Re: [CAD_CAM_EDM_DRO] Pick and Place question

Mark Vaughan wrote:

> Jon
>
> Do you know a little more about the paste.
>
> Reason I’m asking, a pot of solder paste must be at least 10 times a reel of
> solder. Over in the UK 500G of leaded solder is about £7, lead free was £20
> but I can now get that for £12, but solder paste they want £70 for 40gms, I
> presently buy mine from China.
>
> Lead free is going to have tin and silver in it, I assume alloyed before and
> then broken down.

There are a hundred alloys, at least, being used. From pure
Tin, to Tin/Copper, Tin/Antimony/Copper, Tin/Silver/Copper,
Tin/Nickel/Copper and on and on.

>
> You say the solder is tiny balls, is there a special reason for this rather
> than grinding it into a powder.
>

I don't know if it is entirely for particle size uniformity, or
for uniform mixing of the solder with the flux, or some entirely
different reason.

> And flux, what are they using, it must be simple cheap chemicals, but any
> idea what?,
>

Rosin, natural or synthetic, mostly. Again, even a single
manufacturer will offer a dozen or more formulas. There is
no-wash, water-wash, solvent-wash, high-activity, low-chlorine,
etc.

> Like explosives do I have enough under the kitchen sink plus a bit to make a
> good flux for lead free solder. Don’t need to make explosives I’m licensed
> for them.

You can buy it at the hardware store, although that may not be
good for electronics. I got a 500 gm tub of lead-free solder
paste from a distributor as sample! It is going to take me a
while to use that up.

Jon