Using blasting for inlay etchings?

[eastshores]

Just a thought rolling around in my mind.. if I were to get a piece of metal laser cut for my particular design, I was thinking it could be clamped to a headstock or finger board and then sand blasted in order to etch the inlay?

Obvious issue with this would be controlling the depth, but I suppose you have some head room with things like mother of pearl where they can be close, and then sanded down to finish. Is this a thing?

[Ivan Kelsall]

I have to admit to being puzzled by your terminology - ''etching the inlay'' - the inlay being the material which you insert into a recess cut into the fingerboard. However,i think i got your drift.
You want to have a metal sheet (blasting shield) made with a cut-out in it in the shape of your inlay (mother of pearl etc.),clamp it to 'wherever',then sand blast the area inside the cut-out to remove the wood ?. Yes,it could be done,but the resulting recess would be far from useable.The corners would inevitably be rounded & the bottom of the recess would need cleaning up with either a cutter or a sharp tool (scalpel). There's also the possibility of 'undercutting'.That's where the sand blasts away at the wood underneath the metal shield & you end up with an oversized recess,with the bottom of the recess wider than the top.
I've never done any inlay work myself, i do know many people who have,but i do know a bit about 'blasting' in it's many forms.It's a common engineering method of either removing unwanted material (usually corrosion) or for preparing material surfaces for further treatment such as protective coating. From that standpoint,i believe that sand blasting, while it will remove material,it's not precise enough for your requirements.Better to use the tried &tested methods of routing or removing the wood with small tools,
Ivan

[HoGo]

It may work somewhat but there are even more drawbacks. Wood with grain of different densities will erode unevenly, softer parts will go deeper, theough this probably won't be factor with ebony or such. The scaring thing would be instrument covered with the fine particles. You can cover it but some will inevitably get in the tight spaces and will need to be cleaned VERY thoroughly before finishing. some of the particles may get stuck in the wood and more sanding will be required to remove it.

[MikeEdgerton]

I have often wondered about doing this for metal "etching" on banjo parts and such. I always look at the bead blaster material at Harbor freight and wonder if it could be done so you're not alone in the question.

[PlaneSimple]

I have sandblasted for many years in the stone industry..and have thought about the same for inlay. I believe that, with small enough particulate, you could achieve consistency, however the effort to mask off the rest of the instrument effectively and glue the resistant mask (metal as you mention.. or rubber as used for blasting stone monuments), and gear up with respirator, hearing protection, and eye protection.. as well as insuring a very dry compressed air supply.. I have decided it is not worth the effort. I believe that you would be better off with a light colored ink stamp (maybe ultraviolet) for a reusable design and then dremel the image.
If you were really in production.. perhaps laser etch would be the way to go. Sand and air is a huge awkward mess.

Sandblasting a design into metal is bettered by chemical etching.. dutch mordant/acid.. that is much easier.

[eastshores]

Sorry about the terminology - I was going to go back and edit it after I read it.. but I figured my second paragraph would clear it up. Oddly enough though, this technique would probably work to create relief designs in mother of pearl better than what I was asking about!

Thanks for the replies. Really good point regarding the grain of the wood. I also thought of the issue of it rounding out beneath the template.. that's a no-go since you can take wood out but not add it back and maintain the highest quality inlay work.

My local custom wood place features laser etching for wood. That would be another thought but I'm guessing that process must burn some of the surrounding wood so it's probably still done by hand for a reason.

[Timbofood]

My dad used to say:"You can tie you horse up to the Queen Mary but, why would you want to?"
That is not meant as a slam really, it's like so many ideas I come up with, the theory is cool but, the set up is so much more involved it usually is better to use the original concept.
Like a low pressure, steam powered rotisserie. Interesting idea but, I would probably blow the thing up and scald myself beyond recognition!
I have seen some truly beautiful sandblasting work though and I get the idea.

[billhay4]

Many of us test thoughts out loud first. I get accused of all kinds of stupidity because of this, but it's really just processing ideas. That's what this struck me as.
I have often admired sandblasted wood art objects with their topographical maze of hard and soft grain area. I have wanted to try it myself, but the equipment, etc. seemed daunting. I'd like to see it on an instrument.
Perhaps it would work better if you sandblasted all the wood around a logo, rather than the logo itself.
Just thinking out loud.
Bill

[PlaneSimple]

I also thought of the issue of it rounding out beneath the template.. that's a no-go since you can take wood out but not add it back and maintain the highest quality inlay work..

