Polishing and etching: when and how?

Croccifixio · 3rd September 2015, 04:42 AM

Good day to you all. I posted recently about my first Moro Kris (http://www.vikingsword.com/vb/showthread.php?t=20420) and have begun restoration work on the blade while I take my daily lunch.

My question has been asked previously, but I could find no clear guideline on polishing old blades. Specifically, the state of preservation of this blade is good, apart from the active rust spots. The surface is quite smooth and doesn't have scratches that I would normally polish and buff out. However, when I removed the active rust, the steel near the spots shone brightly and contrasts the subdued hue of the rest of the blade. So I'm in a bit of a quandary: should I just polish the whole thing and etch it in warm vinegar? Or do I leave the blade as is?

Additionally, I am loathe to take sandpaper to this blade, as an uncle who also collects told me that sandpaper (even high grits) ruins the patina and devalues the antique. I read here that Spunjer (I think) uses 600-1000 grit to polish, and he makes the most remarkable restorations. So should I just ignore my uncle?

Thanks again, everyone! I'll attach pictures of the blade's current state in a few minutes.

Ian · 4th September 2015, 05:01 AM

Croccifixio:

You will find differing opinions about how best to polish a blade. I think most of us use high grit sandpaper so as not to scratch the surface. I start with nothing coarser than 400 grit and work up from there using progressively finer grits.

Be careful with what you use to etch the blade. Read the forum posts carefully and get an idea of what others use. And remember that each time you etch the surface you will create a little roughness to the blade, so you don't need to have a mirror polish on it before etching. In fact, I have found that if the surface is very smooth you can get droplet formation from surface tension which can give an uneven etch if left to stand. Any oil or grease on the blade has the same effect, so make sure you remove any oil/grease before you etch. I use rubbing alcohol (isopropyl alcohol) to remove any residual oil/grease.

I suggest that you start with cold and relatively weak etching solutions and work your way up until you achieve the effect you want. Highly acidic solutions can damage the blade by etching deeply, so start low and work up--you are not trying to emulate the finish on a keris.

There is a lot of information on these pages. But much of what we do comes down to trial and error. Fortunately, if you don't like the effects of a particular etch, you can again polish the blade and try something different.

Ian.

Croccifixio · 4th September 2015, 06:53 AM

Quote:

Originally Posted by Ian

Croccifixio:

You will find differing opinions about how best to polish a blade. I think most of us use high grit sandpaper so as not to scratch the surface. I start with nothing coarser than 400 grit and work up from there using progressively finer grits.

Be careful with what you use to etch the blade. Read the forum posts carefully and get an idea of what others use. And remember that each time you etch the surface you will create a little roughness to the blade, so you don't need to have a mirror polish on it before etching. In fact, I have found that if the surface is very smooth you can get droplet formation from surface tension which can give an uneven etch if left to stand. Any oil or grease on the blade has the same effect, so make sure you remove any oil/grease before you etch. I use rubbing alcohol (isopropyl alcohol) to remove any residual oil/grease.

I suggest that you start with cold and relatively weak etching solutions and work your way up until you achieve the effect you want. Highly acidic solutions can damage the blade by etching deeply, so start low and work up--you are not trying to emulate the finish on a keris.

There is a lot of information on these pages. But much of what we do comes down to trial and error. Fortunately, if you don't like the effects of a particular etch, you can again polish the blade and try something different.

Ian.

Thanks Ian. I cleaned up the blade as best I could with warm soapy water, alcohol, and dishwashing liquid. Then I tried the warm vinegar etch for 10 minutes. Neutralized with baking soda slurry and cleaned it up with dishwashing liquid and a bit of car polish. Worked really well, and I like the kris even more now! Instead of that yellowish tint, it has a whitish-gray palette which I like more.

Although I have learned my lesson, and will not do this on an older kris with more value (the initial reason for etching was that after removing the active rust, the shiny steel shone underneath and made for a pretty bad contrast to the yellowish patina).

David R · 4th September 2015, 09:14 AM

If you are dealing with localised rust spots or pits you might try a Glass Fibre "pen", a friend of mine swears by them, and I have just got one to try out.

3rd September 2015, 04:42 AM	#1
Croccifixio Member Join Date: Dec 2014 Posts: 33	Polishing and etching: when and how? Good day to you all. I posted recently about my first Moro Kris (http://www.vikingsword.com/vb/showthread.php?t=20420) and have begun restoration work on the blade while I take my daily lunch. My question has been asked previously, but I could find no clear guideline on polishing old blades. Specifically, the state of preservation of this blade is good, apart from the active rust spots. The surface is quite smooth and doesn't have scratches that I would normally polish and buff out. However, when I removed the active rust, the steel near the spots shone brightly and contrasts the subdued hue of the rest of the blade. So I'm in a bit of a quandary: should I just polish the whole thing and etch it in warm vinegar? Or do I leave the blade as is? Additionally, I am loathe to take sandpaper to this blade, as an uncle who also collects told me that sandpaper (even high grits) ruins the patina and devalues the antique. I read here that Spunjer (I think) uses 600-1000 grit to polish, and he makes the most remarkable restorations. So should I just ignore my uncle? Thanks again, everyone! I'll attach pictures of the blade's current state in a few minutes.

4th September 2015, 05:01 AM	#2
Ian Vikingsword Staff Join Date: Dec 2004 Location: The Aussie Bush Posts: 4,194	Croccifixio: You will find differing opinions about how best to polish a blade. I think most of us use high grit sandpaper so as not to scratch the surface. I start with nothing coarser than 400 grit and work up from there using progressively finer grits. Be careful with what you use to etch the blade. Read the forum posts carefully and get an idea of what others use. And remember that each time you etch the surface you will create a little roughness to the blade, so you don't need to have a mirror polish on it before etching. In fact, I have found that if the surface is very smooth you can get droplet formation from surface tension which can give an uneven etch if left to stand. Any oil or grease on the blade has the same effect, so make sure you remove any oil/grease before you etch. I use rubbing alcohol (isopropyl alcohol) to remove any residual oil/grease. I suggest that you start with cold and relatively weak etching solutions and work your way up until you achieve the effect you want. Highly acidic solutions can damage the blade by etching deeply, so start low and work up--you are not trying to emulate the finish on a keris. There is a lot of information on these pages. But much of what we do comes down to trial and error. Fortunately, if you don't like the effects of a particular etch, you can again polish the blade and try something different. Ian.

4th September 2015, 09:14 AM	#4
David R Member Join Date: Jan 2011 Posts: 1,079	If you are dealing with localised rust spots or pits you might try a Glass Fibre "pen", a friend of mine swears by them, and I have just got one to try out.