Improving throwing power of tin bath

I need to increase the throwing power in an acidic tin process. I use the traditional formulation but my problem is to plate inside a tube with 2 inches in diameter without auxiliary anodes that means I need better throwing power. I am not sure if an alkali formulation should be a good aim.

Thanks in advance.

What type of acid tin are you using? We have fluoborate, MSA and sulphate tin processes in our shop, and I find that the sulphate tin has the best throw of all. In fact, with only one anode in the bath, it will throw behind a flat part, coating both sides. Hull Cell ⇦ huh? panels of these baths are coated front and back.

Usually alkaline processes have better throwing power than the corresponding acid process. Alkaline tin has comparable throwing power to cyanide copper.

HAVE A GOOD DAY.

The problem is as follows: I need to plate tin inside a tube 5 inches long and 2 inches in diameter. I can not aplly auxiliary anodes because I intend to use a automatic line. The only way is to use a tin bath with the best throwing power. My sulphate tin process with nominal strenght do not work well regarding my needs because I have only a few tin in microns in the inside of the tube. Maybe somebody know a good literature about new developments in tin bath?

Thanks in advance,

You could use non-conductive shielding on the racks to improve throw inside the tubes. If the tubes' ends are facing the anodes, fixture a plastic panel near the end of the tube. The panel could have a hole cut in it that's smaller than the ID of the tube.