Help... wont take dye

[xgenmods]

Originally Posted by acidrain

They're all different, and it does make a difference. Use dilute battery acid or lab grade acetic acid to lower, and amonia to raise the PH. Only a couple of drops at a time, and then test with a digital meter after it's mixed and settles down.
RED BORDEAUX 6
YELLOW 4A 6
BLUE 4 A 6
VIOLET 3D 6
BLACK HBL 5.5
GREEN SCG 6.6
GOLD S 6
TURQUOISE 5.5
OLIVE DRAB 7.5
GOLDEN ORANGE 7
GREY BL 5.5
BROWN GL 6.5
TEAL 5.5
ELECTRIC BLUE 6
COPPER BF 7
FLOURESCENT PINK unk
BRONZE 5.5
DEEP RED 5.5
FLOURESCENT YELLOW 6
GREEN AEN 6
VIOLET DS 6
GREY NLN 5.5
YELLOW 3GL 6
BROWN BL 6.5
FAST BLUE 5.5
ORANGE 3A 6

So one of those cheap digital ph meters from ebay will work or do I need something better? What would you recommend? Also how thick should I make the oxide layer for the grey dye. I was shooting for .7 mils.

[dmiom]

Just another thought - following on from the suggestions in :

Originally Posted by coopduc

In general, parts won't take dye because they did not anodize or the ano is very thin. ...

given that most of your steps aren't a million miles out, forgive the obvious question but it might be worth checking which way round you had the PSU connected - having the connections reversed might give the results you reported ....

[xgenmods]

Originally Posted by dmiom

Just another thought - following on from the suggestions in :



given that most of your steps aren't a million miles out, forgive the obvious question but it might be worth checking which way round you had the PSU connected - having the connections reversed might give the results you reported ....

Negative to the aluminum plate (cathode) and the positive to the part.

[dmiom]

OK, a few more ideas :

You mentioned distilled water a couple of times - but are all your tanks mixed using distilled or RO water?

I don't know if it will have any effect, and I'm not certain which de-ox/de-smut you're using, but if my memory is correct, the de-ox/de-smut we get here from Caswell UK is used at ambient, not heated?

Is the Grey the first dye you've tried? or are others OK and just Grey bad? We've never used the Grey dye, but, for example, Black is possibly one of the most demanding colours, and Red maybe the easiest - so if you've got any Red or similar, it might be worth trying?

Have you got enough cathode area?

Is this the first run(s) you've done in this ano tank? - if so, things may get better ..... to run properly, the ano tank needs a certain amount of aluminium

Dave

[xgenmods]

Yes this is a new tank. I did try the red dye and it came out a bit dull but otherwise ok. Should the aluminum be changing color at all during the process? I have done a form of anodizing a long time back on personal items with a battery charger. I just started doing anodizing again on a larger scale due to the problems and cost of the local anodizer. I figured cut the middle man and do it in house. I went all out this time and bought a tank and cc 50 amp power supply. Anyways my tank is 20 gallon with a mixture of 1 gallon to 3 gallons of distilled water bought from the store. Everything else is mixed with RO water. The tank uses aluminum for the cathode and has a surface area of around 12 feet. Its a u shaped loop. The tank is agitated with a pvc manifold and a 1100 gph little giant pump.

[coopduc]

A slight dulling of the aluminum is normal even with LCD. At higher CD of about 12 a slight gold tint is not unusual. If you are at 6 CD the part should stay a silver color, if it started out polished, but with less of a mirror gloss.
I don't mean to insult your math skills, but are you sure you calculated the surface area correctly? It is easy to mistake volume for area, or if the parts are thin sheet metal, often times people forget the part has 2 sides.

[acidrain]

Good points you guys!

Another common math mistake is that there are 144 sq. inches in a sq. ft.

[xgenmods]

The nice thing about creating the parts we are making is that I can analyze the surface area of the part in solidworks. How accurate does this need to be? The reason I ask is down the road I might have to do things that are going to be very hard to find exact surface area. I would almost rather model up the part. As far as the gold color. We did a few of these on a battery charger and just let it do its thing wide open. The parts came out looking slightly golden with a nice coating on them. We almost don't mind that look for these if we can do it consistently. Any ideas how to achieve that look using what I have and get it consistent?

[dmiom]

Originally Posted by xgenmods

Yes this is a new tank. I did try the red dye and it came out a bit dull but otherwise ok. Should the aluminum be changing color at all during the process? I have done a form of anodizing a long time back on personal items with a battery charger. I just started doing anodizing again on a larger scale due to the problems and cost of the local anodizer. I figured cut the middle man and do it in house. I went all out this time and bought a tank and cc 50 amp power supply. Anyways my tank is 20 gallon with a mixture of 1 gallon to 3 gallons of distilled water bought from the store. Everything else is mixed with RO water. The tank uses aluminum for the cathode and has a surface area of around 12 feet. Its a u shaped loop. The tank is agitated with a pvc manifold and a 1100 gph little giant pump.

Sounds a good setup

In the early days, after finding that we couldn't do black from a virginal acid/water mix in the tank, we used to run some test plates (just large coupons of 1.5mm sheet) to settle things in and 'seed' the tank. After doing test dye runs, we found that the less demanding lighter colours we do (red, green) will come out OK with virgin mix, whereas getting sufficient ano matrix to hold deep rich black requires a 'run-in' tank, and better temperature control.

With the LCD process type II anodising, we don't really see any noticeable colour change or tinting here during the actual anodising process.

You mentioned that you can get an OK but dull Red. Some of the dullness might be etching due to over-long immersion in the de-ox/de-smut - 6061 shouldn't need anything like 10 minutes in there.

Also, your initial process list went as far as the dye tank, have you been stopping there? - the best of the surface isn't really shown until after the boiling Nickel Acetate seal and then we air-line-dry and dip in / wipe with WD40.

You also asked about accuracy of surface area measurement. Opinions will probably vary on what you can get away with. Gross errors (e.g. only counting one side of a sheet plate) will certainly betray you. Overall, the better you can do, the better the result. Its also a question of whether you're doing one-offs or a longer / colour-matched run. If all your process tank temperatures, chemistry etc. are OK, then maybe you can get away with 10% errors in area for a one-off, but you should strive for perhaps 1% or better as that's one of the easiest variables to control or factor in. Because the lighter colours can work with a thinner ano layer, provided you err on the side of building a slightly-too-thick layer, there is more lattitude that there is for black etc.

Dave

[acidrain]

Once you have an established, consistant, temperature controlled tank, there is a way to do runs starting in CV, then switching to CC which will allow you to skip measuring surface area. We can talk about that later... you're not there yet.

DMiom brings up good points... the etching process is probably too vigorous, and will affect the color.

Different alloys act differently as far as that natural gold color. 6061 pretty much has no color.

Try doing a test piece withouit the etch/desmut steps... just degrease and go.
Be sure to seal afterwards.