Toner Transfer Papers

[KeepItSimpleStupid]

I though a like scruffy is better than smooth. e.g. Scotchbrite pads. I'll attest that Acetone leaves a film. That was annoying for me for a while when trying to measure pA across a gap contaminated with Acetone. Not PCB related.

Some have suggested to place the PCB in an Acetone vapor after transfer.

 

[Mosaic]

I used the scotch brite initially, it's ok for new PCBs, but if u have copper clad stock a year or 2 old, 220 grit paper is the way to go, less elbow grease. Acetone dissolves toner fast, I have seen folks try to reduce toner porosity by using acetone vapor on toner transfers. Too dangerous for my liking, flame hazard etc. (my dremel brushes spark), foiling is much more reliable and requires no particular safety precautions, plus u can make nice silk screens with it.
If I prep/sand an etched board and I can't assemble for some reason I apply a thin wipe of petroleum jelly. Keeps it oxide free for a few weeks. It's almost like a low temp flux, solder flows well on such boards. Hot air vaporizes it., alcohol wipe cleans it off.

 

[jpanhalt]

@KISS

Acetone is quite reactive with many metals, including copper. Here is a YouTube experiment (

) .

I suspect some of the product may be ketene. If one were to stick his nose over the flask, he would probably smell it.

Ethers were our preferred, volatile solvents for removing grease and fingerprints. Alternatively, if you can get good light naptha (e.g., VM&P Naptha that doesn't have a strong smell like gasoline) will probably work alone or with a little toluene. Odorless detergents are also good. If you are worried whether you cleaner leaves a film, let a small drop evaporate on the shiny side of aluminum foil. Then look at it with oblique light to see if there is a residue.

John

 

[KeepItSimpleStupid]

Maybe, I misread the use. I was going from memory. This https://www.diyaudio.com/forums/parts/117978-pcb-toner-transfer-using-acetone.html suggests kinda using it as a release agent from the "back side", but maybe I saw a reference to help fill holes. Maybe it wasn't toner transfer.

We used acetone, followed by Tricloroflorethane, followed by a Freon TF ( unavailable) dip and blow off with a filtered inert gas like Argon for one of, things.

See https://www.besttechnologyinc.com/p...-phase-out-and-replacement-with-3m-novec-hfe/

 

[throbscottle]

John
Ah, ok, completely out of my depth there! But I see what you mean anyway.
So, suppose you have a board dipped in protein solution, and with nice fresh toner transfer on it, the areas without toner also have the protein fixed by heat on them, which presumably is going to resist the etchant to some extent? How do you remove the protein from those areas then?

(Edit) Ooh ok, lots of posts between writing and pressing reply!

Mosaic
I see you've updated the hackaday page then! Good work

I started off using steel wool, eventually I have switched to fine emery paper, give it a wash with dish soap and water afterwards. A rough surface definitely gives better results.

Since the surface of the board is actually covered in regular hills and troughs, I think it would be better yet to use some kind of carborundum paste. Not something I've looked at yet, I only just thought of it.

 

[jpanhalt]

After the usual soak to remove backing paper, I suspect protein in the open spaces will either be washed off or softened and the etchant will take care of the rest. Etchant and water wont get under the toner as that process is diffusion controlled and the protein layer is extremely thin.

John

 

[Mosaic]

Since the surface of the board is actually covered in regular hills and troughs, I think it would be better yet to use some kind of carborundum paste. Not something I've looked at yet, I only just thought of it.

I did a test on surface properties, using a dremel tool to lap the copper to a high polish before toner transfer. Epic fail with the transfer. Enter the scotch brite scrubber (leaves a scoured, 'wettable', surface) , steel wool ( can leave fiber bits) and now 220 grit paper (needs an alcohol wipe down after sanding). The bonding process seems akin to applying glue or epoxy....a scrubbed surface with irregularities provides a larger surface area to bond.
The sandpaper does one additional task: It can locate warps or dimples in the thinner boards that can occur when cutting the boards. This is a cause for improper toner transfer with the clothing 'iron on' process. Laminators usually handle such distortions properly.

Edit: For dbl sided boards the sanding is a required operation: The drilled registration holes can cause tiny copper swarf to adhere to the hole edges which will cause difficulties when laying the toner transfer and can scrape off the toner from the transfer paper.

 

[throbscottle]

Yes, my experience was the same with shiny boards.

 

[Manuel Marques]

I use coated paper some from old catalagos special using the blank side. I made over 100 Pcbs that way .. Ofcourse maybe you have to be patient and also some transfer NOT Good but you can Clean and do it again. After a severel you get the best way and you will see it's easy
Try it !

 

[throbscottle]

I have now switched to using the dry-film photo-resist. Dead easy to use. Going from toner transfer to that stuff is like going from VHS to DVD! Never going back.

 

[Willen]

I have now switched to using the dry-film photo-resist. Dead easy to use. Going from toner transfer to that stuff is like going from VHS to DVD! Never going back.

Hi, What I need then?

-Copper clad board
-?

 

[KeepItSimpleStupid]

Here's a pdf **broken link removed** describing the process and the site hosting has a wealth of info.

Dry film photo-resist removes the presensitized boards from the equation or making your own sensitized boards.

