SMD junk box - Page 1
Forum section: electronics / general

author: elcomtel
author_rank: Regular Contributor
timestamp: October 29, 2013, 07:50:19 am
content: Ok...most of us 'old farts' with a passionate interest in electronics are accustomed to having a 'junk box'. The junk box is the quintessential holly grail of any true hacker passionate about electronics as a hobby.Given that old school electronics enthusiasts have 1000s of goodies inside their junk box, then how does the modern day electronics warrior manage their junk box?A true hacker is bound to have 'squillions' of second hand SMD resistors, capacitors, diodes, semiconductors and the like in their personal junk box. How do you work with a junk box with over an assortment of 1000 unmarked SMD devices?Now I've seen various storage systems for new SMD devices that are very impressive and quite self explanatory, but how does a modern day SMD warrior (hobbyist, technician, engineer, etc) deal used SMD components after several hours of development work where they are left with a handfull (ok...a thimble full) of used SMD devices?Is it that it is not worth the effort to manage used SMD devices and they are all simply swept into the waste bin after they have been used once or do 'SMD warriors' try to manage their used parts inventory with certain used SMD part storage solutions?I don't have a 'Used SMD Junk Box' of yet, but my plan is to keep a large blank notebook (look...I'm old school and when I say 'notebook' I mean the kind made from paper) next to a 'sticky tape' (Cellophane tape, whatever you call it in your country)dispenser.So the plan is that during development work I can place the used SMD device that I have removed from a project into my notebook (think paper) and use clear adhesive tape to hold the SMD part down to the paper, then manually making a personal note with a pen next to the SMD device as to what the used SMD device is.Am I being a too much of a 'tightwad tightarse' and not bother with used SMD passive components or is this a good way to manage second hand SMD devices?I am fully aware of the ESD concerns surrounding the use of 'clear cellophane adhesive tape' as it has been demonstrated by various ESD equipment vendors such as 3M that dispensing short lengths of adhesive tape can generate in the order of 10kV of static electricity.So far this is the only practical solution I can come up with to manage used SMD devices.Another solution that comes to my mind (not having tried this) instead of using 'adhesive tape' would be to use hot melt glue dots on the paper pages and with the help of a SMD hot air gun and a pair of tweezers you could quickly melt the glue dot with the hot air gun to place or remove your used SMD parts.I have also considered using cheap plastic drinking straws, a stapler (or some other method to close the ends) and a label maker (or fine tipped marker pen) to label the straws.BTW...I own a pair of Digital SMD tweezers that measure resistance and capacitance in anticipation of trying to make sense of a small junk box of 10-30 used SMD components during service or development work.Does anyone have any suggestions on how to manage 1000s of used unmarked SMD devices that they believe that works very well?

author: Psi
author_rank: Super Contributor
timestamp: October 29, 2013, 08:00:39 am
content: Quote from: elcomtel on October 29, 2013, 07:50:19 amDon't bother trying to store loose SMT components. When it's only ~$20 for 5000 resistors it's just not worth trying to reuse loose ones.When you buy components on tape they come in a plastic bag with the tape wound up inside and the value/part number printed on a label on the bag.Just cut off a corner of the plastic diagonally, so the tape end can poke out.You can peal the tape back and use what you need then throw the entire bag into the junkbox.Its always best to store them in the original packaging because it has the part number on it.

author: JuKu
author_rank: Frequent Contributor
timestamp: October 29, 2013, 08:13:05 am
content: Just get a selection of parts in different sizes (such ad the Adafruit books) and use the time for something fun.

author: poorchava
author_rank: Super Contributor
timestamp: October 29, 2013, 11:37:19 am
content: I actually do salvage smd components, but only those that could otherwise prove hard to buy in low quantity. My salvage list for smd includes all power devices in larger packages, memories, opamps, low ohmic and high wattage resistors, power inductors, programmable logic, controllers if thay seem familiar and standard logic like 7400 and 4000 series. I just throw them into labelled boxes like 'big resistors' 'memories' 'opamps'. I pack stuff into individual baggies or antistatic boxes if they are especially precious (like high-spec opamps or data converters, LT smps chips).

