melting solder in a pot - Page 1
Forum section: electronics / beginners

author: Capernicus
author_rank: Frequent Contributor
timestamp: April 14, 2021, 10:24:24 pm
content: Can u melt solder in a pot on the stove, does it give off heaps of fumes?

author: IanB
author_rank: Super Contributor
timestamp: April 14, 2021, 10:28:07 pm
content: If it is solid bar solder (no flux), it will not give off any fumes. Do not try to melt flux cored solder though.There are specially made solder pots for this purpose. Since molten solder is very dangerous it is better not to try melting it on the stove. Use something properly designed, and use it in a well ventilated workshop or garage.

author: IanB
author_rank: Super Contributor
timestamp: April 14, 2021, 10:30:40 pm
content: Also use proper safety equipment (eye protection, gloves, shop coat, etc.)

author: Capernicus
author_rank: Frequent Contributor
timestamp: April 15, 2021, 12:23:58 am
content: Im going to try and cast a pcb with a plaster mould!

author: wizard69
author_rank: Super Contributor
timestamp: April 15, 2021, 01:29:12 am
content: Quote from: Capernicus on April 15, 2021, 12:23:58 amThat might not be a good idea. You run the risk of vaporizing any retained water in the plaster and causing it to literally blow lead in your face. For a very similar reason welders do not use a cutting torch on concrete floors and casting operations often have sand floor where the metal is poured.Now people have used plaster in lost wax casting of metals but the plaster is "dried out" in the oven. Further the form is usually supported in dry sand. Still not something I'd recommend.Beyond all of that I'm not sure why you would use lead to cast a PCB. In any event do you melting outdoors.

author: highpower
author_rank: Regular Contributor
timestamp: April 15, 2021, 01:43:28 am
content: Quote from: IanB on April 14, 2021, 10:30:40 pmThat includes wearing a good pair ofleathershoes/boots. Molten lead spills have a knack for finding a direct path to your feet. Thin athletic shoes, walking, or tennis shoes will not protect you. One time is all it takes to make you remember that.

author: Capernicus
author_rank: Frequent Contributor
timestamp: April 15, 2021, 02:01:31 am
content: Quote from: wizard69 on April 15, 2021, 01:29:12 amYes, I noticed on a few vids on utube that the molten metal can bubble fairly furiously once in the mould, and it takes ages to settle down and it can ruin the surface of the cast tremendously, this looks like a serious issue to get over, for mould quality and safety like ur advising me. But I want to avoid using PCBWAY its too expensive, so teaming up with my 3dprinter and a cheap bag of plaster ill give it a go.Quote from: highpower on April 15, 2021, 01:43:28 amIll double check my boots before I get going!

author: BrokenYugo
author_rank: Super Contributor
timestamp: April 15, 2021, 03:35:33 am
content: Melting lead in your kitchen is a bad idea.

author: Ian.M
author_rank: Super Contributor
timestamp: April 15, 2021, 03:57:27 am
content: Quote from: Capernicus on April 15, 2021, 12:23:58 amQuote from: Capernicus on April 15, 2021, 02:01:31 amWTF have I just read???A PCB consists of conductive tracks bonded to (or embedded between layers of) a flat insulating substrate. If you wish to solder to it the tracks must be of a solderable metal or have solderable plating at the pads and must withstand soldering temperatures without melting or debonding from the substrate.There is no way to produce a PCB by pouring molten solder into *anything* let alone plaster or 3D printed thermoplastics.

author: JustMeHere
author_rank: Frequent Contributor
timestamp: April 15, 2021, 04:13:19 am
content: I've read of people using a cast iron skillet to successfully reflow solder.

author: IanB
author_rank: Super Contributor
timestamp: April 15, 2021, 04:17:54 am
content: Quote from: JustMeHere on April 15, 2021, 04:13:19 amThat's not what Capernicus is talking about though. What has reflowing got to do with pouring molten solder into a mould?

author: Capernicus
author_rank: Frequent Contributor
timestamp: April 15, 2021, 04:18:26 am
content: Just think of the plusses!You dont solder to put your components on, you just need to warm it up and stick em in! =)You start off by putting the negative space (insulator) down with some kind of insulator (maybe just give it a clay base?), then you pull out the positive space extrusion, and the lead is supposed to go into these cracks from so many pipe ins, that you snip off afterwards.I havent fully thought it through, maybe I better get back to thinking about it.

author: IanB
author_rank: Super Contributor
timestamp: April 15, 2021, 04:20:46 am
content: I melted about a thimbleful of solder once, as an experiment in tinning the ends of wires by dipping. It was scary enough that I decided not to do it again. Molten metal is really nasty stuff.

author: IanB
author_rank: Super Contributor
timestamp: April 15, 2021, 04:22:55 am
content: Quote from: Capernicus on April 15, 2021, 04:18:26 amThere is a standard way for to make circuit boards at home, by etching copper clad board. It is the way it has been done since forever. If you want to experiment with making circuit boards, learn how to do that.Don't mess with melting large amounts of solder. You will end up at the doctor or in the hospital.

