Electric Griddle Reflow Soldering
Overview:This page explains how I used an electric skillet to reflow solder a project of mine that used all surface mount components, including one QFN-28 leadless PIC18F2520!
Note: Reflow soldering, by the way, is the method of soldering by: first applying solder to the board, secondly placing components, and finally heating the solder and components so that the solder joins the component to the circuit board.
I knew about the "normal" ways to solder: such as hot air reflow stations, soldering irons -- but more impressively (and cost effectively:) I had read about people soldering SMT with toaster ovens and electric skillets! (from Seattle Robotics Society, and more recently -- Spark Fun Electronics).
As my design had to be small, and surface mount components are appropriately small -- I knew SMT was the way to go, and I figured the hot-plate reflow method could take me there. Below are the steps I took.
Tools:For my reflow heater, I used an electric griddle that I picked up from Wal-Mart for around $20 (Presto 07047 Cool Touch Electric Griddle). Meanwhile, if you want to order online -- Amazon has the Presto 07039 Professional 22-Inch Jumbo Electric Griddle for about $30.
Why did I go with the griddle? I looked at the other electric skillets and appliances they had, but got the griddle because I believed it had the largest heating element. I decided that if the griddle didn't get hot enough (i.e. because of cold spots farthest from the element,) then I at least I could put a lot of boards directly on the heating element.
I used Wahl silver solder paste for the SMT components, and regular solder & rosin paste flux for the larger through-hole components.
Note: Solder flux is the greatest thing ever. I've been soldering circuits well enough for years using just regular 60/40 rosin core solder, but let me tell you -- dabbing standalone flux on the circuit board where I need to solder a component makes it 10x easier, faster and cleaner! (minus the extra rosin that is now on the board -- but that generally can be scraped off or removed with acetone). So I strongly recommend solder flux to everyone for soldering through-hole components.
Additionally, I used bent nose tweezers to position the surface mount components on the board, a metal scribing tool to apply flux and scratch flux off, and cherry coke for energy.
Up next: the Reflow Process! -- click here to continue
project added: 5/4/2006