Soldering: Holding stuff to the PCB - Page 1
Forum section: electronics / beginners

author: rthorntn
author_rank: Frequent Contributor
timestamp: May 04, 2018, 06:08:45 am
content: Hi,Any gadgets or tips on how to hold stuff like through-hole 2.54mm headers, so holding the PCB upside down is easy but how do you hold the upside down header in place while you solder the first pin, I was thinking a tiny 'c' or 'bar' clamp would be cool, I also heard a tiny bit of blu-tack could be used?Thanks for looking.CheersRichard

author: tautech
author_rank: Super Contributor
timestamp: May 04, 2018, 06:21:54 am
content: With TH you'd normally populate the lowest profile parts first, bend leads, flip PCB and solder as a group and then snip.Next will be the 2nd lowest, 3rd lowest and so on. When your header fits in the process solder it and normally finishing with radial caps that are commonly the tallest.I do this step by step process with the PCB flipped at each stage/step onto a thin foam on top of the bench mat.Others use PCB holders but I find it's just as easy with the PCB loose and flipping as you go.Hope that helps.

author: MosherIV
author_rank: Super Contributor
timestamp: May 04, 2018, 06:35:58 am
content: QuoteHiYes, bluetack can be used. Be careful it does not melt onto leads of components.Tautech has alsp given good advice.

author: Brumby
author_rank: Unknown
timestamp: May 04, 2018, 07:02:35 am
content: I've never used blu-tack. I tend to follow pretty much the same style thattautechhas described.With headers, I will solder one pin and check that it is sitting flat. If not, then I apply heat to the soldered pin and push it in place with a finger (that is not in contact with the soldered pin).

author: Ian.M
author_rank: Super Contributor
timestamp: May 04, 2018, 07:09:27 am
content: A full time techie will use the burn-resistant callus on the end of their middle or ring fingers of their non-dominant hand, and if you blink you've missed the whole operation!For us lesser mortals, it becomes an exercise in juggling board, part, solder and iron without getting burnt. There are two possible approaches - freehand and using some sort of a jig.For small boards you can do it freehand:Hold the part in place with a finger of the same hand that's holding the board but, as its a header with solid metal pins that will burn you before you finish soldering them, you need to press on one that you are not going to solder (yet). Bend the end of the solder coming off your bench reel to a convenient angle so you can bring the joint and the iron to the solder. If that's not possible, you'll need to hold the solder (same hand as the board) near the joint to minimise the time you are carrying it on the bit, and use flux on the board. Once one pin is tack-soldered, you can reheat it and adjust how the connector is sitting, then solder the opposite end/corner and then the rest of the pins.Supporting the board and jigs:The general approach is to support the board and rig something to push on the part that won't melt. If you've carefully planned the assembly order by height and location, the 'something' can be your bench surface, otherwise you may have to rig something such as a small block of wood on the bench or a piece of card and some tape (or heat resistant tape like Kapton, on its own if you've got some). Foam on its own isn't good unless its fairly heat resistant, though a couple of sheets of kitchen towel on top of it may give you enough soldering time before it melts. Otherwise try a silicone mat. The board may be self-supporting, it may need chocking up if there are no tall components on one side, or you may need to go whole hog and use a PCB vice.I've never liked using Plasticine, BlueTak or similar as it tends to leave a deposit on a heated connector pin which can be a PITA to clean off. OTOH it can be helpful on the track side to retain the parts while you flip the board over, as long as you remove it all before soldering, or for box headers, where it never has to touch any pins.If you've got a lot of bare headers to insert that must be properly aligned and vertical, *DON'T* use a solderless breadboard you care about as a jig - the solder dross and hot pins will destroy it. Ideally tape a few spare boards together and use them to hold all the headers so you can simply drop the board you are working on over them and solder all the pins in one pass. If you don't have spare boards, but the pins are on a 0.1" grid, use a few layers of plain perfboard.'Helping hands' aren't much use for larger boards unless you've got the luxury of a tilt-able PCB vice or can get the board well up off the bench e.g with opposite edges on a stack of phonebooks, so there's space for the helping hands to hold the part. For very small boards, if you can rig an extra arm lower down so you've got three clips, two holding the board by opposite edges and one holding the part up can work nicely

author: voltsandjolts
author_rank: Unknown
timestamp: May 04, 2018, 07:35:56 am
content: For some parts you can design the PCB holes to be slightly out of line, just enough so the component stays put when pushed in.Works well with headers but needs a little trial and error.

author: rthorntn
author_rank: Frequent Contributor
timestamp: May 04, 2018, 08:51:34 am
content: Thanks everyone, any tips & tricks for holding surface mount 2.54mm headers in place (they move when either the solder wire or the tip touches them)?

author: janekm
author_rank: Unknown
timestamp: May 04, 2018, 09:14:01 am
content: The general approach with SMT components soldering with an iron is to put solder on the pad first, heat the pad, push the component leg onto the pad and correct the orientation, then remove the iron while keeping the component held in place. Then "tack solder" a pin on the opposite side.

