Toaster Oven Reflow Soldering

Uses

• the toaster oven in our lab

Warning

I wouldn't breath in the fumes of the toasting process. Plenty of flux and glue and other chemicals in the PCB manufacturing process. Do this with the bay door open or outside.

Background

Using this page as reference : http://instruct1.cit.cornell.edu/courses/ee476/FinalProjects/s2006/ki38/Webpage/index.html Specifically this reflow temperature curve characterization http://instruct1.cit.cornell.edu/courses/ee476/FinalProjects/s2006/ki38/Webpage/kester.jpg

Based on that the curve should look like

• room temp to 300Fahrenheit in ~90 seconds Preheating Zone
• 300F to 350F in ~90 seconds Soaking Zone
• 350F to 420F in 30 seconds peak Reflow Zone rise
• 420F back to 350F in 30 seconds Reflow Zone fall

I characterized the toaster we have in the lab with nothing in it

• starting@450
• 77F @ 0 seconds
• 120F@ 1:15
• 245F@ 3:30
• 300F@ 4:30
• 330F@ 5
• 357F@ 5:30
• 385F@ 6:00
• 400F?@ 6:30 (max of my thermometer)

Process

Based on this I attempted

• 210 sec or so warmup
• 90 sec in #1
• 90 sec in #2
• 30
• 30 cooling from 400

What ended up happening was putting it in at around 250, figuring it would lose a lot of heat on opening the oven and then just watching until solder got shiny most everywhere I ended up chickening out before large polarized caps were able to finish because the oven reached 400+ degrees and I didn't want it to peak any higher than 420