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qiutong
12-12-2008, 10:02 AM
Okay, I'm new here. I read alot of the previous posts and couldn't find/missed the answer to my question. I recently started building an RV-7 and would like to use Alumiprep/Alodine before priming with PPG DP epoxy primer. I would like to dip my parts in the Alumiprep/Alodine solution. My question is: After I have dipped my last part in the diluted Alumiprep or Alodine solution, can I keep the leftover solution stored for future use on the next pieces I need to prime? I've found these forums to be very helpful and I'm hoping that someone will be able to help me out. Thank you in advance.

Brad

Mike S
12-12-2008, 10:41 AM
Brad, first off, welcome to VAF:D

As to the storage of the chemicals, I got a couple of old 1 gallon plastic bottles, with good lids, and just poured the dilute solution back into them when I was done, keep the cap on tightly, store in the stereotypical cool dry dark place.

Be sure to label the bottles, and that way you wont put the etch into the Alodyne or such.

Good luck.

qiutong
12-12-2008, 11:15 AM
Thanks for the quick response Mike,
When you used the stored mixtures later, did they work as well as when they were new, or did they lose some of their effectiveness. I'm hoping they can be used again and again without affecting the results. That way I can save some money, time and not have to worry about disposing of the solution after every use. Thanks again Mike.
Brad

thallock
12-12-2008, 11:21 AM
Brad,

Both alodine and alumniprep will lose their effectiveness after use. The more they are used the weaker they get. However, if not used and stored in a cool dark spot, they will still work after considerable lengths of time (like several years).

Tracy.

Mike S
12-12-2008, 11:35 AM
Thanks for the quick response Mike,
When you used the stored mixtures later, did they work as well as when they were new, or did they lose some of their effectiveness. I'm hoping they can be used again and again without affecting the results. That way I can save some money, time and not have to worry about disposing of the solution after every use. Thanks again Mike.
Brad

Brad,

Both alodine and alumniprep will lose their effectiveness after use. The more they are used the weaker they get. However, if not used and stored in a cool dark spot, they will still work after considerable lengths of time (like several years).

Tracy.

My experience is the same as Tracy's.

The strength does go down, but the solution is still usable for quite a while.

qiutong
12-12-2008, 11:58 AM
Thanks guys,

So I guess I should be able to do my empennage pieces and then store the solutions for...let's say, a year...then do the wing pieces, only I'll let them soak a little longer since the solutions will be weaker having been used previously, right? That's what I was hoping to hear.

Did you guys get your chemicals locally, powdered or liquid? I haven't bought any yet, but I was thinking of ordering through Aircraft Spruce. I'm not even sure where to start looking locally. I'm sure I'll learn all of these things as time goes by and I start to get into "the groove" of building.

I'm also sure that I'll be using this forum to get many more answers as my project moves along. Thanks again for the help.

Brad

rleffler
12-12-2008, 12:34 PM
Did you guys get your chemicals locally, powdered or liquid? I haven't bought any yet, but I was thinking of ordering through Aircraft Spruce. I'm not even sure where to start looking locally. I'm sure I'll learn all of these things as time goes by and I start to get into "the groove" of building.



Don't buy from ACS unless your independently weathly. Get it in powder form. It's cheaper to buy and will cost less to ship. Plus you don't have to mix it up all at once, so shelf life is extended.

I got Dorado Kote 1 from Eldorado Chemical (http://www.eldoradochem.com/). A spec sheet can be found at http://www.eldoradochem.com/pb/Dorado-Kote-1-PB.pdf.

FredMagare
12-12-2008, 02:28 PM
Brad,

Both alodine and alumniprep will lose their effectiveness after use. The more they are used the weaker they get. However, if not used and stored in a cool dark spot, they will still work after considerable lengths of time (like several years).

Tracy.

I respectfully disagree. I have alumiprep (only - no alodine) stored in a five gallon bucket (originally diluted with 2 gals alumiprep/3 gals distilled water). Nearly three years stored and still working great! However, I did have the original five gallon bucket crack. The alumiprep spill seriously etched my garage floor to a depth of about 3/4 of an inch! :eek: If you store in this manner, I suggest you keep the bucket on a tray which will contain any spill.

Mike S
12-12-2008, 02:39 PM
Brad, I found both chemicals at a local automotive paint supply store.

They kept the etch in stock in gallons, and the alodyne in stock in quarts, but were able to order it in gallon jugs.

Fred makes a good point about storage, this stuff is pretty aggressive.

airguy
12-12-2008, 03:06 PM
The Alumiprep is primarily phosphoric acid, and it will do quite a number on concrete or metal if spilled. It will also react vigorously with the binding glue contained in plywood, particle board, or MDF. A couple drops on my MDF workbench caused the wood to pillow up about 1/2".

