New(OLD) surface mount soldering method?

I make these shirts for my wife using 4 mm and 3 mm crystals.
You use a plastic transfer sheet and an iron set to 350’ F for 12 to 20 seconds.
All the crystals are heated and transferred at the same time.
You make a reusable stencil.
Add the components to the stencil right side up, pick up everything with the sticky sheet, apply to material, heat, cool pull off the sheet.

Now I was thinking :astonished: why not SMDs to a PCB.
I’ll give it a try.

Folks have done that - iron with hot side up PCB with solder paste & components on top. Heat iron so board gets to ~150C, hold for a minute to activate the solder flux, then raise temp ro ~220C for a minute to let the solder paste reflow, then let it cool.

Take care not to exceed the upper limit, usually like 250C, or the components will be damaged. I try to stay under 225 in my reflow toaster oven, the solder transition happens after 45 sec or once temp hits 210 or so.

Nothing under the sun is new :relaxed: However, the sheet will hold the components which may or may not be a good thing.

Look at Kapton tape.

Here is the concept:
#1 you have a pattern engraved 1/16 into a substrate (in the shape of the component).
SMDs would be placed on plate top side up.
#2 slide the components into the holes they belong in
#3 place the high temperature transfer tape over the SMDs
#4 pull off the tape, components come with tape.

Place tape on PCB with solder applied.
As Bob said heat from bottom of PCB, let cool pull tape off.
I’ll try it soon.