Anodizing?

[Rizzle]

Anyone familiar with any small and affordable anodizing setups? Are you able to anodize in color similar to FDE, etc.?

[Dr Rockso]

http://www.focuser.com/atm/anodize/anodize.html

This is the site that Ray-Vin recommends in their guide to machining AR-15 lower receiver forgings.

[Dubious_Beans]

Sure. Start here:

http://www.caswellplating.com/electroplating-anodizing/anodizing-products/anodizing-kits.html

[kcstott]

FDE.
No
Anodizing as far as i know doesn't have any opaque colors. Even black is transparent to a small degree

And save you're self the trouble pay someone else to do it. It's not like parkerizing where you can get away with mild contamination. Anodizing needs to be done in a dirt, oil and grease free environment, with as little dust as possible.

The most minute of contamination can ruin a anodize job.

[Dubious_Beans]

Anodizing needs to be done in a dirt, oil and grease free environment, with as little dust as possible.

The most minute of contamination can ruin a anodize job.

^ Truth.

Proper surface prep and a contaminant free work space are the 2 hardest things about anodizing.
The rest is easy.

[Chu]

I just received my 80% lower today. I am attending a build party on the 22nd of this month in the bay area.

Does anyone know of a place where I can get my lower type iii anodized after I finish the receiver a few days before Christmas? I would like to get it done while I am in the area. I don't mind waiting at the shop until the work is done.

Thanks. =]

[Rusty Scabbard]

Setting up a home anodize for type II and coloring is not too difficult. Great info and supplies can be found here http://www.focuser.com/atm/anodize/anodize.htm . Sealer, dye and other stuff is also available from Caswells.
Follow bath temp guidelines, they can make or break the results. Calculate surface area, aim for a current density of 12 A/sq.ft. for 1 hr. If current density is a little off, adjust the anodize time accordingly. An adjustable electronic power supply is ideal. Battery chargers can work but getting to target current density is more difficult. Bath temp, cathode size and location will affect current. The bath will heat up during the anodize, especially if bath volume is small. A tupperware container in a larger water/ice bath to control temperature can work. Anodize bath needs to be well mixed with an air sparger. Wear goggles when using the acid. Remember always add acid to water, never water to concentrated sulfuric acid. Mix up the 15% anodize acid well before you plan to try anodizing. It'll take a while to cool. Neutralize acid and cleanup with baking soda. Costco sell 5 lb boxes. It takes a lot to neutralize 15 % H2SO4. Lye works as well, and can be used to strip a screwed up anodize attempt as long as it's done carefully.

[kcstott]

Problem is you can't type II 7075 it doesn't like it and the power supply to do it right is going to be pretty big.

Something the size of a lower is going to require about 15 amps to type II anodize.

[Rusty Scabbard]

I anodized a couple 10/22's and an AR. The 6061 10/22's came out near perfect with deep, even color. The 7075 AR came out pretty good but not near perfect like the 10/22's I ran the 10/22's at about 5.5A, 70 minutes. Ran the AR at 7A for 80 minutes. Voltage to run 7A was about 14.8. The 7075 mucked up the 15 % H2SO4 solution, but the one I did came out well enough. I agree the 7075 is more difficult, but it can certainly be done. I think Quentin and a few other paperweights are available in 6061 if someone wants a perfect color finish. But I prefer 7075 for the strength. I've almost kluged together a 70V 25A supply to try a type III setup, but haven't tried it out yet. ..Gotta be pretty careful with safety and grounding with this one...

[kcstott]

You will find that due to the composition of the aluminum in the 7075 alloy leaves a smut on the surface and it may not completely anodize. Sound's like you had better luck then I did.
I still don't recommend type II on a receiver. It's just to darn soft.

[ke6guj]

Vaderspade has posted some Type II anodizing info.

http://www.calguns.net/calgunforum/showthread.php?t=271990

http://www.calguns.net/calgunforum/showthread.php?t=611476

[eaglemike]

You will find that due to the composition of the aluminum in the 7075 alloy leaves a smut on the surface and it may not completely anodize. Sound's like you had better luck then I did.
I still don't recommend type II on a receiver. It's just to darn soft.

This.... Many don't understand the difference......

[Rusty Scabbard]

You will find that due to the composition of the aluminum in the 7075 alloy leaves a smut on the surface and it may not completely anodize. Sound's like you had better luck then I did.
I still don't recommend type II on a receiver. It's just to darn soft.

I'm curious how it will hold up as well. I only have about 200 rounds through the type II ano receiver. When it gets up to 2K, I'll check the pin holes for wear. Strength oughta be more dependent on the base alloy but if the color wears through then the hole's are getting bigger.
Regarding the smut, I did a desmut dip before starting. Whatever contaminated the bath came out during the anodize step- it coated the cathode black. 6061 parts did not do that at all. The ano layer looked even at first, but took up the dye kind of splotchy. With really good agitation I think the color would be more uniform. My tank wasn't tall enough or covered completely to really crank up the air bubbles without splashing. Volume was about 3.5 quarts.

[kcstott]

It's not an agitation issue is that alloying elements that have precipitated to the surface during the hardening and aging process. Your color is splotchy due to not being evenly anodized and that is why i said 7075 can not be type II anodized because the results are crapy at best. 6061 is the only alloy that works with any degree of success on a home brew set up. I had my set up for three years and made good money doing it. But on a home set up there are just to many limitations to work with. Unless you want to dump huge amounts of money on rectifiers and coating thickness gages, SG meter, coolant system, and agitation. It get expensive real fast.

