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Soldering with a Toaster Oven
nullset sent in a link to the Seattle Robotics Society about soldering in an unconventional way. Instead of the traditional soldering iron, Kenneth Maxon has successfully used a toaster oven to solder surface mount parts. The "magic ingredient" that facilitates this is a water-soluble solder paste. I wish I'd thought of this back when I had to solder one of those *ahem* aftermarket accessories to my playstation, since the whole process looks easier than trying to hold a soldering iron steady.
Your motherboard has finished. Don't forget to ground it properly!
soldering in an unconventional way
sorry but industry has been doing the solderpaste->heated oven dance for years now.
it's unconventional to use a hand held iron unless you are doing board rework.
Do not look at laser with remaining good eye.
Read the "cooking" times mentioned on the page....the magic is in the solder paste that melts much more quickly than standard solder.... simply sticking a board into a toaster oven with normal solder definitely WOULD NOT work :)
--buddy
Why burn ants when you can put that magnifying glass to good use soldering circuits together in the summer sun? ;-)
Seriously though, wouldn't it be cool if someone modified a laser-pen (or appropriately set up fibre-optic light source) to serve as a soldering iron?
No more fumbling with hot-metal iron pens. Shutter the light and it's cold!
--The more you know, the less you know.
Yes.. I can see the recipe.
Ingredients:
one graphic card
two memory stick
solder and paste to taste
1. little solder there
2. chip here and here.
3. a dash of flux there.
4. in the oven at 350 for 30 minutes.
DING!
OH NOT! That was 350F, not Celcius!!!
Anyone want a byte of my overmelted Board?
I call it "GeForce FX", the FX stands for "Flambee Xtra".
Nouvelles de jeux et technologies en français. TC
I have to confess I'm amazed to see someone use something as commonplace as a toaster oven to do the work of >$60,000 reflow ovens ;-) I'm an engineer in charge of a surface mount line, and there are a few interesting issues to consider when trying such techniques, the biggest of which is "ramp and soak" which in a nutshell is how hot a component gets over a given amount of time. When soldering SMT components, it is imperative that a component recieves no more than 2 degrees C (about 3 degrees F) a second ramp-up in temperature. This is to prevent thermal shock and damage to the components. It is OK for a component to be exposed to soldering temperatures, ideally for as little as possible; a few seconds. When you solder a component in an oven the way this article describes, you run a risk of damaging sensitive components. Passive components like SMT resistors, coils, and simple IC's like logic gates generally take the punishment a lot better than film capacitors, PROM's, etc. Of course, just for foolin' around in the garage, the toaster oven method should be ok, likely you'll not fry the component if you don't leave it in there longer than you have to.
;-)
SMT reflow ovens, essentially, are identical to the ovens used in Pizza Hut where they stick a pizza in one end and it is taken through heating zones via a conveyor and pops out the other side done. In SMT reflow, the zones are controlled in such a manner that the holy 2 degrees C rule is never broken. (I used to joke that on the day I get fired, I was going to stick a frozen pizza in our reflow oven just to see what'd happen.)
My method of soldering IC's to a board is simple and IPC approved: Place the IC on the pads; center it up as well as you can. Using a regular soldering iron, "tack" two opposing corners of the IC to the lands with conventional solder. Don't worry about bridging. Then, apply a small amount of liquid solder flux to one side of the IC, bathing the legs. Then, apply a small bead of solder to the end of you iron and GENTLY wipe this bead across all the legs, from pin one to pin whatever. (Yes, it's counter-intuitative,) and you'll see as if by magic that you'll get very few solder bridges. Apply more flux if required. Clean tip of iron completely of solder, and just touch it to solder bridges. The excess solder will "sweat" to the iron. Clean iron tip again and repeat. When done, clean flux with laquer thinner or similar substance. (If you use no-clean flux, you could just be gross and leave it there if you wished, removing excess with a paper towel.) I find that a simple toothbrush dipped in thinner does wonders.
Or, you can stick stuff in your wife's toaster and take chances that way
Take care now ~!
As other posters have indicated, reflowing solder paste in a toaster oven has been done for years and simulates the standard process for SMT assembly.
Using Solder Paste, you can use a hot air gun to place components on a PCB as well. A woman I know at work (Celestica) made a video demonstrating the SMT solder process using a hot air gun - it came out quite nicely and her joke on customers was saying that she followed the board through the oven (it was vapor phase at the time). Many customers were impressed with her tolerance to extreme heat.
As somebody noted, most components will stop working at 140C and in the oven they will go over 200C - they will survive, but the PCB should not be powered up until the PCB has cooled to room temperature.
If you're going to try this at home, a few comments:
1. Solder paste will only stay reliably sticky for 30 minutes. Make sure that you have your components ready and the oven at the primary temperature before you break the seals on the syringe and start applying paste. Make sure that you don't have more components than you can place in 20 minutes.
2. Solder "paste" is made up of finely ground solder held together by flux. Both the solder and the flux are poisenous and during the solder process you will see a build up of flux on the inside of the oven. Along with this, the solder may form "balls" that can be thrown off the PCB. An oven used for SMT experiments cannot be used for food preparation afterwards.
3. Solder paste must be capped and refridgerated when not in use. If you are storing it in a fridge where food is stored, make sure that it is in something like a tupperwear container and well marked (especially if children are around). It looks like pate or liverwurst, but will sit in your stomach like a ball of lead (sorry, couldn't resist).
4. The PCB coming out of the oven is very hot and will take several minutes to cool down. I've heard of a number of people that have built SMT boards in a toaster oven, only to forget oven mitts and tongs to handle the hot PCBs and ended up dropping the PCB on the floor and burning themselves. One genius I heard about was sitting down when he pulled the board out of the oven without any mitts or tongs... Make sure you have something like a barbeque grill ready for the PCB to sit on when it comes out of the over.
5. The PCB should be as dry as possible. Before putting on paste/components, you might want to put it into the over for a day or so at the lowest setting to try and bake out any water that has gotten trapped in it. Let the PCB cool before applying paste.
6. The PCB pads should be "HASL" ("Hot Air Solder Leveled") for best results (do not try this on bare copper and you may have to experiment with gold finishes).
7. I would suggest using parts with leads on 0.050" (50 mil) centers, 0805 chip components and SOT-23 transistor and diodes. Anything smaller will make applying the solder very difficult. The article indicates the author used smaller spacing components, but not how many and how the PCB was laid out.
8. Do not use surface mount connectors. Unless you are very comfortable with doing your own soldering, you will find that it is difficult to get a uniformly strong joint on every pin.
9. If you are designing your own PCB, you can use Protel's "EasyTrax", which is an MS-DOS Command Line program that can be downloaded for free from a variety of sources (you should be able to find where on Google). I have added IPC standard pad layouts for the library components.
I've done it a couple of times with an old toaster oven and it works surprisingly well. Just make sure you plan out what you are going to do and if there are any terms that I have used above that you are unfamilia with, make sure that you investigate them before trying it out on your own.
myke
Mimetics Inc. Twitter