how is anodizing done

Its a multi-step process using acids, heat, dyes and electrical current. Mark does it in his home.

https://www.youtube.com/watch?v=qr-zd6StOOw

Kits can be bought online to do it yourself, however they're a bit pricey. You have to look at your goal. Are you going to do this to many parts? Or are you just trying to do a couple parts? Many places offer the service and usually have a minimum price of around $65 and I believe they charge by size.

All aluminium and alloy products have a very thin layer of oxide on them (Aluminium reacts rapidly with oxygen). You simply use an electrolytic process to grow a very thick aluminium oxide layer on the aluminium. The oxide has lots of very long tunnels going from the surface of the oxide layer down almost to the aluminium surface. If you then dip the item into a dye bath, the dye gets into the tunnels. If you then drop the item into boiling water the tunnels gets sealed over. That is all there is to it. A simple process that you can do at home. You can even buy kits for it!
To get a really good anodised surface takes some experience, but it isn't too hard to do. The surface becomes really hard too as the aluminium oxide is one tough material. Cox crank cases are always anodised (mostly the dye bit is left out). This produces a very hard surface in which the crank can run without excessive wear. This is the reason that you should never lap the crank in the crank case. If you do, then you will destroy the bearing surface!

Andrew.

Andrew,

I'm not 100%, but I don't think all the machined cases were anodized, only the ones that were slated for color.

Hi Mark,
I am referring to the cases made from extruded bar. This material is quite soft and I am certain it wouldn't act as a suitable bearing material for a crank. The cast cases are a different matter, cast alloy is harder and many small plain bearing engines simply used the cast material as a shaft bearing and all is well.
As a lad, I lapped in a cox 0.49 shaft/case, because it was tight. I thought I was being smart. It resulted in a good bearing clearance. The case lasted about 3 or 4 runs and was completely scrap. I was then told about the anodising on all the Cox cases to give the tough bearing surface.
Ask someone like Larry Renger, he should know the truth or otherwise of my claim.

Regards,

Andrew.

Yes, those are the 'machined' cases. It's a good question and i'll verify, my fuzzy brain says this was brought up before years ago and they weren't anodized. I think the machined/extruded aluminum is actually harder then the cast cases, early Thimble-Drome cases has bearing material in them, as did the first Wen-Mac engines.
I think the manufactures figured out early on that their toy engines really didn't need to be built to last. I remember a lot of guys using Black widow cases cause they lasted a little longer?

Hi Mark,
I will try to contact Larry Renger and find out the truth, he should know as I believe he worked for Cox!

Happy Christmas,

Andrew.

tonsberg wrote:Hi Mark,
I will try to contact Larry Renger and find out the truth, he should know as I believe he worked for Cox!

Happy Christmas,

Andrew.

Larry logs into Stunthanger.com about every day, so you can PM him there. He mostly frequents the 1/2A section. Although he's a member here, he has not logged in in two years.

Rusty

Hello Rusty,
I emailed Larry a couple of days ago and as yet I have not had a reply. I did contact Paul Gibeault and got a reply which doesn't settle the question. Paul thinks that all the Cox crank cases were hard anodised but can't be sure. He emphasised that you should NOT lap a cox crank in the crank case, which makes me feel that the crank cases were hard anodised.
As soon as Larry gets back to me, I will pass on the information.

Happy New Year,

Andrew.

I'm still leaning towards the concept that the only cases anodized were the ones earmarked for color, based on a 'fuzzy' conversation years ago.

Based on the business aspect, that why would you go thru a manufacturing possess that cost money and time without a benefit?

Based on the fact that I never seen it mentioned in any Babe Bee test review, if it was a added value, you would think that it would be mentioned?

Based on the fact that all anodizing was out sourced, so that would mean every case made had to be sent out, then shipped back to be assembled?

Based on the fact that you can't take a case that's supposedly been anodized and dip it in dye and if was because it was 'sealed' why would you seal 'clear'?

I think the reason you don't lap a case is the simple fact that steel is harder then any aluminum, anodized or not, and there's no need to as it will wear in just fine in its own time?

The "bare" aluminium crankcases in all machine finished Cox crankcases are not adonised. The surface is soft, very easily scratched and also very quick to prepare for adonising.

