Homebrew PCBs

>
> *Use kitchen oven - preheat to fuse temperature
> *Monitor temperature with a thermocouple
> *Tape Pulsar paper with toner image to PC board
> *Place PCB with Pulsar paper facing up on 3/4" thick smooth aluminum plate
> *Cover PCB with an oven pot holder to provide insulation from direct heated from above
> *Place in oven
> *Wait until slab reached fuse temperature (monitor slab temp with thermocouple
> *Remove plate with PCB from oven
> *Place on heat resistant surface
> *Remove pot holder
> *Carefully apply pressure to Pulsar paper using a J-roller (used for pressing formica laminate on counters tops...found in orange store).
> *Roll, roll, roll
> *Toss PCB under cold water
> *Peel paper
> 
> Key idea.  Kitchen oven combined with aluminum plate with pot holder insulation, monitored with thermocouple provides uniform, even, controlled fuse temperature.
> 
> J-roller conforms to surface irregularities...don't have to sweat surface texture variations. Any thickness board.
> 
> Works great.
> 
> Maybe able to substitute sort kind of large smooth ceramic tile for the aluminum plate...very cheap..having tried yet.
> 
> Enjoy
>

>
> Hi Mars,
> 
> Neat description, thanks for sharing. I'm curious why the paper needs to be in the oven. Wouldn't it be ok to heat up the board and plate past the fuse temperature, then remove it from the oven, and then roll the paper on at that point? The advantage would be the ability to do double sided transfers. The paper (single or double) could be taped to an alignment jig made out of scrap stock or anything the same width as the PCB to form a pouch open at the top and one side, then you just slip the board into the pouch, roll it, flip it, and roll the other side (if double sided).
> 
> --
> James.
> 
> --- In Homebrew_PCBs@yahoogroups.com, "Mars Bonfire" <mbonfire@> wrote:
> >
> > *Use kitchen oven - preheat to fuse temperature
> > *Monitor temperature with a thermocouple
> > *Tape Pulsar paper with toner image to PC board
> > *Place PCB with Pulsar paper facing up on 3/4" thick smooth aluminum plate
> > *Cover PCB with an oven pot holder to provide insulation from direct heated from above
> > *Place in oven
> > *Wait until slab reached fuse temperature (monitor slab temp with thermocouple
> > *Remove plate with PCB from oven
> > *Place on heat resistant surface
> > *Remove pot holder
> > *Carefully apply pressure to Pulsar paper using a J-roller (used for pressing formica laminate on counters tops...found in orange store).
> > *Roll, roll, roll
> > *Toss PCB under cold water
> > *Peel paper
> > 
> > Key idea.  Kitchen oven combined with aluminum plate with pot holder insulation, monitored with thermocouple provides uniform, even, controlled fuse temperature.
> > 
> > J-roller conforms to surface irregularities...don't have to sweat surface texture variations. Any thickness board.
> > 
> > Works great.
> > 
> > Maybe able to substitute sort kind of large smooth ceramic tile for the aluminum plate...very cheap..having tried yet.
> > 
> > Enjoy
> >
>

>
> James,
> 
> I suspect your suggestion of putting paper on after removal from oven would work fine...I just haven't tried that variation.  Your point about double sided is well taken...I have just done what I call 1 and 1/2 sided boards...big simple ground plane on one side and traces on the other side.  I drill the lead holes through the board then go back on the ground plane side and "relieve" the hole i.e. remove copper from around the hole using a larger diameter drill bit...just drilling in maybe 20 thousands of an inch of so...basically using the conical tip of the drill bit as a shallow countersink.  This removes enough copper so that the lead of the component does not short to the ground plane.  It helps to have a drill press with a depth stop to avoid boring all the way through the board.  
> 
> Steve
> 
> 
> --- In Homebrew_PCBs@yahoogroups.com, "James Newton" <jamesmichaelnewton@> wrote:
> >
> > Hi Mars,
> > 
> > Neat description, thanks for sharing. I'm curious why the paper needs to be in the oven. Wouldn't it be ok to heat up the board and plate past the fuse temperature, then remove it from the oven, and then roll the paper on at that point? The advantage would be the ability to do double sided transfers. The paper (single or double) could be taped to an alignment jig made out of scrap stock or anything the same width as the PCB to form a pouch open at the top and one side, then you just slip the board into the pouch, roll it, flip it, and roll the other side (if double sided).
> > 
> > --
> > James.
> > 
> > --- In Homebrew_PCBs@yahoogroups.com, "Mars Bonfire" <mbonfire@> wrote:
> > >
> > > *Use kitchen oven - preheat to fuse temperature
> > > *Monitor temperature with a thermocouple
> > > *Tape Pulsar paper with toner image to PC board
> > > *Place PCB with Pulsar paper facing up on 3/4" thick smooth aluminum plate
> > > *Cover PCB with an oven pot holder to provide insulation from direct heated from above
> > > *Place in oven
> > > *Wait until slab reached fuse temperature (monitor slab temp with thermocouple
> > > *Remove plate with PCB from oven
> > > *Place on heat resistant surface
> > > *Remove pot holder
> > > *Carefully apply pressure to Pulsar paper using a J-roller (used for pressing formica laminate on counters tops...found in orange store).
> > > *Roll, roll, roll
> > > *Toss PCB under cold water
> > > *Peel paper
> > > 
> > > Key idea.  Kitchen oven combined with aluminum plate with pot holder insulation, monitored with thermocouple provides uniform, even, controlled fuse temperature.
> > > 
> > > J-roller conforms to surface irregularities...don't have to sweat surface texture variations. Any thickness board.
> > > 
> > > Works great.
> > > 
> > > Maybe able to substitute sort kind of large smooth ceramic tile for the aluminum plate...very cheap..having tried yet.
> > > 
> > > Enjoy
> > >
> >
>

>
> 
> Reminds me of an idea I want to try someday.  Combine an aluminum plate,
> soldering iron inserts, and a vaccuum pump - put the pcb and TT on the
> plate, cover with something as if you were doing UV exposure, vacuum it
> down to force it against the pcb (and the pcb against the plate), use
> the soldering iron inserts in the plate to heat it appropriately, cool,
> release the vaccuum.
> 
> Alternately - three layers.
> 
> Top -> lid, strong enough to withstand the vaccuum
> 
> Middle -> flexible plastic sheet that the TT paper is stuck to via
> static cling or something.  Normally it would rest 0.1" or so above the
> PCB.
> 
> Bottom -> aluminum plate with heating inserts and pcb.
> 
> At first, you apply vaccuum evenly to the top and bottom halves, so you
> pump out all the air but don't press the TT to the pcb.  Then, you let
> air back into the top, which presses the TT against the pcb,
> guaranteeing no air bubbles (since the bottom half is still a vaccuum).
> Then you heat and cool the plate to adhere it, then release the vaccuum.
> In theory, perfect adhesion - correct temperature, even pressure, no air
> bubbles.  Should work for UV film too, and you could mount the LEDs in
> the cover to double as an exposure box.
>