Alodyne is photoreactive, meaning that UV light will cause it to decompose. I keep my Alodyne jug inside a cardboard box, taped shut, to keep UV from my overhead flourescent lights and sunlight from getting to it. It's chromic acid and will also be corrosive if spilled, but not to the same degree as the alumiprep.

rocketbob
12-12-2008, 03:13 PM
I respectfully disagree. I have alumiprep (only - no alodine) stored in a five gallon bucket (originally diluted with 2 gals alumiprep/3 gals distilled water). Nearly three years stored and still working great! However, I did have the original five gallon bucket crack. The alumiprep spill seriously etched my garage floor to a depth of about 3/4 of an inch! :eek: If you store in this manner, I suggest you keep the bucket on a tray which will contain any spill.

Yep me too, my 5 gallon bucket has been sitting for a few years and still works fine.

qiutong
12-12-2008, 09:04 PM
Thanks for all the advice and information everyone,

I've looked locally at a few auto parts places and paint suppliers, with no luck, but living near Cincinnati, I'm sure that I will find it somewhere. Now I know exactly what to ask for when I call for information, rather than just trying to explain what I'm trying to do. It seems to be a strange thing for people to understand that I'm planning to build an airplane!

I'll also be cautious about storing it. Sounds like it's some pretty nasty stuff, I'll be glad to keep it until I'm done (hopefully), then deal with it's disposal only once.

This is only the second forum that I have ever posted on. The first one was a job search forum, but this one is a lot more fun. Thanks again guys!

Brad

mikehoover
12-13-2008, 07:25 AM
Thanks for all the advice and information everyone,

I've looked locally at a few auto parts places and paint suppliers, with no luck, but living near Cincinnati, I'm sure that I will find it somewhere. Now I know exactly what to ask for when I call for information, rather than just trying to explain what I'm trying to do. It seems to be a strange thing for people to understand that I'm planning to build an airplane!

I'll also be cautious about storing it. Sounds like it's some pretty nasty stuff, I'll be glad to keep it until I'm done (hopefully), then deal with it's disposal only once.

This is only the second forum that I have ever posted on. The first one was a job search forum, but this one is a lot more fun. Thanks again guys!

Brad

Check to see if you have a FinishMaster in your area. The one here in SC carries DuPont products, DuPont 215 (alum prep) and 216 (alodine equivalent), and Variprime primer.

qiutong
12-13-2008, 07:55 AM
Thanks Mike,

I checked and there is a FinishMaster in Cincinnati. I will call and check if they have the Dupont equivalents available. A lot easier than having to order/ship if I can pick them up myself!

Brad

FredMagare
12-13-2008, 09:08 AM
I'll also be cautious about storing it. Sounds like it's some pretty nasty stuff, I'll be glad to keep it until I'm done (hopefully), then deal with it's disposal only once.


My diluted Alumiprep is not all that aggressive but I still wear chemical gloves when using it. I've spilled some on my skin but I just rinse immediately with water with no ill effects. (If you leave it on your skin, it'll let you know it's there with an itch that starts to feel like a burn but again - rinsing with water takes care of it.)

Regarding my spill - the bucket was clean but old (mia culpa!) which is probably why it cracked. The spill had probably been there for two weeks or more. I think if I had caught it sooner the damage to my garage would have been limited to discoloration and light pitting.

Good luck.

chaskuss
12-13-2008, 12:28 PM
Mr Maxwell,
As others have stated, chromic acid conversion chemicals (including Alodine, Iridite and DoradoKote) are photo-chemically active. DO NOT use them in direct sunlight. If you do, those chemicals will only work that first day! The sun light will ruin them. I store my chemicals in 5 gallon plastic paint buckets, like those sold at Home Depot. These containers have tight lids with an air tight seal. I place the buckets at the rear of my shop, under my work bench. This keeps them away from the shop lights.
I do all my etch/Alodine work in my shop (in shade) with the overhead door open for good ventilation. When I make temporary large vats (for large parts), I use an aquarium pump to transfer the chemicals back into their storage buckets when done.
My experience is that liquid Alodine is good for about 2 years. I am still using the same AlumiPrep I purchased 7 years ago. It's diluted 5 to 1 and still works great. To dispose of AlumiPrep or it's competitors, simply pour it out on concrete. Your garage floor or driveway works well. The lime in the concrete will neutralize the AlumiPrep AND clean the concrete at the same time. Be sure to rinse it off the concrete when finished.
Try to buy your Alodine/Iridite/DoradoKote in powder form. The powder can be stored for many years, if placed in zip lock bags. You can also use it to "freshen up" your fading liquid. Purchasing in powder form will result in a 90% cost savings, as well. I went with MacDirmid's Iridite 14-2, because their distributor in Miami was close to me. Check with Heinkel Corp, MacDirmid and Eldorado Chemical to see if they have a distributor near you. They usually sell the powder in 10 pound lots. This is enough to make 100 gallons of liquid. I was able to dip even the largest pieces using only 40 gallons. Around here, we try to share a purchase of powdered Iridite between 2 or 3 builders. I paid about $180 for 10 pounds about 4 years ago. That works out to $1.80 per gallon. Last I checked, liquid Alodine was over $27 per gallon. MacDirmid also sells their etch chemical (IsoPrep 188) at a discount in 5 gallon jugs.
Charlie Kuss

