[Concepts_Design]

Does anyone have experience with DIY anodizing ? I see that Caswell sells some kits, but not sure of the quality or ease of use.

Basically I need to anodize aluminum parts quite a bit and don't want to deal or rely on local plating companies due to lot charges and their lead times.

All I need Is basic black anodizing for corrosion resistance. I don't really have the need for any other colors or other materials other than aluminum. I do however have the need to anodize plates up to 24" wide by 36" long , usually between 1/4" - 1/2" thick.

Any help Is greatly appreciated , I just don't want to buy a kit that is inferior in quality or has a bunch of useless items for me, such as other colors or materials

Kyle

[SCzEngrgGroup]

I looked into that, and did one batch of parts. That was enough to convince me the cost of having it professionally done was money well spent. It's a nasty, messy, time-consuming process. The results were fine, but it's a big hassle.

Regards,
Ray L.

[Concepts_Design]

Thanks Ray, this was one of my big concerns. It certainly doesn't seem like a clean process, I can't even stand painting... But the lead times with platers are killer

[inov8r]

Would something like John Norrell's moly resin work? The stuff is super tough and adheres well to aluminum. Oh and easy to use!
John Norrell Arms - FAQ's

[jcposada]

I have the Caswell kit and am happy with it, but I do not use it for production work and have never done anything that large. It will work just fine, but you are looking at a big power supply and large tanks. Attachment 273666Attachment 273668Attachment 273668

[GLCarlson]

I looked into that, and did one batch of parts. That was enough to convince me the cost of having it professionally done was money well spent. It's a nasty, messy, time-consuming process. The results were fine, but it's a big hassle.

Regards,
Ray L.

I completely agree. I'm a chemist by training (that is, predisposed to like this kind of mess, and -at least once upon a time- competent to do it). I've tried anodizing off and on for 30+ years, as various kits and "easy" methods have appeared. One can do it...if one is prepared to set up and maintain a major wet chemistry project, and learn enough to do so consistently, in addition acquiring the necessary hardware to do appropriate testing and QC to get a commercial quality result. The various kits do work, but "it's a big hassle".

[DiverBob]

I have a multi color anodizing lab setup in my basement. This is a process that you can do at home but I would recommend a professional shop for the size of pieces you are talking about. It is best to do small pieces at home. One of the main pieces of equipment you need is a good DC power supply that you can control the current and let the voltage float. The general rule for anodizing is 12 amps for every 1 square ft (144 square inces) that you are anodizing. This is to build a 0.001 layer in one hour. This also requires a tub large enough to get your piece into it and in enough 15% sulfuric acid to submerge it. That alone would be a major expense. You will also need a large dye tank that can be heated to 140°F. That's why I say keep to the smaller stuff. My anodizing tank is 18" by 24" and 5" deep. That's the limit I have and my power supply limits the number of square inches. Look on YouTube and search for anodizing, there are several good guides out there. I even have one that shows my setup (search for Bob Sweeney) if you are interested

[SCzEngrgGroup]

Thanks Ray, this was one of my big concerns. It certainly doesn't seem like a clean process, I can't even stand painting... But the lead times with platers are killer

You need to check around as prices vary greatly. I use a local shop with excellent prices, and generally get a 1-day turn-around. Cost works out to about $1/part. It would take me days to do it myself.

Regards,
Ray L.

[FuriousGeorge]

It's a process, and there is definitely a learning curve, but it can easily be done at home once you get it down... for small parts. You can get pretty good quality on short runs without using the Nickel Acetate sealant (really nasty stuff) and just using distilled water. That being said, you will need to either invest a LOT of money in a rectifier or hook up multiple car batteries together for parts of your size. You will need a 75 amp 15 Volt power supply for just ONE 24"x36x0.5" piece at a time(720 Rule Anodizing Calculator). For that kind of output, I would just go with a professional shop- it's probably not worth your time and money to do it yourself.


Bob, what are you using for sulfuric acid where it incurs a major expense? I just use battery acid from Napa (NAPA AUTO PARTS). At $30 bucks for 5 gallons, the cost is pretty negligible. One five gallon tank can yield 10-15 gallons for anodizing once diluted with distilled water.

[mactec54]

Concepts_Design

Your parts are to big for a kit that you can get from Caswell, although they most likely could custom something for you, the power supply would have to be a commercial unit, I have been doing it for 30 years, If you have a proper set up there is no mess at all, but for doing large plates like you have you will need big tanks, you basicly have to build your own system,Your power supply would have to be a minimum of 100Amps 30 plus volts more is better, It most likely is better for you to get it done with a large commercial anodizer


FuriousGeorge

The Nickel Acetate sealant is not nasty at all, you only use 150mils max per Gal, your Acid tank & your stripping tank, is much worse than any of the other chemicals used for anodizing

[FuriousGeorge]

The stripper is definitely the nastiest component, no question there, although you don't have to use it often. I much prefer the acid to acetate tho- the mist suppressant Caswell sells really works, and I'm never dealing with boiling acid. The sealant, on the other hand, really spits out fumes tho and I don't see much of a use for it in small quantities (prototyping)when I can just use distilled water. Obviously, the nickel acetate better for sealing but it's not worth the hassle for me. An ounce of nickel acetate per gallon of water seems far from diluted to me, but I'm no chemist.

