True plated vias at home

[coppercone2]

will swabbing it with 30% hydrogen peroxide and 98% H2SO4 work? it burns anything. Very cheap too.

https://en.wikipedia.org/wiki/Piranha_solution

You can mix it in tiny amounts in a test tube using drops actually. Would work well for VIA's if you make 20 drops up (like 1mL)
]
Then put it on a formed glass fiber swab that is inserted into the holes.

[IconicPCB]

spindle speed is immaterial; it is the combination of spindle speed versus linear feed.
In fact taking it slowe (lower spindle speed ) produces less smear for two reasons

spindle bearing runout is lower and generated heat is lower.

Chemical desmear process can take place in highly alakaline  ( PH=11) solution at 60C for a few minutes.

A good source of high speed spindles is Alfred Jaeger  a German company.
A 60K RPM spindle will set you back a few thousand Euro.
You will need a small three phase inverter to drive the spindle ( small - 400watt).

In terms of activation chemistry Think and Tinker from USA have a product, a conductive ink.

I recommend it.


I have used palladium suspension from Atotoech. Very finicky suitable only for continuous production excellent results. Can not recommend it for one off production.
I am using  a Russian idea based on copper hypophosphite. Suitable for stop start production. HIGHLY RECOMMEND IT.
Requires an electropolishing cell consisting of a high current source( say 10 amps per square decimeter of copper).
Excellent results with minimal chemistry , better adhesion to hole walls than anything I have used to date.

[coppercone2]

im gonna try making a plating gun that blows up copper wire in a tube with a argon feed. I am curious.

Is the surface finish by a 8k spindle ok for a 0.8mm to 0.3mm via ?

Base solution = warm sodium hydroxide? What do you mask the PCB with? Can you just lay the drilled board on a flat plane on glass on a hot plate and put a drop of strong hydroxide solution on each via hole and heat then rinse? Don't want to make large corrosive baths up. Also less masking.

[IconicPCB]

The gun idea might work.
There is a company using plasma in hard ish vacuum.
They start with fr4 only sheet.
Drill it and then it goes into the plasma chamber.
A mixture of gasses is used to clean the fr4 sheet and hole walls and then a sliver of copper is evaporated in a tungsten crucible.
The atoms are deposited allover the sheet.
The sheet is ready for electroplating.
It is then flash electroplated and from there on it is treated in conventional process including additional pating weight post masking.
Advantages if this approach reduced chemical load at the end of process.

On the question of base solution itis a mixture of two chemical sodium hydroxide and one other the name escapes me... let me have at least one coffee first ting in the morning.

[coppercone2]

I imaigned doing something like that with a 'vacuum kiln" but its a rather complicated apparatus.

I made a ghetto gas diffuser a while back using those coffee straws and an old mini epoxy-can (the paste bondo stuff). I will try to flow some argon through it and blow a 'bridgewire' in front of the flow to see if the most crude way works first before I try to to make some kind of sealed focused apparatus (I have a feeling it might take a few iterations). I was going to use this just to see if I can make smoke laminarish.

[coppercone2]

what is chemical load? The amount of chemicals that are stuck in the PCB and offgass?

You can make super-bases, is it one of those? Maybe hydrogen peroxide and sodium hydroxide?

[IconicPCB]

Chemical load ...of waste byproducts.

Regulation and disposal there of.

The alkaline mix consists of sodium and calcium hydroxide. Dissolves glass.

[coppercone2]

any idea what the sodium hydroxide does to the epoxy? are any toxic compounds formed or can it be neutralized to salt, evaporated and burned maybe?