Reflow using a frying pan on an open fire. - Page 1
Forum section: electronics / general

author: mrpackethead
author_rank: Super Contributor
timestamp: November 20, 2018, 10:50:12 am
content: When we go camping in the holidays and i have a bit of spare time, i would like to be able to do some development work in the evenings. We dont' have electricty, so i'm wondering if we could use a frying pan on an open fire to reflow my boards. We have twigs of various sizes and i'm thiking that would be a way of controling the fire size and probalby we can approximate a reflow curve pretty welll.Has anyone else done this>

author: ar__systems
author_rank: Frequent Contributor
timestamp: November 20, 2018, 11:21:01 am
content: That's a fitting thread!

author: jaromir
author_rank: Unknown
timestamp: November 20, 2018, 11:23:29 am
content: I'd try to estimate reflow profile from here

author: Gyro
author_rank: Super Contributor
timestamp: November 20, 2018, 11:56:58 am
content: Coming to an ebay shop near/far from you!

author: ar__systems
author_rank: Frequent Contributor
timestamp: November 20, 2018, 12:10:04 pm
content: Ah, that's how they get those cheap components!

author: rea5245
author_rank: Frequent Contributor
timestamp: November 20, 2018, 01:02:35 pm
content: I run a wood-fired brick oven pizza shop and when business is slow, I'd like to use my oven to reflow my boards. But when the Board of Health inspector comes around, I need a maitre d' who can stall him until the boards are finished. Has anyone else done this?

author: ar__systems
author_rank: Frequent Contributor
timestamp: November 20, 2018, 06:26:43 pm
content: Quote from: rea5245 on November 20, 2018, 01:02:35 pmJust offer him a LARGE slice of complimentary pizza. Most profiles are less than 5 minutes. The boards will be long out of the oven by the time he is done.

author: jmelson
author_rank: Super Contributor
timestamp: November 21, 2018, 05:24:49 pm
content: Quote from: rea5245 on November 20, 2018, 01:02:35 pmJust tell him it is a new, experimental type of pizza crust you are working on, and it has to stay HUSH HUSH so your competitors don't steal your idea. Tell him when it is perfected, you will invite him back for a taste test!Jon

author: rea5245
author_rank: Frequent Contributor
timestamp: November 21, 2018, 05:34:20 pm
content: Even better idea: I'll feed him a romaine salad.(For non-Americans and people seeing this years later, there's currently an outbreak of E coli contamination in romaine lettuce in the US.)

author: schmitt trigger
author_rank: Super Contributor
timestamp: November 21, 2018, 05:39:07 pm
content: And don't forget to tell him that the solder paste is a new kind of salad dressing.

author: mrpackethead
author_rank: Super Contributor
timestamp: November 21, 2018, 11:52:40 pm
content: I am really really tempted to try this, though i think i will probably resort to using a charcoal weber kettle bbq. This will make for an interesting youtube video.. Can get 'resonable' temp control on the bbq.

author: cdev
author_rank: Super Contributor
timestamp: November 22, 2018, 12:23:25 am
content: LOL..Quote from: mrpackethead on November 20, 2018, 10:50:12 amIt would be next to impossible to get even heat and not overcook your board that way.

author: Clear as mud
author_rank: Regular Contributor
timestamp: November 22, 2018, 01:22:24 am
content: Does your pan cool off fast enough when you take it off the fire? I think it might be possible to get the temperature curve close enough that it will work. Start with something you don't really care about, and see if you can get it right. To me, the harder part would be remembering to bring all the SMD components and boards to assemble, and tools to do it with, and keeping all those things organized while camping in the wilderness. Are you sure you don't want to just read a book or something?

author: mrpackethead
author_rank: Super Contributor
timestamp: November 22, 2018, 01:23:40 am
content: Quote from: Clear as mud on November 22, 2018, 01:22:24 am

author: mrpackethead
author_rank: Super Contributor
timestamp: November 22, 2018, 01:26:38 am
content: This was a bit of a spoof post, but actually i think just for fun, i might try it. on the webber.

author: rea5245
author_rank: Frequent Contributor
timestamp: November 22, 2018, 01:45:46 am
content: Quote from: mrpackethead on November 22, 2018, 01:26:38 amLead-free solder, I hope.

