 So, our next speaker is Rick Pannen with his talk vapor face soldering with a deep fryer. So Rick has been doing hardware design for some time now. He actually considers himself a full stack developer from the hardware world. So basically going from software to hardware, it's everything from doing circuits to firmware development on embedded Linux. He usually does his stuff in a small series production in order to be able to give out some of the samples to the community where he has also been spending a bunch of time. He's trying to slowly move to a process of being able to do as much as possible in-house and this talk is a result of that process. Please give a great round of applause at least at home to Rick Pannen. Thank you. Hi, welcome to my talk vapor face soldering with a deep fryer. In this talk I'll first explain the reflow process in detail and then I'll show you how vapor face soldering works and how to do it with a cheap deep fryer. Reflow soldering basically consists of three steps. First you apply some solder paste to a circuit board. Then you place your components onto the solder paste and finally you apply some heat to do the actual soldering. For that you need some solder paste. Solder paste comes in a hundred thousand varieties. Most of them have different melting points and different ingredients but the common lead free paste that you use these days are melt about 210 to 225 degrees and the majority of the solder paste has a limited shelf life and has to be kept in the fridge if you're not using it. So for home use I would recommend using the solder paste that comes in syringes because it's lesser amount and it probably won't go bad unless you use a lot of solder paste. Also it's a bit easier to apply. Our solder paste comes with a temperature profile that tells you exactly how many seconds you should ramp up the temperature to a certain amount and then you have a soaking face where for several seconds you keep the temperature at the same point and then for a very short amount of time you ramp up the temperature to the reflow phase that's when the actual soldering happens and then you have to remove the temperature to cool it down. For applying the solder paste there are two basic methods. The first one is a direct paste application. So you can do that manually by just taking your syringe and applying a small amount of solder paste to each pad where you want to put your S&D components. Then the next step would be a modified CNC mill or 3D printer where you put in a solder paste syringe as a tool head and then load in your paste layer from your electronics design software and the printer then or the CNC mill automatically applies the solder paste to the pads on the board and for industrial applications there are also inkjet printer like devices that apply the solder paste automatically to PCBs but these devices are very expensive and probably not suitable for home use. For home users I would recommend getting a stencil for solder paste applications because stencils have become very cheap in the recent years and it's much simpler to apply the solder paste with the stencil than doing it manually. So stencils can be used also in different ways. The simplest and cheapest one is just putting your boards on a desk and using some tape to apply your stencil to it so you position it over your board and then you fix it to your desk and after that you use a rake to wipe your solder paste to the board. I will show that later in the demo. For home users I would definitely recommend getting frameless stencils. When you order a stencil at your PCB house you always have a check box where you can say I want a frame or no frame. The first time I ordered a stencil I took the frame version and that looks like this so you get a gigantic thing and there in the middle is actually my ... can't really see it ... maybe like this ... this is the actual board and yeah this is the stencil it has some some aluminium framing around it and that's definitely very expensive for shipping so you'd rather want something like this so a frameless stencil that can be used very easily for the method where you just put it on your desk. If you do a lot of the same boards then there are stencil printers or manual stencil printers that's where you use the stencils with a frame but these stencil printers are not cheap and I think the tape on desk method is pretty simple to use so unless you make a batch production of boards I would always just get the frameless stencil and do it on your desk. For industrial environments there are automatic stencil printers that have a conveyor belt pull in the PCB do all the positioning and then automatically apply the solder paste to the stencil. After you've put the solder paste on your board then you need to place your components again the cheapest way and what most home users will do is just take all the components manually with some tweezers and put it on your board. Because of the way that reflow soldering works and you will see that later in the demo you don't have to position them too exactly because the surface tension of the solder paste when it starts to melt will pull the the components into position so you don't have to be too precise with positioning you shouldn't place it right next to the footprint but if it's not exactly where it should be then this should be resolved while in the reflow soldering process later. So I would always be comment getting some good tweezers if you do the manual placement and not using the two euro things from the DIY store because yeah they were bent easily and some good tweezers really help with this process. The next step would be a pick and place machine that takes a file from your design program that has all the positions of the components and the rotation that it needs after picking up the components from a reel or from a tray and then uses little suction cups to place the components on the board. These have become a little bit cheaper in the recent years but it's quite a hassle to program it for a lot of components. So unless you're doing more than 20 boards or so it's not really worth getting a pick and place machine and programming it and getting all the rotation and the pickup correctly. So yeah for projects where you do one to five boards