Hot Air Soldering Gun From a Desoldering Iron With a Vaccume Pump

Here I'll show you how I converted my desoldering iron into a hot air soldering gun.
Some may ask why is this tut when there is the easier one wit the iron from digikey. Well the answer is, digikey doesn't ship to europe and all I managed to find here is this type of desoldering irons. One more thing is that this conversion is totaly reversible, you can use your desoldering iron to desolder in just one minute - no modifications to the stock irons are made.

What you will need for this tutorial

1. Desoldering iron 40W with a built-in vaccume pump - $ 6
2. One bottle cap
3. One screw 5x20mm
4. One fishtank air pump - $ 6
5. 1m (3ft) flexible hose-pipe - $ 0,3
6. 1cm of hard hose-pipe
7. 1m (3ft) thin copper wire

You will need a drill machine and 2,7 or 3mm drill bit

so let's start...

Step 1: The Iron

First we need a desoldering iron. I bought mine for 4 EUROs or about US$6 from the local electronics shop.
It is 40W and you can find the same at ebay.
First we must disassemble our desoldering iron. It has a body, a yellow cylinder, a spring and a piston.
The spring and the piston we don't need, so we pack them together, in case we deceide to use the iron as it is meant to be used.

Step 2: The Cap

Now we need a bottle cap. These caps are used with many bottles, mainly bottles for chemicals or from the drugstore.
I was wondering how to put the hose from the air pump into the yellow cylinder, when I found that this cap fits perfectly to it.

Step 3: The Screw

This is easier to find I think. We need 5mm screw, that is about 20mm long.
The idea is to drill a hole through it. I try drilling with a 2mm bit, but I broke it, so I dill a hole with a 2,7mm - no troubles this time.

Step 4: Fishtank Air Pump

I think any fishtank air compressor will do the job. However I was looking for a cheap one, but with variable speed control.
It turns out that the speed control cost much than I was ready to spend, but found this 200L/h with 2 speeds for 4 EUROs or US$6. I thought - that's what I was looking for.
The same can be found on ebay too.

1m or 3ft from the propper sized hose-pipe will be sufficent, it costs me about 30 cents.

You will notice that, when the piston is removed, the yellow cylinder becomes loose and we need something to press it against the body. I use about 1cm of somekind of a hard hose-pipe I've got at home. You can use whatever you find fit.

Step 5: Tunning

Now that we have everything ready, we just need to connect the parts.

With this assembly I managed to get as high as 240'C, enough to melt a sn63/pb37 alloy but just not enough to reflow a smd board.
So I made just one more tunning of the device.
You'll need about 1m or 3ft of thin wire, copper will be best, then wind this wire into a coil with a 1,5mm diameter.
I wound it around a watchmaker screwdriver, but everything that is 1,5mm, hard and stright will do.
Now put this coil into the desoldering iron shaft. This way, the coil will be heated from the iron, and when the air flows through it, it will release more heat than the bare shaft itself.
With this tuning the temperature rised to above 310'C, that is high enough to reflow the smd parts.

Step 6: Some More Tunning

So you have a Hot air soldering gun for just under 10 EUROs or US$15.

One more tunning. I sewed myself a strap to hold the yellow cylinder to the iron body, but you can use a rubber band or scotch tape.