SparkFun Electronics Commentsurn:uuid:214d0e4e-f1b1-d287-ce26-ac5b4c9f82492024-03-28T13:30:55-06:00SparkFun ElectronicsQCPete on Reflow Toaster Oven - a Qwiic Hack!QCPeteurn:uuid:4ccb5cac-d2bb-062b-1b4d-de2d7c12b8422020-06-29T12:45:05-06:00<p>Hi EJLANE,<p>Thanks for chiming in here. It is great to hear that most people are having good luck with the paste lasting so long. I hope that I keep enough projects going in my garage that I'll use this jar within 2 years - hopefully sooner, just need to keep on inventing :)</p><p>With your skillet method, do you manually attempt to create a soak zone before ramping up to reflow or just set to max and watch the paste?</p><p>I'm curious to know how necessary the soak is in a toaster oven setup. Maybe for designs with smaller parts that are less prone to be heat sinks, the soak may be unnecessary? Or could be shortened?</p><p>PS I, too, usually spring for the metal stencil from JLCPCB. It's seems crazy that they can offer a decent sized stencil for only 7 bucks more!</p></p>
Customer #599093 on Reflow Toaster Oven - a Qwiic Hack!Customer #599093urn:uuid:545309db-7a67-575b-407f-d908b08a5ac02020-06-27T18:35:03-06:00<p>Exactly!<p>I do small batches of boards (maybe 5-10 about once a year or so. Some are fine pitch with some tough bits, but so far it's never been a huge issue.</p><p>I have 4 kids, but the youngest are 14, so no worries about the freezer. I keep the stuff in the very top (quick freeze area), and triple-bagged.</p></p>
EJLane on Reflow Toaster Oven - a Qwiic Hack!EJLaneurn:uuid:8fddbf69-e51b-9e39-d4e3-02a6c9f67e462020-06-27T14:22:58-06:00<p>I have some here that is now somewhere between one and two years old. I don't go through it all that quickly. I've got little kids, so I don't keep it in the fridge or anywhere near food. I find that as it gets old it gets to be thicker and a little harder to work with. The parts don't stick to it so much anymore.<p>But I only do this with components on the top side, and am careful not to jostle them while transferring to the hot plate. Still melts and flows wonderfully and is super easy.</p><p>I sometimes use a toothpick, like you said, and sometimes I'll spring for a stencil. Just depends on the complexity of the board and what kind of timeframe I'm looking at. Doesn't cost too much to add a stencil to an order at JLCPCB, and a stencil from Oshstencils comes in the mail really quickly. This old paste has worked well for me both with and without the stencil.</p><p>If I was doing production work all day and the little bit of extra time mattered, then sure, getting fresh paste would make sense. For what I do, having it take an extra minute because it's a bit thick and not so sticky really doesn't matter at all.</p></p>
john luke on Reflow Toaster Oven - a Qwiic Hack!john lukeurn:uuid:d5a664fe-9a19-679e-e0e2-ada1572e9b272020-06-26T17:20:12-06:00<p>Have been considering a similar project but was planning on using a pure copper plate
with thermocouple( s ?) attached in the fry pan. Thoughts ?</p>
Customer #599093 on Reflow Toaster Oven - a Qwiic Hack!Customer #599093urn:uuid:cd975cf7-ad5b-0fad-86b7-990c81e3475c2020-06-26T16:37:41-06:00<p>I don't see it happening in the near future, but now that you've given me a push, maybe it'll happen ;)</p>
QCPete on Reflow Toaster Oven - a Qwiic Hack!QCPeteurn:uuid:ee548378-4267-d8dd-ffdb-34871f77a1ae2020-06-26T15:08:42-06:00<p>A mounted probe tip sounds like a good idea. That will most likely be my next upgrade. I think I'll give it a try with the stainless steel one we offer here:<p><a href="https://www.sparkfun.com/products/13715" rel="nofollow">Thermocouple Type-K - Stainless Steel</a></p><p>Thanks again for all your advice! I'd be interested to hear about how you solve the door kicker. Please report back if/when you come up with something. Cheers!</p></p>
QCPete on Reflow Toaster Oven - a Qwiic Hack!QCPeteurn:uuid:d70dee0c-fcc7-14a2-f04f-d97af2f9749b2020-06-26T15:02:08-06:00<p>Hi #818,
