Hull cell size for Sulfamate Nickel electroforming

A. Dear David Casale,

I have no experience with the 1 liter cell and a lot with the 267 ml one.
I can only imagine myself that the larger scale makes the handling a bit more difficult, especially in cases where you try to modify your electrolyte to the optimum conditions (based on the visual impression of the HC-panels) and have to try out different additions and not in incrementing amounts, however I don't know if this is a situation which you will often have. If using the 267 ml. cell, a good practice is to produce only one Hull cell per "electrolyte shot" and empty and refill for the next HC. In your place I would also think about e.g. thin base material as cathode and look at the deformation of this panel after the HC plating too.

Furthermore I have no important arguments pro and contra and I'm curious to learn arguments in favour of the 1 ltr cell.

Other considerations is if the HC still fits in a scientific approach where you can (and maybe should) analyse your electrolyte via CVS, ICP-MS [on eBay affil links] , Polarography, HPLC etc. The HC will only indicate appearance changes and you should hope it does before you have already trouble in you're electroforming process.
I know that I probably will arouse a lot of people with this remark, but I really think that the analytical capabilities are severely improved since the times of Mr. R.O. Hull, as such I would use the Hull cell only to determine limits for certain (appearance influencing) contaminants / breakdown products, or use it for the "determination" of brightener(s) needs if the brightener(s) cannot be analysed.

Best regards,

A. The 1 Liter size allows for a more convenient and intuitive conversion if you control your tank solution in g/L. That is the only reason for the larger size. The 267 mL cell was based on a convenient oz/gal conversion. Most people still just use the much more common 267 mL cell and they do the necessary math conversion before making adjustments to their process tank.