This will be a more advanced how-to with using heat transfer stencils to create intricate designs for acid etching.

This is a followup to my very first Instructable on basic acid etching. I won't go over all the mixing and such. Checkout the other how-to for that info.

https://www.instructables.com/id/Acid-Etching/

Etching is a great way to personalize your knife. Maybe with a makers mark or just add some unique design to your boring EDC. Hopefully this provides you with detailed yet easy to follow instructions on how to acid etch your knife. I am still new to this whole etching thing and I won't pretend to know everything or have all the processes perfected, so feedback and tips are greatly appreciated.

FAIR WARNING!!! I can not be held responsible for any damages or injuries as a result of trying this process. (But if you hurt yourself then that means you really screwed it up...)

Step 1: Supplies

Supplies

Ferric Chloride (PCB etch) - Found at electronic part stores and some say Radioshack.
Premixed with distilled water.
Link to Ferric Chloride information
Plastic container
Iron
Tape
Press-N-Peel Stencil transfer - This is what you'll use for your detailed stencil! :D
Link to P-n-P
Etch resist/Stencil - IE. Nail polish, stickers, vinyl, electrical tape, Sharpie marker
Acetone
Cotton swabs and/or Q-tips
Rubber gloves and PPE (personal protective equipment)
Beer (optional and only if you're of age...)

Step 2: Designing and Printing the Stencil

I'm no good with photoshop/editing software so you'll have to look up another tutorial on how to use it!

Basically

Use photoshop to import your design onto a 8 1/2 X11 template
Size the image layer it over a sample picture to get an idea of what your result will be.
I usually print out the image to see if I've sized it properly.
Create an 8 1/2 X 11 black template.
Make the image black and white, flip it horizontally and invert the colors.
This is because whatever is white will end up black. Flipping is very important with lettering.
Everything must be backwards!
Fill up a whole page with numerous images/designs. I personally use the same image at least 4 times in the event my heat transfer doesn't work and I have to try again.
Once the page is created you'll need a laser or toner printer. A photocopier will also work.
Print the prepped template onto the dull side of the Press-n-Peel sheet.

You now have a sheet of one time use stencils!

Step 3: Prep Work

Preparation is the most important step in this whole process. If you don't prep properly the results will be poor and very frustrating.

Disassemble the knife. You don't want to get any acid on the scales, liners, or washers. Try to remember where all those little screws came from and store them safely in a container or magnetic tray. If you don't feel comfortable taking the knife apart then ensure to mask off any part of the knife you don't want to get the acid on.
Clean the blade with acetone. This will provide a clean surface for the etch resist to adhere to. Try not to touch the blade with your bare hands after cleaning. The oil from your fingers will mess with the etch.

Step 4: Applying the Stencil

Now the tricky bit!

I use a bright light to shine through the stencil so I can tell where the design will be. Use some tape to hold the stencil in place. Dull side down!
Use the iron on medium heat to press on top of the shiny side. A flat surface is easier but obviously a hollow grind blade can be done with some patience.
You'll know when the stencil has transferred when the toner is dark and the image visible through the shiny side.
Don't skimp on heat and time! Make sure you are very thorough with the iron, move the iron around and use the tip to press the stencil down.
Rinse the stencil and blade under cool water to set the stencil.
Carefully peel the stencil from a corner and voila!
Use nail polish to mask off the remainder of the knife. Trust me, where ever there is exposed steel you will etch! Front, back, top and bottom. I also cover the back in electrical tape (Learned my lesson the hard)

Step 5: It's Etch-time!

Ready?!

Put on your rubber gloves if you haven't already from mixing the acid. Ensure you are in a well ventilated area. The acid is causing a chemical reaction and there is a vapour byproduct. Do this outside or under a vent/stove hood.

Use a cotton Q-tip to soak up a bit of acid. Apply the acid to the steel in the stencil. Rub the acid lightly into the stencil and you will feel the Q-tip start to "bite" the steel. The tip of the Q-tip will start to turn black as the acid removes some metal.

I have found that short (40 second) dips with quick rinses under the tap gives me the best results.

I do short dips because it gives me better control over the end result. This process also preserves any of the laser factory markings on the blade.

My actual timeline is approx. 40 second bath, 10 seconds in the air, rinse under the tap, 10 seconds in the air, then repeat. If this actual process makes any difference to the end result... I don't know. But it seems to be working for me.

Be careful of fingerprints. When rinsing the blade try not to touch it with your bare fingers You may leave behind a fingerprint mark on the blade.

Step 6: Cleanup and Reassemble

Use nail polish remover or acetone to remove the nail polish and the blue stencil transfer.

It will require a few cotton pads to remove all of the residue. I also use a Q-tip to get into all the nooks and corners.

Put your knife back together and enjoy your handy work!

Step 7: Results

Hopefully this tutorial has helped guide you through the stencil etching process.

Let me know if you have any questions :) Your best bet is to experiment with cheap knives before you move into $1000 customs. No one wants to see a bad etch job on a custom knife!

A few last things to keep in mind.

The concentration of acid will change the etch
The temperature of the acid will change the etch
Different steels react differently to the acid.
Acid is dangerous so close attention must be given at all times
Drips of acid into your stainless steel sink will leave marks... don't ask
The acid is dark orange and will stain your skin and clothing.

Good luck and let me know how your project goes!