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Reflow soldering with a butane lighter

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Just though I'd let you guys know the results of my little experiment. This is my first time reflow soldering so I wasn't sure what to expect. I was told to use the frying pan, but that seemed a little wasteful, heating a chunk of steel, several KGs in weigh.


So I decided to try something different. The part I soldered is a msp430g2231 in a QFN package, and as far as I can see all pins are fine and no solder jumps. I've programmed the chip to invert all pins, using the WDT interrupt every 32ms, I've measured the output with a bus pirate, which gives me 14hz and 15hz, so I'm assuming the chip held up alright. I realize this is only one peripherals, but I think it's the most temperature damageable one.


Now I understand that to do reflowing properly, you have to follow certain rules about temperature increase and decrease gradients, but it's fairly difficult to control the temperature when using a gas flame. I did burn of some solder mask.


What I had to start with was a board with a QFN foot print on it, and the ground pad was plated through to the underside ground plane. I applied the heat from ~5cm below the vias at the ground pad. The solder paste liquified in under 10 seconds.


I just though I'd share a quick and dirty way to do some reflow.


Solder paste has lead content. Butane lighter was just a generic china made one.


If any one knows of a better way to test if the part is damaged please tell me.

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A friend tried to reflow something with my butane mini torch... the results were quite bad. I wouldn't recommend this method at all... BUT, the next best thing you could do with this method is to use a little copper plate and pliers, apply the heat to the copper plate only and press it against either the chip or the underside of the board. Essentially the same thing as frying pan, but more location specific ;)

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I've seen a lot of people re-purpose infra red ovens into their own re-flow oven. I actually use a dedicated Walmart $20 electric Griddle for all my surface mount soldering. The built in thermostat enables me to ramp up the heat slowly. I get good repeatable results and have yet to damage any parts.

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bluehash:Not sure about the temperature, I actually tried this twice, and the first time I had way too much solder paste, and I think the chip shifted a bit. But this first time the lighter was running on fumes so it was a fairly small blue flame. I haven't tested this first one yet, bit I think I need to clean up the solder first.


The second time was done with a fully fueled lighter, so the flame war roaring(I'll need to turn it down).



SA: As for the location specific bit, I think my ground plane was acting as the heat spreader.


zeke: I considered a heat gun, but heating the board and not blowing the part of the top would mean the heat gun is heating the underside, and adjustment would've been pretty difficult(my board is only 5x5).


rcouto: Yea, I'd love to have my own diy reflow oven, but I'm living with my parent, which means I can't occupy too much room. This was just something I could do on my work bench, I just clamped the pcb to a heat resistant surface, and applied the heat from the underside.

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What do your parents recommend?

What insurance coverage do they have on the house?

Do they approve of the flame technique?



There's a ton of safer ways of doing this. The electric frying pan is probably the lowest tech yet safe method.


No matter what, keep on experimenting!


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Parent is just starting to learn electronics, so no recommendations from there yet.

I know there is insurance on the house, I'm not sure if it's insured for soldering accidents.



I do understand that the safer ways are, well safer, and will make a permanent electric reflow oven, but I think there could be a portable reflow oven that could be hacked together using a butane lighter. Would possibly benefit people with limited workspace and limited budgets. Even though the electric ovens don't cost a lot, butane lighters cost much less.

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OSPID still costs 85USD + shipping, the machined aluminum block would cost a fair bit too.


However thanks for those links I've now got an idea of where to start to build my own reflow oven.

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