author: ebastler
author_rank: Super Contributor
timestamp: April 15, 2021, 04:30:03 am
content: Quote from: Capernicus on April 15, 2021, 02:01:31 amYes, this is absolutely the right way to make PCBs. Especially for use with those $3000 FPGAs you want to work with, as discussed in your other thread.Youarea troll, right?Fair warning to others: Please don't feed!

author: Capernicus
author_rank: Frequent Contributor
timestamp: April 15, 2021, 04:42:15 am
content: Quote from: ebastler on April 15, 2021, 04:30:03 amIm not going to make an FPGA dev board with it!!!Its more for something crude and nondetailed/miniaturized like a high voltage marx generator, where all I need is picofarad capacitors resistors and spark gaps, then I can pour it out in one hit, a finished product.

author: ebastler
author_rank: Super Contributor
timestamp: April 15, 2021, 05:00:06 am
content: Technical plausibility aside (which I doubt for both, your PCB-casting and your FPGA project) -- your claims on budget are ridiculously inconsistent. You are throwing around top-of-the-line $3000 FPGAs and GPUs in one thread and at the same time are proposing homemade PCBs here to avoid a $20 order from PCBWAY or JLCPCB. Sorry mate, I can't take you seriously.

author: Capernicus
author_rank: Frequent Contributor
timestamp: April 15, 2021, 06:00:48 am
content: Even if FPGA's were $20, ur still better off making em yourself if u want large numbers of things.

author: viperidae
author_rank: Frequent Contributor
timestamp: April 15, 2021, 06:40:25 am
content: Have you even considered the surface tension of liquid solder? It's not going to flow through a mould without force.Traditional moulds use gravity or large feature sizes. You'll need to hold your components in the mould while you pour too, since soldering to your solder tracks will turn them into a puddle.

author: Gyro
author_rank: Super Contributor
timestamp: April 15, 2021, 08:31:58 am
content: Quote from: Capernicus on April 15, 2021, 04:18:26 amJust think of the minuses!Solder has very poor conductivity compared to copper.

author: Capernicus
author_rank: Frequent Contributor
timestamp: April 15, 2021, 09:36:57 am
content: Quote from: Gyro on April 15, 2021, 08:31:58 amyou could electroplate it in copper sulphate, then the resistance would go away a lot.

author: fcb
author_rank: Super Contributor
timestamp: April 15, 2021, 09:48:59 am
content: QuoteI needed a good laugh. Please let us know how this goes.

author: Capernicus
author_rank: Frequent Contributor
timestamp: April 15, 2021, 10:03:09 am
content: Quote from: fcb on April 15, 2021, 09:48:59 amlol

author: Ian.M
author_rank: Super Contributor
timestamp: April 15, 2021, 10:27:00 am
content: One could make ceramic PCBs by painting the traces onto the ceramic using a slip made from silver art clay then kiln firing it. However you need sheets of high temperature ceramic, and if its got to be through hole, you'll probably have to send it out for laser drilling. That certainly wont be cheap.It is *POSSIBLE* to 3D print with lowish melting point metals but its far from simple:Conceivably this rig could be modified to print solder or even a high copper 600-700 deg C melting point brazing alloy from wire to make your tracks. Its going to need an inert atmosphere. Use a removable bed and transfer it to a resin printer to over-print the tracks with the PCB substrate using high-temperature resin. Congratulations: you've now got a crappy single sided low resolution PCB for an initial investment of tens or hundreds of thousands of pounds and a per-unit cost far higher than PCBWAY will charge you for five fine geometry double sided PCBs with solder-mask, silk-screen and ENIG on the pads!

author: Capernicus
author_rank: Frequent Contributor
timestamp: April 15, 2021, 10:49:56 am
content: Your taking it too far!How much harder than making little lead army men can it be? That's what I was watching when the idea popped in my head.

author: Ian.M
author_rank: Super Contributor
timestamp: April 15, 2021, 11:08:29 am
content: Take some solder (wire), bend it into a complex shape, put it onto a heat resistant surface and heat it to melting point with a hot air gun. You will find that it wont stay where you put it as surface tension will pull it together into blobs leaving gaps between them. The same will apply if you were trying to cast tracks from liquid solder. The casting needs pressure, normally provided by the weight of liquid metal in the sprue, to force the liquid metal into the fine detail of the mold, and to get it to fill fine channels, you'd need the mold to be preheated above the solder melting point so it doesn't chill and block off the channels. Each channel would need a vent hole at the far end and a runner and riser feeding it from the sprue.You *COULD* get there by lost-wax casting using a 3D printed pattern:https://hackaday.com/2020/12/07/how-to-get-into-lost-wax-casting-with-a-dash-of-3d-printing/

author: Capernicus
author_rank: Frequent Contributor
timestamp: April 15, 2021, 12:12:53 pm
content: Thats a nice smooth surface on that one. So im seeing a tree connecting all the pieces together that the solder runs through, A circuit is a tree at times, maybe if I make it in a tree shape fanning out downward, that would work? Would make for a strange looking PCB, but I dont mind that if it would cast successfully.Ive been doing 3d printing without supports lately, im getting good at it too. So this would be another form of constrained modelling to suit the fab process, perhaps.

