etching gainclone pcb

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Till today, I was using protoboard/veroboard and point-to-point wiring. Now I am confident that I can make my circuit layout. Yesterday, I went to my electronic part supplier for tda7294 (which I build successfully with my layout) He offer me for blank PCB and eatching powder and said do art-work by permanent marker pen on pcb. Put the pcb in PVC pot add eatching powder and warm water.

I google with "etching pcb" and got lot-off stuff. Laser printing toner transfer method is popular.

First, I have to make art-work. I use windows paint-brush. Major problem is alignment of IC's pin & coponents. I found LM3886tf & TDA7294's pin alignment is different.

1) How to calculate distance between pins ?
2) How to draw on paint-brush. The distance looks on Computer monitor does not print the same distance.
3) I experienced 4700uf 25v caps are different sizes with different brands.

How the experienced members manage these problems ?
 
You could try this way:

Easy PCB (Printed Circuit Board) Fabrication, Using Laser Printer Toner Transfer, with a Household Clothes Iron and Glossy Inkjet Photo Paper

Basically, if you can print the pattern with a laser printer, onto glossy inkjet photo paper, you can use a hot clothes iron and transfer the pattern to the copper. The laser printer's toner is mostly plastic, and copper etchants cannot eat plastic. And voila!

I've done it hundreds of times. You can go from a computer-based design to a finshed board in less than an hour. But you have to get the details done correctly. So read the link.

There's also a good recipe for etchant, there, that's better than any of the powder types I've used, and is very cheap and made from two very-widely-available chemicals.

Cheers,

Tom
 
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Gootee's toner transfer method works very very well, but you have to find a good quality paper to use for this. Most cheap "Photo" paper just has a plastic like cover that will come away with the heat of the iron.

The stuff I use is Kodak Ultima 270 g/m2 paper. This has an ultra glossy finish like "real" photographic paper (the stuff you used to get 35mm prints on) and allows the toner to peel clean away under heat. The only thing you need to do is use a sheet of plain paper between it and the iron, or the iron sticks.

I just use regular old ferric chloride etchant as it is easy to get. I store it in an old 2L juice container (I have no young children who might drink it!) and use it in a Tupperware tray that is inside a washing up bowl filled with hot water.
 
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I used to go the photoresist - film route for etching PCBs. But this toner transfer method sounds pretty attractive.

Does anyone have a good suggestion for a paper that will print and transfer without pinholes? The list of papers on Gootee's site hasn't been updated in a while and these office supply stores and paper manufacturers have a way of selling old wine on new bottles (eh... "rebrand") their papers every 20 minutes.

Thanks,

~Tom
 
For more information on the toner transfer pcb etching method, check out PulsarProFX.
They discovered the toner pcb process, and offer free tips, and sell some very useful supplies that really help to improve the process.
To eliminate pinholes, try using their Green Toner Foil. It is a foil-like sheet (mylar?) with a heavy pigmentation layered onto one side. After you transfer the toner to your pcb, just iron the pigmented foil over your toner to "seal up any open pores." Pretty slick process... very fast and simple to do... and it works like a charm. Turns a tedious task into a no-brainer that works perfect every time.
And if you'd like to make your boards more "professional" looking, get some white toner foil as well so you can use toner to make your silkscreen, and then iron over it using the white pigmented foil to impregnate color into your toner. I use this same method to label my front panels and stompbox enclosures. They lots of custom foil colors to choose from, even flourescents and metallics.
These guys also offer DryTransfer Decal Kits too. Very nice product... tho a bit pricey.
The toner foils cost about 9 bux each... but they last forever! Worth every penny too!

Check out their shockwave flash tutorials in the Decal Pro section of their site while you're there... because it's a very similar process, but more complex.
 
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After learning expresspcb I am facing a problem. I have seen lot-off threads which claims the attached pictures are ready for etching. For example LM1875 shows pin 1 is left side, if i etch, and turn the pcb at component side pin 1 would be right side. How should I proceed?
 
Don't you have an option to 'mirror' the print out ?

Use 2 parts H2O2 ( Hydrogen peroxide) ( bought from a chemist ) to 1 part HCL solution bought from a regular supermarket or the corner grocery store. called ' cleaning acid for cleaning purposes.
Works VERY fast . Be careful about the HCL fumes and I think you MUST look up the web for safe usage of HCL even in solution form. Complete etching takes place in about 3 minutes or so !

As for printing using the Laser printer method ( inkjet will not work). Use high quality glossy paper from product brochures ( cheap ) or better still some low cost photo printing paper. It needn't be glossy but make sure you print on the correct side. You might need to try ironing on the image a few times to get the hang of it. If it comes out bad, clean the surface with paint thinner and do it again. I touch up errors with nail polish diluted with amyl acetate ( or nail polish remover ). Make sure you do NOT reverse the image. The image must be what you see on screen ( from the component side). When you iron it on it gets reversed ! CHECK the image that you ironed on to the copper board BEFORE you etch. Make sure it isn't reversed.
 
Yes I mean't the JetStar film .
With the toner method you don't need any expensive paper or a photo sensitive coating on the copper laminate. Just a good laser print on paper (as explained) and a plain clean copper laminate board. No exposing time either just time to 'iron it on' !
 
Toner transfer method is the best for DIY starters, but u need a little practice to get "right" time, heat and pressure to use with iron. I had made many gainclone PCBs just like this only

I agree, it may be best method and I need little practice to get right time, heat and pressure to use with iron.

Okey. Today I tried, but all circuit does not appear on pcb. I think there is no confusion till circuit printed on glossy paper. Please find what is my mistake.

1) I put pcb copper side up on the piece of MDF.
2) printed glossy paper, printed side at copper.
3) Put the iron on the paper upto 5 min. ( There is no way to find circuit appear on pcb or not. Because paper stick with pcb. If circuit not appear on pcb more heat required )
4) After 5 min. I found glossy paper is still white, (means, heat does not effect) PCB becomes very hot & little BEND. after 2 min I put it in full glass of water. After 10 Min glossy paper removed very easily but few part of circuit does not appear on pcb.

I think, equal pressure & heat is required to all the area of pcb. OR what ?
 
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