[Bryan Turner]

I've run a few pieces, and will +1 the "it's a big hassle" comments. Those are very large pieces to do in-shop if it's not your regular business.

My setup:
- Wash tank (distilled water)
- Degrease tank (warm acetone)
- Deoxidize tank (sodium hydroxide / lye)
- Anodizing tank (acid - see below)
- Dye tank (distilled water with fabric dye)
- Sealing tank (pot with steam rack)

- Keep the anodizing bath cool. Add ice if needed.
- Sodium Bisulfate works fine, no need for sulfuric acid.
- Go slow; long, cold anodizing is much stronger (thicker) than hot, fast anodizing. But too cold and the pores are too small for dye.. It's a tradeoff between strength and color.
- You can seal with near-boiling distilled water or steam instead of sealers.
- I used Acetone to clean the pieces, then Sodium Hydroxide to bite the metal before anodizing (distilled water rinse between each step).
- I used fabric dye, works fine if you steam-seal. Alternatively, just heat the dye pot and drop your piece in, but the color won't be as rich.
- No steel! Use aluminum, niobium or titanium for all connectors. Aluminum gets annoying because your connectors anodize and no longer pass electricity efficiently.

--Bryan

[mactec54]

I'm never dealing with boiling acid.

Yo don't boil the liquid when using Nickel acetate, 180 deg to 185 deg Max, there is almost no vapors from it at all, but what you are doing with water works well also,not as good but gets the job done, at a much higher temperature

[DiverBob]

Bob, what are you using for sulfuric acid where it incurs a major expense? I just use battery acid from Napa (NAPA AUTO PARTS). At $30 bucks for 5 gallons, the cost is pretty negligible. One five gallon tank can yield 10-15 gallons for anodizing once diluted with distilled water.

I used NAPA also for the acid, I was thinking more along the lines of all the large tanks needed, the size of the power supply and heating the dyes and sealer as expensive. I have a fairly small setup and it wasn't cheap, but I wanted to try it out as I had several hundred parts that needed anodizing and I wanted to do multicolor anodizing.

[Concepts_Design]

Thanks guys. Looks like i'll have to stick to sending parts out. It's really not too expensive , $200 lot charge, it's more of a timing issue. I had to work 40 hours over the weekend in order to get the parts to the platers today in order to get them back in time to meet my customers lead time, it's something I'd like to avoid if possible. but it sounds like it's a huge mess and the results could turn out bad, I'd really hate to lose work due to a bad anodizing job that I botched. medical device companies always want their aluminum anodized or it be made out of stainless. And unfortunately they have ridiculous lead times that want you to make, however the upside is they are usually willing to pay to get things expedited, which makes working thru the weekends worth it sometimes

[FuriousGeorge]

Yo don't boil the liquid when using Nickel acetate, 180 deg to 185 deg Max, there is almost no vapors from it at all, but what you are doing with water works well also,not as good but gets the job done, at a much higher temperature

That is fantastic! Caswell says to heat it to 210 F which is the sole reason I DON'T use the Nickel Acetate. Where are you getting that number from? I've always been a bit suspect of Caswell's guide, so this is refreshing news to hear.

[FuriousGeorge]

Thanks guys. Looks like i'll have to stick to sending parts out. It's really not too expensive , $200 lot charge, it's more of a timing issue. I had to work 40 hours over the weekend in order to get the parts to the platers today in order to get them back in time to meet my customers lead time, it's something I'd like to avoid if possible. but it sounds like it's a huge mess and the results could turn out bad, I'd really hate to lose work due to a bad anodizing job that I botched. medical device companies always want their aluminum anodized or it be made out of stainless. And unfortunately they have ridiculous lead times that want you to make, however the upside is they are usually willing to pay to get things expedited, which makes working thru the weekends worth it sometimes

One thing to note is that you don't have to scrap bad parts- You can strip the anodizing off and try again.Still, you're 100% making the right choice by subbing this job out for stuff that size. Don't be afraid to try it for small parts tho, it can be really nice to control the process yourself if you're in a pinch.

[mactec54]

That is fantastic! Caswell says to heat it to 210 F which is the sole reason I DON'T use the Nickel Acetate. Where are you getting that number from? I've always been a bit suspect of Caswell's guide, so this is refreshing news to hear.

Yes there are some that run at that temperature, the MTL from specialty color is best to use

[FuriousGeorge]

Yes there are some that run at that temperature, the MTL from specialty color is best to use

Thanks!

[MichaelHenry]

Yo don't boil the liquid when using Nickel acetate, 180 deg to 185 deg Max, there is almost no vapors from it at all, but what you are doing with water works well also,not as good but gets the job done, at a much higher temperature

Water in the solution will exhibit significant vapor pressure at 180 °F - a little over half an atmosphere, so approximately 50%. The nickel acetate will reduce that somewhat, but I'd think that one would still see significant water vapor.

Mike