Acid ph & Dye Q's

[ISHY]

Hi All

Just come to do an ano run after about 3-4 weeks of no use although I have periodically turned the pumps on the circulate dyes etc I have a small problem.

Ran some parts (same parts as I run on a regular basis) neither have dyed very well, they take the colour but it's dilute compared to the original vivid colour. I have run 5 parts ano'd together then dyed 3 red 2 blue.
Do you think both my dyes are now about usless, they were made up at the same time?

I did notice also that the last blue part I did before my break didn't look quite as vivid.

Also I top up my ano tank occasionally with D.Water does anyone know what the ideal ph of the acid should be?
Can a weak or too strong acid tank cause this?

If it is my dye running out, do I need to scrap the 25 ltrs or can I buy one tub on dye and replenish rather than replace ?
I have had this dye made up for approx 9-10 months and have used it regularly but not excessivley.

Any help would be appreciated.
Thanks
Ishy

[acidrain]

The dye PH is probably off. There is a sticky with all of the colors and their PH levels.

Testing acid strength by PH is not possible... it's pretty much off the scale. Adding distilled water to bring it up to level is the way we all do it, and there is no problems as long as you kinow the correct level.

The real way to test acid stregth (and disolved aluminum) is called titration, and if you're really interested, here is the process:

Here is what you will need to titrate your anodize tank and keep it within operating parameters.

1. 0-50ml burette (recommend self zeroing burette)
2. 400ml beaker
3. magnetic stir station
4. stir bar
5. bottle of lab grade 1.0 N NaOH reagent (sodium hydroxide)
6. hand held ph meter
7. 0-10ml Pipette
8. PH Buffer Solutions to calibrate PH probe. Get a 3.01, 7.01 and 10.01

TITRATION INSTRUCTIONS

1. FILL BURETTE WITH NaOH
2. PIPETTE 5 ML OF ANODIZE BATH INTO 400ML BEAKER
3. ADD 200ML OF DI WATER TO BEAKER
4. PLACE STIR BAR IN BEAKER AND SET ON MAGNETIC STIR STATION
5. PLACE TIP OF PH PROBE INTO BEAKER CAREFULLY AVOIDING CONTACT WITH STIR BAR
6. SLOWLY ADD NaOH TO BEAKER FROM BURETTE. ADD UNTIL PH METER READS 3.6 THEN RECORD READING FROM BURETTE. THIS IS READING A
7. CONTINUE TO ADD NaOH UNTIL A PH OF 8.5 IS REACHED. RECORD NEXT READING FROM BURETTE. DO NOT TOP OFF BURETTE BETWEEN READINGS. THIS IS READING B

CALCULATION

G/L H2SO4 (SULFURIC ACID) = A x 9.8
G/L ALUMINUM: = (B-A) x 1.8

You want your target of g/l of H2SO4 to be between 180-200 g/l
You want your target aluminum to be between 10-15 %

If you’re over 15% remove half of your bath and top off with DI water then re-titrate. If your aluminum content is below 10% calculate how many pounds of aluminum sulfate to add to the bath to bring it back up to 10%. I have an excel spread sheat that will help calculated values if you're really interested.

you can purchase all that you need online at Cole-Parmer: Scientific instruments and lab supplies including digital microscope cameras multimeters pressure gauges nitrile gloves flow meters silicone tubing mixers and more

[gcdrummer02]

yes, nitrile gloves are a must for anodizing. I found out the hard way what the acid does to latex.