Solder paste

First we cut a stencil on the lasercutter out of card stock. Then we taped the mask to the board and used a spatula to spread the solder paste evenly.

The thickness of the paper is around 0.25mm.

We then placed the smd components and then placed the board on a heating surface. Because the solder paste is low temperature ( with a melting point of 138C we heating up the surface to 150 thinking that not 100% of the heat would make it from the device to the board.

The components self-right themselves and the solder gets out of the way as if by magic. Here’s the final product:

We also bought a reflow oven. The key parameters here are to define the preheating and reflow temperatures and times. These can be saved into different “programs”.

![]( 2.jpg)