What solution to use to calibrate digital ph?

[Coltsaa]

Just received my digital ph meter for Caswell. Was wondering what would be the best solution to use to calibrate with. Thanks in advance for any help.

[bhhodges]

i dont use one so im not sure----but what about distilled water ph=7 or at least that what i learned in school anyway.

bill

[Coltsaa]

Bill, thanks for the reply! I am just starting to electroplate nickel with Caswell equip. So far I'm having a blast. Good results. I just want to learn how to keep everything working properly.

[Gabourie]

I have 2 digital ph meters and they are great . I did not get them from Caswell. I got them at a hydroponics store. They have the solutions for calibrating. Also they should be stored with a storage solution to keep the tip moist. In theory distilled water should be 7, but it would be better to get the correct solution to test them with, for the fun of it I checked some distilled water I purchased at a store and it was not 7. One of the meters I have uses a double calibration, 1 at 7 and 1 at 4. It cost a little more but it is a good one, (water proof too).

[dadkar2]

There are standard pH solutions available from Omega and others that are easily available on the internet. Here is one link

http://www.omega.com/ppt/pptsc.asp?r...10&Nav=j01

Daigger also carries a variety of them. They are safe, easy to use, and last a long time. I bought the 4.0, 7.0, and 10.0. For under $20 you can purchase all three at the link above. You only need the small size. The distilled water idea is great, but I found a good 0.5 pH variation between several distilled water suppliers!! Hard to believe. Also, if you're calibrating your nickel solution, the required value around 3.0 is too far away from neutral to trust the pH meter. Likewise with alkaline copper (flash copper) at around 10.3. The solutions help in these cases.

When using it, always dispense a little from the bottle into a clean container. Don't dip your pH meter into the bottle because you risk contamination.

Kind regards,
Ken

[Coltsaa]

I have also found differences in the distilled water ph. I'm going to order some test solution asap.

Caswell manual says the the nickel solution should be in the 3.5-4.5 ph range. Does this seem to work for most? What have you found to be the best ph range for the Caswell electroplating nickel? Thanks!

[dadkar2]

I have had my nickel drift out of this range a little (eg 4.9 on one occasion and over compensated it once to 3.0). However, the nickel continued to function correctly. The nickel plating solution will tend to go flat despite pH management after some time. In fairly heavy use my solutions have consistently lasted about 6 months. It is not clear what process takes place at that point, but the chemistry problem is beyond simple pH and the only recourse is to discard and replace.

Drag in from other solutions is my theory on what causes eventual pH drift and solution failure, and my dual rinse method has helped sustain solution life.

I have found that the electro-nickel solution works much more reliably now since Caswell started including the new leveler additive. It's significantly better than it was a year ago.

I only use a 2 gallon set up so replacement isn't a disaster. But you still have to deal with the disposal problem in a healthy way.

Ken