HA III Anodizing - any hobbyist out there?

[Mobius]

I've been trying to find a shop to have my KL3 re-anodize to HA III, hopefully in something other than natural color. A respectable CPFer already helped to strip the unit (if you're reading this you know what I'm cooking /ubbthreads/images/graemlins/wink.gif) so the KL3 is just waiting for a dip in those wonderful baths /ubbthreads/images/graemlins/smile.gif. I've called up many places and as a reputable local shop points out to me frankly, it's probably just a $5 job but the smallest batch they can start with is $75. Since I don't have 15 other KL3 to split the cost it's just too steep for a single piece.

So, here I am, looking to see if there's any small shop out there that provides reasonable quality with affordable cost. Please feel free to PM or post if you can or you think someone who can take up this job.

 

[Vee3]

You're probably out of luck unless you can make friends with someone at an anodizing shop.

I deal with three anodizing shops in SoCal, and all have the same minimum - $75. It just isn't cost effective for them to do small orders (Thus, the minimum lot charge). Class III anodizing takes (IIRC) four separate solution dips to complete the job. Many shops only do natural color in Class III since most customers only require colors for Class II (Sulfuric, or "soft" anodize).

Keep in mind that if you have dipped your part in a Drano (Or other caustic) solution to strip it, it will now have lost .001" or more material on the surface. This can cause fit problems in some cases....

 

[XtremePyro]

I have set up a small anodizing line to do my flashlight parts.
So far only doing Type II but im working on figuring out a way to do Type III in small batches so that I could harcoat my parts and small runs or single parts for CPF'ers since I know that is a stumbling block for many of us. There are addatives that allow Type III to be done at room temp however the higher amps required for Type III qickly raise the temp especially in smaller tanks, which means the tank still has to be cooled. So doing hardcoat anodizing on a small scale is difficult for the small scale operator but not impossible, and I for one am working on it, so maybe in the not so distant future
we will see alot more one-of parts in HA-III

Tim

 

[cy]

Tim, good job setting up to do HA. I used to routinely do batches at 150-250 amps in large several hundred gallon tanks. it had air agitation with cooling coils.

like you stated dificult to set up at home, but not impossible. having that much sulfuric acid around induces acid fumes on everything. everything metal in the entire vacinity will be coated with a light layer of rust or corrosion.

 

[greenlight]

how hot does it need to be? do you need a kiln? I passed one up for free last week at a garage sale, but I know they are available used cheap.

 

[Dr_Joe]

You might want to send it to Pablo (PEU on CPF) in Argentina. He's about to have several batches of his Neoca BL lights HAIII anodized in several colors. He might be able to add your KL3 to one of them !
Joe

 

[Mobius]

Dr_Joe - thanks for the info. Pablo probably has a lot on his plate already so I'll leave him alone /ubbthreads/images/graemlins/smile.gif

Tim - you're the most promising lead I have so far /ubbthreads/images/graemlins/wink.gif. Keep up the good work and hope you'll have a breakthrough soon.

 

[cy]

Modius, there is someone doing a A-19 extenders for Surefire. Several people are sending in their 6P to get HA'd. you should be able to get in on the group HA.

could someone please give a link?

 

[gadget_lover]

[ QUOTE ]
greenlight said:
how hot does it need to be? do you need a kiln? I passed one up for free last week at a garage sale, but I know they are available used cheap.

[/ QUOTE ]

The anodizing bath itself is heated. That's hot acid with some sort of agitator to keep it properly mixed.

I will NOT be doing this at home.

Daniel

 

[Mobius]

cy - thanks for the heads up. I was looking at that thread too but those A19 and 6Ps should already be taking an acid bath by now...

 

[mut]

You might try Peak.
I think MJ posted that they could possibly do some HA for CPFrs.

mut

 

[HarryN]

HA III actually requires the bath to be cooled, not heated. The current going through the bath will do all the heating you want, and more. Typical bath temps are 0 - 5 C IIRC. (Cy would know)

While it is not the only factor, bath temperature is a major difference between HA II and HA III, and the cooling is feasible, but requires real thought.

 

[gadget_lover]

Thanks Harry. Now that you mention that, the need for cooling is what I read.

At least I correctly remembered that you don't need a kiln /ubbthreads/images/graemlins/smile.gif

Daniel

 

[XtremePyro]

Yep, Putting current through a solution will raise the temp.
Temp is just one of the factors that affects the crystaline growth of the aluminum oxide. Current density, voltage, and holding your mouth just the right way are some others( just kiding on that last one ;-)
Doing regular ano the oxide builds up to around 0.001" before it reaches the disolution point, and you start to "burn" the part. Im still not totally aware of what happens on the chemical level when you burn a part, but its not good. So you cant just simply run a part longer to get a thicker coating of oxide. And if you just lower the temp (hardcoat is usually done just above the freezing point of water) then that in turn lowers the current density and it just takes the part longer to anodize. But low temps and a higher current density somehow causes the oxide to grow in a much smaller crystaline structure and thicker layer. Again im still trying to figure out the chemistry involved there. There is an adative, glycolic acid, that supposedly allows hardcoat to be done at room temp, which means less heat has to be dissipated. However
there seems to be some controversy over how well it works.
So more reading, research and testing are in order.
I'll stop rambling now.
Tim

 

[HarryN]

I would just like to note to the group that Tim (XtremePyro) is very good with his ano II work. I sent to him two parts that have are VERY difficult to work with, very small groove and holes - some would say it cannot be done.

Tim did a first round for me - great results on 99% of it, even some of the holes that others had said "no way". Not only that - he is willing to play with the parts to see if there is "some way" to get into those little tiny holes.

I for one am impressed - color was great, etc.

 

[cy]

Tim, cooling is required for HA to prevent sulfuric acid from eating into anodic film already built-up. total thickness including penatration into material is up to 3 mills.

chromate dip is becoming less common due to epa regs. use to dip parts into chromate without a thought.