Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum "sand" blasting action parts, keys, etc

Can someone tell me if glass micro balls are suiteable for the job, or is it necessary to use vegetal material ?

Do you know the name of the product, its size, ?

thanks

I'm using 150micron glass beads at the moment, but would prefer something a bit smaller. To reduce the aggressiveness I turn the blasting pressure down to suit the material I'm cleaning (beech, brass, steel), and also move the part further away from the blast nozzle. Some experimentation is needed..!

Not sure I'd recommend bead blasting keys - you'll eat the wood grain, and probably just push the dirt further into the material....

Great Ady, thanks for the answer.
you re using glass if I understand well.

could there be a lower size ?(I have seen 80-150 microns is it what you use as 150 microns)

how large is the "spray", and your nose ? (2mm is OK?)

no real problems with felts/leathers ? they can be cleaned with air later ?

you said beech; suiteable for keys (epicea, pine, etc) ?

Regards

I'm using a 1/8" (roughly 3mm) nozzle, 50-80psi, and will vary the distance from the nozzle depending on the part I'm working with. For example - Blüthner carriages. Steel spring mounted on a beech body. I generally concentrate on the spring, and let the "overspray" clean the beech. Hope that makes sense!

I'm not keen on bead blasting pine/spruce etc.... The summer growth is so soft that the beads will eat it away too quickly - that only leaves the growth rings behind. It's not very pretty.....

For wooden parts, we use baking soda blasting media mostly, at something low like 25psi. Often using only a glancing stream, almost never at 90 deg.

JI

Thanks, specific for blasting or typical powder ?

Is not it much sensitive to moisture, necessitating specific arrangement not to clog the gun tubing ?
I would be more at ease workinh parts with backing soda than with glass...
Regards

We also use baking soda but you have to be careful because it will leave a non bonding film on parts. So if you are painting something you have to wipe it down with alcohol.

The soda we use is specifically graded as blasting media. It does not clog as easily as the fine glass beads we use for S&s rails.

JI

I have a very small tool called an "air .eraser" It is similar in design to an airbrush. Very gentle and controllable.

Does anyone have a sandblaster that they recommend. The last two I had bought from Grizzly tools just didn't hold up. The sand would bust a hole in the brass nozzle.

Thanks all for the tips

I thought you need to have a ceramic more for glass beads and possibly other (but not corindon or sand)

I suppose the nose is replaced regularly. The tool I am may be buying is having 5 ceramic noses provided.

Regards

MSk, those "air erasers" are probably the most adapted tool, but they seem to be in a trend and much expensive.

As others one need a good air compressed flow.

Is baked soda useable with classical sandblasting equipment ?

What size the nozzle ? any particular method (I mean with a cabin) Then is it possible to use the cabin as the recipe for the soda, and blast outdoor ?

Very dry air, I understand... Hear bad stories with the aspiration clogging for misconception of the original venturi, for instance.

I di not find specific baking soda particles , but i not chase too precisely

Any idea of the size ?

Regards

horror freight carries it. I don't know how expensive it would be to ship a 50lb container to France.

I use the same gun and the same ceramic orifice for all the different media. I think I'm using the 3/32" orifice/nozzle.

ji

If you use a sort of "Pen" it must be gentle, but too gentle is not it (too small, long job)?

Thank you.

Are there concentric tubes to have the beads going up in the gun ? (venturi in the handle of the gun ?)

I did this with baking soda. First tried with a little gun from ebay, but it's not efficient. Doing it outdoors is wasting a lot of powder. So I bought this:

https://drive.google.com/file/d/0B_95UWYosSDIUXJEblJoQWNEcDg/view?usp=sharing

https://drive.google.com/file/d/0B_95UWYosSDIMFlrSFZ5SDNDdnc/view?usp=sharing

It recicles the stuff so it took 10kg to thoroughly clean hammers, whippens, keys, frame, and rail stack. Still 2-3 kg left in the system.

Around 3-4 bars, to avoid removing wood between fibers, or max 6 if you don't mind that, and want speed.

