My Breakfast with Reflow

My Breakfast with Reflow

My prototype boards for the striplight came in this week, woohoo! Now starts the process of putting the design through its paces and making sure it works but before that can begin the boards have to be first assembled.

According to the guys over at SparkFun there’s no better way to do bulk surface-mount soldering in the home than with skillet reflow. According to universal truth, there’s no better use for a skillet than for making delicious fluffy pancakes. Thus it follows that any activity combining the two must be a doubleplus good.

Besides, heavy metals poisoning is the sweetest sauce.

LED Serial Striplight Prototypes

Seeing as this was my first foray into the world of skillet reflow I have to say that so far I’ve been impressed with the results. The only tricky part is placing the little components on the board without bumping the ones that you’ve already placed. Once you have the solder paste down and all of your components placed on the board, there’s nothing more to do than simply place the board on an electric skillet, turn it on, wait until all the solder has melted, then turn it off and let it cool. That’s it.

The biggest obstacle was finding the soldering paste. A number of places sell it but a lot of them insist on overnight shipping with cryo-packing and the shipping often comes out to be more expensive than the paste itself (which is already quite expensive since you’re forced to buy far more than you’ll ever use). Phil was so kind however as to point me to Ameritronics who will gladly sell you solder paste in small quantities at a reasonable price and the stuff they sell is formulated to have a greater shelf-life without refrigeration.

I’ve now reflowed two complete boards and already I found the second one substantially easier to do than the first (which already wasn’t that bad). I do still seem to have a problem in putting too much solder paste on the IC pads resulting in solder bridges. However a little touchup with fluxed solder-wick fixes this. I’m probably using too wide of a needle for dispensing paste.

6 responses to “My Breakfast with Reflow”

  1. tom says:

    Dude! I hope that solder’s LEAD FREE!!!

  2. Ben says:

    More pancake photos please!

  3. Waffle Institute of America says:

    fuck pancakes

  4. ewertz says:

    Finally, a reference to DIY pasting without stencils. I was wondering if it was feasible or not. Having not done any paste+reflow before, I was wondering if the texture of the paste and the apparent narrowness of a syringe+needed were incompatible.

    So, clearly there’s a lower limit to how much and how small you can work this way. Do you have any guidance on what’s reasonable to try to do first-time, as well as after one’s already fugged-up a dozen or so? ike “your cat can lay down paste with a needle for SOT-23s AND SSOP-16” and/or “only a paste-foo master can vanquish QFNs>16”.

    I’ll check out your older blogage for tidbits of wisdom on boards+paste+skillet-stencils, but if there’s anything else you can/will offer up, i’m all eyes.

    Thanks to the reference to your paste dealer.

    regards, and niiiiiiiice…..
    -e

  5. ewertz says:

    Oops, should be “syringe+needle” in P1. And BTW — picked you up from Hackaday.

  6. Zero says:

    If you’re having trouble dispensing the solder paste and bumping parts have you considered making a pantograph to enhance your fine motor skills?

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