Measuring parts surface area for cc anodizing ???

redlaser666 · 03-18-2013, 10:42 AM

I am going to try to do some anodizing using a constant current rectifier and I know that in order to calculate the current and time needed for anodizing I need to know the surface area of the parts.

How do you measure or calculate the area for complex shapes like gun bodies or frames?

Is there an easy way to estimate the measurements?
If not, how do you measure this stuff?

Thanks!

xsvdynastypballa · 03-18-2013, 06:13 PM

Run a constant voltage instead of cc. Really the big reason to run a CC setup is to get consistency, but with the complexities of markers today trying to calculate exact surface area is not plausible.

The only way to get it exact is to get the surface area from the manufacture. Which I have not tried yet.

redlaser666 · 03-18-2013, 08:51 PM

OK. If I use constant voltage how much voltage and current are you using for a single body? My first experiment will be using a VL Triad body as a sacrificial test subject.
I have a 30V 10A adjustable supply and a small one gallon cooler I will be using. I will also use a Lead wire bent to cover one side of the tank.

I would appreciate any more suggestions to get me started.

My goal is to anodize a raw FMB autococker body I have had for a few years and I think it is finally time to give it some color and finish the project.

xsvdynastypballa · 03-18-2013, 11:41 PM

15v for One to one hour to one and a half hour should get you what you need.

It will probably put you roughly around 4a. Don't freak out if its not, that was just a guess.

Its something you will need to tune in though. Temps and acid concentration will both play a big role in you success.

All I can says is you better have some good agitation! You can't get to rough!

redlaser666 · 03-19-2013, 10:53 PM

Thanks for the tips.

I am planning to use a fish tank pump to help agitate the acid and use frozen water bottles to control the temperature.

redlaser666 · 03-24-2013, 03:00 PM

I did some measurements on one of the practice bodies I have and came out to be around 130 sq inches. Using the 720 calculator that would come out to be 5.42A for 72 minutes using 15V. This is for a .7mil coat at 6a/sqft

So pretty close to what xsvdynastypballa recommended!

Thanks!

Stepchild · 03-24-2013, 08:30 PM

I'm not a fan of using constant Voltage at all. To each there own but I have always had much better results with constant current.

If I remember correctly caswell's ano forum had a post with a list of paintball parts and guns with their approximate surface areas somewhere.

Another way to do it. Get a test piece of aluminum that is exactly 1 sqft. Put it in the ano bath and adjust your voltage to the point where you are getting the amperage you want. Say 6 amps. This will give you the voltage you need to run to get the 6 amp/sqft you want for your specific ano bath. You can then put the parts in the ano bath without measuring the surface area. Now put you rectifier in constant current mode and turn the current up until your rectifier holds the previously determined Voltage for a min or so. This will set your rectifier to run at 6 amps/sqft no matter what the surface area is.

If you want to test it. Put a 1 sqft piece of Al in the ano bath and find your voltage to run it a 6 amps. Then put a 2 sqft piece in there and turn the current up until you reach the same voltage. You will be running at 12 amps give or take.

OK, with that said. This is not a full proof method but does work well. The voltage you will want will change over time as your acid bath changes. So I would recommend re testing every month or so to make sure it hasn't changed a lot. I have been using this method for years now without a single issue as long as I re test every once in a while.

redlaser666 · 03-24-2013, 08:46 PM

WOW! This is a great idea!
Thanks, this is just what I needed!

I will not be doing a lot of anodizing, 4 or 5 guns at most in the whole year so this simplicity will come real handy.

xsvdynastypballa · 03-25-2013, 09:04 AM

Quote:

Originally Posted by Stepchild

I'm not a fan of using constant Voltage at all. To each there own but I have always had much better results with constant current.

If I remember correctly caswell's ano forum had a post with a list of paintball parts and guns with their approximate surface areas somewhere.

Another way to do it. Get a test piece of aluminum that is exactly 1 sqft. Put it in the ano bath and adjust your voltage to the point where you are getting the amperage you want. Say 6 amps. This will give you the voltage you need to run to get the 6 amp/sqft you want for your specific ano bath. You can then put the parts in the ano bath without measuring the surface area. Now put you rectifier in constant current mode and turn the current up until your rectifier holds the previously determined Voltage for a min or so. This will set your rectifier to run at 6 amps/sqft no matter what the surface area is.

If you want to test it. Put a 1 sqft piece of Al in the ano bath and find your voltage to run it a 6 amps. Then put a 2 sqft piece in there and turn the current up until you reach the same voltage. You will be running at 12 amps give or take.

OK, with that said. This is not a full proof method but does work well. The voltage you will want will change over time as your acid bath changes. So I would recommend re testing every month or so to make sure it hasn't changed a lot. I have been using this method for years now without a single issue as long as I re test every once in a while.

This is how I operate, but I didn't figure he had a chiller to the keep temps consistent so I recommended to just run at 15v. I figured it would be less figuring for him with little change if any in results.

I guess I might have chosen my words wrong. Technically you would still be running in Constant Current. You would just be setting your voltage at 15v and noting your current.

I am unfamiliar with switching between constant current and constant voltage. My power supply is just a simple cc work hoarse. I would say keep your PS in CC mode if that keeps current steady and lets voltage fluctuate.

Ford · 01-18-2020, 02:14 PM

Quote:

Originally Posted by redlaser666

I did some measurements on one of the practice bodies I have and came out to be around 130 sq inches

Sorry to resurrect the dead, but has anyone else tried to calculate surface area of a cocker body? Math and I have a tough relationship but i'm In the ballpark more like 65-70 inches of surface area on a unibody.

I'm guessing maybe this 130 figure accounts for barrel, trigger frame, back block, front block?

Again, math is that hot girl I was always afraid to talk to in high school so I could be way off myself.

Ford · 01-20-2020, 06:28 AM

Well, in case someone else gets stuck on this issue, I put down the caliper and scratch paper, downloaded Fusion 360 and imported a CAD file form this site: http://www.zdspb.com/tech/misc/cadfi...utococker.html

Downloaded the top most option which matched my project best. The app is telling me the surface area is 86.676 inches squared.

Stepchild · 06-10-2020, 02:11 PM

Quote:

Originally Posted by Ford

Well, in case someone else gets stuck on this issue, I put down the caliper and scratch paper, downloaded Fusion 360 and imported a CAD file form this site: http://www.zdspb.com/tech/misc/cadfi...utococker.html

Downloaded the top most option which matched my project best. The app is telling me the surface area is 86.676 inches squared.

This sounds about right. There are so many cuts and internal air passages on modern bodies, it would be almost impossible to really measure the surface area by hand. CAD files are a good way to do it but but most companies are not going to release either CAD files. Kinda cool that zdspb has a cocker file though.