I always do the manual placement and then in industrial environments there are also these pick and place machine like in the middle but for very high volume production there are also machines called ship shooters that have a revolving turret that picks up components and then shoot them to the PCB. Once your components are placed on the board you will need to solder it and the cheapest method here is to use a hot air gun. If you ever did this you will know that it's not as easy as it looks. So you set your hot air gun to a temperature and you set the airflow and often if you set the airflow too high then you blow your components of the board or if you set the temperature too high you burn some components or you desolder stuff that you don't want to desolder on other parts of the board. So it's mostly used if you do replacement of single components. So you want to rework a chip or replace one or if you do really just a few components then this can also be the method to use but I'd always recommend if you do that then use some solder paste that has a lower melting point. So I listed one from Chipquick here that I am using for hot air reflowing and that melts at just 135 degrees C. So that makes it way easier to get the setting right on your hot air gun. The next thing is using a modified pizza oven. So you get a cheap pizza oven and you put some thermocouples into it to have a good temperature measurement and then most hobby users add some controller for example an Arduino based controller that then tries to keep the temperature profile that you've seen on the solder paste. That works well for some stuff but because these ovens have these heating coils on the top you have to be really careful with the placement of your PCB underneath it because there are some spots that are hotter and some are colder and in general it's hard to get good results with a pizza oven. Often you have to add some airflow to get a better distribution of the temperature. Sometimes it's hard to ramp up the temperature fast enough and it's kind of a hassle. So I also used this method and that's why I switched to vapor phase soldering because that's a process that's much easier to control at home. In industrial environments you have large reflow ovens that have different zones with different temperature and then you have a conveyor belt and your PCB goes on this conveyor belt through the oven and through the different zones and then by just adjusting the speed of the conveyor it's very easy to control the heat that is applied to the board. Instead of using an oven for reflow soldering you can also use vapor phase soldering and that's a very simple concept that has been around since the 1970s that works by using a phase chamber with a heater on the bottom. Phase chamber is just a sophisticated word for a cooking pot. So yeah just like a cooking pot you have some kind of container and underneath it you have a heat source and then inside of the container you have a liquid called galden. Galden is a liquid plastic that has some very unique properties. So the most important one is that it has a boiling temperature of about 200 degrees so there's galden for different temperatures just like soda paste so there's one that evaporates at 170 degrees and some that evaporates up to 260 degrees and now when you apply heat to this galden at some point it begins to boil and then it forms a vapor that is heavier than air so it stays at the bottom of this chamber and that way you have a low temperature on the top of the chamber and higher temperature on the bottom of the chamber and the temperature will be exactly the boiling temperature of the galden. So it's just like with water if you cook water then you get water vapor and unless you put it under pressure the water vapor will have exactly 100 degrees and not more and that's just like with the galden vapor that if you have galden that has a boiling point of 230 degrees then the vapor will have exactly 230 degrees and unless all the galden in the face chamber has evaporated nothing will change so you can never get a too high temperature and in most of these chambers for vapor phase soldering you also have a cooling system on the top so because galden is pretty expensive you don't want to use any of it now if you put a PCB in this chamber and slowly lower it into the vapor then the temperature on the PCB will slowly rise to the galden's boiling temperature and as this galden vapor condensates on the parts of the PCB and it does it everywhere where the vapor touches the PCB then it will very evenly heat up all the components and also the solder paste on the PCB to exactly the galden's boiling temperature and that way you have a process that's very easy to control because it's not really possible to overheat your components or the solder paste so by timing the lowering and the lifting of the PCB into the vapor you can very nicely follow the temperature profile of your soldering paste one drawback of this process is that the galden is very expensive so if you have a large industrial vapor phase reflow oven you need some liters of it and as you see here five liters costs about a thousand dollars but for the process I'm showing now with the small deep fryer you just need a very small amount so I use about 250 milliliters and at least in Europe you can get 400 milliliters of the 230 degree galden at beta layout for 88 euros so for the deep fryer vapor phase soldering you need to buy a deep fryer for about 100 euros and galden for 90 euros so the whole process can be done for under 200 euros and if you're worried about the safety galden is actually very safe because it's it's basically inert so it's no problem if you breathe in the vapor or if you even swallow it on the safety instructions that come with a galden say if you breeze it in then you should go outside and take two or three deep breath and if you swallow it you should drink two glasses of water in an industrial environment you have these large vapor phase machines that also use a conveyor belt and automate the whole process and yeah these are very expensive but for lap use and prototyping there are these smaller machines that also cost a couple of thousand euros but they are basically a container with a heater on the bottom a temperature probe