author: ebastler
author_rank: Super Contributor
timestamp: April 15, 2021, 12:20:36 pm
content: Quote from: Capernicus on April 15, 2021, 10:49:56 amAha! Now it makes perfect sense. Tin soldiers are to PCBs what FPGAs are to GPUs: They have very little to do with each other.Seriously though -- PCB manufacturing is a solved problem. I am in the dark what you are trying to achieve here. Have you considered making your "PCBs" from cookie dough and silver paint, or from cardboard and aluminium foil?Quote from: Capernicus on April 15, 2021, 06:00:48 amI assume (I hope!) you are talking about making your own PCBs, not making your own FPGAs?If so, you are quite wrong. Have you looked at the volume pricing at JLCPCB and other vendors? 100 PCBs will cost you hardly more than 10. In contrast, your homebrew process is bound to scale far less effectively. So the more units you need, themorereason you have to go to an outside vendor who has a properly streamlined, automated manufactring process.

author: ElizatronicWarfare
author_rank: Contributor
timestamp: April 15, 2021, 12:25:38 pm
content: This is clearly fake and intended to waste everyone's time. Having bad ideas is one thing, doubling down to the point of parody when advised against them is another. Don't feed the troll.

author: Zero999
author_rank: Super Contributor
timestamp: April 15, 2021, 12:34:36 pm
content: Quote from: Capernicus on April 15, 2021, 09:36:57 amThat will only produce a very thin layer of copper, which will hardly reduce the resistance.People aren't trying to put you off learning electronics here. We're advising you against something which is dangerous and will not work.If you want to make your own PCBs. Buy some copper clad board and an etchant such as feric chloride. If you have a laser printer, or can use a photocopier at the local library, toner transfer can be used to get the artwork onto the board, before etching. There are special proprietory papers but ordinary copier paper works quite well, although I've found clay coat magazine paper is the best. Another much better method is the photographic process, but it requires more equipment and chemicals: UVA lamp (UV LEDs, blacklight, or insect killer tubes, never use germincidal UVC lamps), photoresist, or use presensitised board and a developer such as hydrogen peroxide. You don't need a specal tank for etching, just use a small plastic tray and heat the solution in the microwave.There are lots of tutorials on how to make your own PCBs.

author: Ian.M
author_rank: Super Contributor
timestamp: April 15, 2021, 12:37:50 pm
content: You could of course make your own PCBs from scratch. Most people would start with copper-clad FR4, but the next step back would be copper foil, etched and lightly oxidized so that Epoxy resin will bond to it, an appropriate laminating resin and glass-cloth, with a vacuum press to hold them together till the epoxy reaches a 'green' cure.However I feel that's too simple for you, so why not refine your own copper from ore and roll it down to foil thickness, make your own epoxy resin from precursor chemicals and weave your own glass-cloth from hand pulled glass fibers?On the more serious side: I have seen some reports of success using a thin layer of acrylic spray paint as an etch resist and ablating it where you don't want copper using a consumer grade CO2laser cutter. e.g.https://hackaday.com/2017/08/22/laser-etching-pcbs/Unfortunately the spot size is too large to allow fine pitch PCBs or even tracks between 0.1" pitch pads.

author: tooki
author_rank: Super Contributor
timestamp: April 15, 2021, 05:30:12 pm
content: For the benefit of the other readers not the OP: The closest thing this crackpot idea reminds me of is a long-abandoned electronics construction technique called ECME. Take a look:

author: calzap
author_rank: Frequent Contributor
timestamp: April 15, 2021, 05:45:36 pm
content: How about using Wood’s metal? All you need is a pot of boiling water to melt it. Has the toxic advantage of adding cadmium to the lead.Mike in California

author: ebastler
author_rank: Super Contributor
timestamp: April 15, 2021, 06:15:09 pm
content: Quote from: tooki on April 15, 2021, 05:30:12 pmThank you! That is a great find. Quite an impressive level of automation, integrating the manufacturing of passive components, circuit boards, and partial assembly (well at, least the sockets) in a single automated workflow.A nice article here in the New Scientist:https://www.newscientist.com/article/mg17623656-200-the-chunkiest-chip/.This one is behind a paywall, but you can find free copies of the text on some Vietnamese (?) sites with English language course materials. (Where else?)

author: Capernicus
author_rank: Frequent Contributor
timestamp: April 16, 2021, 12:39:42 am
content: Quote from: tooki on April 15, 2021, 05:30:12 pmThat looked good, I was quite impressed. The circuit is nice and solid looking if its based apon an embossment, maybe not quite as detailed, and they did get something like 50,000 radios out of it or maybe more? (Way too many, they probably started giving them away for free.)Compared to the hand soldered to the chassis sausage systems it was against, it looks like a much superior product. (And much less manpower required.)Imagine if they moulded the chassis and the inner circuit at the same time, and u sorta get the wholer radio in one hit! =)Use clay slip, and clay slip mixed with graphine for the conductor.