PCB Reflow Fumes...

[SolarSunrise]

After years of hand soldering PCB's, I finally decided to buy myself a hot plate and lead free solder paste to try reflowing my boards. In my first try, I liquified the board into black goo and generated quite a lot of fumes because of too much heat. In my second try, with a thermocouple this time, the board stayed in tact and the reflow was successful, but still unleashed very, very unpleasant smell (not the usual flux fumes!).

Is it always like this? Does PCB's produce this very unhealthy smelling fumes every time it's subjected to lead free reflow temperatures (240C in my case)? If so, is it dangerous like my nose suggests? I really don't want to get lung cancer from this... By the way the PCB material is FR4.

Thanks in advance!

Update: After some googling, apparently burning PCB's gives out highly toxic fumes... Well that's something new and very very important...

[Stonent]

After years of hand soldering PCB's, I finally decided to buy myself a hot plate and lead free solder paste to try reflowing my boards. In my first try, I liquified the board into black goo and generated quite a lot of fumes because of too much heat. In my second try, with a thermocouple this time, the board stayed in tact and the reflow was successful, but still unleashed very, very unpleasant smell (not the usual flux fumes!).

Is it always like this? Does PCB's produce this very unhealthy smelling fumes every time it's subjected to lead free reflow temperatures (240C in my case)? If so, is it dangerous like my nose suggests? I really don't want to get lung cancer from this... By the way the PCB material is FR4.

Thanks in advance!

Update: After some googling, apparently burning PCB's gives out highly toxic fumes... Well that's something new and very very important...

Are you placing the board directly on the hot area? I've fixed a board before that had an unseen fault in a regular oven before.  The instructions I used said to raise the board off of the metal by using some small foil balls or pieces of wood to keep the board from burning.

[ConKbot]

Ive worked with a 'real' batch reflow oven at work, and yes, it does smell slightly like burning FR-4 on the hotter cycles.  The boards arent charred or discolored, however no, I wouldn't want to be breathing it either.

[zapta]

1. Does the board have solder mask on both sides?

(my thinking is that solder mask and ground plan will limit the amount of particles released by the fiberglass).

2. What kind of temperature profile do you get? Typically the peak temperature is only for a short time.



3. How do you know that the smell is from the FR4 and not the paste or component? Have you try to bake a 'dry' board?

[M4trix]

I'm amazed how she's handling with the hot plate without any problems. 

http://www.faze.co.za/Video/Soldering.html