author: Peabody
author_rank: Super Contributor
timestamp: November 22, 2018, 02:04:46 am
content: Quote from: mrpackethead on November 22, 2018, 01:26:38 amYes. You were making fun of me. But that's ok. I'm just looking forward to that pizza with sausage, pepperoni, and flux.

author: IconicPCB
author_rank: Super Contributor
timestamp: November 22, 2018, 07:46:20 pm
content: You mean gastric reflux?

author: Clear as mud
author_rank: Regular Contributor
timestamp: November 23, 2018, 02:46:54 pm
content: Quote from: Peabody on November 22, 2018, 02:04:46 amOK, I get it. I hadn't seen your threadsManually controlled toaster reflow ovenandReflow using two hot plates?until after I posted in this one.FWIW, the only way I have done reflow is using a manually-controlled toaster oven. I've posted more details about ithere.

author: cdev
author_rank: Super Contributor
timestamp: November 23, 2018, 04:25:24 pm
content: I have two tiny thermometers which are super helpful in that situation. They use a bimetal spiral which responds pretty quickly to changes.They are very fragile. I will try to find a picture of something like them online and if I cant find one, take a picture of them and attach it here later.The boards I have made are all very small and very simple in terms of what needed to be 'reflowed' (just a few smd parts which were getting placed). These parts need vias too which I do with bare copper wire soldered on both sides with the excess cut off. If I am feeling wasteful, I thread the copper wire through all the vias and solder them all at once. For RF circuits I try to use the back for the ground and place parts that need ground on tiny pads literally right on top of the vias, not have a ground plane on top except where an edge mount coax connector is being connected. Because otherwise you need so many vias it is very difficult. Other than this this works okay for small simple boards.

author: cdev
author_rank: Super Contributor
timestamp: November 23, 2018, 04:43:17 pm
content: You definitely would want something that heated evenly but still cooled off fairly fast to do this. So a digital hot plate is ideal on the temperature precision but still maybe a bit too slow to cool off to be 'ideal' for reflow without a fan nearby. (On cold days, they can also be helpful as a heater!)If you are going to use a skillet, one with a copper coating on the bottom would likely be best.Make sure you mark the skillet clearly somehow so nobody ever uses it for food.I've attached two photos of the kind of thermometer I've used for that, although the current version is a bit overpriced.You will notice there is a small vane which you can let the thermometer itself move - it then shows you what the highest temperature it recorded was.These sit right on the top of a heating surface, and they respond to changes instantly. Very low tech but that seems appropriate for electronics while camping. Maybe for repairing your Geiger counter after the apocalypse?http://ptc1-com.3dcartstores.com/Thermometer-675F

author: Peabody
author_rank: Super Contributor
timestamp: November 23, 2018, 05:29:35 pm
content: Quote from: Clear as mud on November 23, 2018, 02:46:54 pmThanks very much. I've replied to your post in the "manual oven" thread. I'll also make a new post to the hot plate thread about temperature control.I didn't realize that my other threads were quite so goofy. That wasn't intentional. I had just watched several hours of project videos on making a reflow oven out of a toaster oven, and they were all just way more time, effort and money than I wanted to get into. And it did seem to me that if you could follow the actual temperature of the board in real time, which is basically what a controller would do, maybe the process could be controlled manually without needing a controller, a power supply for the controller, solid state relays, thermal insulation, etc, etc, etc.Then further, with the alternative of two cheap hot plates, one fixed at 180C, and the other at 230C, you don't even have to ramp anything or follow anything except maybe a timer. And there's no risk of material overshoot.But I am anxious to see the campfire or backyard grill results from mrpackethead. I'm just hoping that it will all work upside down - him being a Kiwi and all.

author: cdev
author_rank: Super Contributor
timestamp: November 23, 2018, 06:00:38 pm
content: You should consider getting a digital hot plate. Some are sold as preheaters for soldering/rework. Some are sold for labs to do lab stuff. They offer fine grained control over the temperature.

author: mrpackethead
author_rank: Super Contributor
timestamp: November 23, 2018, 10:36:10 pm
content: or just do a toaster oven conversion.. Seriously its a one night project. and they work remarkably well, can be done for a hundred bucks or so.

author: cdev
author_rank: Super Contributor
timestamp: November 23, 2018, 10:52:51 pm
content: I have an old convection oven waiting to be converted but I've been able to use my hot plate to do everything Ive needed up until now, I like being able to see clearly whats melting when. The oven has a glass window but not enough light inside to see that clearly.