OSHSTENCILS.COM sells stencils by the square inch. They have 4 mil stainless, 3 mil Kapton, and 5 mil Kapton... I usually use the stainless ones. They also sell syringes of solder paste. I keep mine in the fridge. I have year old paste that works fine. There are now pastes that do not require refrigeration... I don't know how good they are. QFN44 pads are spaced 0.5mm. You don't have to get the chip set down perfectly. Surface tension will align it when the solder melts. I've hand placed chip scale packages with like .25mm pads. I use a modified toaster oven. My temperature control PID is derived from Lady Heather's temperature control algorithm. There are a LOT of Arduino, etc reflow oven controllers out there. --------------------- > Can anybody comment on the toaster oven approach? Is it practical for things like this? How much does a solder mask cost? How much other stuff do I need? Does the solder paste need to be refrigerated and other quirks like that? What are the chances of a newbie getting a 44-QFN right on the first try?

I used to do SMT If the solder paste does not absorb moisture when stored it should be OK People have had success with an iron frying pan on the stove . I have used a hot air paint stripper gun with a metal funnel to re flow the paste. There cheap SMT re work stations on Alibaba now <$100 On Thu, Jan 25, 2018 at 5:10 PM, Mark Sims <holrum@hotmail.com> wrote: > OSHSTENCILS.COM sells stencils by the square inch. They have 4 mil > stainless, 3 mil Kapton, and 5 mil Kapton... I usually use the stainless > ones. They also sell syringes of solder paste. I keep mine in the > fridge. I have year old paste that works fine. There are now pastes > that do not require refrigeration... I don't know how good they are. > > QFN44 pads are spaced 0.5mm. You don't have to get the chip set down > perfectly. Surface tension will align it when the solder melts. I've > hand placed chip scale packages with like .25mm pads. > > I use a modified toaster oven. My temperature control PID is derived > from Lady Heather's temperature control algorithm. There are a LOT of > Arduino, etc reflow oven controllers out there. > > --------------------- > > > Can anybody comment on the toaster oven approach? > > Is it practical for things like this? How much does a solder mask cost? > How > much other stuff do I need? Does the solder paste need to be refrigerated > and other quirks like that? > > What are the chances of a newbie getting a 44-QFN right on the first try? > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. >