Impin' Ain't Easy

[chuckbuick]

Here's a SMD version of culturejam's Game Of Tones.  I call it the Imp in reference to it's small size and, of course Tyrion Lannister.  That would be Tyrion and his buddy Bronn a la Pulp Fiction on the front of the pedal.  Credit for the art goes to the WWW.

The board uses board-mounted pots and LED.  I ditched the clipping switch to make it 1590A friendly.  It has 4148's for clippers now but I may swap them out for LED's.

This was also my first attempt at using solder paste.  It was a little hard to regulate the amount of paste I laid down on the pads but I think a little practice will go a long way.  It cut the board populating time in about half, which is pretty darn cool, I think.

[jimilee]

It's almost small enough to put a second hotter pcb in there and have a mini KoT. That'd be bitchin' for sure.

[GrindCustoms]

Some people win Nobels for less than that!

[cooder]

Microscopic awesomeness.... big time!

[TGP39]

Wow. You did a fantastic job with the smd layout. Looks so clean. Talent just overflowing around here. Unbelievable.

[jubal81]

Really beautiful work inside & out. Toaster oven? Hot air gun?

[wgc]

Cool, cool, cool!  Love that artwork, awesome layout.

Let me know if you want some ideas for the solder paste application.

[chuckbuick]

Thanks for the nice comments, guys.

It's almost small enough to put a second hotter pcb in there and have a mini KoT. That'd be bitchin' for sure.

I've got room to stack a couple more boards in there.  Pots and switches are a whole different story.

Really beautiful work inside & out. Toaster oven? Hot air gun?

Hot air.  When I moved all my pedal stuff from work to home earlier this year I picked up one of these.  This is the first time it's really come in handy.  http://xtronicusa.com/home/#!/~/product/id=15959845

Let me know if you want some ideas for the solder paste application.

Yes, please.  The method I used for this build was "go for it!"

[alanp]

I tried using my hot-air gun on some SMD boards I have, it doesn't work (or at least it doesn't with cheap hot-air guns and 60/40 rosin solder!) SMD boards are damn near not there, vertically.

Impressive stuff, Chuck

[wgc]

Those hot air wands are great, that was actually how I learned smd.  Lots of fine lines at first with air flow vs temp settings.  But once you get the hang of it, it can be very efficient. Until then, easy to scorch a pcb, or blow your smallest parts right off the card table.

As for solder paste application, there are syringe tips available in plastic with various size openings. They thread right on the end of the tube.  http://www.mouser.com/ProductDetail/Apex-Tool-Group-Formerly-Cooper-Tools/KDS2512P/?qs=sGAEpiMZZMvNdIckKBEZytb9vnukxEwmnVhqzUH18PI%3d 

The blue or green ones are probably most appropriate if I remember right. The solder tends to harden a bit though from the pressure of extraction and they plug up as a result. Should be able to do a complete pcb with one though. A bit easier to get consistent dots on passives pads. For soic, just run a straight line right across the middle of the pads, as if you intend to short them all together. They will break up evenly at reflow and only rarely will you have a short.

The best way though is with a stencil, like in actual production. This is usually stainless steel foil cut from the "paste" layer in your gerber to match the pcb pads. Done with some tweaks to avoid solder balls and other issues, and provide consistent deposits on the pads about 4-6mil high, with about 90% size reduction. 

The stencil is lined up with the pcb and a blob of solder paste is wiped across with downward pressure, filling the openings over the pads. Remove the stencil, and start populating, triple check, and then reflow. It's very much like silk screening. Automated in production, but also easy enough to do by hand.

I've been thinking about laser cutting some stencils in kapton sheet but just haven't had time or inclination. I don't mind hand soldering, part of the fun, and about as quick for me.

Also, there's a place called dirtypcbs.com that will do stencils for you with your pcb order. Also, you can get 10 boards at this size for $14 shipped. I have a pcb on its way and expect decent results. I will keep you posted.

[chuckbuick]

Thanks for the info, Billy.  I think a smaller tip will help.  I'll check into the rest of this stuff but I think a stencil is probably a bit much for one-off stuff.  Thanks again.

[wgc]

Hey Mark

sure thing.  Smaller tip for sure, not sure what brand you're using but the chipquick stuff has a tip you can't change out afik.  look for the 35g syringes by kester, etc.

I agree about the stencil for one offs, partly why I haven't done it myself yet. 

Although I have to say, if you think the paste reflow helps improve time, the stencil makes the paste application really quick.  You could probably populate a pcb in 10min...!

[Govmnt_Lacky]

The little guy looks like the guy from GOT 

EDIT: Duhhh! I guess that was intended huh? 

[m-Kresol]

That is awesome. Love the SMD part and the cover art is hilarious!

[juansolo]

My OCD is twitching at the two backwards resistors...

Awesomeness though!