author: c4757p
author_rank: Super Contributor
timestamp: October 29, 2013, 11:49:10 am
content: I have a vast quantity of tiny, paper (so somewhat non-static-inducing, though not dissipative) coin envelopes, and cardboard trays sized to hold them (just made from extra cardboard panels scored, folded and taped). I do salvage SMD parts and hold onto extras (I love my junk box as much as any old fart), so I slide them into envelopes with as much of a part number as I can get and a bit of a description, and then the boxes are somewhat roughly sorted (common analog, esoteric analog, discrete semi, simple digital, complex digital, passive). I can flip through the envelopes pretty quickly. It's not as nice as a good old-fashioned junk box, but it works quite wellI don't keep stupid things like simple resistors, but I do keep e.g. low-tempco, high precision resistors, unobtainium caps, etc.

author: miceuz
author_rank: Frequent Contributor
timestamp: October 29, 2013, 12:18:18 pm
content: I do keep SMD components too (well, maybe I don't care about 10k resistors and 100nF caps as I stock them in reels)The solution I came with is an office binder with transparent polyethylene sheaths bind in it. I just mark the part number and some important parameters (opamp, high speed, +15V max) on an antistatic bag and put it into the sheath for opamps.

author: elcomtel
author_rank: Regular Contributor
timestamp: October 29, 2013, 03:08:24 pm
content: Quote from: c4757p on October 29, 2013, 11:49:10 am@c4757p I like your solution, because I have been familiar with this type of storage system and I know it works well.My training discourages the use of paper for it's potential ESD hazard risks, but I personally have to say that I have found paper not as bad as the ESD doomsday pundits suggest.From the posts there appears to be some sort of trend which is: Not to bother with cheap passive components such as resistors and ceramic capacitors, while recycling semiconductors is not such a bad thing.Given how easy some SO, SOIC, SSOP devices are to remove compared to an old fashioned DIP IC, recycling some semiconductor devices sounds very acceptable.

author: Whuffo
author_rank: Regular Contributor
timestamp: October 29, 2013, 03:21:03 pm
content: Something I've found over the years is that the passives (resistors, ceramic caps, etc) remain valuable while the chips tend to become obsolete. Your mileage may vary; I've still got thousands of 1/4 watt metal film resistors from decades ago that are still very handy. My chip assortment would be best placed in a museum.

author: Kjelt
author_rank: Super Contributor
timestamp: October 29, 2013, 10:10:51 pm
content: YES! I do have a SMD junk box see picture.Is it handy? NoDo I use it? NoWhy do I have it? Paperweight no just kiddingSomestupidcoworker threw away an entire racksystem with passive SMT components a few years ago without giving anyone noticesince they were too large (1206 and 0805). I saw the result lying in a trashcontainer: an entire pile of SMT components, and I just could not help myself and fill a small bag with the stuff. That's why I have it. I have tried to salvage something from the box onetime because I didn't have the part in stock anymore. I gave up after two hoursSo I don't recommend doing it this way.

author: Kjelt
author_rank: Super Contributor
timestamp: October 29, 2013, 10:14:33 pm
content: Then for the real stuff, I salvage new SMD parts that are thrown away or sold at fairs if they look usefull to me, mostly in strips or even complete rails.Capacitors, resistors, chips whatever is usefull. I redesign for instance now all my designs with 7k68 0,5% resistors instead of 10k 5% resistors since I have 20000 of them, so why not? I use what I have. I don't re-use used SMD components however, so desoldering smd ic's from used pcb's is not my cup of tea.

author: TerraHertz
author_rank: Super Contributor
timestamp: October 30, 2013, 05:26:26 am
content: Quote from: Kjelt on October 29, 2013, 10:10:51 pmMan, that's both funny and tragic at the same time. I hope the idiot (no strikeout) was publicly flogged.Hmm... they're useless as components, because randomly mixed. But how much does that weigh, and what would you sell it for, with postage to Australia?I'm thinking sculpture structural elements/mini-tiling art.

