Modified laminator for PCB Toner transfer

If you use the toner transfer method for your PCB, this hack is for you.

Toner transfer is my favorite method for rapid PCB prototyping down to 10 mil traces. The basic steps are already described thoroughly, you can find some good tutorials on the net :

1. Laser print the drawings on an appropriate paper (inkjet printing on a very glossy paper then spraying toner powder on wet traces and dusting off excess toner is a method I’ve tested with success too, very convenient since it works with any home inkjet)
2. Iron the paper on PCB’s copper faces
3. Soak in water to remove the paper
4. Etch

Step 2 may be very frustrating using an iron. I’ve tried it many times but even with clever tricks like toner transfer with dowel , my success rate is rather low.  With a laminator, results are much much more reproducible but you have to laminate the PCB several times to fuse the toner solidly on the copper, « several » meaning « until you’re sick and tired » (15 to 20 passes).

Step 1 Principle

So I decided to hack the laminator by slowing down its rolls’ motor using a triac controller. Instead of laminating the PCB in 10, even 20 passes, the motor is switched on 1/2 second then off 10 seconds (off-times of 3s  & 6 s can also be selected). That’s about the right amount of heat for the toner to fuse and stick to the copper. So you can feed once and attend to something else until the transfer is finished, the result will be consistent and perfect.

Comments

[HarveyH44]

I usually only pass my boards through twice, different model though. Worked great from the start, no modifications needed.

Look for a laminator, that will handle thick pouches. Use thinner PCB material. Unless you are doing some high power boards, with large, heavy parts, you really don't need the thick stuff. You'll most likely find a case for you project eventually.

Another bonus point with thin board, it's easier to cut (paper cutter), and drill.

[hobby16]

@Harvey,
You must have a higher temperature laminator.
I initially tried the temperature hack (shorcut the internal thermostat and use an external regulator for testing) but since the machine started to smell bad, I didn't try further.
Where do you buy thin PCB ?