DIY/Home Photoetching II

[BrassBuilder]

Step 7
The smallest roll that can be ordered is a 24" x 10' roll. Actually, there is a "try it out" roll that is 6" x 3', but unless you are doing just a couple of small parts, you will need the 24" x 10' roll. At the time I wrote this, the cost was $59 shipped. I was also lucky in that my parts are 6" long. I could cut a strip of photoresist, fold it in half, cut it, and then take both halves, fold them in half again and cut them. I used this board to get the width I needed evenly across the width of the photoresist. Also...very important...use a yellow "bug light" to illuminate your room. DO NOT USE your fluorescent of incandescent bulbs. They give off UV and will start to expose the film.


Step 8
Once you have the film cut to size, peel the first layer of clear film off. The resist is actually three layers. There are the two clear outer layers and the blue resist center layer. I pull the clear layer from the side that the resist rolls into you. It will lay flatter than if you start on the side that rolls away from you. I hope that made sense.


Step 9
Spray the resist and the brass with distilled water. I don't know why the distilled water beads up on the brass, but it does. It hasn't hurt anything as far as I can tell.


Step 10
Now position the resist on the brass. I do two parts at once.


Step 11
And start to squeegee the water off.


Step 12
Dry the water as you squeegee it. Once you aren't getting any more water coming off, that should be good to go.


To be cont.
Same bat time. Same bat channel.

[BrassBuilder]

Step 13
Now trim the resist to size. I use a sharp Exacto knife.


Step 14
This is one of those steps that will need to be adjusted. You need to take a hairdryer and dry the resist to the brass. If you don't get it completely dry, the resist will not stick at all. I dry the brass for 3 min. I dry one side for 30 seconds and then flip it over and dry for 30 seconds. I do both pieces at the same time and keep alternating until my 3 min are up. I use an on-line timer to keep track of the time. Keep the brass up so that the heat is not absorbed into any underlying material. I use the hairdryer on high and it gets hot . It is hot enough where I don't want that on my hand for more than a second or two.


Step 15
Once the resist and brass is dry, insert the brass into your mask. The way I do it is to draw my parts out in TurboCad, print them on overhead projector material and then tape two of them together to make an envelope. I use alignment marks in the corners to get everything lined up perfectly. I then tape two of the edges together. You only need to do this if you etch from both sides. Etching from one side is considerably easier. I cut my brass just a tad bit bigger than my mask. That way I can tape the long side and lock the brass to the clear sheet so it won't move when it gets flipped over.


Step 16
Expose the artwork for 3 min. I use one of those halogen construction lamps for the exposure. I took out the clear face plate as that had UV protectant on it. I think there is a pic of the gizmo that I use in the other thread. The glass is two sheets of 1/4" thick glass. Make SURE that it is not UV glass.


Step 17
I cut through the tape that I used to hold the brass in place and remove the brass from the mask.


Step 18
You should see a pretty good burned image now.


Stayed tuned for the next exciting chapter!

[BrassBuilder]

One last picture. Here is the gizmo I built.

[BrassBuilder]

Step 19
Now it is time to pull the second layer of clear. Using a piece of tape, grab the corner of the clear and just get it started to pull away. Once it is started and you can see it is not pulling the resist up (if it does, try a different corner), yank the clear off as fast as you can. DO NOT DO THIS SLOWLY! Fast is the word here. Every once in a while I get one that the resist did not adhere to the brass and you can either touch it up with a marker or salvage what you can. I've done both.


Step 20
Place the brass in a container of soda ash. I mix up 10g of soda ash with 1 liter of distilled water. A liter of distilled water is 4.25 cups. I use a kitchen scale to measure out the soda ash. I leave it in the mix for 1 minute. This time is critical. If you leave it in too long, the resist will soften and peel off. Been there. Done that.


Step 21
After taking it out of the soda ash mix, rinse the part off with tap water and use a brush to strip away the resist on the bare metal parts. After I get this done, I can take my fingernail (what I have left since I bite them off), and actually feel the grooves in the resist along the length of my part. It is also a good idea to use latex gloves during this stage.


Step 22
And then dry the brass. First with a paper towel...


Step 23
...and then with the hairdryer. You will be able to feel the resist go from sticky to not sticky.

[BrassBuilder]

Step 24
Once that is done, throw them under the lamp again for another 3 minutes. This helps "set" the resist.


Step 25
Before you put the brass in the etchant, correct any mistakes with a permanent black marker. In this case, I only had one corner that needed filled in. I've been getting pretty good results now that I've done about 30 of these


Step 26
Here is the setup I'm using for clamps. These are all plastic. I can do two at a time. I have a bigger tank that I can run four at a time, but two works for me. I quit using the ferric chloride and now I use a mix of hydrogen peroxide (2 parts) and hydrochloric acid (1 part). You want the 3% hydrogen peroxide and the 31% or so of hydrochloric acid (muradic acid). When you first mix it up, it will be clear. As you run brass or copper through, it turns green.


Step 27
And in the etchant


Step 28
Upclose shot.

[BrassBuilder]

Let's finish this up. Comments are welcome.

Step 29
I'M MELTING!!!


Step 30
After it is done etching, run the part under the tap water to rinse off the little bit of etchant left on it.


Step 31
And toss it in a lye mix. I put maybe a tablespoon full of lye with a liter of water.


Step 32
And rinse again.


Step 33
Dry the parts and you are ready to use!


The end

[BrassBuilder]

When I first started experimenting with photoetching, I tried to cheap out and did the photo paper and an iron process. Google it and you will find all kinds of info on it. This gave so-so results. Then I switched over to press and peel blue. This was better but still not what I wanted. The problem with both of those techniques is that it was harder to do double sided etchings. I then switched to the photoresist method but bought my resist from China. This worked much better, however, the China photoresist was all over in terms of quality...even from the same supplier. I then switched to this Puretch resist and once I got the technique down, I have been extremely happy with the quality of the etchings. I want to try some stainless steel and etch some car trim or emblems and see what happens.

I hope you found this somewhat informative.

Thanks for reading.

Mike

[Tony]

Great results from your work, very informative, going to have to try itThanks for your time to write this up

[BrassBuilder]

Hey Tony! Thanks! I hope it saves you some troubles. I've been messing around with photoetching for a couple of years now and I thought I would post this to save someone some hassles. Some people have pretty good luck going the cheaper methods, but I was never really happy with the results.
Mike