On Sat, 30 Jan 2010 07:38:30 -0000, you wrote:
>Hi,
>
>A few questions regarding MG Chemical's Liquid Tin product:
>
>1) I just purchased a bottle of Liquid Tin. In the bottom of the (unopened) bottle, there's a lot of white precipitate and a few black things. It doesn't mix in if I shake it. Is this normal or did I receive a defective product?
Mine is like that, too. Works fine.
>
>2) I understand that the tinning process is very stinky and produces toxic gases. Is it ok to use it outside, since my lab (a.k.a. garage) is not well ventilated? Does cold (down to 50 deg or so) or heat (up to 90 deg or so) affect its operation?
>
And the chemicals are nasty, so use gloves, avoid fumes, etc.
Temperature does have an effect on all chemical reactions, but the 90
degrees is not a problem, although you might be happier at 60 degrees.
>3) Can I re-use Liquid Tin by pouring it back into the original bottle? Or should it be discarded after one use?
At that price, it goes back into the bottle. It can be used again
and again.
>
>4) How do I dispose of Liquid Tin in an eco-friendly manner?
>
Not sure, hazardous waste collection seems to come to mind.
>5) Any hints on using Liquid Tin to ensure good conductivity and prevent copper corrosion?
3 to 5 minutes as they mention. Make sure the boards are clean, a
brief scour with a scotchbrite pad is good. If you have an area that
doesn't plate, then pulsar recommends a bit of buffing with whatever,
and re-immersion in the bath.
Note that this is a tin plate, not a tin/lead, so solder coating some
of the SMT pins (especially fine pitch) is a good idea.
There's a tutorial on SMD soldering at www.avrfreaks.net that has a
lot of useful tips. Generally a flux pen is good, and I've found that
sweat soldering to the pre tinned (with solder) pads works well for
TQFP packages.
Harvey
>
>Thanks,
>Jim
>
>
>
>
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