Etching pattern welded steel (Damascus)
Etching pattern welded steel (sometimes called Damascus) was a rather tricky process. The first time I tried it, it took 5 attempts before I was happy with the results. I have just finished 2 more Damascus sided planes and am pretty confident that I know what I am doing now.
The above photo shows the set-up.
B) Ferric Chloride (the etching acid)
C) Hot water rinse bucket
D) Neutralizing solution bucket
E) Baking Soda
F) measuring cup
H) glass 9"x9" cake pan
The steel sides of the plane are sanded to 600 grit. This is way finer than I typically go, but if the surface is not really smooth, the serrations in the steel left by a more coarse paper will be visible - even after etching (learned this after round 1:)
The challenge with etching a plane is the fact that you have infill material (in this case, Ebony) touching the steel that is to be etched. Normally, a knife blade can be dipped in to the various solutions - which happens very quickly and more importantly - the coverage is consistent. On a plane, the various solutions need to be brushed on which makes it difficult to get an even etch. As the solution runs down the sides of the plane - the etch rate changes accordingly. I could not think up a way to cover the bronze lever cap or protect the Ebony sufficiently to dip the plane.
Here is the process.
Use the Acetone to clean the steel surface to remove any wax, oil or fingerprints. This is pretty critical as anything on the surface of the steel will retard the etching process and it will be visible!
I mix the Ferric Chloride with distilled water - 50/50 - one full measuring cup of each. I dump this into the glass pan.
I boil a kettle of water and put 1/2 of it into the rinsing bucket and the rest into the neutralizing rinse bucket - along with a bunch of baking soda. I don’t have a measurement for how much... just a little pile at the bottom of the bucket.
The three photos above show the etching process. This took about 20 minutes to do each plane. I was brushing the Ferric Chloride solution onto the sides being as careful as I could not to get too much on the blue tape or the bronze lever cap. I did not worry about getting any on the sole as this would lap out after the mouth was filed. The 01 tool steel (the sole and the cross pins) are affected by the etchant as well - but they turn a pleasant dull grey. After about 10 minutes of constantly bathing the sides in etchant, I take a piece of 2000 grit wet/dry paper and wet sand the surface of the sides. This removes the black crud (my scientific name for it) and exposes fresh steel to be etched. You have to be very careful to sand evenly - right up to the edge of the tape - or the etch will not be consistent. Then re-apply the etchant for another 10 minutes or so until it looks like what you are after.
At this stage, you will feel like a hero because the sides will look amazing. This next step is often where the wheels fall off and you will want to chuck the plane out the window.
Once you are happy with the amount of etching - you have to rinse off as much of the etchant as you can and then neutralize it. And fast. I use a second clean brush and warm/hot water to rinse off the etchant and then immediately rinse that with the baking soda solution. This sounds easy, but as the water recedes off the sides - rust usually appears. The best solution I found to keep this at bay was to use a hair dryer (not the one on used for the bandsaw) and remove the water as quickly as possible.
NOTE: If you do not pre-rinse the etchant off, there is a rather foamy reaction between the full strength etchant and the baking soda solution.
Here is a shot of the neutralized and dry plane. Note how grey everything is. This will darken as soon as you put something on the steel to protect it from rusting. I used WD40 and then a coat of paste wax.
The finished XSNo.4D
The finished SNo.4D and a few shots of the pair.
I need to re-thank my friend Brian Buckner who was a huge help last time I did this. I had a print out of his email instructions with me which were once again a great help. And if anyone else out there has any suggestions about how I might improve this process - I would love to hear from you.