Soldering fpc connector - Page 1
Forum section: electronics / general

author: Hornnumb2
author_rank: Regular Contributor
timestamp: April 21, 2025, 04:04:07 am
content: I need to put on a new fpc connector and was going to use hot air from underneath board, but there are a few components there, should I be ok. I don’t want them falling off. Thanks

author: nctnico
author_rank: Super Contributor
timestamp: April 21, 2025, 08:44:15 am
content: Use a soldering iron with a big (chisel shaped) tip and flux. Set it to 330 deg C. Works like a charm.

author: GridWork
author_rank: Contributor
timestamp: April 21, 2025, 12:10:43 pm
content: Quote from: nctnico on April 21, 2025, 08:44:15 amThis plus flux, lots of flux.

author: squadchannel
author_rank: Frequent Contributor
timestamp: April 21, 2025, 12:21:21 pm
content: 0.5mm pitch is possible with hand solder. with a lot of flux.

author: Fflint
author_rank: Frequent Contributor
timestamp: April 21, 2025, 01:08:41 pm
content: Heating from the opposite side? No way... You'll sooner burn the traces off than melt solder applying hot air from the "wrong side". The only way it makes sense to heat the other side is with these preheating devices you set to 90c for example and you then you have much easier time melting the solder from the top.As others said, a small tip and a microscope is what you need. 0.5mm pitch is no problem at all. Even less if you have good flux (so called bga flux is best). Just remember to clean it after or it will eat your device sooner than you think.

author: nctnico
author_rank: Super Contributor
timestamp: April 21, 2025, 05:00:47 pm
content: No to the small tip! Use a wide tip which can wet 3 or 4 contacts at the same time. This make the amount of solder less critical and also heats the joints faster which gives the flux less time to burn off (and not work). The worst mistake to make on fine pitch components is using a small tip. Only use for a fine tip is to attach a botch wire to a fine pitch part.

author: pcprogrammer
author_rank: Super Contributor
timestamp: April 21, 2025, 06:28:26 pm
content: A big hollow horseshoe tip is also good for drag soldering. It can hold more solder than a chisel tip.

author: thm_w
author_rank: Super Contributor
timestamp: April 21, 2025, 11:49:00 pm
content: Quote from: Fflint on April 21, 2025, 01:08:41 pmNo this is a common technique.youtu.be/pcdsfq9DPl8?t=1287I don't think its needed for the FPC though as explained above.

author: u666sa
author_rank: Frequent Contributor
timestamp: April 22, 2025, 02:00:54 am
content: Quote from: Hornnumb2 on April 21, 2025, 04:04:07 amYou should be fine.Be sure to clean pads and apply new solder. Solder paste would be better. Hit it from bellow, medium air, and flow the FPC connecter into its place.With solder iron its also doable, but the results won't be as good as hot air.P.S. Easy on flux. You don't want flux inside your FPC connector. Use some flux on solder pads, if you using solder paste it will already have flux, otherwise if just solder apply some flax to pads, but not a lot. So that it don't get inside the connector.

author: Fflint
author_rank: Frequent Contributor
timestamp: April 22, 2025, 02:47:31 pm
content: Quote from: thm_w on April 21, 2025, 11:49:00 pmWell, yes looks very nice indeed. I bet you need to dial in the heat, the airflow, the distance and the timing just right. If you're capable of doing that... I concede it is a nice technique. No risk of overheating the plastic inside the port.It's probably even better for removal.But personally I see no point(during reinstalling) unless you're doing a lot of them, you have opportunity to practice and it matters if you spend 30 vs ws 20min. I'd still just take a small tip under a microscope any day.No, not a big tip. A small tip. Not the smallest "dot" that is 0.1mm across. I use that one for 0402 resistors and caps exclusively. The small "cone truncated at an angle" with a diameter of 1.5mm is my favourite for anything with legs. You can drag it if you like. But I prefer to just touch the tiniest bit of solder to it. Press on the leg and feed 0.25mm flux cores solder into the gap.You only have to hold the part when starting. Once you've soldered two opposite legs all the other rake 2s per leg.Also, if this (electronics) ifs your hobby and you don't own (an optical - that is not camera) microscope, do yourself a favor and buy one. I found so much more enjoyment in this hobby after I bought a microscope and quality tweezers.

author: Grandchuck
author_rank: Super Contributor
timestamp: April 22, 2025, 05:17:11 pm
content: As Fflint suggested, solder two opposite legs. Do not worry about any bridges between traces. When all are soldered, apply a little more flux, wipe tip on a damp sponge and then draw the tip along any solder bridges to remove them.