Salvaging Components using B&Q 1800W heat gun

Was asked what and how...Salvaging Components using B&Q 1800W heat gun.

I have a somewhat huge pile of PCB with both through hole and smd components and it is time to clear some shack space out.

I used to salvage with a normal soldering iron and suction pump. This is a faster but needs a bit of care to always produce usable components, especially where they have plastic involved.

Through hole is easy, clamp the PCB vertically in a vice, with the component side partially facing downwards. Then with the heat gun running hot for a few seconds before you bring it near the board bring it up to the solder side. It takes seconds only for the solder to heat up enough and the components fall out or you have to 'encourage them' with a pair of long nose pliers. If you work from the top of the board and move to the bottom in time the board will be completely salvaged. The leads can be bent over so this might cause a problem so you may need to pull them out..

For smd the method is a little different, the board is best held in one hand, the solder is heated to point where it is melted slightly, then with the board held over an aluminium foil sheet on a hard board hit one corner hard, either hit the PCB onto the board or hit the pcb above the board. It will be a matter of trial and error but you will soon figure out how hard. Anyway, a nice pile of solder splatters and components will appear. IC are obvious, R will have values on them but C and L will not. I found an easy way to ID the L was to mark the L SMD with a small permanent marker (fine gold spot).

Note that SMD discrete components range in size from 0402 to 1206.

Some PCB seem to be much more susceptable to burning before the solder melts so the ability to salvage components will vary.

Only do this in a location with LOTS of ventilation as all sorts of fumes will be created. And exercise extreme care with some components, especially small electrolytic or tantalum capacitors will have a tendancy to 'detonate' if over heated so only apply heat to the solder side.

The B&Q heat gun by itself has a 2" nozzle, this works but it also has a couple of attachment nozzles and I started with the 2" reduce to 1" reduction adapter. This may be enough but I also dug through the copper pipe connectors in the garage (we had some plumbing done) and found a 22mm to 15mm reduction adapter and this fits exactly in between the heat gun adapter and the main nozzle. I added some self tapping screws to keep the adapters in place.

NB Use a set of safety glasses when doing this along with a set of leather gloves so you don't burn your hands. Proceed without either and frankly you are asking for trouble.

Make sure you have a bucket of water or similar close by if the board bursts into flames, one will at least! I measured the jet of air produced from the heat gun after 10 minutes running and it was at almost 600 degrees C. The nozzle will stay very hot for a long time after use, as will the salvaged PCB so keep fingers away unless you want to remove all finger prints from them and don't bring anything flamable close by.

I would not use the method on a board you intend to use again afterwards.