Homebrew PCBs

On Saturday 29 May 2004 10:14 pm, crankorgan wrote:
> > I've seen those heat guns,  never thought about using one to get
> > parts off a board,  and didn't know that they reached solder-melting
> > temperature.  It shouldn't be a surprise,  though,  since they'll make
> > paint bubble up pretty good...
>
>  Roy,
>      The machine for changing surface mount chips has a heat gun on
> both sides of the board. The nozzels move together. There is a
> temperature control. The company that makes them is called HART. You
> put a dab of stuff on the chip. When the stuff turns clear the chip
> will lift off. With the heat gun you preheat the bottom of the board
> and then go in for the kill from the top. I mount the board in a bench
> vise so it does not fall.

Sounds like a good plan to me.	:-)

> Years ago people used a propane torch.

I think I may have tried that years ago,  I don't really remember.  I know my 
brother tried it a while back,  in his driveway -- the problem with that is 
it's too darn easy to set the board on fire,  and those fumes are pretty 
nasty.

> I used to worry about hurting parts with heat until I saw a wave soldering
> machine and surface mounted parts being soldered in a toaster oven. Some
> heat guns also come with deflector tips to localize the air. The heat gun
> also works great with shrink tubing and bending plastic.

I used one for heatshrink when we were making "fans" to go on the end of 
"snakes" (think audio, going between a stage and a mixing console somewhere 
out in the audience area).  A typical fan had 16 or 24 lines going down,  and 
3-6 coming back up,  each one having a 3 foot length of heatshrink over it.  
To try it any other way would've been *real* time-consuming...