IC Holder when trying to hand solder... - Page 1
Forum section: electronics / general

author: alank2
author_rank: Super Contributor
timestamp: September 10, 2015, 11:12:08 pm
content: When I try to solder an IC like a TQFP32/44 or SOIC, I typically position it on the pads and then try to head the pad and tack one corner and then the other, and finally once it is stable finish soldering it.One problem is that sometimes the iron will barely touch the pin and throw it off and require realignment, or sometimes the solder wicking into the joint itself will pull it off center.So I had this idea, what about a small weight that you could put on top of the chip before soldering it. Imagine something that comes to a fairily sharp point with weight over it that extends out to a flat edge that can be on the pcb outside of the chip area. Does anyone have or use a tool like this?

author: Monkeh
author_rank: Super Contributor
timestamp: September 10, 2015, 11:21:02 pm
content: I have a better idea: tape.

author: Aodhan145
author_rank: Frequent Contributor
timestamp: September 10, 2015, 11:24:32 pm
content: bluetack. unless it has a gnd pad on the bottom

author: KL27x
author_rank: Super Contributor
timestamp: September 10, 2015, 11:42:12 pm
content: ^+1. It's hard to beat blutac-on-a-stick if you have more than a couple to do.I like the idea though. Maybe if you have to solder one 100 pin QFP, once in a blue moon. I'm having a hard time figuring out how you're going to get one size to fit all, though.How about whipping up something like a small spring loaded arbor press? Nah... talk about overkill.Edit: I think I see what you're saying. How bout take one of these.http://www.amazon.com/Ansen-Tools-Cushion-T-Handle-10-Piece/dp/B00A7OOTJW/ref=sr_1_2?ie=UTF8&qid=1441929728&sr=8-2&keywords=extra+long+1%2F4+allen+keyAcetylene torch to put a couple bends in it. The rubber grip would be the part that extends and acts as the pivot. Grind a point on the end. If I had an acetylene torch...

author: Deathwish
author_rank: Unknown
timestamp: September 11, 2015, 12:07:24 am
content: SWMBO's finger...........

author: langwadt
author_rank: Super Contributor
timestamp: September 11, 2015, 12:26:14 am
content: Quote from: alank2 on September 10, 2015, 11:12:08 pmpush down on the chip with the tweezer you use to place itfor welding some use a "3rd hand"http://www.pirate4x4.com/forum/attachments/shop-tools/651549d1328501308-3rd-hand-helping-hand-photo-1.jpg

author: John Coloccia
author_rank: Super Contributor
timestamp: September 11, 2015, 12:56:29 am
content: I just hold it down with the tip of a tweezer. Pretin one pad, place part, hold down with tweezer, reflow the pad. Solder the other pads. Then i go back and reflow the original pad with just a touch more solder. You could also simple pre-tin the pad, add a little flux, place the part and then reflow, skipping the final reflow at the end.Takes a lot longer to describe than to do. The only real trick is to somehow get one hand free so the other can hold down the part...pretin the pad or place the part, flux and drag solder a pin to tack it into place. Whatever...just get a hand free.

author: Deathwish
author_rank: Unknown
timestamp: September 11, 2015, 01:01:57 am
content: being serious, try a little bit of double sided tape under it

author: DimitriP
author_rank: Super Contributor
timestamp: September 11, 2015, 01:02:44 am
content: Here is another method...but you get the idea... :http://blog.kotarak.net/2009/08/soldering-weight-for-smd-work.html

author: alank2
author_rank: Super Contributor
timestamp: September 11, 2015, 01:06:28 am
content: Quote from: DimitriP on September 11, 2015, 01:02:44 amThat is exactly what I'm talking about, but I was thinking smaller.

author: DimitriP
author_rank: Super Contributor
timestamp: September 11, 2015, 01:10:37 am
content: Another version:http://dammitcoetzee.com/2009/07/how-to-make-soldering-fine-pitch-surface-mount-rediculously-easy/

author: Jeroen3
author_rank: Super Contributor
timestamp: September 11, 2015, 05:34:44 am
content: With HASL finish, the board and the pin already have a bit of solder. So you can use your tweezers and left hand as weight to tack a few pins with the right hand.Then you can solder the opposite side, and it's fixed for the rest.Without HASL finish, you'll need to first create a few tinned pads.

author: Unknown
author_rank: Unknown
timestamp: September 11, 2015, 07:39:13 am
content: Two solutions I quite like:1) Kapton tape.2) The eraser-end of a pencil to prod the thing against the board. It seems to provide just enough friction to stop it scooting around while I tack down some pins on tinned pads.

