Low Cost Solder Pot for the Hobbyist
by coalpeck in Circuits > Soldering
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Low Cost Solder Pot for the Hobbyist
As a Hobbyist do you struggle with paying over $100 for a solder pot that will be used for soldering a handful of circuit boards in your spare time. Don't feel alone because I also struggled with the same issue and after experimenting with a few designs the following design was found to do the job. For less than $30 a Hobbyist can purchase a few generic items and have a solder pot to do the job.
Supplies
One - 1100 watt / 120 volt single burner
One - Cast Iron skillet
Kester 186 No Clean Flux
Acid brush
Newspaper
Parchment or Freezer Paper
63/37 solder (one pound bar will be sufficient)
High Temperature tape if required to cover thru-holes
Pre-heat Solder Pot
Add solder to the cast iron skillet and bring the temperature up to where dipping newspaper into the melted solder turns the newspaper brown. Usually around 360 to 400 deg. Fahrenheit. Be careful not to overheat as not to warp the board, or overheat components. Best method to dial-in the pot for the first time is to have a few practice boards to learn where the settings should be for the best results. After that the settings should be consistence for each soldering event.
Best solder I found to use is a 63/37 blend one pound sticks for $20 to $30 per-stick on Ebay, but it goes a long way for the investment.
Prepare Circuit Board
In order to hold the circuit board when dipping into the solder pot install a 1-1/2" to 2" bolt and nut in one of the mounting holes of the board. If no mounting holes are present a set of metal barbecue tongs can be used but could take additional practice and a steady hand. I found the bolt and nut to work best.
If some of the thru-holes are not to be soldered then high temperature tape can be used to mask the holes. This can be purchase on Ebay or an electronic supply outlet. It comes in varying widths.
Flux Circuit Board
With an acid brush and Kester 186 No Clean Flux brush a light coat of flux on the circuit board. Do not over flux, a light coat will do. Allow the circuit board to set for a few minutes. An option is to pre-heat the circuit board with a heat gun if the room temperature is chilled. Pre-heating the circuit board with the heat gun will work but this is not necessary if room temperature is comfortable.
Clean Solder of Slag
With the parchment paper or freezer paper lightly brush over the melted solder to clean the slag until the surface of the solder shines. Need only the clean an area slightly larger than the circuit board being dipped.
Dip Circuit Board
Hold the circuit board with either the bolt or tongs and place in the solder as to float the circuit board on top of the solder. Do not apply any downward pressure to the board and hold for three to five seconds and no more. Again, a few practice boards will perfect the technique and be flawless once mastered.
Allow Solder to Freeze on Board
Once solder dip is complete hold the circuit board without turning over and allow time for the solder to freeze. 10 to 15 seconds should be sufficient time. Blowing a little air on the board will ensure the freeze is complete. Flip the circuit board over and inspect for bridges and proper solder connections. The solder connections should be smooth with no stringing or large balling. If not, correction to the pot temperature or flux application will have to be adjusted.
This is not rocket science and the variables are very forgiving, so once dialed-in it will be repeatable every time.
Unless the circuit boards are used in commercial or consumer products to undergo extensive testing this technique will provide a professional outcome for the Hobbyist.
YouTube Video
View the supplied video that will demonstrate the complete process.
YouTube video: youtu.be/XAtLwu6T44w
I hope this Instructables is helpful for the Hobbyist when budgets are tight and a professional job places the final touch to a circuit board of valued time and effort.
Thanks for viewing and Instructables for publishing.