This would not be the case for adonised aluminium.

I am not in the business of speculating. Much easier to wait for Larry to give a definitive answer.

Regards,

Andrew.

As I was woken at 4.00 am, I penned the above reply. I also put the words "Black Widow reworks". Up popped a thread, entitled just that, which was posted on the 1/2A section of Stunthanger on the 18th December 2012. Sorry I can't give a link, I have forgotten how one does it.
Larry clearly states that you must not lap a crank into a crankcase, quote "Only the anodizing provides a hard enough surface, to withstand hard use; cut through that and you are doomed to a short life"
Obviously the Black Widow is anodised black! However I have built up many cox reedies with plain case to far better than Black Widow specs. These have had a very hard life indeed , either the piston cylinder wears (genuine TD items) or the crank breaks (using killer cranks now). I have never had excessive wear in the shaft case area. Which leads me to believe that all cases are anodised. But I could well be wrong. Mr Renger is the man who knows, he is probably on vacation right now sunning himself!

Regards,

Andrew.

WIKI sez:
1956 Babe Bee 049 (Cat#350 - Manufactured Nov 1956-Jan 1996)
The classic Babe Bee was the first engine Cox produced with an extruded machined anodized bar stock aluminum crankcase. This crankcase was machine made and was much cheaper and faster to make than the cast aluminum crankcase of the earlier models. This engine was also supplied in thousands of RTF (Ready to Fly) airplanes sold in department stores worldwide. It has an integrated 5cc fuel tank. Max output power was recorded around 0.057 bhp (42 watts) @ 13,500 rpm on 15% nitro.[12]

tonsberg wrote:...Mr Renger is the man who knows, he is probably on vacation right now sunning himself!

Regards,

Andrew.

Hi Andrew. I'm surprised he hasn't responded. Maybe the email address he used for his Stunthangar registration is not one of his main mailboxes. He was logged in at SH yesterday. If you don't hear back from him by the end of the holidays, it might be worth PMing him over there. If you don't wish to join SH, I'll be glad to post the PM in your behalf. I'm interested to hear his reply too.

Rusty

Hello,

I've been corresponding with Larry for many years and sent him a email couple days ago, here's his reply:

"Only the colored cases were anodized. Also, the high performance engines used a better, more expensive alloy."
Sent from Larry's I-pad

Second reply:

"Tee Dee, Killer Bee and Venom engines all had the better material and anodizing. Black Widow, Texaco, etc. only anodizing."

So there's something I never knew, Cox used two different grades of extruded aluminum?

Also, here's another twist to this thread, I got ahold of Mud (finally) and he says for a time (late fifties-early sixties) all the cases were anodized? The story gets deeper, hopefully well get more info.

Hi Mark,
Looks as though I was wrong big time on this one. I can't remember where my erroneous info came from, but I certainly believed what I read! Still not got a reply from Larry, I must assume that his email address is out of date on his Stunthanger profile. I should have PM ed him instead.
Interesting info about the two grades of alloy used in the extruded material used by Cox, that certainly is new to me. Interesting that Mud claims that at one stage, all cases were anodised, maybe that is the origin of the info that I read.
All in all worthwhile looking a fool if we learn a little more about manufacturers. It is stuff like this that I find so fascinating.

Happy New Year,

Andrew.

Lol, it looks like you might of been half right and I was half wrong...or visa versa!

Unfortunately there's so much info lost to father time or just heresay that become fact, Info becomes fact...because it was printed or posted somewhere.

According to Mud, after the cases were machines they were sent out to be anodized and returned, the was stopped in the early 60's.

As a collector I find these type of questions very interesting, it's like discovering a new version of a plastic plane I never new existed. I'm still waiting for more info from 'Mud' and will post more ASAP. Meanwhile evidence may have been under my nose all this time, look at the early (c. 1958) 'mint' Babe Bee from a Super Cub 105, if your notice the aluminum has a slight 'tint' or 'hue' to it, often seen on anodized aluminum, or its just the light reflecting off of it?

GO BEARS!!!

A quick way to check if an aluminum part is anodized is with a volt/ohm meter set on ohms. Anodized surfaces do not conduct electricity. Hope this helps.