Etching boxes

[MR COFFEE]

Since we drifted over to adding top plates of etched brass - Soggy mentioned pop rivets to attach...

There's no need. The pot nuts and a thin sheet of double-sided adhesive (like they sell for attaching pickguards) will hold on for GOOD.

Just be real careful to line it up before you press it down. Once it touches, it ain't gonna let go.

[soggybag]

Sounds intriguing Mr Coffee, I'm not familliar with this materials can you point me to them on the internet? Or give me a brand name?

[gez]

Can anyone tell me if it´s possible to acheive the same results using UV Varnish that i use to make PCB´s ?

You mean photoresist paint, the stuff you spray/brush on boards to develop them?  Yes, it works...

[Samy]

Yes gez ! Photoresist paint.
I´m gona etch a box today . 
Just a little offtopic question, does anyone knows were to find cool black/white paterns to make cool etched boxes ?

Thanks.

P.S. Sorry my English ! 

[AdamB]

I can't seem to get the toner to stick properly to the top of the aluminium box...

I'm using PnP blue to print my design (black background, white lettering where I want it to etch). I've sanded the top down using low, medium and then fine sandpaper until it's really smooth, then washed it with a brillio pad (steel wool sort of thing with soap imbedded in it), then I pre-heat the box with the iron, place hte PnP and iron it on for like 5 or 6 mins. When I quench and peel the PnP off large chunks of the toner haven't stuck down.

I've tried a bunch of different iron temp settings, and I have no problems using PnP to make PCB's, dunno what to try.

I'm using a taiwaneese 'BB' box.

Any ideas?

-Adam

[spudulike]

I've tried PnP, photo paper, Avery label backing, glossy magazine paper, everything. Best results probably 80% transfer. Touched up with nail varnish/sharpie etc. Still rubbish. Tried etching face down, and applying with cotton bud (q-tip). Ruined half a dozen 1590Bs. Im giving up but respect to those that can 

[DavidS]

I had a similar problem, with largeish regions of the PnP not adhering, but managed to work around it eventually. I think what is happening is that gasses, maybe from the PnP, maybe just heated and expanded air bubbles, are getting trapped between the surface of the box and the PnP sheet, and being all sealed in around the edges, can't escape, so the PnP doesn't stick in those spots. I got the best results by starting to iron on one edge of the surface, working my way across the surface of the box until the entrire thing was hot, with the PnP making contact on 99% of the desired area. I found it helps to move from the middle to the outside as you work across the surface. There were still tiny little spots where it didn't quite stick, but these were pretty small, and I did touchups with nail polish. I went through alot of pieces of PnP to get it to work! But I really like the results.

I'm going to try the photoresist paint method soon, seems like it will be easier, unless there are some unforseen complications...

[MR COFFEE]

Soggy,

Sorry I didn't catch your post earlier. My email's been acting up. 

You can get the double-sided adhesive from Stewart-McDonald

http://www.stewmac.com/shop/Glues,_adhesives/Pickguard_adhesive.html

Works fine.

[MR COFFEE]

Adam,

Don't use the Brillo pad. That's what's screwing up the adhesion. It has soap in it. You can use chemical cleansers, but the final step has to be a dry, no-residue abrasive or you get areas that come up when you peel the backing.

I learned the hard way that a NEW, DRY Scotchbrite pad is the best "final clean" just before you apply PnP when you are trying to get PnP to actually stick to the metal. And DON'T rinse the box or pcb with anything, just blow it off with compressed air to remove any loose dust before to iron on the PnP. Plain steel wool doesn't work very well because it leaves an iron residue and oils (used in the manufacture of the steel wool). You can also get by with a clean NEW sheet of fine black oxide sandpaper (but NOT the "between finish coats" kind - it contains a wax) if you can't get Scothbrite where you live. Most grocery stores here in the States seem to carry Scotchbrite alongside the sponges and such, and it is about as good as it gets.

And one more trick I figured out. You can take a blank sheet of PnP and iron it over the top of your resist pattern (after you've had a sucessful peel), and it will improve the ability of the PnP to resist your echant, which is really helpful it you have longer etch times. It's the only way I have been able to get finely detailed PCBs with 2 oz. copper-clad. It thickens up the resist. And uh, I suppose I should mention, too, that yeah, you peel off the second sheet of PNP before you etch (before somebody tries leaving it on and complains it doesn't work...)

Cheers

[Samy]

I´ve tried with photoresist paint, i usually make pcb´s with this method and it´s a little tricky ! Perhaps i have a bad can! I can´t have a regular surface of photoresist paint, there are alot of times that i have small grains in the surface, that really piss me off because i must touch up or that will come off when is in contact with the acid ...
I´ve tried to etch a box with that method and i had two different results, first try was ok, the second time was a complete disaster ! The acid was too stong and a quick corrotion is not good idea !! I will try next time with PnP...