Reflowing on an Induction Stove

[scaru]

I was talking to JackCY, and the topic came up of reflowing on a stove. He has an induction based stove so we were wondering whether you can safely reflow on that using my method. (Posted below)

1. Get a pan you don't care about and place it on the stove.
2. Turn the stove onto high
3. Place the star on the pan
4. Wait until the solder will melt on the star and then turn the stove down to low
5. apply solder to the junction points
6. grab LED with tweezers and orient it the correct way
7. place it on the star
8. make sure it soldered then pull the star off the stove

The worry was that there might be some residual voltage in the pan that could damage the LED, I have never used one of these stoves before but I'm guessing there isn't as it would be a safety hazard.

[nitro]

I use a old coffee pot lol

[Slim_Pickens]

I wouldn’t worry about it because the electrical pads on the MCPCB are completely insulated from the bottom of the board. Or I’m missing something?

[Flomotion]

Hmm, interesting. On reflowing, I use my variable electric heating element stove, and this:

http://www.ebay.com/itm/280649393840?ssPageName=STRK:MEWNX:IT&\_trksid=p3984.m1439.l2649

[bushwhacked]

I have never soldered in my life but I took apart a t6 dropin just to see driver and guts for myself. After reading so much on here about soldering and reflowing etc I decided to use my wood stove to see what happens when I put the star on. After about 2 seconds I was able to remove the led, it kind of made a mess with the solder and I dont have a wick or sucker. I will be getting some soldering tools and some paste to see if I can reflow back on without damaging anything. I know its not induction but it works really fast.

[ryansoh3]

@Flomotion

Hmm, interesting. On reflowing, I use my variable electric heating element stove, and this:

http://www.ebay.com/itm/280649393840?ssPageName=STRK:MEWNX:IT&\_trksid=p3984.m1439.l2649

I see that the IR thermometer has an emissivity display; do you know if it serves any purpose? Can you change it?

Thanks!

[Spasmod]

@nitro

I use a old coffee pot lol

Don’t you find it a hindrance trying to hold the emitter with tweezers while it’s inside a coffee pot ?

[gmarsh]

@ryansoh3

@Flomotion

Hmm, interesting. On reflowing, I use my variable electric heating element stove, and this:

http://www.ebay.com/itm/280649393840?ssPageName=STRK:MEWNX:IT&\_trksid=p3984.m1439.l2649

I see that the IR thermometer has an emissivity display; do you know if it serves any purpose? Can you change it?

Thanks!

Technically you’re supposed to set the emissivity of an IR light meter in order to get an accurate temperature measurement, otherwise you can get a significant amount of measurement error.

I used a thermal camera (Fluke TI25 IIRC) in my day job for evaluating prototyped electronics - we’d use it to look for hot parts/spots, verify proper operation of cooling systems, etc. We sprayed everything with conformal coating spray to make sure everything had the same/known emissivity.

I’ve done the “frying pan reflow” trick several times for soldering parts onto PCBs. I use the side burner of my gas grill and an old cast iron pan. I tape my Fluke thermocouple probe to the frying pan with some kapton tape, and adjust the flame on the burner as I go, trying to follow something that looks like a normal reflow temperature profile.

[Hopback]

I use an induction hob for reflow, the only major problem I’ve encountered is being caught by Mrs H!

Get a thermocouple and monitor the temp of the pan (I over cooked a couple of leds before I realised) and use solder paste….cant go wrong!

[JackCY]

Ah, yes we did, the issue with the inductions stove, for you people in the US where they are not that common as I found out.
Is that, induction stove heats up metalic/magnetic objects you place over it.
The stove itself, the glass gets warm from the pot but otherwise it’s cold, you can even touch the glass if you did not cook for long as the pot is heating up not the stove itself.

There is a induction going on, there is a spiral I believe below the glass and it generates current in the pot/pan due to the current flowing through the pot the pot heats up. This is quite a lot of current and low voltage if I’m not wrong. It works only with cookware that is magnetic.

My issue with this is, will it fry the emitter when I place it on the pan when the cooker is on?
Since some current might flow through the emitter and damage it.

In an induction cooker, a coil of copper wire is placed underneath the cooking pot. An alternating electric current flows through the coil, which produces an oscillating magnetic field. This field induces an electric current in the pot. Current flowing in the metal pot produces resistive heating which heats the food. While the current is large, it is produced by a low voltage.

Another thing to be wary of is that even though aluminium cookware doesn’t heat up from induction, aluminium foil is another story. I won’t go into the physics, but due to the thinness of foil induction very much works with it. The heat generated in aluminium foil by induction is uncontrollable and extremely high in temperature, so do not boil food covered in foil and never rest aluminium foil on induction hobs – even when they’re turned off.

What happens when you put aluminum foil on the stove, the part in the middle melted as it was not underwater and got exposed to air.

So I would not like to see my emitters turn shining over the cooktop shortly and then burn away. Since heat is not primarily generated underneath but in anything you put over the cooktop that reacts well with the magnetic field.

I’ll have to check with Scaru again, if he tried it or not.
Anybody else tried induction stove?

It’s not an issue of some charge, there is a strong magnetic field on certain frequency that heats up metal objects. Some quite rare induction tops can heatup even nonmagnetic/nonferous cookware. Because they have a different frequency.