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Fast Lad Performance . Ace Hobby . Esprit Model

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CAD - Engineering - Technical > Home Anodizing
 
 
JCadwell
Key Veteran
Location: Richland WA/ Morro Bay, CA

Anybody out there doing this?

I'm using low current density anodizing in sulphuric acid, via Caswell Platings method.

I'm having problems getting a consistent sheen. I polish the parts, and then clean them as well as possible, but without a desmut bath. I can get the part to anodize evenly, and take dye evenly with both RIT dye and Caswell's dyes, but the part looks evenly colored but chalky when it is done. Am I overcooking the parts on the anodizing side?

Thanks, John Cadwell
02-26-2004 Over year old.
 
 
Hawk4flyer
Senior Heliman
Location: Deland,Florida

what type of metal??

How long are the parts submerged?

Are you stripping them before annodizing?

What is you current drop through the loop?

also, be sure to use really hot fluid with RIT dye.

Have you considered combinding the RIT and annodizer.

Lots of variables.

If you submerge the items for more than 15 minutes your prob'ly cooking them.

Be sure to strip them in sulf. acid just before plating.

(must note; I've never read the Caswell method. I worked a plating shop for a little while.)
02-27-2004 Over year old.
HOMEPAGE  
 
 
JCadwell
Key Veteran
Location: Richland WA/ Morro Bay, CA

6061 Aluminum.

Low current density of 4 amps/sq Ft. Using dropping resistors to limit current flow. Using the 4 amps the typical part takes 90 minutes, according to their literature. The advantage of low current density is no heating of parts or fluid, so less fumes, and easier to control. Slightly safer.

I'm not stripping any anodizing off, these are fresh machined parts, thoroughly cleaned. I've tried polishing to brilliance, as well as matte finish. I wash with soap and water, and I've also tried alcohol and thinners.

I'm not using a nitric acid desmut bath. Sulfuric will work?

I'm using fluid at about 140-150, as per instructions with Caswell dye. Caswell works a lot better than rit, but the dye costs a lot more. Go figure.

https://www.caswellplating.com/kits/lcd_ano.pdf has info on LCD anodizing.

I'm getting even color uptake, and consistent anodized surface, just not brilliant colors. They look overcooked.

Thanks, John Cadwell
02-27-2004 Over year old.
 
 
Hawk4flyer
Senior Heliman
Location: Deland,Florida

Sounds like you've got all the "eyes" dotted and the "T's" crossed.

Yes you can use SA to etch. just a couple of seconds though. You can also buy at the local paint store stuff called aluminum prep. Its just acid etch and soap. If you use these stuff, also rub the parts with scotch brite to help the soap clean out the grain. Rinse completely!!

Yes, low amper current is safer. I've never used low current, I find it just as easy or safe to vent the fumes. But, to each their own right.

After you machine these parts, what are you doing to prep them for plating? If the answer is nothing, you should at least etch them.

What is the size or shape of these parts. Billet alum. or thin sheet?

Is your conductor creating to much resistance? (wire used to hang the parts in the bath)

I would suggest that you first try the etching. If your still getting a powdery finish, try cutting the dwell time.

edit: Ok read the link you posted.

Are you applying the sealent? (caution!! polishing compounds leave a residue, wash the part before applying any sealant.)
02-27-2004 Over year old.
HOMEPAGE  
 
 
JCadwell
Key Veteran
Location: Richland WA/ Morro Bay, CA

I've tried anodizing both billet and machined parts. My results vary. I'm not using an etch. I usually lap the parts with sandpaper if they are flat, then polish with a polishing compound, and clean thouroughly, to the point of being able to pass the water drop test.

The anodizing is consistent across the part, and it takes color evenly. The finished part just looks hazy, or kind of milky. I'm sealing with boiling water. I think I may be anodizing the parts too long...

Thanks, John Cadwell
02-27-2004 Over year old.
 
 
JuanRodriguez
Elite Veteran
Location: Rochester, New York

I wrote an article on "Home Anodizing" which was published in Model Helicopter Technique in the Oct-Nov-Dec , 2000 issue.....

