Electronics > Manufacturing & Assembly

My way to professional prototype at home.

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carloscuev:

--- Quote from: amspire on March 24, 2013, 02:30:19 pm ---A lot of great information there. Thanks. I will give the process a go.

So it looks like for double sided boards, I will have to give up the toner transfer and go to dry film.

And I had just finally modded my laminator too to boost the temperature!

Richard.

--- End quote ---

Well, I've tried toner transfer and it worked, but now there's a new problem, not only the alignment of the 2 layers is important, now the new problem becomes the alignment of the 2 layers and the PCB, take a look at the youtube video, the guy still uses toner trasnfer :)

chickenHeadKnob:

--- Quote from: carloscuev on March 24, 2013, 05:02:38 pm ---hope all of you can find this large post useful

--- End quote ---

Yes! very useful, muchas gracias. You are saving us all time and frustration. I have been looking for phosphor-copper alloy and there seems to be multiple types: ones with relatively low phosphor around 0.02% upto 0.06% and just copper which is intended for electroplating and then higher mixtures plus other metals which are intended for brazing rods, ect. I am thinking that the problems with just using regular copper sheet or bars isn't so much the lack of phosphor but rather the alloying metals like zinc interfere and pollute the electrolyte. If I find a good source for anodes I will let the forum know. Searching right now just in Canada/U.S. to start.

carloscuev:

--- Quote from: chickenHeadKnob on March 24, 2013, 09:29:20 pm ---I am thinking that the problems with just using regular copper sheet or bars isn't so much the lack of phosphor but rather the alloying metals like zinc interfere and pollute the electrolyte.

--- End quote ---

Yes, I think so too. I was trying at first with spirals of nude grouding wire, awful results. I got better results with plumbing copper pipe. I think this wire made just for grouding is made of a nasty mixture of copper, zinc, carbon and what not. But definitively Phosphor Copper works miracles. I don't know the content of phosphor on this one, all I know is that it's called Plus 4 Phosphorus-Copper (http://www.galvanolyte.com.mx/indmeta.htm) maybe that 4 means 0.04% ? I'll call and ask :)

peter.mitchell:
Im curious on this, has anyone tried plugging vias in DIY boards with solder paste, eg;

Drill out holes for vias
Get a griddle/electric frying pan/small cooktop
Place a large, very flat block of Aluminium on top of it.
Using an accurate thermocouple, get the temp to 190~ degrees
Place board on plate, wait for board to reach temperature.
Using a syringe, carefully fill the holes with 63/37 eutectic solder paste (smallest particle size preferably, with no clean flux)  until it just comes out the top and wets the surface on the top.
Turn off the heat, wait for temp to drop to 175~ degrees
Flip the board over, turn the heat back on
Fill vias from the other side in same manner.
Turn off heat, wait for temp to drop to 175~ and remove board to cool.

Using an aluminium plate would be nice, keeping an even temperature across the board. Additionally, 63/37 won't stick to it, and its fairly soft, so easy to mill flat.
Flatness would be important, this would stop the solder from flowing out the other side of the board, and would apply even heat to the board, meaning minimal temperature needed.
Eutectic solder would be good, because you wouldn't need the board to fully cool between turning it over and it is very easy to tell when it is a safe temperature to flip.
Small particle paste would be nice too, to allow it to fill the voids easier.
No clean flux in the paste may be necessary; if flux residue got caught inside the via you wouldn't want it to corrode your board.

krivx:
How do you stop the solder from failing out of the vias when you solder the parts?

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