About a year and a half ago, I published a blog entry that described how to build board with surface-mounted parts using a toaster oven. Well, thanks to Mike WB8ICN and the Flying Pigs QRP Club mailing list, here’s another, perhaps simpler technique.
This new method is found on the website of the Electronics Research Group (ERG), a company run by Cash Olsen, KD5SSJ, to sell a bunch of ham-related kit, including a spectrum analyzer and small function generator. Olsen’s method uses solder paste applied with a syringe (he’ll sell you a syringeful for about $6), a coffee cup warmer, and a small heat gun.
You apply the paste to the pads, position the components, then put the board on the coffee warmer. This gets the solder paste to start melting. At this point, you start with the heat gun, slowly bringing the board up to the point where the solder paste “reflows.”
I wish I’d have used this method to make the SMD CI-V interface. While I got the thing to work, the parts moved around while I was soldering them. I think this method would have been easier and produced a nicer looking board.
I might just try using this technique to build a simple DMM calibrator from the Maxim 6126 ICs that I’ve had for a while. The 6126 is a high-precision voltage reference that comes in an eight-pin SO package, which has a lead pitch of only 25 mils.
UPDATE 12/11/06: Another idea for holding down surface-mount components to a PCB that has been floating around the QRP mailing lists is to use a product called Blu Tak or something similar. This stuff is a re-usable adhesive normally used to put posters on walls.
Apparently, you use a small amount of it on the ends of a component to hold it down while you’re soldering the leads. Then, you simply pop it off.
I don’t know that there’s anything magical about Blu Tak. It seems to me that any similar product would work just as well. Another correspondent mentioned a product called AllStick, and I just checked my office supplies drawer, and I have something called HoldIt. I’m definitely going to try this next time I make something with surface-mount parts.
Roger Lawson says
Hi! I’ve just seen your comment about the Maxim 6126 precision voltage reference – I am also intending to build a calibrator using this chip, but I cannot find a UK source that will supply less than 80 of them as a minimum order (at about 90p (say $1.70) each!). Have you any idea where I could buy just one or two ( I only need one but I always like to have a spare!).
Regards, Roger L.
Dan KB6NU says
Hi, Roger–
I got mine as samples right from the Maxim website. Perhaps you can try that as well. If you can’t do it directly from the website, there might be a local representative who’d get you a few on the side.
73, Dan KB6NU