Take a look at that if you have a chance....

I was able to get very nice results.....
02-28-2004 Over year old.
 
 
JCadwell
Key Veteran
Location: Richland WA/ Morro Bay, CA

Any chance you have a copy of the article? I don't know where to get one. Thanks, John

Thanks, John Cadwell
02-28-2004 Over year old.
 
 
JuanRodriguez
Elite Veteran
Location: Rochester, New York

JCadwell

Shoot me a PM with your home address. I may still have it on my computer but if not, I'll burn off a copy of the article from the mag...
02-28-2004 Over year old.
 
 
Hawk4flyer
Senior Heliman
Location: Deland,Florida

Sounds like you've got everything under control. I'd say test 4 or 5 parts each at 15-20 minutes intervals. i.e. put all the parts in at the same time. then at 20 minutes pull one. then at 40 minutes pull another. and so on.

If nothing else that will show you how far you need to take it.

Hope all works out well.
02-28-2004 Over year old.
HOMEPAGE  
 
 
Jagboy69
Key Veteran
Location: Lake Mary, Florida (20 mins East of Orlando)

There was some guy I came across doing this in his shed with igloo coolers and battery chargers... But I think he blew himself up!
03-19-2004 Over year old.
HOMEPAGE  
 
 
jerrythercpilot
Veteran
Location: --South Florida --

Try a phoshoric acid etch prior to anodize. It will bring out a little better sheen. Phospohoric acid is sold under Ospho in Home depot and the like.
05-13-2004 Over year old.
 
 
cforcht
Key Veteran
Location: Chelsea in BFE Iowa

Jcadwell
here is a link to a guys site that walks you through the process. it works. i tried it in my shop in 5 gal. buckets and rit dye. i used the boiling water method for seal simply because i didnt have to put any money in to it in order to give it a try. the first attempt was a machined alum round slug. with 3 different finishes on it for comparison. one was machined the next sanded with scotchbrite. and the last was a mirror polish. i left it in the acid too long and cooked it which killed the mirror polish but the results were still excellent color and depth. no chalky residue like you describe. and i used a common larger battery charger and nothing fancy.

http://www.focuser.com/atm/anodize/anodize99.html
05-14-2004 Over year old.
 
 
jerrythercpilot
Veteran
Location: --South Florida --

The best, longest lasting dyes are the inorganic (salts) ones, the Rit dyes are organic and won't last very long. Also, consider sealing with Nickel Acetate solution.(This works much better than Hot water seeling). You can buy this, sulfuric acid,etc from Chemical supply house in Humble TX. I don't remember the name but I'm sure you can find it with Google and thy sell to anyone as long as your forst name isn't Mohamed. Caswell in Upstate NY sells supplies too. But they market the seeler as some proprietary snake oil.
05-14-2004 Over year old.
 
 
JCadwell
Key Veteran
Location: Richland WA/ Morro Bay, CA

I got the anodizing to work quite well. I was having problems with lack of aeration causing bubbles to form on the parts, and smutting (dirty metal that needs to be removed with acid. Cleaning and dipping in nitric (I think) acid will desmut, and adding a fish tank aerator will keep the tank aerated.

Thanks, John Cadwell
05-14-2004 Over year old.
 
 
jerrythercpilot
Veteran
Location: --South Florida --

almost forgot, sodium or potasium Dichromate works well as a seeler too and is better suited for sulfuric acid color anodize seeler.

The 6000 series alloys ie 6061 anodize very very well but the casting alloys found on most engines are 2000 series and contain Copper and look lousy anodized if you can even get anything more than a dark grey out of them.

You may be able to find AMS 2472 on line. It spells out concentrations, times , amps/sq ft, etc very well. Also AMS 2471 is useful too.

I do coatings for a living and set up a good line in my garage with tupperware and a 12 volt power supply., Also put a ziplock bag of ice in the tank when anodizing to keep the temperature down. Anthing above 80-90 will start to cause ti to self seal and it won't tak the dye very well if at all.

Jerry
05-14-2004 Over year old.
 
 
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CAD - Engineering - Technical > Home Anodizing
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