author: Smokey
author_rank: Super Contributor
timestamp: October 30, 2013, 06:08:26 am
content: About the only smd parts I keep around are still in their digikey bags from when I ordered them for some project. I usually get at least a couple extra and try to use common parts between projects.I did get a couple smd resistor and cap kits for random values when tweaking some circuit. That is worth stocking.I went through a desoldering smd parts from the junk box phase but I don't think I ever actually used any of the scavanged part for anythng.

author: george graves
author_rank: Super Contributor
timestamp: October 30, 2013, 06:17:40 am
content: I think salvaging parts is a false economy. Unless it's something like a transformer, button, knobs, heat sink, case, ect.Here's how I store my SMD parts.More info here:http://www.digitalunderpants.com/diy-smd-resistor-capacitor-kit/

author: SeanB
author_rank: Super Contributor
timestamp: October 30, 2013, 06:42:39 pm
content: Get some potting boxes and a litre or two of clear gelcoat and make your own paperweights.

author: owiecc
author_rank: Frequent Contributor
timestamp: October 30, 2013, 07:11:34 pm
content: I personally salvage only big resistors and tantalum caps (markings). We do however have problem in the lab with all leftover components. People buy 10pcs of 14.367kOhm 0.01% 10ppm resistors because they need it in the project, they use two and the bag with remaining resistors goes to the project box. We now have 20 various boxes with random parts in them. Every now and then these components will be moved to more generic SMD resistors/capacitors/diodes boxes where they are almost never found. After a while some students will come and use the precious 14.367kOhm resistors for pullups.Quote from: george graves on October 30, 2013, 06:17:40 amWe have this storage thing in a lab. One day new guy came to the lab and accidentally dropped it on the floor. All caps sizes 0603 and smaller nicely jumped out of their compartments. Some got back to random compartments but most landed on the floor. We told him he has to sort them all during the weekendI think Box-All has a bit safer solution.

author: Greyersting
author_rank: Regular Contributor
timestamp: October 31, 2013, 12:54:57 am
content: Quote from: george graves on October 30, 2013, 06:17:40 amWow that is amazing. I do mine this way but will probably switch to this(Warning- Terribly small collection)

author: Smokey
author_rank: Super Contributor
timestamp: October 31, 2013, 01:53:22 am
content: One thing to note about keeping SMD passives in those snap lid boxes is that as the parts get smaller you REALLY don't want them loose. For stuff like 0402s when you open the snap lid they stick to the sides and the lid and the little buggers go flying. Even if you put a piece of foam or something inside they stick to the foam and once again, go flying. You want to keep that stuff on the cut tape, even if you have to cut it down into little 1cm pieces to fit in the snap lid containers.

author: BravoV
author_rank: Super Contributor
timestamp: October 31, 2013, 01:58:45 am
content: I store all salvaged smd components sorted by type in those 35mm film canisters and still have plenty of them.Random image from Google, for those who never used a film camera.

author: FoXX
author_rank: Contributor
timestamp: October 31, 2013, 03:58:10 am
content: QuoteNice idea BravoV, thanks

author: poorchava
author_rank: Super Contributor
timestamp: October 31, 2013, 06:17:25 am
content: Quote from: george graves on October 30, 2013, 06:17:40 amNot true. Especially that knobs, buttons and the like are mechanical and can be worn out, especially that they are low quality. Salvaging 0805's when I can buy them at 0.80€ for 100pcs is dumb. Salvaging a 5€ Linear Tech smps chip or Allegro 0.5kW stepper motor controller is worth it IMO.Quote from: Kjelt on October 29, 2013, 10:10:51 pmIn our company guys in production hall have ~20kg like that. Those are the parts that were rejected by pick-and-places for whatever reason

author: TerraHertz
author_rank: Super Contributor
timestamp: October 31, 2013, 08:24:41 am
content: Quote from: poorchava on October 31, 2013, 06:17:25 amDo they keep them to recycle? Or just for lack of anything else to do with them?As with the previous post I'd consider buying them, if they're for sale. Because it's such an amusing 'material' - like 'hundreds and thousands' (those multicolour sugar dots on cakes, etc) but electronics. Worth a few dollars just as a conversation piece, though I have some ideas for use as an art material.