It looked similar to this:

old hammers
https://drive.google.com/file/d/0B_95UWYosSDIN1ZXbG1GekpXYzg/view?usp=sharing

old whippens https://drive.google.com/file/d/0B_95UWYosSDIUlNSRG9OaU55WEE/view?usp=sharing


The results:
new hammers https://drive.google.com/file/d/0B_95UWYosSDIQk5xNmw0ZWhCdVk/view?usp=sharing

new whippens
https://drive.google.com/file/d/0B_95UWYosSDIVHI3eXB3cTduMTA/view?usp=sharing

whippens blast https://drive.google.com/file/d/0B_95UWYosSDIMEI2U3pMMy1xbWc/view?usp=sharing

Blasting erases numbering, so I had to find ways to keep track of that. Hammers off the shank threaded in order on an electric wire. Trays for whippens etc.

https://drive.google.com/file/d/0B_95UWYosSDISnRnMkh6eFZZVUk/view?usp=sharing
https://drive.google.com/file/d/0B_95UWYosSDIc3U4UlI0d3h2Z2M/view?usp=sharing
https://drive.google.com/file/d/0B_95UWYosSDIeWlORUlQbnBPS1k/view?usp=sharing

Everything was blown clean of soda with compressed air, 8 bar. I had mounted a water separator at end of air hose, not on compressor.
You need a big compressor, at least 5 kw motor, 2-300 liters tank, 4-500 l/min. It's possible with less but it's a pain.

https://drive.google.com/file/d/0B_95UWYosSDIV3VvZWpnMGVCS3M/view?usp=sharing

I know, I'm overcompensating

Jinorden....so your whippens...you just blasted them whole....no disassembly ? What about the center pins...will you re-bush and pin or just broach out as need? They look great...thanks for posting the pics. Ken

Great equipment ! I feel very small as I strive to obtain 500 liter at 4bars. (coupling 2 compressors)

I would not have enough space for such equipement anyway. You get them second hand ? you need 380V 3 phases for those sort.
The best I could find in 220 V is given for 700liters at 4 bars, with 4 cylinders and 2 engines.

Ever try the "erasers" ? I do not really see what makes them so expensive , out of the fact that some can be used also with water.

I plan to have a simple "box" for sand blasting, but only if worth and if it works.

The more it goes the more new actions will be envisaged I think.

I have nothing against complete overhaul but it is more expensive than new parts, and centers can present a problem if not rebushed.

I am amaze that the soft cloth do not suffer with soda blasting.
You work from the side (at 30° or so) ? or protect the cushions beforhand ?

the wood is clean but well yellow, I thought it would come more whitened (that said one can always employ some wood whitening agent, to get rid of humidity marks, some are very efficient)

Thanks a lot for the pics .

WHat was the cost of the whole equipment ?

Hi Ken and Olek,
Thanks!

Yes, you do need 380V.
I found it secondhand on swedish "craiglist". I hunted for something like this for 3-4 months. Paid 250 euros, but normally it's more like 700-1000. New it's 3-4k I think, but more modern.

The wood is yellow as it's really old, I think original from 20's. What do you think, it's possible to not have ever been changed? NY M. It was dark brown. But for me it is enough that it looks clean, as I'm not working for a client. I'm moving very slowly, as I don't have great vision and get fed up quickly working with two pairs of glasses on top of each other.
I am not sure what "erasers" are, I suppose some bleach?
About centers, I became quite good with rebushing, but it would be crazy to do 88 whippens and 88 hammers, so I repin if alcohol doesn't fix it or is too unstable. Some had verdigris, so I rebushed them. I try to get 4 swings, not more. The idea is to not obsess over getting it 100% perfect, but close enough. Also, the soda gets everywhere, no need to disassemble in my opinion. But I cleaned manually the place where spring moves, and used B6 pencil, also cleand and polished spring's end with dremmel.

About felt, you can destroy the rest cushions if you let the flow come sideways. Best is to start perpendicular but farther away, like 30cm, and close in watching that the air presses it straight down. It cleans it from gray dirty color to quite nice yellowish white. The other felts, if just going carefully, they hold great if not damaged already.

The frame and rails, I did it with the door open, and lost some but very little soda, as I still was directing it in the box.

About building or buying cheap cabinet with no suction, the problem is you can't see much inside when blasting.
Glad you liked it! And you're right, it's not worth it unless it's your own piano, and you see it as a learning project, as it is in my case.