PH for all tanks

[ole454]

I purchased the ano kit last year and had good sucess at first. I have come to the conclusion that I mixed my first bucket 1/2 rate. Got that fixed. Now I have blotches on my parts. I have the caswell 25 amp rectifier.
Here are the steps that I use.
1 Machine parts
2 deburr
3 clean in hot soapy water
4 blast with glass beeds (dull finish is fine)
5 clean in hot soapy water
6 Tank #1 degreaser (190')
7 distilled water spray
8 Tank #2 desmut (110')
9 distilled water spray
10 Tank #3 ano (65'-70')
11 distilled water spray
12 Tank #4 black dye (140')
13 distilled water spray
14 Tank #5 sealer (210')
15 wd-40 or (LT sealer (90'))
At first I used WD-40 for the last step, Then I used the LT sealer (90 degrees). I read yesterday LT sealer is not recommend with dye.
Question (1)
Are these steps close?
Question (2)
What step #6 sealer should I use with dye wd-40 or LT?
Question (3)
What step #6 sealer should I use without dye wd-40 or LT?

I did not check PH for any tanks at start up.
Question (4)
How critical is well mantained PH for all tanks?
Question (5)
Are some more important than others?
Question (6)
Is there a list of recommended PH for all tanks? (I found it for Dye)

I am in the process of changing mix in tank #5. That seems to be where the problem is coming from.
Question (7)
How do I know when a tanks solution has gone bad?

If you need any other info I will supply it.

Thanks in advance, any reply would be appreciated.

Michael Olsen
Ole's Machine

[acidrain]

You have de-smut and de-grease reversed... it would go:
Strip or etch
de-smut
Degrease
ano
dye
seal
Since your parts are not etched or stripped, you really don't need the de-smut step at all.
If your "blotches" are well defined ovals or long stripes, it's the grain of the aluminum showing through.
If they are hazy random blotches, I suspect your beadblast method is too heavy.
Try 60psi at some distance (3 or 4 inches) and just a quick back-and-forth dusting. With beadblasting, less is better.
As for your PH levels, the only thing you have to worry about is the dyes. There is a sticky with all the different colors and their respective PH levels.
As for sealer, I suggest the high-temp sealer for non-food related parts, but many have had equal success just steem sealing. For food related parts always use steem sealing.

[radmaximus]

Hey Acid, I guess I've been doing it backwards then too. Is the Caswell Manual wrong it has step 2 degrease, step 3 de-ox? I haven't had any problems at all with any of the colors! Everything working fine.

Rad

[ole454]

Originally Posted by acidrain

You have de-smut and de-grease reversed... it would go:
Strip or etch
de-smut
Degrease
ano
dye
seal
Since your parts are not etched or stripped, you really don't need the de-smut step at all.
If your "blotches" are well defined ovals or long stripes, it's the grain of the aluminum showing through.
If they are hazy random blotches, I suspect your beadblast method is too heavy.
Try 60psi at some distance (3 or 4 inches) and just a quick back-and-forth dusting. With beadblasting, less is better.
As for your PH levels, the only thing you have to worry about is the dyes. There is a sticky with all the different colors and their respective PH levels.
As for sealer, I suggest the high-temp sealer for non-food related parts, but many have had equal success just steem sealing. For food related parts always use steem sealing.

I am doing the degrease and de-smut in the order that is in the caswell book.
I am using 7075 alum.
What is steem sealing?
When I take the part out of bucket #5 (before the final sealer) the areas that become blotches are white, almost like a chalkie look to it. I will get a pic of the blotches.

[destroyer125]

7 series aluminum needs to be anodized half the time you would anodize 6061. That is dissolution. Start over from the stripping process and try again.

[M_D]

We clean our parts in a heated cleaner, rinse, etch, rinse, desmut, rinse and then anodize. There have been no problems for us with that order of processes. If you don't etch you may not need the desmut process, but some heated cleaners will do some etching and leave a smut depending on how long they are in the cleaner, so a desmut step may result in cleaner looking finished parts, without the extra step needed need to hand clean them after they are sealed.