The reason Type III works so well is the acid bath is a different concentration, The bath is refrigerated, and the current density is higher by as much a three times. So that 15 amps i guessed at will now be 45 amps requiring refrigeration of the bath.

As for the soft anodize layer. I'm not talking about pin hole wear. I'm talking surface wear. Type II has to be cared for in a different way it's soft it will ding, scratch, and fade. No thanks. These aren't paintball guns. The are service rifles and require a surface coating that can stand up to normal wear and tear.

Here's my copy and paste from my old web sight when I was doing this stuff.

Anodizing
First off I’m no expert at this. What I know is from pure trial and error and research on the web and talking with people in the industry. I’ll explain it the way I learned and make it as easy to understand as possible.
Lets start off with what Anodizing is as a process and as a surface treatment. Anodizing is a controlled oxidation of the surface of an aluminum part that can be a very hard and very durable surface. Type II anodizing is the process we are talking about here since I have never performed Hard Anodizing (type III) I will only say that it is performed in a cold acid bath at higher current levels to achieve the hard layer. ( because that is about all I know about the process )
Type II Anodizing is a very simple process that is performed in a sulfuric acid bath that is around room temperature plus or minus a few degrees with approximately 65 degrees F being Ideal. As DC current is applied through the part and a plate in the acid bath a reaction happens that causes the surface of the aluminum to change to aluminum oxide. The longer you leave the part in the bath the thicker the layer of aluminum oxide will be, But only to a point because as it gets thicker the acid is also eating away at the newly formed layer and it will reach a point of equilibrium and the layer will cease to grow. The typical thickness is only about .001.

The acid that is used is sulfuric acid and it is in a very dilute concentration. Around 10% acid to water is typical. I start off by buying pre mixed battery acid from Napa auto parts. A 1.5 gallon container is around $8.00 Then mixing this with distilled water at a ratio of 3:1 water to acid makes about 6 gallons. In my experience plus or minus a half gallon is not critical. ALWAYS MIX ACID WITH WATER NEVER WATER WITH ACID. Meaning pour your water into a container suitable to contain acid and then add your acid to this. Doing it the other way will create so much heat that you can cause the water and acid to boil. Very bad. It can get hot enough to melt the plastic container it’s in.

Power supply and set up.
I use a 12v variable current power supply that can handle up to about seven amps. This is about ideal for small parts. A lead or aluminum plate is placed in the bottom of the bath and the negative side of the power supply is connected to it. The part needs to hang in the bath buy a aluminum wire or titanium wire and connect it to the positive side of the power supply. Set your amps based on the part’s size and turn on the juice. Sit back and watch it run for about an hour then rinse in cold clean distilled water. then either dye the part in a heated dye bath (no hotter then 125 degrees F) then seal in a boiling water bath again clean distilled water.
Then polish with simi chrome or duraglit polish and thats it your done. Now I know I left out a lot. But I'm not going to reinvent the wheel here. Plating has all the info and supplies you could ever want.

What I will tell you is that it is a royal pain to do and you can not stop for very long between steps. As in minutes. If you stop for an hour or longer you run the risk of contaminating your part or allowing an oxide layer to build up. Either way this is bad. The part needs to go from the degreaser to the rinse to the anodize solution to the rinse to the dye to the sealer in one movement. with little to no delay between steps especially after anodize and before dyeing or sealing. This is the critical time to get things done. When I anodize I plan the day around it.
Bath temp is another critical part. If the bath is to hot the anodize layer will be to soft and will not hold up to any use. You must keep the solution temp at or near 65 degrees F and no hotter then 75 degrees F.

Clean distilled water must be used. Reverse osmosis is OK according to Caswell But I have had no luck with it and well you have no clue when the last time the filters where changed. So just go and buy distilled water and use it for your anodize solution, rinse, dye, sealer, and stripper. DO NOT USE TAP WATER. or bottled drinking water. It has minerals in it and will contaminate your parts.
One key is absolute cleanliness. Use of rubber glove is essential and rinsing them along with the part at each step is critical. Use of long cuff Nitrile gloves also recommended for handling parts to and from the acid bath

Stripping parts.
Stripping can be done with Pure lye and distilled water 1 Table spoon per gallon is enough to strip parts clean of the anodize layer. Red devil lye was the stuff to use but it has since been discontinued due to drug manufacturing. But once again Caswell will supply a stripper that works perfect.
I know I’m plugging Caswell But they have been a great help in being able to get supplies and info from. They pay me nothing to post my opinion. I’m just a loyal and satisfied customer.

Here’s the steps in a very basic form
1. Part preparation. The part should be clean and polished ready to go with no anodize layer on it.
While wearing rubber gloves dip the part in heated degreaser and gently wash it with a rag or soft cloth for finely polished parts or a tooth brush for parts that are bead blasted or scotch brite finished
2. Rinse in clean cold water.
3. At this time you can use a product called Desmut this is a chemical etch that further removes oxide layers. Rinse after Desmut dip.
4. Secure part on an aluminum rod (welding rod works well) or use titanium wire to hang part in acid bath.
5. attach negative lead to a plate in the tank and attach positive lead to hanger wire that is outside of the tank.
DO NOT LET LEADS (WIRES) TOUCH BATH, DO NOT LET ANY OTHER METALS COME IN CONTACT WITH ACID.
6. Connect leads to power supply (rectifier) and set amps accordingly. 30 milliamps per square inch of surface area
7. Let part run for approximately 90 minutes.
8. Dye part in heated dye bath (110 Degrees F) until darker then color desired.
9. Seal in boiling water or add sealant powder from Caswell.
10. Lightly polish with a soft cloth and some simichrome.
Sit back and admire your work


That was from back in 03' or 04'