author: nanofrog
author_rank: Super Contributor
timestamp: October 31, 2013, 08:37:28 am
content: Quote from: BravoV on October 31, 2013, 01:58:45 amThey're extremely similar to insulin test strip bottles.Prescription pill bottles can come in handy for small part storage as well (particularly if you get the labels off, as they're translucent). Great for quick ID of screws IMHO.

author: BravoV
author_rank: Super Contributor
timestamp: October 31, 2013, 09:51:11 am
content: Quote from: nanofrog on October 31, 2013, 08:37:28 amWell, not quite, especially the dark one like above examples, the older the better, since they're NOT biodegradable, and will maintain it's elasticity/plasticity especially the cap which is the most important part for sealing out the moisture, and with adding just an approx. a tea spoon of those silica gel beads in it, the stored components in there will last for decades to come, yeah, I'm a pack rat.

author: george graves
author_rank: Super Contributor
timestamp: October 31, 2013, 11:23:05 am
content: Quote from: poorchava on October 31, 2013, 06:17:25 amKnobs, transformers and cases wear out? LOL.I don't salvage parts - I feel my time is worth more then the the effort it takes to remove the case, hunt the part down, Identify it, look up a data sheet/part number, desolder it, test it, store it - blah, blah blah. Not to mention that if you ever want to make a product using this "found part" in a design, why rope yourself into it? When there could be so many better parts - who knows it could be NLA?!?!I get the attraction to getting parts for free. I use to save little parts too - well when I was 10. I chucked them all eventually. I guess it depends on what you feel your time is worth. I guess I can't be bothered.

author: poorchava
author_rank: Super Contributor
timestamp: October 31, 2013, 12:45:58 pm
content: If you can afford new parts and have a reasonable source to buy them, then fine. If you have no access to Digikey or Mouser with reasonable shipping rates - then you salvage.As for knows, transformers and cases - they obviously don't wear out. On the other hand potentiometers, buttons, switches, connectors, socket etc do. I had a few situations when I used salvaged mechanical part in a prototype and then couldn't figure out why it didn't work.

author: TerraHertz
author_rank: Super Contributor
timestamp: October 31, 2013, 01:15:59 pm
content: Quote from: george graves on October 30, 2013, 06:17:40 amWhy on earth is that thing 10 units wide instead of 12? Isn't it clip-together modular?

author: kayvee
author_rank: Regular Contributor
timestamp: October 31, 2013, 01:18:41 pm
content: Probably as they are sold in multiples of 50, so yeah

author: george graves
author_rank: Super Contributor
timestamp: October 31, 2013, 04:16:07 pm
content: Quote from: TerraHertz on October 31, 2013, 01:15:59 pmIt is in that pic. Yes, it's modular. You can do what ever works best for you.It's in that configuration so it fits into the mother ship.Wooden storage system - I made by hand - with reclaimed lumber. For scale - that's a standard craftsman tool box below. I'll do a blog post in it soon. I wanted to make one more anyways. I just got a label printer so I can make a semi-professional label for each box front.

author: nanofrog
author_rank: Super Contributor
timestamp: October 31, 2013, 08:50:25 pm
content: Quote from: BravoV on October 31, 2013, 09:51:11 amI like the fact the ones I have (test strip bottles), the lid is attached to the bottle and fits tight.They're also white, so it makes it nice for writing with a sharpie anywhere it fits.Quote from: BravoV on October 31, 2013, 09:51:11 amYou're definitely not alone. I do the same thing if I think something can be repurposed or get occasional use.