author: neslekkim
author_rank: Super Contributor
timestamp: September 11, 2015, 09:16:24 am
content: Quote from: DimitriP on September 11, 2015, 01:10:37 amCool ideas, but I wonder how much weight you can use before you destroy an led?I can't say I have had problems soldering smt ic's so far, but not done too many of them, and not the tinyest ones, but have done quite a few leds and resistors, and tend to use more than needes since I crush some (using tweezers to hold, easy to destroy leds), and lots of them fly around.

author: anachrocomputer
author_rank: Regular Contributor
timestamp: September 11, 2015, 03:22:25 pm
content: Yet another version (from Fran Blanche):http://www.frantone.com/designwritings/design_writings5.html#hold

author: Mechatrommer
author_rank: Super Contributor
timestamp: September 11, 2015, 08:46:11 pm
content: 1) put solder flux on pads2) position the chip3) get a bit of solder on to iron tip4) press the chip in place a little bit with tweezer5) solder the chip leg corner to corner6) done, very minimal leadtime...

author: timb
author_rank: Super Contributor
timestamp: September 12, 2015, 12:02:40 am
content: Quote from: Mechatrommer on September 11, 2015, 08:46:11 pmThis. Normally for QFP and *SOP packages I use a flux pen to flood the footprint with flux, then drop the chip down. It will "float" on the flux, which allows you to nudge it in position with your tweezers. Then press down on it with said tweezers, apply a little solder to the tip of your iron and tack one pin down in each corner. Easy peasy.Just avoid snorting that line of coke/smoking that rock of meth/guzzling that triple shot espresso before hand.Sent from my Tablet

author: KL27x
author_rank: Super Contributor
timestamp: September 12, 2015, 01:56:36 am
content: I do it a little differently. I plop the chip down, first, roughly over the pads. Then apply liquid rosin over the top of the pins, with a syringe, getting all the pins and pads in a go. Then align and hold down the chip, typically with tweezers. Tack down one pin, pressing directly down on top of the pin with a lightly loaded tip. Verify alignment. If I'm using a bevel tip, there's no need to lift the tweezers and/or turn around the pcb to get the other corner. I will tack down the chip somewhere in the middle of the other side, never lifting the tweezers. Whether the bevel tip hits one, two, or 3 pins, it doesn't matter. Then finish with a modified drag solder.I can see no reason to use a hold-down tool. Flux is my first third hand. But I will probably make one, eventually, just to see. I suspect it will be useless for me. But maybe it will prove to be useful for something I have been doing wrong all my life. Or maybe it will be useful for some problem I have just not had, yet.

author: ShamilaBW
author_rank: Newbie
timestamp: September 12, 2015, 07:11:52 am
content: Quote from: Mechatrommer on September 11, 2015, 08:46:11 pmThis is what I do as well. I've done up to 208 pin qfp packages. I use a flux pen. Position the chip on the footprint roughly and put flux on with the flux pen so that the pins as well as the pads are wet. Then carefully position it with the tweezers and tack a pin or two on one corner while holding down with the tweezers. Check alignment (you can do a bit of correcting) then tack the opposite conner. After that it takes seconds...Sent from my X98 Air 3G using Tapatalk

author: alank2
author_rank: Super Contributor
timestamp: November 12, 2015, 11:41:34 pm
content: I walked the aisles of Harbor Freight and found this:http://www.harborfreight.com/spring-hook.htmlI might have to add a small weight to give it a little more downward force, but maybe not, haven't tried it yet other than to see if it holds a part in place. I'm tired of placing a part, getting it right, and then having the solder pull it off center when I try to solder the first pin.

author: KL27x
author_rank: Super Contributor
timestamp: November 13, 2015, 12:01:15 am
content: Your problem stems from using two hands to tack the pins. You do not need to feed solder into the iron. Flux the pads, first. Then hold the IC with one hand while you tack it down with the iron. Tweezers work great. Blue tac on a stick is da bomb, if you are doing a lot of ICs.My apologies, if you have only one hand.

author: alank2
author_rank: Super Contributor
timestamp: November 13, 2015, 12:17:22 am
content: Quote from: KL27x on November 13, 2015, 12:01:15 amI've got two hands all right. So you have to have enough solder on the iron tip that it will wick into the joint? I'll have to try this too.

author: KL27x
author_rank: Super Contributor
timestamp: November 13, 2015, 12:34:04 am
content: With a fully loaded 3mm bevel tip, I can solder over a dozen 0603 SMD passives without touching solder.Drag soldering IC's, OTOH, takes almost a clean tip to start off with. A freshly cleaned, sponged/wiped bare tip will generally still have enough solder to tack a pin if you flux the pads. I guess it depends how meticulous you get in your cleaning.

author: bson
author_rank: Unknown
timestamp: November 13, 2015, 01:24:33 am
content: A small 1 or 2g calibration weight works great for hot air. Permits blowing fairly strongly at slightly oblique angles without the part moving. I just put it on top of the IC.