author: tautech
author_rank: Super Contributor
timestamp: May 04, 2018, 09:22:04 am
content: Quote from: rthorntn on May 04, 2018, 08:51:34 amTin one pad. Hold header in correct position and apply iron onto header pin melting the pre-tinned pad. Double check alignment. Solder remaining pins.Like Jane says !

author: frozenfrogz
author_rank: Frequent Contributor
timestamp: May 04, 2018, 09:26:14 am
content: For some jobs something like this might come in handy:https://www.thingiverse.com/thing:1623014There are commercial options available as well:https://au.rs-online.com/web/p/pcb-work-frames-holders/1628766/I tend to simply have the PCB fixed to something and then use a good pair of tweezers to get all the parts where they belong.THT components usually hold themselves in place if you give opposing leads a little bend.Edit: For small pin headers I would definitely recommend tweezers or - if headers are the highest point on the board, simply let them touch the table and support the PCB so it sits snug -> Some Playdo / putty could help you out here.

author: Mr. Scram
author_rank: Super Contributor
timestamp: May 04, 2018, 09:52:21 am
content: Blu Tack works well enough. I prefer it over bending the leads as you retain full control over where those go. You need to be mindful about the stuff heating up and losing adhesion though.

author: austfox
author_rank: Regular Contributor
timestamp: May 04, 2018, 11:36:53 am
content: Whilst we are on the subject, Weller make a PCB holder which has an extendable arm that holds components in place. Ocassionally I see them on special and have toyed with the idea of getting one, but up to now haven't.Does anyone here own / use one and find they work well?

author: Gregg
author_rank: Super Contributor
timestamp: May 05, 2018, 02:45:45 am
content: Self closing tweezers like these:https://www.amazon.com/Fiber-Cross-Tweezers-Closing-Straight/dp/B078ZMGVR5

author: bson
author_rank: Unknown
timestamp: May 05, 2018, 09:59:09 am
content: Most of the time I just put a small wood block under the part I'm soldering to avoid marring the ESD mat. For more complex needs I use a Panavise. 301 clamp on a 312 base. (For SMD a board holder that holds it level, but those don't need constant flipping or adjusting like TH.)

author: PA4TIM
author_rank: Super Contributor
timestamp: May 05, 2018, 10:59:56 am
content: In my case it is board repair and they vary from very small tot very big. I have not found a system yet that is usable for all. I made several but non of them are truly universal and if it is close it becomes to complex.This one turns out to be very usable for flat PCB's to measure on but soldering on thew underside is not always handy because the rod in the middel. It is versatile, the rods make it flip-able but turned out to be also handy to hold non rectangular boards (slipping rubber or plastic disks over the rod to fill the space) See:http://www.pa4tim.nl/?p=5775Also used a glue-clamp (if that is the right term)http://www.pa4tim.nl/?p=5283that worked well but is a bit bulky.I also made these :http://www.pa4tim.nl/?p=5521Worked very well but to bulky because I often have rather big things on the bench and I have not much room to put it elswhere in the meantimeMy now most used fixtures are two adjustable mini jacks used for things like milling. I have no picture here but they are the same idea as the ones in this video only bigger and not magnetic. I clamp the pcb edge between the adjustable part and base.https://youtu.be/DNnhfOGhRDM

author: Rick Law
author_rank: Super Contributor
timestamp: May 07, 2018, 04:40:49 am
content: I am just a hobbyist so my experience is not extensive. That also means I don't have a big bag of tricks.But a few times when I struggled with that, I reach for what was at hand -- Scotch tape (regular stationary magic/invisible tape for paper) works well - particularly with the through-hole stuff. With SMD's they don't work as well. It is too easy to melt the glue on the tape making the component sticky.

author: BergRD
author_rank: Contributor
timestamp: May 07, 2018, 12:06:06 pm
content: I was part of a Kickstarter for a great little bit of kit called PCBGrip Vise.I can try to get some pics up later but here is their website and it can do quite a bit including holding SMT (within reasonable size) components so you can solder well. At the time it did not cost me much and I cannot state the current prices but you might want to check them out and good luck!https://pcbgrip.com/

author: tszaboo
author_rank: Super Contributor
timestamp: May 07, 2018, 12:14:04 pm
content: For 2.54 headers and such, I just hold one end and solder the other one.And also Xcelite has a cross lock tweezers, very useful for holding stuff together.

author: Psi
author_rank: Super Contributor
timestamp: May 07, 2018, 12:20:30 pm
content: For 2.54 headers just design the PCB so the holes are offset a little on each alternate hole .Just enough so the header jams in a bit. This will hold them enough for soldering.The other option is making the holes small so they are more of a friction fit however this is trickier than it sounds due to hole tolerance. You would really need to specify to the PCB fab that the holes are friction fit so they make them exact.This is why i prefer the first method of offsetting every 2nd hole a little.

