Steiner VCF (TL071/2N3904) troubleshoot (FIXED!)

[drakfluga]

Lead is not a nice substance to get on/in you, that's true. However, handling lead with your hands is no problem as long as you wash your hands afterwards. Lead does not penetrate your skin. It gets into your system through digestion.

And now for some science:

Lead (pB) has a melting point of 327.46°C. My 60/40 solder claims it has a melting point of 280°C, so even slightly lower than lead. So, at around 300°C, the lead in your solder will melt and enter a liquid state. For the lead to enter the fumes which you see emanating from your solder point it would have to be at or above its boiling point, which is 1749°C. This is a lot higher than the temperature in a regular ceramic kiln, and nowhere near the kind of temperatures you can get from a soldering iron.

Bottom line: If you don't put your fingers in your mouth, eyes, nose or other orifice while soldering, you will not get lead into your body.

The flux is another story altogether. It's not healthy to breathe in the fumes, so you should solder in a ventilated space. But don't worry about the lead.

[elmegil]

I have not once said there are no dangers. Just that it is not physically/scientifically possible for MOLTEN lead to be in the fumes. You'd have to BOIL the lead (which takes about 6x higher temperature) for it to be IN the fumes. There are plenty of other avenues for the lead to get into you besides inhalation (you yourself point out the foolishness of licking your fingers to create shorts), so of course you need to be very careful about ALL the vectors, and you do need to avoid the fumes for other reasons.

[yusynth]

Hum... this is going far off topic. Let's get back to Steiner VCF.

[tazer]

it's a great filter Yves, have built one sorry to drag it off topic but it was going there anyway. You do a great job out there keeping us all right and designing good stuff, the resonance on this filter is a ripper.