and some kind of controller and these are exactly the same as deep friars so deep friars also have some kind of heating coil at the bottom and they have a controller and somewhere there's a temperature probe to keep the temperature that you set on the controller and I've looked at lots of these devices and finally I found one that fits very good to my use case and the size of the boards that I'm usually making and that is a WMF mini fryer it is quite small and it has a lid that is sealed so there's not much vapor escaping and a very nice thing it is that when the lid is closed by turning the handle you can lower and lift the basket inside it has a container that can be taken out that is quite flat on the bottom and that is also important because if you have the heating coils inside of the container you need a lot of the expensive galvan to put that much in it that it fills it up above the heating rods and because the heating rod here is in the bottom that's you just need about 250 milliliters so the whole bottom is covered with galvan the temperature sensor in this device is just at the point where the if you put in cooking oil then it's just where the lower level indicator is on the container and the temperature sensor is basically outside and it measures the temperature of the container at a certain height when we're using this for vapor phase soldering this temperature sensor will be above the liquid which is pretty nice because it will basically measure the temperature of the vapor and not of the liquid the only drawback is that it can just be set to 190 degrees and not more which is I think kind of due to the fact that you shouldn't fry something like potatoes with a higher temperature because there can be some cancerous stuff developing if you fry it with too much heat but yeah that's no problem for vapor phase soldering so we have to somehow modify it that we can turn the temperature higher fortunately this device doesn't have any electronics it's all pretty discreet so it has the temperature probe and that has a certain resistance and then you have the knob in front where you set the temperature and you that's also just a potential meter where you set a resistance and then it just compares the resistance of the the temperature probe to the resistance that you set on this potential meter and if it's higher it switches off the heater so the you just have to turn the knob a little bit further then you can choose to have a higher temperature range on that device and you can do that by opening up the bottom and then there's a little metal piece that stops the potential meter from turning too far you can take a screwdriver and bend that up a bit and I guess it works the same for all the cheap deep fryers on the market so they should be all basically the same and just have a mechanical limiter that can be removed so yeah you bend up this little metal piece and then you screw the bottom part back on and then there's a second limiter that you see when you take off the knob on the front there's a little plastic part that also stops the knob from turning too far so just take a sharp knife and cut away that plastic part and then you can turn the knob as far as you want to prevent too much of the precious gallant to escape through the lid we also need to add some cooling I just used an old PC cooler that I found somewhere in our basement I also wanted to add a water cooler at some point and looked at some water coolers for graphics cards but the ones I found were too expensive or not really available or not really fitting but I'm still looking to add that and then probably I would lose where even less garden through the lid so now let me show you how that all works here I prepared the board I'm gluing it with some double-sided tape onto my desk and add some some old boards around it the upper one I also glued to the board then I put the stencil on it taped it onto the upper board and used again an old board to rake the solder paste over it and as you can see that works pretty nicely so it's not that hard to use that solar paste now I'm putting some components to the board and I have attached a temperature probe to the basket you don't really need that it's just for this demo to to show how it works the temperature probe is not working really well so it's not 30 degrees where I'm doing this it's plus minus 10 degrees I think it was damaged at some point so you make sure that there's enough galvan that the whole bottom of the container is covered with it then you put your basket with your board on it and switch on the deep fryer so I put it to about where 210 degrees would be if it would be on the scale and then it takes about three to four minutes until some vapor is forming on the top of the PCB here I waited a bit too long because I had to figure to handle the camera so you see it's already starting to solar so I should have lowered it much sooner but now I'm lowering it and as we can see the temperature is rising quickly to where it should be and here you see through the glass how the soldering works and how the components are put into place by the surface tension of the solder paste and yeah you can just watch it through this window and see when everything is nice and shiny and and everything is soldered and then you switch your switch off the deep fryer raise the basket again and wait for a few minutes for it to cool down I didn't wait long enough here so you see there's some vapor escaping it's not dangerous but it's expensive so you should maybe wait a bit longer and now you see we have a nicely soldered board thank you so much Rick I think it's really cool like reducing the friction in this entire process I think it's important to keep be sure that it's possible to like innovate with like low amounts of resources because as we've seen before with the community like that's really something that drives things forward so questions and I was actually thinking about something myself like this entire process like what has been one of the biggest obstacles because like watching the talk it seems like you really overcome everything among the way when there was a little itch or something like what has actually proved to have been a problem because I guess there must have been something yeah the biggest