to use for parts later no? How long will it "Keep"?

Secondly, does alodine "where-out"? I noticed that towards the end of my wing ribs, i had to leave them in the solution at least twice as long to get equal results to some of the earlier ribs... could it be that this alodine is now "shot" and i should just get rid of it?

Regardless, im ordering another gallon of each right now just to have on hand... Hmmm?
 
Yes it certainly does wear out. I do believe alodine should be kept in a dark place. I tried to keep as little air in my containers as possible. If you need a large container but not deep try to find a shallow one and put your parts in and cover it over . Put the cover back on after you remove your parts and return the contents back into a sealed container as soon as you can. I believe air and light effects alodine, but that is just my experience.
Ron
 
Derek

I premix about two litres or so of Alodine and store it in a photograghic film processing drum. The ones for processing film negatives...remember those? And only because I had one.
It keeps the Alodine in the dark, where it's happiest. It's been there, well, a long time and still works great. However, I have a stash of flaked alodine that I use to "fortify"
the solution now and then. For Alumiprep '33', I keep in a large mouth plastic jar, sealed from fumes, for use as required.
 
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To store my Alodine I'm still using the long flat rubbermaid containers my wife had the extra Christmas wrapping paper in. I figure I have about 6 months before she notices they're gone. :D
 
WRT to Alumiprep, no real worries. It's just an acid, and it keeps.

BTW, the guy next door is a PhD in chemistry, and works for a major firm here in town. Showed him the documentation on the chemical cocktail that's Alodine, and he said "oh, be careful with that stuff....keep your skin covered, immediately wash off any that gets on you, and DON'T pour it down the drain!" Pretty conservative guy, no tree-hugging BS, but did get pretty animated when he saw the chromic acid listed.

Seems most RV builders are pretty smart about stuff like this, and if you're using AKZO primer, the precautions in using Alodine seem pretty minor by comparison.
 
I kept myself pretty well protected when I used Alodine. Even so, I noticed that fingers got yellow, even when handling with gloves.

In the end, I decided that at my age, the stuff will kill me a lot sooner than a plane crumbling with corrosion and I stopped using it.
 
This is all Henkel says about storage of Alodine 1201 -

9. Storage Requirements:
ALODINE 1201 coating chemical will freeze at 32? Fahrenheit. It is
recommended that the product be stored where freezing will not occur.
However, should it freeze, simply thaw it in a warm place and stir it prior
to use.

https://tds.us.henkel.com//NA/UT/HNAUTTDS.nsf/web/5966875CA5C37A6E852571ED0055ED8E/$File/ALODINE?%201201-EN.pdf
 
Alodine

I use it almost every day at work..Big jet overhaul facility. It is fairly toxic, and we mix large dipping tanks wich get a PH check occasionally, so we can add some more (powder) when needed. The more you use it, the more contaminated/weak it gets. For the purpose of our little RV's, keep in mind the most important thing is alodining the edges, and the drilled holes. That is where the alloy is exposed. A quick wash with scotchbrite and soapy water will prep everything well, as will alumiprep (mechanical vs. chemical etch). A good trick for small parts is a large ziplock bag...a couple OZ of alodine,part in bag and slosh it around. I use a spray atomizer, or cheeze cloth for applying to skin panels. Its not good to allow it to dry before rinsing. There is also a niffty alodine "pen" that resembles a fat magic marker available, which requires no rinse if your just doing a small spot. One important thing to remember, is dried Alodine on a rag is extremely flamable, as it becomes an oxidizer, so watch where you dispose rags/towels if not rinsed extremely well.
 
Alodine Observation

I used my batch of alodine yesterday from last weekend, which was stored in a 5 gal pail. I have to say, good thing I ordered more. The stuff I stored was almost worthless. Maybe would have worked, but i wasn't going to wait a half hour for it. I ended up adding about 3 pints of fresh to my existing 2.5 gallons.

More importantly though - I may do away with using alodine alltogether. For parts that fit in a container (ribs, etc) I usually alumaprep - alodine - prime with Akzo Nobel Epoxy. For skins, I have skipped the alodine step, (because of the hassle of alodining a large area.) I alumaprep with a squirt bottle and hit every square inch in a circular motion with a maroon scotch brite pad, rinse thoroughly, dry and prime

I have noticed that when I dimple parts (ribs) that were alodined, then primed, the dimple causes flaking of the primer at the dimple. However, I can dimple the skins (alumaprep and primer only (no alodine)) all day long and it doesn't even phase the continuity of the primer at the dimple. (equal cure time).
 
Alodine storage

Some Alodine I bought approx 3 years ago has developed some sediment, little flakes of black material floating in the liquid. Not knowing the Alodine should have been stored in the dark, I did not do this, but the amounts of light would have been very small.

Do the experts here think this material is usable?
 
Bluebeard said:
Some Alodine I bought approx 3 years ago has developed some sediment, little flakes of black material floating in the liquid. Not knowing the Alodine should have been stored in the dark, I did not do this, but the amounts of light would have been very small.

Do the experts here think this material is usable?
Click to expand...

Generally, sediment in the Alodine are salts which result from the active ingredients reacting with the aluminum. These sediments are usually green or blue in color. Best to drain off the sediments when you place the Alodine in your storage containers. This is easy to do, as they sink to the bottom. I've not seen black sediment, unless your Alodine was made from the powdered version. Simply try to Alodine a scrap piece of metal to determine if the Alodine is still good.

FYI, Alodine [and it's competitors] are photochemically reactive, so do not use them in direct sun light. Store Alodine and AlumiPrep in air tight containers [5 gallon paint buckets work well]. Store in a dark place. Keeping it away from light helps extend it's life. My experience is that liquid Alodine has about a 2 year shelf life. AlumiPrep on the other hand lasts MUCH longer. I have some AlumiPrep which is over 10 years old.
Charlie
 
Having recently tried out some fresh Alodine, I expected the aluminium to change color a bit, but it did not change appearance at all - is this normal?
 
Mine changed color

Bluebeard said:
Having recently tried out some fresh Alodine, I expected the aluminium to change color a bit, but it did not change appearance at all - is this normal?
Click to expand...

Below is a link to my kit log entry showing the alodined wing ribs. This was alodine 1201 diluted per instructions; after about a 3-4 minute soak (new alodine). The ribs would need to soak twice that long towards the end of the batch to get equal color.

http://www.mykitlog.com/users/display_log.php?user=dbro172&project=2102&category=0&log=151637&row=26
 
More than one version of Alodine

Bluebeard said:
Having recently tried out some fresh Alodine, I expected the aluminium to change color a bit, but it did not change appearance at all - is this normal?
Click to expand...

Bluebeard,
Which version of Alodine are you using? The 1201 version contains a dye, which turns the aluminum a nice gold color to tell you when it is ready to be removed from the dip tank [or sponge or other application method] Alodine 1001 does not contain a dye, and will not change the color of the aluminum. Like all chemical processes, heat affects the time required for the conversion to take place. Warmer = faster.
Charlie
PS Liquid Alodine 1201 [as well as it's competitor Iridite 14-2] appears as a brown liquid. Did your Alodine come in liquid or powdered form?
 
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Thanks for that Charlie.

My Alodine came as a brown liquid. It's no longer in its original container so I will have to do some research but I think it is Alodine 1200 from memory.
 
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