tips for desoldering gun - Page 1
Forum section: electronics / general

author: djacobow
author_rank: Super Contributor
timestamp: November 12, 2018, 07:08:37 pm
content: I bought a Hakko FR-300 desoldering gun. It looks like a nicely made tool and seems to "work" in the sense that when I put it over a pin a pull the trigger, it sucks away most of the solder.But I'm having trouble because it never seems to remove *all* the solder. It sort of leaves the joint looking like I had used wick. Mostly dry, but when the joint is cold, there might be just enough wetting on the pin and hole to hold the pin place. If It's a two or three pin part, no biggie, I can just heat the joints. But if I am trying to remove a part with many pins (say, a large header) or distant pins (say, a heatsink) I feel like I'm not much better off than before I used the tool.So, are my expectations for this tool too high, or is it possibly defective, or is this (most likely) a technique problem.When I bought the tool i imagined I'd just be doing zip, zip, zip, zip, reclaimed heatink, zip, zip, zip, zip, zip, reclaimed screw terminal. I am futzing not just as much with hot air (and burnt fingers) as ever.

author: james_s
author_rank: Super Contributor
timestamp: November 12, 2018, 07:15:34 pm
content: I usually wiggle it around a bit to push the pin away from the wall. No desoldering tool can defy physics, if a pin is pushed up against a plated through hole there will be a bit of solder in there that it can't suck out. Also you might try a smaller tip, if the tip is too large it won't put all the heat right where it needs to be and make a good seal. Another thing that can be useful is add a bit of fresh solder to the joint before you try desoldering it. It takes some practice but you'll get the hang of it after some time. Some boards are just going to be harder to desolder from than others too.

author: helius
author_rank: Super Contributor
timestamp: November 12, 2018, 07:36:15 pm
content: Quote from: djacobow on November 12, 2018, 07:08:37 pmThe tool is as fast as that but not automatic. Technique is required as with everything else.The owner's manual covers the operation fairly well, but it omits some details. The circular motion should be continued during pumping, and the pump should be kept on briefly after the tool is withdrawn. This prevents blockages.As the pump is activated, cold air rushes in around the lead, which can freeze it to the PTH if it is not kept wiggling.

author: jmelson
author_rank: Super Contributor
timestamp: November 12, 2018, 10:45:06 pm
content: Quote from: james_s on November 12, 2018, 07:15:34 pmYes! The Pace manual actually describes this. First, you apply the hollow tip to the tail of the PTH lead, and wait for the solder to melt, ALL the way THROUGH the board. I usually count to 5. Then, while running the vacuum pump, you orbit the tip enough to make the component lead walk all the way around the inside of the hole. This usually leaves the hole totally empty of solder, and the component lead does not re-stick to the PTH walls. You can't do this with the bulb or plunger solder suckers, the vacuum doesn't last long enough.Jon

author: djacobow
author_rank: Super Contributor
timestamp: November 12, 2018, 11:40:38 pm
content: Thanks, folks! What I was missing was indeed the "stirring" of the pin a bit in the hole. Once I did that, I was able to remove a 2x20 header on the first try.Much more excited by my new tool, now!

author: james_s
author_rank: Super Contributor
timestamp: November 13, 2018, 01:13:00 am
content: Pretty soon you will wonder how you ever got by without it. Seriously I wish I had bought mine 10 years before I did.

author: Styno
author_rank: Regular Contributor
timestamp: November 13, 2018, 08:41:48 am
content: Another option would be to use a solder pot filled to the brim (or a solder fountain), place the board on top, wait a few seconds and remove the component using a plier. Then clean the PTH using an ordinary suction pen.Or am I suggesting something silly now?

author: ar__systems
author_rank: Frequent Contributor
timestamp: November 13, 2018, 11:21:36 am
content: Pace have a nice video about using of their desoldering gun.Skip down to the use of desoldering gun.

author: jmelson
author_rank: Super Contributor
timestamp: November 13, 2018, 09:59:22 pm
content: Quote from: djacobow on November 12, 2018, 11:40:38 pmYes, a really high-end desoldering station that can remove parts with no damage is really great.Jon