Thanks for commenting! I updated the post to highlight convection type.<p>I remember reading somewhere that the fan can potentially blow small parts off the board, but I haven't had an issue with this yet. I also have been taking pretty good care to push my parts into the paste just a bit. This is most likely helping them keep position.</p><p>What type/brand of solder flux do you use, and do you know of a good online source? I am lucky in that I can usually ask SparkFun production nicely and they will fill up my little jar from their massive jugs of the stuff, but I very rarely get into the office these days, and it'd be great to know for others without such sources.</p><p>Turning the paste containers every so often sounds like a good idea. Thanks for the tip!</p></p>
Customer #599093 on Reflow Toaster Oven - a Qwiic Hack!Customer #599093urn:uuid:20da394a-12b7-d175-ce75-c33546f5ee402020-06-26T12:27:54-06:00<p>The <a href="http://www.burke.tv/Tom/Cookbook/ReflowController/index.shtml" rel="nofollow">original (not safe for a publication) writeup</a> of the oven - a little more inf on there on the particulars...</p>
Customer #599093 on Reflow Toaster Oven - a Qwiic Hack!Customer #599093urn:uuid:850d3dea-ea65-780d-166c-3f9acae7ba282020-06-26T12:23:11-06:00<p>I'd maybe worry about the fraying - most people misunderstand how thermocouples work.. If the fraying gets through to the wiring, that coul be no bueno. Not dangerous, except that the temp reading could be wrong, and so things could go bonkers.<p>On mine, I drilled a hole through the oven wall and mounted it with the probe tip just <em>under</em> the wire rack. It never gets touched, and there's no issue with the door beating up any wiring. You might consider thiat simple mod to your setup.</p><p>I can't remember, is it a K-type you need for this temperature range (I think so) - take a look at something like <a href="https://www.auberins.com/index.php?main_page=product_info&cPath=20_3&products_id=101" rel="nofollow">this probe from Auber Instruments</a></p><p>Also - I've been considering adding a door kicker to mine ever since the second time I used it. If I run off to the bathroom or get otherwise distracted, it will burn the boards from letting them heat soak too long. The prepreg (or maybe glue) between layers softens up & the boards can "potato-chip"</p><p>The faster ramp-ups might imply it's just closer to one of the quartz elements. That's what I like about the above probe - it's always in the same spot, and so your oven configuration never changes. That's one of the most important parts of any process - making sure configuration doesn't change! As soon as it does, all your calibrations might just go right out the window. Fortunately, the solder curve has a lot of margin</p></p>
QCPete on Reflow Toaster Oven - a Qwiic Hack!QCPeteurn:uuid:6e488b73-911e-f022-b100-a495cb861ec42020-06-26T10:46:39-06:00<p>Good to know. Thanks for that info.<p>I currently have mine weaved through the rack a couple times and then it "floats" about 1 inche above and in front of the PCB. It enters the oven through a small crack in the door in the upper right. It's kind of hard to see in <a href="https://cdn.sparkfun.com/assets/home_page_posts/3/3/1/9/IMG_3500.JPG" rel="nofollow">this pic</a>, but if you zoom in, you can see the thin brown wire. The end is already kind of frayed, but I'm guessing that isn't an issue?</p><p>It doesn't really have to bend too much, so I'm' pretty sure it's really low stress on the thermocouple. I am thinking that next time I setup, I may move position to behind the PCB in the back, just to make swapping out panels a little less tedious. One time during testing I moved it forward closer to the glass, and it seems to indicate faster ramp ups. I'm guessing it might have just been positioned in a node of the moving air from the fan?</p></p>
Customer #536818 on Reflow Toaster Oven - a Qwiic Hack!Customer #536818urn:uuid:75c1ac0a-9e6f-011e-884f-9933a41f10a32020-06-26T09:34:42-06:00<p>Pete,
You didn't specifically mention it is a convection oven, which helps to reduce temperature variations. I built mine with a PID temperature controller from Auber Instruments through eBay (about $75). There are now kits from China that include the PID, thermocouple, solid state relay, and relay heatsink, all for about $25 USD.