problem was finding the right deep fryer so yeah I ordered I think about three different ones and now everywhere I'm using my browser I get some advertisements for kitchen appliance that last for some time but yeah finding one that can be modified easily and that has this flat bottom so yeah I ordered a lot of them and send them back but yeah finding the right one then then the processes is pretty easy once you have the right one also the the modification takes just a few minutes sounds a lot like trial and error on that part I mean it's awesome that it worked out and I guess like it's just part of the prop process with like the advertising stuff if you do something like that and want to misuse a part and then use a private browser tab for that because I'm not really interested in kitchen appliances but the algorithm doesn't know that that's that's great yeah just just and now we will be taking the questions that I've come in for the internet and so one person is asking so if the gallon is 230 degrees can it be can the solder be lead free the solder basically yeah yeah I'm using that free solder for for yeah it doesn't make sense to use let it solder with with this process because it works just fine I know a lot of people who do who use the method or a cheap Chinese reflow oven they use leaded solder paste just because it's easier for to to get the lower temperature right but for this it really doesn't matter so it works great this was leaded so the paste and also in the demo I used lead free solder paste that's awesome I think that was an important thing to to be able to to figure out so another person is asking so with the discussion about foreignated chemicals is there a need to revisit the safety classification of the gallon or like is that fine I think so you're really using just a little of it and there's as long as you don't heat it up too much it's completely safe if if you would manage to somehow heat up the gun above 290 degrees would break down and there would be some hydrofluoric acid coming out of it that would be very very bad but so so you have to make really sure that you have enough garden in it because it's the only way that that could happen that you heat up the vapor too too much I think would be to put too little in it if it's just very little bit in it it could be that the bottom gets too hot and then it could break down but you really get it it's hard to to get the vapor above 290 degrees if it's not under pressure or anything so I think it's pretty safe and it lasts very long so I probably I bought this 400 milliliters and it probably will last forever from time to time there's some residue in the in the gal but you can just run it through a coffee filter and then it's fine again so it's it's you're not really using it up it's it's just like a tool and then it will last a very long time so I and extending on the last thing so someone who's a bit freaked out with chemicals and stuff like that for instance me like how do you actually go about it like what's the absolute worst thing that could happen the worst thing is a hydrochloric acid forming when you when you get it too hot so it's something so I would recommend to if you do that do that outside take all the precautions use safety goggles use use gloves and maybe also use your your FFP to mask if you're if you're really afraid of it and then if you do it outside and and never look away if why they're using it so if you're done using it or if you walk away from it disconnected from the power and yeah it was everything so so it's really hot 200 you don't want something that's 230 degrees on your on your hands so so just don't be stupid sounds like a same precaution but the garden is actually so if you have seen the film the abyss it's it's an old science fiction movie where they are underwater and they're breezing in a liquid that has oxygen in it to go deeper and that is actually the same stuff and there are yeah you can find pictures on the internet where they have rats in in small glasses with the stuff in it and they're breezing it and so it's really yeah unless you make it too hot it's really inert and it doesn't react with anything I'll refrain from asking you how the movie ends I think yeah no worries cool so next question is do you need to do you need to remove the condensed galvan vapor from the components or how does that work there's actually very little on it so they feel dry so I don't I don't clean the boards afterwards I think I think that's fine and there's not really much left so yeah there's stuff condensating on it but I think most of it drops down and and they're not wet to the touch so so yeah I don't I don't clean the boards afterwards okay I think it's good in these kinds of situations to like figure out what someone who's a bit more experienced or very more experienced like yourself basically handles and doesn't that kind of kind of situation so one of the next questions is that if whether you have checked if the plastic can safely be heated to 230 degrees and I think they're basically referring to the deep fryer here oh that's that's all there are some plastic parts but the container is metal and there is on the top lid there are some plastic parts I made some experiments first and nothing melted but yeah I have to see see what happens I used it I don't know 10 or 20 times and it's fine until now but yeah yeah probably this device is not made for that kind of heat but it's made for 190 degrees and 230 is not too far from that so until now it it caps up nicely but again yeah it's a heck it's not really really made for this so for me it works fine but you have to be careful if you try it out yourself cool thank you I will just check if there are any like last on the falling rope questions I don't know how to say that in English and I think that was actually everything for now so as I said previously Rick like thank you so much it's it's really great especially considering that as the more you can take in at home the easier and faster this process will be and basically also lower the cost and like I at least personally feel that that's very important so I want to say thank you and I think that the audience agrees with me so thanks a lot okay then yeah have fun soldering at home we will thanks okay bye bye