Soldering P1 using a skillet

Hello all,

I have just moved from prototyping on the photon to making a custom board with the P1. I would ideally want to hand solder the first few boards. I can do 0603 or most SOIC packages quite easily. I have looked at the tutorials on sparkfun and have purchased this Skillet. I cannot find the Kester easy 256 on Can anyone recommend another paste that works?

I can hand solder the other parts on the board i would only need the skillet to mount the P1 to the board. In this case would i need to stencil? Can i just apply the solder paste using a syringe on the P1 pads?

I use a pair of tweezers for holding other smd components, would there be anything other than that which is recommended to place the P1 on the board.

Please advise on what is the right direction to take. I am comfortable with an iron but as i read from the other posts the yield is not fair and this would be my first time using a reflow skillet.

I have hand soldered a dozen prototypes using the P1.
Please stay away from the skillet, it’s the worst way to solder a part.
I have one of these (see below) and its by far the best way as the platform bed heats the board up from the bottom, then the IR lamp solders it from the top. The key is to put your part/ parts on and place them on the bed for at least 4-5 minutes, then turn the IR lamp on. As far as soldering goes I have tried paste and it does work, but I have also tried soldering each pad on the PCB, then use a good solder flux and place then on the soldered PCB pads and also on the bottom of the P1. I have not had one issue using this method. Good luck,.


Thank you for the advise. Seems like a sound investment for the price. What’s the name of flux you use.

Yup, skillets are bad, you can easily de-laminate a PCB that way. As well as an IR rework station you could equally use one of these they make some attempt at replicating how I would be reflowing it in a proper conveyor reflow oven.

Buy a metal stencil and a tub of solder paste, apply the paste, carefully put the part on, cook it and done. You’d only need flux if you had to fix something afterwards. You can buy metal stencils from places like PCBway, you can even get very cheap plastic ones online, but they are frankly awful.

The best flux I have found is this one.

I owned the oven Viscacha shown. That was actually the first thing I bought to do SM parts. What I discovered was that it had hot and cold spots in it. Some boards would not reflow properly and some would do great, yet others would turn the PCB brown like over cooking a pizza. with all my trying, I could never get it to work right. I wound up giving it away.
Maybe others had better luck, but the IR station never gave me a problem and its cheaper.

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Yeah I have never used one of the tiny ovens and never would but I know lots of people do. Seems odd that it would have significant cold spots given how small it is. Another popular option is to build your own using a toaster oven - lots of projects and videos out there for adapting one of those.

If you are going to use ROSIN based flux be very sure you have extraction on your workbench, that stuff is nasty. Sure once or twice isn’t going to kill you but why get into bad and dangerous habits. Plenty of colophony & halide free fluxes out there, in my experience the biggest difference between most of them is how much mess and stink they make. Always clean off any residues when you have finished IPA/Flux remover and a brush/qtip should do the trick.

Maybe they have changed the design of them over the last few years. Mine had 3 heater pipes in there. If you were to careful and placed a PCB in the tray just under the pipe, it would cook those PCB’s under it. But the ones in-between were just fine. The heat was just not even across the bed.

I agree with what your saying about the flux, Many just spew out vapors like an electronic cigarette. But the one I gave the link to is much less than using regular solder. It is very nice.

@mikemoy, my T962 (which I got last year) has very good heat distribution, especially after applying the numerous “fixes” described on available forums. That includes changing the masking tape to Kapton tape, firmware upgrades and adding a ds18b20 temperature sensor at the cold junction to improve accuracy. :smile:

@Viscacha, what is your go-to flux?

Part of the problem may well be its pretty much impossible to know what you are getting, they might look the same and have the same model number, but inside its very much pot luck, the same is true of eBay soldering irons.
You’d get far more even heating with elements like this than hot little bars for example, but I don’t know if one of those tabletop units exists that uses them.

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We currently use CW8100, also a Rosin based flux, tbh its just the one we’ve always used and hence the one on the system. I can tell you if you use it on a board and then put it in an oven you get a nasty sticky mess but then that’s not something you would normally do. We’ve had samples of many others over the years I don’t recall any being particularly terrible.
Using flux here usually infers rework, rework infers something has gone wrong and naturally that is something you try to keep to a minimum ;). Manufacturing processes use their own fluxes - paste & solder wire have flux already and Wave soldering uses a much simpler water soluble flux. I’m aware some people love to spread flux everywhere whatever they are soldering …

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@peekay123, Thats good to hear, I agree with Viscacha in that its a crap shoot what you may get, maybe just my luck I got one of the crappy ones. The other reason I prefer the IR over the oven is that I can see what I am doing. I can see when the part starts to reflow and if i may need to nudge it a little to line it up better, which I cant do in the oven. Doing BGA parts on it is a snap, which i would not even attempt in an oven.

Yup, I am one of those people that will use that pen flux on a board before I solder anything. I cant see anyone soldering a TQFN package without it. The pen is real nice, Its not that thick honey type paste one would typically think of.

Thank you @Viscacha and @mikemoy for all the wonderful suggestions. I was looking at the T962 but steered off it after the need to customize so much of it to get it to work right. Not that it wouldn’t be fun but was looking for something that works. The ebay link you posted unfortunately does not ship to Canada. Fortunately i live close to the border.

I would have thought if you searched eBay you will find plenty of similar listings for both IR rework stations and ovens that do ship to Canada.
For a shock to the system check out this bad boy a professional level piece of kit and even that is lacking some of the fancy alignment tools you find on some models (split optic cleverness that shows you the underside of the BGA and the pads you are lining it up with)

Shock to the system indeed! I found quite a few sellers shipping international but price ranges from USD $250- $450. The link you shared came up to CAD $200 with shipping and on a good day the border shipping place is a 20 min drive so went ahead and got it.

Let us know how that setup works out for you.

Sure thing!!

I received the unit and have tried using the heating plate to salvage some SMD components. I basically heat it up for 4-5 mins and then used the IR lamp for maybe 30 seconds. That was enough to lift the components off. How long do you turn the IR lamp on for when soldering the P1? Also since the light from the IR is quite bright the provided shield does not really do much. What eye wear do you generally use to help see the components better?

If you look at the datasheet for the photon (or any well documented surface mound component or device) you will see a graph for a “Reflow Profile” when reworking or soldering the device you are working on should roughly speaking try and follow a similar path, the hotplate gets you part way there and also prevent excessive thermal strain on the PCB (it can go all wonky if its very hot in one place and cold everywhere else). Now you cannot easily measure the temp your parts are getting to so I would suggest using visual clues, if using lead free solder paste like SAC305 that has a melting point around 220C , on the reflow graph you will see a Time Above Liquidous, this is typically quite short 10-30 seconds and an absolute max of ~260C, beyond which you start destroying things. This is where the advantage of using paste and a stencil comes in, you can see it go from grey goop to shiny silver, the device will probably shift about a bit as surface tension pulls it into alignment and you know you’re done…

Maybe stencil and paste is the way to go then. I see OSH Stencils are pretty reasonably priced.
So according to the re-flow profile

  1. Heat it up to 150 C
  2. Put the PCB with components on for 2 mins
  3. Turn on the light
  4. Wait until solder re-flows
  5. Turn off light, plate and let it cool down.

That makes things so much easier and professional looking once completed.

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