In Praise of the Dental Pick - Page 1
Forum section: electronics / projects

author: German_EE
author_rank: Super Contributor
timestamp: May 14, 2017, 01:49:45 pm
content: What?I was just at a fellow tinkerer's house and he was desoldering a capacitor from a PCB by heating the joint and pulling on the component, it came out easily but the hole in the PCB was still blocked by a film of solder. What did he do next? He took a dental pick from his toolkit and, whilst heating the pad, used the pointed end to push the remaining solder out. As a dental pick is stainless steel the solder won't stick to it.One of those 'why the hell didn't I think of that' moments.

author: Gertjan
author_rank: Frequent Contributor
timestamp: May 14, 2017, 02:15:27 pm
content: For many years I use for the same purpose wooden cocktail sticks.Works very nice for holes in multilayer prints!regards, Gertjan.

author: janoc
author_rank: Super Contributor
timestamp: May 14, 2017, 02:32:58 pm
content: This is what the desoldering needles are actually for:On the other hand, if you are only cleaning a hole in the board after removing a component lead, simply use a solder sucker and suck the solder out. You may need to add a bit of extra solder first for it to work better.

author: BrianHG
author_rank: Super Contributor
timestamp: May 14, 2017, 03:16:08 pm
content: Sorry, but this one goes against the Dental Pick.... The dental pick can damage the through hole plating if you are not careful.For cleaning the holes, I just add a little solder if needed, heat up the hole, then tap the PCB on my work-bench while holding the iron on the hole. The weight of the liquid solder drops right out of the hole instantly and completely. 0 damage, only requires 1 hand holding the PCB and one hand holding the iron. No clamps/PCB holder and you can evacuate an entire 40 pin dip IC socket in 20 seconds with ease.Now, with a hot air gun heating up the entire section of a PCB, you can evacuate a whole bunch of pads at once, but, this method should be reserved to removing everything from a PCB and watch out for slashing solder with so much all at once.

author: macboy
author_rank: Super Contributor
timestamp: May 15, 2017, 04:22:22 pm
content: Quote from: janoc on May 14, 2017, 02:32:58 pmI like those desoldering needles. They are great for 3+legged components that you can't just wiggle out 1 leg at a time, things like power transistors and TO-* packaged rectifiers. Now I have an excellent desoldering station, so I don't use them as much, but they are a really useful, inexpensive tool to have handy.

author: RoGeorge
author_rank: Super Contributor
timestamp: May 15, 2017, 04:29:19 pm
content: https://hackaday.io/project/7574-the-devil-is-in-the-details/log/24730-toothpick-your-pcb

author: AndyC_772
author_rank: Super Contributor
timestamp: May 15, 2017, 05:24:47 pm
content: This is the main reason I prefer to work with SMD, even for prototyping wherever possible. I really can't understand why so many people seem to regard through-hole as easier, and are reluctant to switch.I'm sure I've damaged many more boards trying to clean out a plugged hole, especially where there's a solid plane without thermal relief involved, than I've ever damaged SMT pads.

author: Fungus
author_rank: Super Contributor
timestamp: May 15, 2017, 05:49:50 pm
content: Just heat it up and whack it sharply on the bench.Clean as a whistle.(doesn't work well for large PCBs, obviously...)

author: janoc
author_rank: Super Contributor
timestamp: May 16, 2017, 10:20:19 am
content: Quote from: AndyC_772 on May 15, 2017, 05:24:47 pmSome folks, especially the older ones among us, don't have the eyesight nor confidence for dealing with parts that are the size of a speck of dust.Prototyping with them is a pain, some can be soldered on a veroboard, but most won't fit and adapters or breakouts need to be used. Breadboards are right out unless you solder everything on an adapter first. Also when developing a circuit it is waay easier to desolder and replace a through-hole part for most people then to desolder the SMD versions. All you need are pliers/tweezers and an iron, optionally solder sucker. Everyone has that. SMDs are often not removable without hot air or destroying something. Of course, if you have hot air, it is easy, but not everyone has it.Also there are situations where an SMD version of something is decidedly inferior - e.g. connectors tend to be worse mechanically because they aren't as well mechanically supported as the through hole ones, the parts have worse thermal/power ratings due to smaller size, etc. Things like SMD crystals are a lot more expensive than their through hole equivalent while they are almost the same size (some packages), etc.So I can understand why people stick to through hole parts. I am also frequently mixing and matching when prototyping for this reason - passives in SMD and the rest through hole, depending on what I need (or have in my junkbox).