Faceplate etching tips...need some!

[Govmnt_Lacky]

So... I am going to make yet another attempt to etch an aluminum faceplate. I have only ever gotten 1 to etch decently and that still was not the best 

What I have been doing is cutting the aluminum to size (full face), then I use a green scotch brite pad (under running water) to rough up the etching area along with some Dawn dish soap to remove the grease and oils. Once this is done, I iron on my PnP blue transfer for what seems to be forever 

Here is my problem.... I think the scotch brite is not roughing up the aluminum good enough OR the sheet aluminum I am using has recesses in it. When I do the transfer, I get spotty areas on the plate that just WILL NOT STICK! I use the tip of the iron on these areas but the toner will not transfer. BTW.... I do this same process with FR4 and I never have a problem doing transfers with the PnP.

Should I try sanding with a fine course paper (330 or 400 wet) under running water to rough up the plate more? Could the Dawn be a problem?

Tips??

[gtr2]

How thick is the plate, aluminum type?

The aluminum acts like a heatsink so you really need to heat the plate first before applying whatever media you are using, but I never had good success with the PnP for faceplates, plus it's ridiculously priced.  It also depends on your toner, what printer are you using?

I use a HP laser, a laminator and sterling paper and then reinforce the resist with acrylic paint on the large areas.

It's a challenge either way, but I've had good success (only a few minor pits) with plates as large as 1590DD.

Josh

[davent]

Speculating here... Undulated aluminum? The copper clad is going to be perfectly flat ensuring good contact with the iron, the aluminum maybe not.  Take a marker and draw lines across the faceplate, stick your sandpaper to a perfectly flat, hard sanding block and then sand, you'll probably find areas where the lines are not getting sanded- low spots, need to sand the full face until all the markers lines are removed. Marker it again and resand to check for flatness. Again, i'm guessing.

dave

[madbean]

This is what I would do - Use 220 grit sandpaper or foam block. First sand vertically then horizontally. Repeat. Now cross-hatch sand (diagonally). Finally, clean with Acetone. Pre-heat the aluminum with your iron, then place the PNP down on it. Use the thinnest aluminum you can get away with, I think.

This might help: get one of those flat griddles to apply heat evenly while you iron the top.
http://www.walmart.com/ip/Presto-Cool-Touch-Electric-Griddle/3576547

[Govmnt_Lacky]

Definitely going to sand the plate first. I think there are small recesses in it that need to be leveled.

I can get the PnP to stick pretty well... unfortunately, there were a LOT of spotty areas where the toner would not adhere and quite a few were around the lettering and graphics which made it unusable.. This leads me to believe that it is either recessed areas or contamination. I ruled out the contamination as I use the same process for etching FR4 which I always have good success with.

I use a Xerox laser printer for all of my toner needs. Like I said... No problems with FR4 transfers.

As for the "preheating the aluminum" or using a griddle/pan to warm it. I really dont want to go there because it not only makes it a one-time shot to apply the graphic corretly but it also runs the risk of overheating and having the toner smear 

Im going to try sanding the plate (it is thin aluminum.... maybe 2mm) with some 220 to start and then use some 330 or 400 wet to prepare the surface for good adhesion of the toner.

Will report back with success or failure! 

[Stomptown]

I've done a bunch of faceplates recently with pretty good success. I sand down to 600 grit and I do use PNP Blue. It takes a couple trys but it works pretty well for me. I always tape the transfer to the faceplate so it does not move. Then I place the iron directly to the transfer for about 30 seconds. Next, I remove the iron and run my finder across the faceplate (I protect my finger with a oven mit) to help the toner transfer process. Then I run the tip across the plate with a piece of paper towel between the iron and the plate. Next, I remove the tape from the corners and I place the iron on the faceplate again; this time with a paper towel between the iron and the plate and leave it for a minute-ish. I then remove and run my finger firmly across it agian with the oven mit/glove. Then the tip of the iron across the enclosure. I repeat this process until I am confident all the toner has been transfered. I also run the tip of the iron across it

[Govmnt_Lacky]

Next, I remove the iron and run my finder across the faceplate (I protect my finger with a oven mit) to help the toner transfer process.

Finder??

Could you elaborate on what you mean here?

Thanks! 

[muddyfox]

i kinda get it's finger but i'm not really getting this. you're rubbing the hot aluminum with an oven mitt? won't that smear the toner?

[Govmnt_Lacky]

OK! Finger 

I understand that it will not smear the toner since, by this time in the process, the toner "should" be adhering to the aluminum to prevent movement BUT.....

How does running your oven mitted finger across the PnP HELP with the transfer?

[Stomptown]

The same way that running the tip of the iron across the surface helps it adhere ti the box. If you simply place a hot iron on the surface for a couple minutes and remove the PNP you will find many spots where the toner has not transferred. If you exert pressure to the hot surface via the tip of the iron - or - the tip of your finger helps a lot. I only recently started using my finger tip and it seems to help.

[muddyfox]

And you find that you miss more spots if you only apply pressure with the iron tip? Or is that too aggressive on the soft toner?

[Stomptown]

I was doing a faceplate the other day and adhesion was an issue. I decided to use my finger and it seemed to help out. This is something new I tried out and I am happy with the result. I think the biggest thing is that I know for sure that I am going over the entire box with my finger while it is harder to know with the tip of the iron. I was also able to remove the air bubbles more effectively that with the iron...

[Govmnt_Lacky]

I was also able to remove the air bubbles more effectively that with the iron...

Needle or safety pin??

I know it might leave a tiny hole but that could be covered up with enamel if needed.

I plan to do spot etching... NOT dipping. As long as there is a good transfer near the areas that I plan to apply the Ferric... I am good. Problem is, there is ALWAYS a bad spot near lettering or graphics 

[billstein]

Have you tried using a laminator?

[Govmnt_Lacky]

Well. I have finally raised the white flag of defeat 

I now bow down to you faceplate and enclosure etchers.

Tried 5 different times with 5 different techniques. Sanding, prepping, toners, even different irons. All turn out like garbage!

Maybe I will just etch some FR4 for the faceplate as I have always had good results with copper clad.

Done with aluminum for a while.