The fluid (and air/sand) dynamics of sandblasting will cut to the interior.. it should not undercut unless cutting deeply. As an example, sandblasting a letter in stone will eventually create a v shaped cut (unless it is a very large letter).. further blasting will create an ever expanding hollow at the bottom of the cut.. the worm as we called it.. which we would intentionally do to create natural contrast.
The bigger problem with sandblast is lifting/blow-off of the resistant mask.

[thistle3585]

I have a blasting shop that does very fine glass etching up to large signs. This is very possible using a photoresist mask material. I have blasted a number of materials similar to MOP. There are some limitations on how fine of a line you can engrave. I use 180 grit silicon carbide in my booth for doing small projects. We charge 65 cents per square inch to engrave something and have a $12.75 minimum charge.

Laser engraving is an option but it doesn't really work very well with MOP. It burns the edges of the shell. I do all of my inlay work with a laser and the MOP and abalone is actually laminated on to a backing so it isn't as thick and dense.

Left to right is laser etching on MOP, follwoed by laminated abalone and laminated MOP and maple. All of these were done on a laser including the pocket in the headstock which is shown with the pocket cutout for the name Lauren. The mud flag girl TR cover is sandblasted and filled with white enamel. If someone wants to send me a piece of MOP then I'd be happy to sandblast something on it for you to see how it comes out.

[Timbofood]

Thanks Bill, I thought I was the only one who simply ran the ideas straight out of the mouth!
It often gets me in "interesting" conversations, some much more entertaining than others. The "Shoot from the hip!" Projects can sneak up on you, like my new bench. (See builders section, not a whit of mandolin content but, shooting from the hip)
Thistle, I have seen some pretty amazing glass blasting but, WOW! That's pretty cool stuff, how delicate can you get with "line art"? I'm not looking to have anything done right now but, this is sure stored in memory bank for future reference.

[bradlaird]

I remembered hearing of this idea before and racked by brains for a few minutes and remembered. Cutting inlay recesses by sandblasting is mentioned in the back of Earl's banjo book "Earl Scruggs and The 5-String Banjo", 1968. I remember reading it way back in the 70s and thinking "Huh? Sandblasting?" but I guess it worked for Burt Brent who wrote that "how to build a banjo" section.

My only experience with sandblasting an instrument was in college. Somebody gave me a cheap import fiddle that looked like it was dipped in plastic. (It might have been!) I sanded and scraped until I was blue in the face and barely made a dent in it. So a buddy of mine took me down to the tractor shop and we blasted it off. A little stain and it looked 100 years old. Still sounded pretty bad but made a better lookin' wall hanger.

[Ivan Kelsall]

Brad - I remember reading that going back a long time & i thought that it was a poor idea then. I think that for the OP's purpose,it's an even worse idea now,
Ivan

[thistle3585]

Tim,
There isn't much of a minimum line size when frosting glass where you really aren't going very deep. If you want depth in order to do a colorfill then you need to be about a one point line. Another option is to do a reverse etching. You could coat the entire piece in black enamel then blast/strip the color off where you don't want it. The pockets I cut in my headstocks to receive the inlay are twice as deep as the inlay. I then flood it with super glue so that when I do my finish sanding I don't go through the laminated shell veneer. I'm actually sanding the clear super glue down instead. You could do that same approach if you were going with a reverse etching. Just need to make sure your colorfill is compatible with your glue.

I've stripped lacquered wood products in my blasting booth. The key is very low pressure and stop before you get to the wood. You'd still need to finish the job by hand sanding. It doesn't work on poly finishes.

[Timbofood]

I knew that the glass work is really "shallow" compared to what you've done, thanks for the little tutorial.
I can imagine, that the knowledge of just when to stop comes with a bit of practice. I don't think that is a project I will be undertaking soon. Very cool to see what folks are doing though.

[belbein]

Have to admit that I didn't read everything above because I'm late to get to the gym. But in terms of etching: you can use a fine "etcher"--anything from a needle to a dental pick to an Xacto blade--to etch most inlay materials. Even metal. I particularly use it when I want to get a shadow or 3D effect.

There's a great site on the internet somewhere, where an amazing artist demonstrates "scrimshaw." That's what the "etching" you're talking about it. And yes, you can do scrimshaw on your inlays. I thought I'd posted it before (search "scrimshaw") but I'll try to find it and post it again.

[PlaneSimple]

There is no cheap way to start sandblasting with control. Before spending money on a Harbor Freight blaster, realize that there is a HUGE $ difference between a blaster (actually mix-valve) that is designed for accurate flow and those consumer grade models (which may be great for stripping rust etc.)