Electronic – Sensibility and health hazards of reflowing computer PCBs in a domestic oven


This is a bit of a fringe question, SE-wise, but I think EE is the best place to ask it.

Some acquaintances of mine had a problem with their laptop – the graphics card stopped working. They've received (from someone else) instructions as to how to "reflow" it.

Unfortunately I don't have the link to the text (and it's not in English anyway), but the relevant bit instructed to heat the card in a convection oven set at 180 C for 5 minutes.

I was asked about my opinion about this fix and answered that while it's conceivable that it might work (my only idea was that it could perhaps remove solder connection defects, since the board is old enough to be pre-RoHS), I advised strongly against performing the fix in an oven still used for food preparation.

To my dismay I recently learned that the acquaintances in question went ahead and performed the fix, in an oven used for home cooking no less. Interestingly enough, it worked, at least for now.

Therefore, I want to ask the following two-part question:

  1. What are the health hazards associated in performing this sort of rework in an oven used for preparing food, and how to deal with those dangers? I would prefer for the answers to concentrate on the possible contaminants left over in the oven, rather than, e.g. increased risk of catastrophic failure of the PCB's components.
  2. How can this sort of rework be effective in rendering the board operational again?

Preferably, I'd like an answer that addresses both parts, but for obvious reason I'll also be satisfied with a quick response on only the first one.

UPDATE: Thank you for the answers so far. Since the most popular ones present opposing opinions, and the number of the respective upvotes is comparable, I think I should wait a day or two before accepting either. This is in the hope that someone would be able to provide concrete data relating to the subject.

UPDATE 05.01.2013: I'm still going to leave the question without an accepted answer for some time. Seeing as how none of the answers have hard data to support them, I'm a bit apprehensive with going the either way. Sorry for that.

Best Answer

They are almost certainly not in any danger. Not any more than the fact that they handled the board and possibly ate something before washing their hands. Direct transfer probabilities are much higher than a double outgassing transfer, first to oven and from oven to food. In the oven of course you have the potential for outgassing, which then coats out on the inside of the oven. I doubt that there is a lot of this. On top of it, people typically preheat the oven which would spike the temperature up again beyond this "reflow" temp and this would liberate the bad stuff (if it was there) and carry it out of the oven. i.e. it would be baked out.

Boards are relatively clean, lead is not very volatile, there are VOC present but once heated they dissipate etc. you wouldn't want to use an oven that is exclusively used for this, but once in a while is most likely very very safe.

In fact the oven elements when new outgas on first use, after cleaning the oven there are chemicals left on surfaces that outgas. Those would be the best comparables and more concerning than the PCB.