The authoritative public forum
  for Metal Finishing since 1989
  

  -----

Acid Tin Plating Problem After Soldering

September 25, 2008

Hello everybody,
I have two acid tin baths vat and barrel. In the two baths I was maintaining the stannous sulfate 30 gms/ltr and sulfuric acid 100 gms/ltr. Now I had a problem with my barrel plating After plating the components appear good, absolutely no problem. But when we are doing soldering, blisters appear on the plating surface. The same components when we were doing in vat no problem. I was using the same cleaning process for both barrel and vat and barrel plating time is 45 min, vat is 10 min.Can any one tell where I do mistake.

Ram Sai
Plating shop - Jeedimetla, A.P, INDIA

---

September 29, 2008

Hi Ram,

I must say that I am very new to Tin Plating and I am learning from other people's experiences.

What do you mean by "blisters" ? Can you enclose a photo?

Thanks,

Maurice Mason
Plating Engineer - Danbury, Connecticut, USA

---

Sir,
Last time I gave tin bath operating parameter sulfuric acid 100 gms/ltr. It was not 100 gms/ltr and is 100 ml/ltr. And blisters means bubbles on the plating surface.

Ram Sai
PLATING SHOP - HYDERABAD, A.P, INDIA
September 29, 2008

---

September 30, 2008

GENERALLY THE CLEANING TIMES ARE DIFFERENT FROM BARREL TO VAT BATHS; ALSO THE CONCENTRATIONS MAY BE DIFFERENT
I BELIEVE THAT BLISTERS IN SOLDERING COULD COME FROM BAD CLEANING OR ETCHING AND ALSO FROM TIN POLLUTED
THE BEST AND EASY WAY IS TO CHANGE FOR A NEW BATH

Ricardo Burstein
Bnei Berak, Israel

---

There is too little specific process information to give a precise answer here. In general, blistering can be caused by poor cleaning and rinsing. Furthermore, barrel rinsing is inherently more difficult to achieve than jig rinsing in a vat; this because the barrel can retain more solution and is more difficult to remove because of its complex shape and containment of parts. My initial recommendation would be to improve the rinsing of the barrel and its components.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
October 2, 2008