author: Ian.M
author_rank: Super Contributor
timestamp: May 07, 2018, 02:30:58 pm
content: Quote from: voltsandjolts on May 04, 2018, 07:35:56 amQuote from: Psi on May 07, 2018, 12:20:30 pmStaggered footprints for header retention and alignment:https://www.sparkfun.com/tutorials/114However, that's only any good if you are designing the board yourself and the PCB house can hold tight enough tolerances repeatably. If its someone else's board with a straight footprint, you are SOL.Another method I have used is a couple of rubber bands and a strip of folded corrugated cardboard, or two strips of plain card stapled together. Take the strip of card, notch the edge of it for the length of the header and height of its base, insert header in the edge of it and fold the ends of the card in opposite directions about 1/2" from the header. Insert the header + card in the board (you may need to notch the card to fit round existing parts) then hold the card+ header in place with rubber bands round the PCB, which are clear of the ends of its footprint so you have good access for soldering.A quick & dirty alternative is to put one or two closed top jumper caps on the middle pins of the header and put one rubber band round the board over that. The end pins can then be soldered before removing the band and soldering the pins it covered. You can also hold small headers with your finger without getting burnt if you've put one or two closed top jumper caps on them, and if you use pliers or forceps, the jumper cap prevents them marring the surface of the pins.

author: MarkL
author_rank: Unknown
timestamp: May 07, 2018, 02:33:15 pm
content: Manufacturers also offer "kinked pin" versions for many of their connector series. When ordered this way, several of the tail pins are purposely bent so that the part retains itself while being soldered. Just search for "kinked pin" on Mouser, Digi-Key., etc.If just a connector or two, I usually put a pair of long 0.1" jumpers on the two far ends of the header, and put the board upside down on a towel that's been folded several times. It pushes the header snug against the board while soldering.

author: PA4TIM
author_rank: Super Contributor
timestamp: May 07, 2018, 06:17:21 pm
content: Quote from: BergRD on May 07, 2018, 12:06:06 pmWow, would like to have a PCBgrip kit too but the price is rather high. The way I would like it, it is over 300 euro. But this probably can do what I often deed, mount several PCB's above or next to each other so I can measure while repairing coupled PCB's (I often make extension wires but it is alway a hassle to keep them safe and turning one around is even harder. I think I can mount three pcb vice clamps on one "backbone" PCBgrip and so turn all of them the same time

author: tautech
author_rank: Super Contributor
timestamp: May 07, 2018, 08:25:29 pm
content: Quote from: NANDBlog on May 07, 2018, 12:14:04 pmRarely I've needed to use something like these ^ from my fly tying bench....hackle pliers.Here's a selection of the various styles available:https://www.caddisflyshop.com/hacklepliers.html

author: nanofrog
author_rank: Super Contributor
timestamp: May 07, 2018, 09:53:20 pm
content: A similar version of ^ would be a pair 31-SA tweezers.Other odds and ends that don't cost a fortune that could be useful:HemostatsSegmented CNC Hose (make great helping hands and probe holders*)Kapton tape (handles temperature much better than blue tack)Panavise (324,350or396) and Bernstein Spannfix (9-240) vises are suitable for PCB work (others too, but not as versatile).* Search"diy helping hands"(upper left SEARCH button), and the results will point to some links for inspiration.

author: KL27x
author_rank: Super Contributor
timestamp: May 08, 2018, 04:30:16 am
content: For the standard 0.1" (2.54mm) pitch headers, assuming you have more than one SIP row of them and they are all aligned on same grid, I will turn the pcb upside down and stick the headers into a solderless breadboard to make them nice and square while I solder them.

author: BergRD
author_rank: Contributor
timestamp: May 08, 2018, 11:42:32 am
content: Quote from: PA4TIM on May 07, 2018, 06:17:21 pmI got in on the KS so the price was lower and ofc in USD$ which helped. Think I got the VK5 edition since I had no Panavise at the time and ran me 25$ USD at the time. Since I don't do major projects (yet) and just getting back into hobby electronics as my 2 son's age and leave us (1 in local college, 1 on the way this fall) I may end up getting more as I get into larger projects. I'm glad he had the idea and thought to go to Kickstarter and I was glad I could help with my small amount. He's had 3-4 campaigns now for various things he sells and likely will have others in the future; keep an eye out!

author: jolshefsky
author_rank: Regular Contributor
timestamp: May 08, 2018, 01:33:52 pm
content: When I can bend the component leads, I usually do that.For some components, if I can't bend the pins, I flow just enough solder into the hole from the same side as the component then, after getting it positioned just right, I reflow the solder and let it absorb maximum heat, then remove the soldering iron and quickly plunge the lead into the molten pool. This is usually enough to tack the component in place. That's how I do things like DIP sockets and Molex connectors.In either case, if it's a 3+ pin package, I'll usually solder one corner, then apply pressure and reflow the solder so the component sits flat.