As for solder paste shelf life, I store mine in the fridge, inside a sealed glass bottle, and turn the containers every six weeks to keep separation to a minimum. I have also used liquid flux to thin paste that has thickened in storage.</p>
Customer #599093 on Reflow Toaster Oven - a Qwiic Hack!Customer #599093urn:uuid:d319084d-4ae4-3460-5816-8b1aad1ca3db2020-06-26T09:14:20-06:00<p>To answer your question about thermocouples - they last forever. So long as you don't bang them around. They're formed by a weld of two dissimilar metals. The only thing that will break them is severe shock/twisting, or if they corrode. And the high-temp inside the stainless tubes are, I believe, sealed.</p>
Customer #599093 on Reflow Toaster Oven - a Qwiic Hack!Customer #599093urn:uuid:582e0dd3-b0c2-0fc6-9a8d-1b8f2835c5d52020-06-26T09:11:39-06:00<p>My oven is still going. I don't use it real often - it goes in batches. Every year or two I'll have a project that ends up running multiple batches through as I troubleshoot, etc. I think the last project was middle of last year. It was something I call a "pi plate" - 4 pi zero Ws on a single carrier card with IO broken out, some status LEDs, and a couple lines of communication between them...</p>
Customer #599093 on Reflow Toaster Oven - a Qwiic Hack!Customer #599093urn:uuid:293d6fae-5298-83b6-46af-8a0b7cb4f6862020-06-26T09:07:30-06:00<p>It seems to work okay still. Very few tombstones. I don't have the steady hands or eyes that I used to, so I try to not go below an 0603 if I can help it.<p>I don't buy stencils, so it's a somewhat arduous process of putting it on with a toothpick, and then using the toothpick to scrape some of the muck between the traces to reduce the number of solder bridges. It doesn't matter, though, I always manage to get a few.</p><p>I suppose I should put in an appropriate warning...
<strong>DO <em>NOT</em> USE THIS TOOTHPICK FOR YOUR TEETH!</strong></p></p>
scharkalvin on Reflow Toaster Oven - a Qwiic Hack!scharkalvinurn:uuid:7104f3f9-bcf9-2642-87be-65e5b56cd6592020-06-26T08:59:35-06:00<p>Regarding the use of a skillet, I've read somewhere that putting a layer of sand in the skillet will even out the heat to avoid hot spots.</p>
QCPete on Reflow Toaster Oven - a Qwiic Hack!QCPeteurn:uuid:d212f4ca-9913-f560-9b21-60aeae3e3d712020-06-26T08:48:38-06:00<p>Haha :) Indeed. It's funny that the article at <a href="https://www.x-toaster.com/build-a-toaster-reflow-oven/choosing-an-oven" rel="nofollow">X-toaster.com</a> also has this warning in all caps and bold: " <strong>DO NOT COOK FOOD IN YOUR REFLOW OVEN!</strong> "<p>I bet, on about half of our tours at SparkFun someone always jokes about throwing a sandwich or a pizza through our big toaster oven (whoops, I mean reflow oven).</p></p>
QCPete on Reflow Toaster Oven - a Qwiic Hack!QCPeteurn:uuid:c97b1e65-dcb8-4bb9-f722-d30882fc0d2b2020-06-26T08:40:39-06:00<p>Dang. 5 years?! That's great! But I'm guessing that you may still want some fresher paste when it comes to finer pitch assemblies like 0402s, BGAs and stuff?</p>
QCPete on Reflow Toaster Oven - a Qwiic Hack!QCPeteurn:uuid:ee1759fb-4112-56d8-442f-ca9b10aeffb12020-06-26T08:37:42-06:00<p>Hi Tom,
Thanks for sharing! Great article. Love the "poor man's solder reflow oven" title :) Are you still occasionally reflowing some SMD components at home with your toaster oven? I'd be curious to know how long mine might last, but then again, it would only be another 60 bucks to grab a new oven if/when this one bites the dust.<p>This has got me thinking... Do you know how long thermocouple probes typically last? I know it's a relatively cheap part to replace, but I wonder if there's any cleaning/storage techniques that could prolong its lifespan. I wonder which part of my setup will die first. Probably the heating elements or the control knob potentiometer. Maybe the servo?</p><p>PS congrats on getting published in Spectrum. Looks like you got a lot of buzz in the comments!</p></p>
Customer #599093 on Reflow Toaster Oven - a Qwiic Hack!Customer #599093urn:uuid:7884b7f6-4b0b-b5d2-350a-fc45da802b652020-06-26T07:27:00-06:00<p>Actually... I keep my paste in the freezer, and it lasts over 5 years. Just be sure to let it thaw before you try to squeeze it from the tube!</p>