Michael Burbidge
12-13-2008, 05:52 PM
Elderado no longer carries Alodine power. A month ago I did an extensive search and finally found a place that carried small amounts (2 lbs). I got mine from http://www.pegasusautoracing.com. It was $80 for 2 lbs. You need just over an ounce per gallon. So yes it is very inexpensive compare to the liquid form from ACS.

I think Alodine is a trade name. The stuff I bought was called Iridite. But it is the same stuff and is working very well.

Here's the exact page http://www.pegasusautoracing.com/productdetails.asp?RecID=6081

PJSeipel
12-14-2008, 07:22 AM
For the folks who are new to the powder....please read the MSDS before you use the stuff. Chromic acid in concentrated form and packaged as a powder can do quite a number on your lungs if you use it without a respirator and inhale some by accident. Since hexavalent chromium is carcinogenic, it could cause further problems down the line as well. Point being, don't try to mix it on a windy day with the garage door open, and make sure whatever container you put it in is spill-proof.

Also, always add the powder to water, never the other way around or you risk a big splash of concentrated acid.

I bought 5 lbs from El Dorado several years ago, and unless you're trying to make 40 gallons and dip large parts, the 2lb from Pegasus ought to get you pretty far. I've alodined just about everything using some large flat tupperware containers, or for the long things like spars the foodsaver bag rolls work very well so long as you don't poke holes in them.

PJ Seipel
RV-10 #40032

chaskuss
12-14-2008, 01:43 PM
Elderado no longer carries Alodine power. A month ago I did an extensive search and finally found a place that carried small amounts (2 lbs). I got mine from http://www.pegasusautoracing.com. It was $80 for 2 lbs. You need just over an ounce per gallon. So yes it is very inexpensive compare to the liquid form from ACS.

I think Alodine is a trade name. The stuff I bought was called Iridite. But it is the same stuff and is working very well.

Here's the exact page http://www.pegasusautoracing.com/productdetails.asp?RecID=6081

Interesting! Pegasus is owned by Chris Heitman. Chris built an RV-9A. I've used both Alodine 1201 and Iridite 14-2. They are both essentially the same product. You can even mix them, I have. I purchase my Iridite (the nearest Alodine distributor is in Atlanta) from Allied Welding Supply in Hialeah, Florida (just north of Miami) I paid around $180 for 10 pounds, but that was 4 years ago. It came in the same can as shown on Pegasus' web site below.

http://www.pegasusautoracing.com/productdetails.asp?RecID=5590

If you are ever in the SE Florida area, I have about 25 gallons now in liquid. I could probably spare about 10 gallons of it.

PJ is correct about being careful with chromic acid solutions. I always wear latex rubber gloves. I advise wearing long sleeve shirt and pants to prevent minor spills from getting on your skin. Also keep extra socks at the ready. The few times I spilled it on myself was when trying to ladle the acid out of very large, temporary vat tanks (doing large skins). I seemed to spill it on my socks. I would just slip off my shoes and socks. I would then rinse off my feet and ankles using the garden hose.
Once I purchased an aqurium pump and hoses, I never spilled it on myself again.
Charlie Kuss

bruceh
07-23-2009, 11:03 PM
My Dad recently donated a bunch of stuff to my RV project. He gave me a quart each of Alodine 1201 and Alumiprep. He probably bought these 20 years ago, so I was curious whether they were still effective. I don't know how these were stored.

Tonight I played around with etching and alodining some scrap aluminum. The Alumiprep was mixed 1-1 with water, sprayed on, scrubbed with a scotchbrite pad, and it seemed to be very effective at etching the aluminum. Water sheeted right off in the rinse.

Next I brushed on the alodine. Nothing. No noticeable coloring change. I dipped it for several minutes. Still nothing. No color at all.

Alodine definitely has a shelf life, and the Alumiprep is still relatively effective after 20 years. Now I need to figure out how to safely dispose of the alodine.

rjcthree
07-25-2009, 07:36 PM
The alodine solution breaks down with light, primarily, per the materials engineer at work. Time will do it too. Check the website, it's got disposal requirements, and be warned, it's intensive.

Rick