I have made a couple of desoldering guns, from the iron with the suction bulb attached. Below is an example - Not mine. They can be made DIY for $50, easy, assuming that you have a few of the parts laying around. Here are my design tips...
Buy the hottest iron, you can find. The same iron design comes in different fixed heats, depending on the maker. This one from Amazon was the hottest 120v I could find, but not the cheapest. Get the hottest.
https://www.amazon.com/ECG-J-045-DS-Electric-Soldering-Temperature/dp/B00068IJSG/ref=sr_1_fkmr0_2?ie=UTF8&qid=1541381154&sr=8-2-fkmr0&keywords=desoldering+pump+bulbI used a Radio Shack brand, for one, but they went out of business.
Get an iron that has replaceable tips. The one from Amazon does have replaceable tips.
Remove the bulb and shorten the bulb tube. You want it short as possible, but long enough to keep the filter off of the iron.
Use a short piece of automotive grade/heat-rated silicone tube to attach a
metal, 1/4", small engine, fuel filter to the bulb tube. Remove the filter guts and put in a little piece of brass sponge. Do not get a fuel filter that has a center tube.
Use automotive grade/heat rated silicone tube, going from the filter to the pump. Leave the tube long, maybe 24", to keep heat from reaching the pump.
Add a switch system. You want the iron to stay on continuously. But, you only want the suction to operate during the removal process. The problem with leaving the pump running all the time is that the air cools the iron tip. I made a foot switch using a voltage regulator and a solid state relay.
I used nebulizer pumps. They are cheap, at the secondhand/thrift stores. And, it is easy to change them from blowing to sucking, by swapping those lines.
Watch YouTube videos on how to use a desoldering gun. There are a few tricks.
These work well for me. I would not hesitate to make another one.