Etching : a handy hint.

[brett]

Hi
I've just etched my first box.  Here's a time-saving tip I used:

To minimise sanding back unwanted paint, mask the design with PVA/craft glue.  Leave a couple of mm/tenths of inches around the design.

After the paint hardens, the mask can be removed with warm water.  This is much easier than removing paint.
cheers

[cakeworks]

tis a good idea but you still have to sand off the pnp

pics?

[markm]

This just occurred to me......
You could always just use Laqer Thinner -or- Carburetor Cleaner on the paint AND the PNP and both would come right off!
Laquer Thinner will eat ANYTHING! 

[cakeworks]

Laquer Thinner will eat ANYTHING! 

Including say... aluminium?

[markm]

Laquer Thinner will eat ANYTHING! 

Including say... aluminium?

Hell No!!
My body guys at work use Laquer Thinner to clean their paint guns.
Guess what those are made of?? 
Aluminum.
That's right fella,
Enclosure material 

[cakeworks]

so would this be more ideal for cleaning the sanded enclosures prior to the etching instead of the lighter fluid?

[markm]

so would this be more ideal for cleaning the sanded enclosures prior to the etching instead of the lighter fluid?

ummm....you could if you wanted to I suppose.

Hi
I've just etched my first box.  Here's a time-saving tip I used:

To minimise sanding back unwanted paint, mask the design with PVA/craft glue.  Leave a couple of mm/tenths of inches around the design.

After the paint hardens, the mask can be removed with warm water.  This is much easier than removing paint.
cheers

It would eliminate sanding off the paint/PNP mask.

[brett]

Hi
Maybe I should have explained a bit more.
First, you apply a PNP + paint mask and etch it.
Then you paint the box top, some of which goes into the etching and some sits on the top.  Usually, you have to sand off the whole top (the paint in the etched part is retained coz it sits lower than the top).

But if you mask most of the top with PVA glue, then paint, you can get rid of most of the paint by soaking and dissolving the PVA.  That'll only leave a small area of paint around your design to sand off.

I'll post a photo tonight.

cheers

[Pushtone]

I use my wifes nail polish remover to take off the PnP mask on my PCBs and my etched boxes.

[mojotron]

If you guys are looking for some safer stuff to use - I use a citrus based cleaner (instead of lacquer thinner - it does not work as fast as lacquer thinner, but it is safer) to take off fuser/paint and clean with Acetone before etching (it takes a couple of cleanings - but it works and is cheaper).

[markm]

If you guys are looking for some safer stuff to use - I use a citrus based cleaner (instead of lacquer thinner - it does not work as fast as lacquer thinner, but it is safer) to take off fuser/paint and clean with Acetone before etching (it takes a couple of cleanings - but it works and is cheaper).

I use my wifes nail polish remover to take off the PnP mask on my PCBs and my etched boxes.

Two more good ideas!
Thanks guys 

[brett]

Hi
Nail polish remover is acetone with a little oil added, and is usually cheaper to buy in the harware store.
I've been using the citrus stuff to remove PNP for a while.  I started with Big Kev's Goo Remover, but curreently use CitroClean, which is cheaper and less oily.
cheers

[R.G.]

For removing oils and to some extent paints, there are two approaches: solvents and degreasers.

Solvents dissolve oils, grease, and paints (paints to the extent that the solvent works on the chemicals involved).

Degreasers chemically attach to petroleum molecules and float them away.

It is possible to remove all oils and greases with degreasers. It is NOT possible to remove all oils and greases with solvents, only to reduce their concentration by diluting them. The dilution may be sufficient, but there will always be some left. On the other hand, degreasers are not as aggressive as solvents, and there are some things degreasers (like even lawyers...  ) will not do.

Etchant is completely blocked by any surface treatment that keeps it away from the metal. Any oil - including fingerprints, as you know - will work as a resist, and any film that the etchant will not attack works as a resist. That includes oils, greases, paints of all kinds, PVA glue, plastic film, many inks, the adhesive and substrate of most tapes, fused toner, and anything else you can think of that won't dissolve in etchant, which is most organics that don't just dissolve in water.

Any succession of steps which involve masking, etching, deposition and removal can be done. In many ways, this replicates the formation of integrated circuits, with the exception that there's no good at-home way to redeposit metal layers. Even regrinding the surface flat to leave material in the valleys is an IC as well as a variation of lithographic technique.

Simple paint masking works too. You can cut a stencil for a pattern to be painted, apply the stencil and paint. Then retouch the paint and etch. Using Brett's suggestion, you can then leave the original mask, paint it all and simply abrade away both the new paint and the original mask leaving the paint in the etched area.

Finally, the paint in the etched area does not have to be a single color. You can paint multiple colors or swirl-paint and leave that pattern in the etched area.

[gez]

Hi
Nail polish remover is acetone with a little oil added, and is usually cheaper to buy in the harware store.

You can buy 'acetone free' nail polish remover.  I use it to clean up boards and remove photo-resist.