DIY Hot Plate for SMD Soldering Using Raspberry Pi Pico

[@iainmcculloch5807]

I've been thinking about building something like this for a while. Thank you for the gentle push to get me going. :)

[@OMNI_INFINITY]

*Thanks for posting that! Was using a raised LED desoldering plate similar to that and it only had the 2 wires coming into it, so I usually only touched the board with a chopstick or other non-conductive item when it was plugged in. That said, it heated the boards too much and I want to have a MUCH SAFER AND RELIABL option with an actual temperature control so it doesn't overheat any PCBs.*

[@AlexBerg1]

So cool!

[@123DragonHeart]

Thanks!

[@vedaprakashms]

loved it

[@123DragonHeart]

Thanks!

[@peterkrause5187]

Hi. Great vidreo, well explained and informative learning as well! Would you recommend doing dual sided PCB's on this by using 2 diferrent temp smd past and is the heating cycle related to a SMD past profile? Thanks Peter

[@josefjelinek]

I would probably not use wood myself even though it is tempting... There are some high temperature alternatives like phenolic resin (bakelite) sheets or PTFE sheets (probably too expensive). I would probably opt for something like G10/FR4 / PCB without the copper layer... which should be accessible for people working with PCBs, particularly because it is the theme of this video.

[@conorstewart2214]

PTFE sheets are not a good idea, if they get too hot they will start to offgas. Plastics in general aren’t a great idea unless they are thermoset plastics because otherwise they could melt. At least with wood it would burn and you could see it more easily. G10 or FR4 is likely a good idea, it doesn’t really matter if it has copper on it really and you could always sand or grind it off if you wanted too. If there is enough separation between the hot plate and the mounting material it should be fine anyway as the temperature down at the mounting points should be lower.

[@123DragonHeart]

I'm running the hot plate at max 205-210C, and I've run a few tests where it was on for half an hour or more without any issues so far. The mounting points don't get as hot because of the standoffs, though I'll run a long test again and measure the wood temperature. Bakelite is a great option, and I had a few smaller sheets of it, but cutting it and sanding isn't the most fun thing because of all of the dust ir produces.

[@josefjelinek]

@@conorstewart2214 PTFE is used to coat frying pans. True that cheap PTFE can start decomposing at ~260C, but at that point wood is already at risk of burning your house down (starting at ~200C).

[@josefjelinek]

@@123DragonHeart I do not think your solution is inherently unsafe, but ising something better can make it easier to have smaller standoffs, use some insulation on the bottom and make it heat up faster and keep the temperature more stable for the pid control...

[@Hacker-at-Large]

I think I'd just go with FR4 (Garolite). It's cheap and what actual circuit boards are built on. Sheets up to 8mm thick are available on Amazon.

[@hobidanmainan1023]

Cool. I'll have to try making it myself using a bare ATmega (currently that's all I have on my desk). There 's a little question, does controlling the SSR not need to synchronize with the phase angle of the AC line? No need for zerocross reading?

[@jbatesmdJohnnyEBates]

Where is the file for lazer cutting the board you mentioned. Did I miss it?

[@andreaswolfesberger6140]

i use a Pizzaoven for SMD and classic components soldering (even mixed components) since years......

[@123DragonHeart]

That's cool, I've seen a lot of projects using ovens for soldering, I'll make one for sure due to better temperature consistency and the fact that multiple boards can be inside at once! I love the hot plate because there is access to PCBs if I'm reworking a board like desoldering something!

[@projectnightmares1374]

Do you even stock the Raspberry Pico? pretty sure you are back ordering these till august, even though your website says you have stock.

[@restorer19]

For a 12 bit ADC, should 4086 be 4096? Less than a °C of error, in any case.

[@123DragonHeart]

Yup, 4096... My mistake sorry for that, must have glanced over that number a hundred times without noticing hahaha!

[@EzekielMudd]

Does anyone have a link to the hot plate?

[@conorstewart2214]

You can find loads of versions online. They are called “PTC hot plates” or some variation on that. The PTC means Positive Temperature Coefficient which means that as temperature increases the resistance also increases which reduces the power to the heater, this is good because if you just connected it straight to mains voltage then it would rise up to a certain temperature and wouldn’t be able to go higher. This is also why they have temperature ratings, they won’t be able to get higher than this so make sure you choose one with a high enough temperature that it will work with whatever paste you use.

[@paulturner5769]

NTC is "Negative Temperature Coefficient". The X axis at 2:50 wasn't labelled "Thermal" was it?