If we have to strip parts, we often clean them first with the heated cleaner, then strip them. If you have contaminated surfaces it can act as a masking agent and the stripper or etch doesn't always work as evenly as it could.

Your problem does sound like disolution though, pictures could help to verify that.

Steam sealing is using steam from boiling water to seal the parts, or you can imerse them fully in boiling water. I think the nickle based additives for the sealer tank improves the quality of seal, so we use that method. I can't remember the ph value off the top of my head, but the ph of the sealer does make a difference, if it gets too far out of range the parts come out with a dirty film (which will clean up), although sealer ph isn't the only thing that can cause that. When you get everything right, the parts should look spotless and clean when they are taken out of the sealer and dried.

[ole454]

This may sound like a dumb question but what is the etching process? You don't use the degreasing step? I have tried a few parts only in the ano tank for 45 min.(instead of 90) and they have come out nice. Thanks for the help.

[destroyer125]

Etch process is with sodium hydroxide. A white crystaline dry substance you mix with water. Possibly your problem is coming from Not etching? Degrease the parts lightly with a toothbrush and some dishsoap. Mix some sodium hydroxide up (just alittle added to about 2 gallons of water) at between 70-120 degree's and let them etch for about 2 minutes or so, less if the parts are highly tolerance sensitive. Then wash followed by the desmut step, hand dry then blast with glass beads, then degrease again. Amazingly enough if your Deburring your parts with a vibratory tumbler, those things are as good for degreasing parts. Mix some corncob up with soapy water and run them for about half hour or so and it will actually wash and lightly scrub them.

[M_D]

The parts have to be degreased somehow, we use a heated cleaner for that since we do a relatively high volume of parts and most of them are too complex to successfuly clean by hand.

The etch removes the outer surface of aluminum (just like stripping previously anodized parts does), and in doing so gets rid of the oxidized surface (assuming the surface is oxidized) which results in a better anodized layer. Etching isn't always needed. For parts that have mechanically de-oxidized (machining, polishing, sanding, etc.), skipping the etch gives good results in most instances. Etching tends to dull the parts, depending on the etch time, etch temperature, and concentration. It can be done and still leave a decent glossy finish, but it still dulls the parts somewhat.

We vibratory tumble most, but not all of our parts. It does leave the parts fairly clean if the water and detergent are kept fresh, but for parts that are deburred this way we find it essential to etch them well. If we don't, the colors aren't as even and vibrant, because vibratory (or rotary) tumbling tends to oxidize the surface quickly. Plastic media does not seem to oxidize the surface as bad as ceramic.

[destroyer125]

Originally Posted by M_D

The parts have to be degreased somehow, we use a heated cleaner for that since we do a relatively high volume of parts and most of them are too complex to successfuly clean by hand.

The etch removes the outer surface of aluminum (just like stripping previously anodized parts does), and in doing so gets rid of the oxidized surface (assuming the surface is oxidized) which results in a better anodized layer. Etching isn't always needed. For parts that have mechanically de-oxidized (machining, polishing, sanding, etc.), skipping the etch gives good results in most instances. Etching tends to dull the parts, depending on the etch time, etch temperature, and concentration. It can be done and still leave a decent glossy finish, but it still dulls the parts somewhat.

We vibratory tumble most, but not all of our parts. It does leave the parts fairly clean if the water and detergent are kept fresh, but for parts that are deburred this way we find it essential to etch them well. If we don't, the colors aren't as even and vibrant, because vibratory (or rotary) tumbling tends to oxidize the surface quickly. Plastic media does not seem to oxidize the surface as bad as ceramic.

Mind sharing your degreasing chemicals name? Im tumbling parts in a plastic media then polishing to a high shine with chromium oxide treated corncob with an activator added, seemed like they would need to be degreased afterwards as the activator is somewhat oily.