True that it is a bit expensive on a per ounce basis, but with the volumes necessary for purchase for the 'real stuff' it is not bad...and this is one of the best means of applying soldermask to a homebrew board that I have found. I've tried every method that I could think of, or find on Google, and never came up with anything that gave results even close to this. I even went so far at to buy the 'real stuff', which was epoxy based, had to be mixed prior to use, had a very short (1 week) shelf life after mixing, and required a minumum purchase of a 5 gallon bucket of developer. Total cost about $250. The stuff from China was about $6.00 - $7.00 per tube, had a long shelf life, and I could make several boards with a single tube.
Does anyone have a better solution?
--- In Homebrew_PCBs@yahoogroups.com, Simao Cardoso <simaocardoso@...> wrote:
>
> storan4wd wrote:
> >
> > I think the real lesson I've learned is that the mask is designed for
> > stencil printing only; quick drying isn't a priority as it's not
> > intended to have anything in contact with it when curing.
>
> As a side note, did you ever consider that such cheap eBay stuff, sold
> from china, is not even similar to real soldermask?
>
> It must be repackaged stuff, the eBay seller can say what he wants with
> his package. I don't know to read chinese, but to see what it really is
> you could try google goggles from a camera phone and translate, if you
> have the real manufacture package. EBay sellers say it's uv curing ink,
> but it can just be UV curing EPOXY GLUE.
>
> But if you look to one more expensive seller (the one who started to
> sell the stuff as soldermask) he has a working method, see item
> 260937497342. He lays a bit of it at pcb center and spread it with the
> mask directly. Expose for some time and them it should require extra
> curing after solvent washing. A couple of years ago i asked him a msds
> or that he just say what could be used as thinner for it. His answer:
> 'this is just chinese crap, no msds/documentation was ever written'.
>
> You should know that real LPI soldermask is half the money by quantity
> compared to that stuff.
>
> BTW (and off topic) Does anyone ∗really∗ know what PM or PMA solvent
> is???? I must know (and be sure) to use with real soldermask... :/
>