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.

Comments

[profpat]

what voltage did you use to power the copper wire coil?

[delwin]

the copper wire coil is not connected to any power source, it is only for better heat transfer, it is a kind of a heat sink, increasing the surface of the heated walls of the shaft, and slowing the air going through,
:)

[profpat]

got it!! thanks!

[ch3oh]

Is there anybody who can tell me how to remove pump - mine holds like welded.

[luzik1980]

can unsolder atmega 20 PDIP and atmega 664 PDIP (no smd) ?

[Tangoforce]

Nice idea but shame you didn't do it the other way around - a vacuum powered desoldering iron. I used one once many years ago (£800 worth) and it was absolutely excellent. Those electric suction desoldering irons are still better than normal suction plastic ones but suction desoldering irons are superb because there isn't a limit to the suction.

I have one in my tool box.. maybe I'll look for a small vacuum and have a go..

[RetroPlayer]

Look for a vacuum pump for air conditioner servicing. Pretty decent power in a small affordable pump. I actually tried to reverse an aquarium pump to suck in air, but it was only good enough to use as an SMD pickup tool. Wouldn't pull solder.

[luzik1980]

Thank you very much, I understand everything, copper wire from the transformer (power supply) will be good?
Will you make a movie from work Hot air soldering gun ?

[delwin]

I'm glad the explanations helped.
The copper wire from a transformer ... well these wires have a protective lacquer for insulation, may be you should remove it first, it will bake when you put it in the shaft, also I was using a quite thin wire ~ 0,3mm , but you should try with what you have, it could be even better than mine.
As for the video ... sorry, I don't have a camcoder.

[luzik1980]

I have question to you :

1 how long it takes the solder melt at a temperature of 240 C ?

2 I do not understand step 5 Tunning: I wrap the copper wire to the screwdriver and put the desoldering iron?

[delwin]

Hi luzik1980,
as I have pointed out in step 5, the 240'C is not hot enough to solder/reflow smd parts, because it is the AIR temperature, and as it gets out of the soldering gun it cools down quickly, also a PCB is a heatsink by itself so the solder won't melt. So step 5 is all about boosing up the hot air temperature.

Without this copper wire wound into a spring, the air flows through the desoldering iron freely, and what heats the air up is the inner area of the shaft, that the air is going through. Even more the velocity of the air in the tube is quite low, so I guess the flow may be laminar, so only the outter layer of the air is heated, and so not all of the air is heated equally. To solve this situation we create a obstacle in the way of the air flow, that do two things for us. First it make the flow turbulent and second it increase the hot area that the air is in contact with. So now we have more equally heated air and more heat conducted to the air. That's it.
I hope this clears out the theory behind step 5, but what you have to do is just put the coil into the hallow shaft of your desoldering iron, and that's it.

[delwin]

Sorry, the pump is 200L per HOUR. My mistake.

[soldering iron]

This is excellent guide about how to make cheap soldering hot-air gun. Recently I had to replace heater assembly on my hot-air hand piece ( part of the Pace MBT250  soldering station). The cost of that part (heater assembly only) was USD125.00 (without shipping charges). It is also possible to buy the complete ThermoJet handpiece assembly (TJ-70 for the  MBT250-SDPT  Pace soldering station) for $335.00. When you compare those cost to your costs - it is huge difference.

[Madcat Mayhem]

Sigh I had too much coffee. I did manage to get an iron to melt solder. Now I just need a 200L/hr pump and some copper wire for the element bore.

[robosilo]

200 ml/minute?

[Madcat Mayhem]

That air pump is 200L per minute? What the hell? Are you positive its "per minute" and not "per hour"? If thats true I must be unlucky because all the pumps here are either overpriced or grossly underperforming.