[chbot] SMD experiment #1

[Chris Hellyar]

On Wed, 2008-05-07 at 12:11 +1200, Next Kiwi wrote:
> G'day Chris
> 
> I am using a toaster oven successfully here, I even do the odd BGA. We have 

BGA = Scary blind alignment...  What's your rework rate on the BGA's
placing them manually?

> found the most valuable tool is "flux paste". I use this to clean up the 
> board afterwards. Flux paste is magic stuff. It is a must if you are doing 
> MLP or QFN packages.

By flux paste do you mean one of the water based flux carrier solder
pastes?  The only thing I know as flux paste is the stuff you use for
copper downpipe soldering, which is not really the scale we're looking
at here! :-).

> You did the right thing by putting the temperature sensor very close to the 
> board as the temperature around the oven can vary.

Yeah, I played that game before I committed reflow, as it were... Hence
the reason why my -50 to +250c thermocouple cable is looking a little
brown...  The temperature varies by 35c front to back level with the
wire shelf inside the oven, and without watching it carefully you can
hit 320c in under 2 minutes at that height (Hence the cooked looking
cable, not to worry, I have 4 spares).

The other amazing thing I found is how hot the outside of this wee oven
got when it's only running for 5 or so minutes.  The little 'caution hot
surface' sticker is not big enough!  It's quite understandable given
there is no thermal insulation, but damn...

> To clean the flux off I use electrolube FLU
> http://images.google.co.nz/images?hl=en&q=electrolube%20FLU&um=1&ie=UTF-8&sa=N&tab=wi

Might have a look into that, thanks...

Cheers, Chris H.