 

[Mosaic]

KISS, Is there an Ebay supplier you'd suggest, I am interested in comparing the results with toner transfer.

 

[Mosaic]

I found this with instructions and a complete kit:
https://www.ebay.com/itm/10pcs-Phot...076960?hash=item5b05f6b020:g:dVkAAOSwxH1UKe6b

It seems though that it will take longer than toner transfer and requires two more liquid baths and a UV light setup with a UV darkened room...IE. Daylight is a bad thing.

Given that the yellow Ebay toner transfer paper requires no soaking to peel off....as the transfer is complete it can go direct to the etchant I am wondering as to the benefit of the photoresist. I suspect my experience with toner transfer qualifies me as a high skill level at it which mitigates the benefits of the photoresist.

 

[KeepItSimpleStupid]

I never did dry and never did toner transfer. I did do pre-sensitized and make your own pre-sensitized, For the latter, it wasn't my call. The lab had recipes for making masks up to 4" x 4"; the size of the mask aligner. An oven and spin coater were required to make the sensitized boards. The spin coater limited the size. Spin coater - vacuum chuck that spins up to 5000 rpm. The dry transfer eliminates the size issue.

The major problem with photo is getting a mask dark enough. Transparency paper really doesn't work. Translucent polyester paper worked really well for me. I don't currently have a source of paper. When I used Polyester paper and thru-hole parts, I was able to print a parts legend on the paper and glue it with say Scotch 77 or Scotch 90. Probably using adhesive laminate would work better since I now have experience with that.

 

[mvs sarma]

Nice to watch the topic packing up again. we get pcb papers for toner transfer on ebay. they cost around 1.25 to 2.9$ for 10 A4 sheets.
https://www.ebay.com/sch/i.html?_from=R40&_sacat=0&_nkw=pcb+toner+transfer+paper&_sop=15

I generally have pre print and use cut pieces of the special paper stuck to the pre printed paper to achieve more PCBs per A4 sheet.
This special paper obviates the need to wash scrap etc after toner transfer. while the copper clad half cool,
lift from a corner and gently peel off, the artwork stays. with artwork with lot of ground plane, after peeling , little editing would be needed.

all the best
sarma
vu3zmv

 

[throbscottle]

Hi, What I need then?

-Copper clad board
-?

Welllllll...
**broken link removed** is a pretty cheap roll of the stuff.
You don't need a particularly dark room, just close the curtains, and cover the board when your not actually handling it. You can expose the board in daylight, just watch the colour of the resist. It's better to have a controlled light source.
Peel the backing off the film by putting a piece of sticky tape on either side at the corner. Pull them apart and one will be stuck to the backing and one stuck to the film.
You can print the design on transparency, or tracing paper, or plain paper. You can use an inkjet printer, and some people say this works better for them.
I've got details as fine as 0.003" to come out, though not very reliably. 0.005" works ok.
Large areas work perfectly, no need to touch up like you do with toner transfer.
The film works much better if you slap it on the board when the board is wet. You can pass it through a normal pocket laminator with no modifications, or press it with an iron on a cool setting, cool enough to touch.
All you need to process the board is two common and cheap household chemicals, washing soda (or soda crystals) and lye (or caustic soda), aka sodium carbonate and sodium hydroxide. You don't even need to measure them out, just chuck in what you think will make an average strength solution.
This was a big help https://www.instructables.com/id/How-to-make-a-printed-circuit-board-PCB-using-th/ I made a version of his light box (mine is less power-hungry!) You can ignore the stuff about chemicals unless you are making etchant too. Others report nail polish curing lamps work well.

Honestly, it's no harder than doing the toner transfer method and it's a lot more reliable!

 

[Willen]

Welllllll...Honestly, it's no harder than doing the toner transfer method and it's a lot more reliable!

Sounds awesome! But it seems that the project needs little more strange materials/chemicals. It is pretty hard way for a people living in less accessible place like me.

 

[throbscottle]

Honestly Willen, if you can get the photo-resist film, there is nothing strange about washing soda and caustic soda! They are commonly available and cheap cleaning products, I'm sure you can get them, even in Nepal! All you need to do the exposure is daylight, if it is consistent enough where you live, if not then there are other cheap and common UV devices available.

Whilst I'm at it, I just published this: https://www.instructables.com/id/Somewhat-Complete-PCB-Fabrication/

 

[Willen]

Honestly Willen, if you can get the photo-resist film, there is nothing strange about washing soda and caustic soda! They are commonly available and cheap cleaning products, I'm sure you can get them, even in Nepal! All you need to do the exposure is daylight, if it is consistent enough where you live, if not then there are other cheap and common UV devices available.

Whilst I'm at it, I just published this: https://www.instructables.com/id/Somewhat-Complete-PCB-Fabrication/

I do not know about photo-resist film here. If something could be available, that will be in Capital city, where I never been there till now. Around local market some people have 'screen-print' business, they paint something in thin cloth (stretched to the frame) and expose to sun light and then wash and print cards through the cloth. I guess it'sa same technology as you are saying. But sad thing is that no one share the idea what are they doing. They think that sharing idea is a harmful step for their business.