Customer #599093 on Reflow Toaster Oven - a Qwiic Hack!Customer #599093urn:uuid:7a794a1e-ac53-0d56-7c09-d61b0804669e2020-06-26T07:23:44-06:00<p>I made my own & posted it in EE times long ago (2012). I like the way you simplified by using a servo to control the temperature knob - Clever!<p>I also find I have to open the door to get the cool down ramp. They have no active cooling, and no forced air from an external source - so whaddaya gonna do? ;)</p><p><a href="https://spectrum.ieee.org/geek-life/hands-on/the-poor-mans-solder-reflow-oven" rel="nofollow">IEEE Spectrum Article</a></p></p>
QCPete on Reflow Toaster Oven - a Qwiic Hack!QCPeteurn:uuid:ebc9209a-3c17-fa11-58dc-957586fff7842020-06-25T13:25:53-06:00<p>Thanks dude. Going into this, I was a little doubtful that a servo would work (so unlike me). I kind of thought I'd end up ripping it open and putting some SSR in there to have more direct control. But I was pleasantly surprised when I started seeing the plots. I swear, a standard hobby servo can solve pretty much anything!</p>
QCPete on Reflow Toaster Oven - a Qwiic Hack!QCPeteurn:uuid:1938712b-c4e9-cc26-91f1-ed596e6f49c12020-06-25T13:20:31-06:00<p>Hey #773!<p>Thanks for your kind words and great feedback.</p><p>Indeed, the skillet seems to be successful for a lot of people (including our very own founder, Nathan). Although it's pretty old now (2006), he wrote <a href="https://www.sparkfun.com/tutorials/59" rel="nofollow">a great blog post here</a> and shared his experience with skillet, toaster oven, industrial batch oven and hot air. He too, ultimately decided that the skillet was his favorite. We actually still have his skillet in the entry way at SparkFun. It's always a crowd-pleaser with the tours!</p><p>Thanks for the tip about the paste, I had no idea it could last that long! We fly through the stuff in production, and so never even come close to the expiration date. But I imagine this little 50g jar is gonna last me a long time with my garage reflowing.</p><p>"Bio-pick&place" :) I love it!</p></p>
Customer #134773 on Reflow Toaster Oven - a Qwiic Hack!Customer #134773urn:uuid:60895dcf-1451-2005-681d-34e7cbe4b5132020-06-25T12:30:50-06:00<p>I reallty should add that you want to make sure that nobody tries to use that griddle for the morning pancakes or other food once you've used it for electronics!</p>
Customer #134773 on Reflow Toaster Oven - a Qwiic Hack!Customer #134773urn:uuid:94623910-3bf0-b1b1-aaeb-e442679cbd732020-06-25T12:28:23-06:00<p>Hi Pete!<p>Great project, and great writeup!</p><p>One comment that I'll make, though, is that those "ideal curves" aren't really as sacred as most people think. They are designed for "continuous" reflow ovens such as the one in SparkFun's production department, and these days for the parts designers to have a "target" for their parts designs to be able to survive.</p><p>I've had good success over the years using a flat electric griddle, a non-contact IR temperature guage to measure the temperature, and a couple of steel (NOT plastic -- they're too thick) spatulas (check places that sell "outdoor cooking" stuff for big ones!). The technique I use is to first use plastic stencil to put the solder paste on, a "bio-pick&place" machine (i.e., my hand, magnifying glass on a stand, and tweezers) to place all the parts, and then turn on the griddle (usually having it's temperature setting cranked up to max), and using the IR guage to watch the temperature. Once it's hot enough, <em>carefully</em> use the spatulas to transfer the board[s] onto the griddle (BTW, there will be "hot-spots", so beware if your board is too big, you may have to reposition or more times) and then watch for all blobs of paste to reflow, wait maybe 5 seconds, then again <em>carefully</em> use the spatulas to transfer the board to a heat resistant area (I usually use some scrap PCBs) to cool.</p><p>I've used this technique to do boards about 8" x 10" with around 100 parts, down to ones less than 1" x 1" with maybe 4 or 5 parts. The only problem is when you get things like 100 pin quad flat packs (e.g., some microprocessors) -- I've found that it's simpler to just leave them off during reflow, and solder them on by hand later, as they seem to almost always twist out of position.</p><p>One other related tip for the beginners: solder paste normally has a "shelf life" of about 6 months. If you seal it well (in a clearly marked container!) and store it in a fridge (just make SURE that nobody tries to eat it!) you can extend that to about two years. (BTW, don't freeze the stuff.)</p></p>
bboyho on Reflow Toaster Oven - a Qwiic Hack!bboyhourn:uuid:b9a8ebad-93ce-2e5e-e58d-69f9411bed402020-06-25T11:46:26-06:00<p>Sweet! I'm impressed by the use of the servo to control the temperature! =)</p>