Sand-blasting instead of hand-paper sanding

[Martin Lavoquet]

Hi everyone,

I am working in a Wood company in Vietnam. We have a lot of manual operation for sanding, especially when our wood panel have curved edges or hardly accessible places (such as shapes etc). We mostly use MDF and not plain wood.

I am considering of buying a sand blaster. Nevertheless I think sand is to abrasive (unless pressure can be regulated and blasting radius chosen). Soda seems a better alternative but I think it will accumulate some residues on my panel right ? Basically I would like to use sand blasting instead of using manual operation with sand-paper.

Our process is the following :

Cutting with CNC
Raw sanding (manual and sometime automated for the top/bottom of panels)
Sealer
First layer paint (Spray painting, roller for top/bottom of panels)
Sanding
Second layer paint
Top coat

When using a blasting technology and MDF wood :
- is it appropriate to use it for the raw sanding ? (only for curves edges and hardly accessible places)
- Is it appropriate to use it for sanding after the first layer of paint (won't it remove it) ?

Thank you all, I ll keep you inform with my experiment,


Martin L

[Rick Lizek]

Sandblasting is not an alternative to sanding. It will remove paint and texture your material but you will find out soon enough. Crushed nut shells are often used to remove paint with the least amount of texture damage. Even flap wheels are limited to sanding curved surfaces compared to sandpaper. Contact abrasive companies instead of forums for technical help.

[Martin Lavoquet]

Thank you Rick.

Well, my only problem is to fasten the process of sanding in difficult areas. As i stated in my first post and as you did, sand might be too abrasive. (what abt soda?).
Maybe someone has overcome this problem, sand blasting might not be the most suitable option, there might be a better alternative in order to do that sanding job without sand-paper.

[Rick Lizek]

Giving a picture of what you are sanding would be useful. Been in the business for 40 years and went through profile sanding in the early days with pine and that is the most difficult because the pitch clogs paper rapidly. What you are sanding is easy. There're are companies who can sell the proper product to do the job fast and efficient. We did that kind of research before the Internet with no problem. Any pro trade magazines go to your area. Sandblasting is not the way to go for mdf products based on your extremely sparse product iinformation.

[Martin Lavoquet]

Here is a sample of what we are sanding with sand-paper : twice, once when its raw, and another time after the first layer of paint.
The pictures below are a Dowel and a shaped panel, both after the first paint layer.

I need sanding on the whole Dowel, and sanding on the edges of the shapped-panel.
Both dowel and shapped panels are "hand-sanded" one by one. With a sand blaster, I could blast the whole stack of panel at once don't you think ?

Any suggestion?


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[Rick Lizek]

I think you are way off in that approach. We use a abrasive blasting to texture wood, not smooth it. See www.quickwood.com

[Grant Wilkinson]

Sand blasting the dowel, even if it results in the finish you want (and I don't believe that it will) will be very inefficient. Hand sanding that dowel should take no time at all and will result in a finish ready for paint.

Sand blasting the edge profile will, I believe, destroy the details in it, no matter what you use as a medium. As has been said, sand blasting was never designed to be an alternative to sanding. One thing that you may want to look at is your CNC operation. We do a lot of mdf work on our CNC and the edge results are clean enough to eliminate sanding. We had to tweak the feed rates from those recommended by the manufacturer, and bits dull very, very quickly, but the results are ready for paint. In terms of the sanding between coats of paint, that is tedious, but necessary. I think that sand blasting will end up removing much of the paint that you have applied. After all, you really need just to scuff it.

[Andrew Joiner]

My experience agrees with Rick. Sandblasting will not smooth but erode a texture.

Funny, how the world has changed. When I made a living in woodworking years ago, I would not freely share my "trade secrets". I worked hard at proving my methods and processes. If I had a unique way of saving time or building better for less cost I kept it to myself. The last thing I wanted was to have a competitor win a a bid on a job I was good at.
Today anyone can learn from the internet freely. However,what works in your shop with your tools and materials is still best if tested and proven by you.

[Jeff Monson]

My experience agrees with Rick. Sandblasting will not smooth but erode a texture.



I totally aree. Blasting will not replace sanding, no matter what the media.

[Mike Lysov]

I know it is a very old one. I found it before buying a sandblaster and I did not have too much hope for it.

However it turn out to be much better than I thought.
I have not tried it on paint yet but that thing is very good for cleaning edges of laser cut out pieces.

It does two good things, it polishes them a bit and it removes black stuff quite efficiently. I had a few pieces of 16mm cut outs that had black edges. Under no time(less than 1 minute) sandblasting made them very light brown on the edges, almost the same colour as MDF and they came smooth.

I think all recommendations above are related to coarse sand but I have decided to try sandblasting with a fine sandpit sand which is by the look has very tiny sand grains and it worked very well not to mention the cost of the sand. The shop I have bought my sandblaster from has a bucket of 30/40 grit sand and they are selling it for ridiculous $37 for 3 litres. The one I have bought is a 15-20 kg bag for just $7. It just came wet inside the bag but it dried very fast after I left for one day outside.

I still think that nothing is better that an orbital palm sander to remove residue from the top and the back of cutouts. However if you need to sand edges using sanders or sandpaper it will make the process very slow, you and the pieces that you are sanding will be all covered in black. With sandblasting it is just a matter of seconds and you have clean from black edges and fingers.

And now I know for sure now that if any of my customers says "I do not like black edges of laser cutting" I can always offer them to sandblast edges for just a bit extra.

I want to try soda blasting just to see if it is faster and easier. I would try dry ice but these dry ice sandblasting machines are very expensive,

[Wayne Lomman]

Martin, sandblasting won't give you a smooth surface. It will erode the shapes and give you a textured surface profile instead of smooth. Using it after painting will remove the paint. Soda will not help. It is still individual particles impacting the surface at an angle whereas sandpaper is rubbing across the surface and this is the action that makes things smooth.

Since you are working with mdf, consider changing your finishing system instead of chasing better sanding. The best approach is to use a two part (post catalysed) primer and do your sanding then. It binds up the furry surface of mdf. So long as you have a reasonable machined surface it will be good. You apply a good coat of primer, sand and then top coat. This is less coats than you are doing at the moment. Spray everything as well, it will be quicker and provide a better finish. Cheers

[Jerome Stanek]

for the flat panels I would use plum creek mdf less sanding

[michael langman]

If there was some kind of a soft rag wheel that conformed to the profile, and was charged with a fine abrasive. Just thinking.

[Martin Wasner]

do you use that shape frequently? Enough to justify having a sanding head made to match the profile?

Media blasting will not do what you need it to. At all.

[Geoff Crimmins]

The dowels could be sanded quickly on a lathe. The trick would be in finding a way to hold them on the lathe that would allow them to be quickly mounted and dismounted. I agree that sandblasting typically removes finishes and textures wood, though I haven't tried many different media or air pressures.

-Geoff

[Dave Cav]

I can't believe this zombie thread is still alive.

[Martin Wasner]

I can't believe this zombie thread is still alive.

Dang it! I give people crap about responding to the dead all the time too!

[Mike Lysov]

I can't believe this zombie thread is still alive.

As I said I knew I was bringing up the very old thread. I found it when I was trying to find opinions about sandblasting edges. I read it as "no good", "won't work" or something close but still wanted to try and it was not as bad as others said in reply to the OP.

It may still not work for the OP with painted edges but it is working for me using a fine sand on laser cut out pieces. They are no simple geometrical shapes so sanding them with sandpaper takes a lot of time while sandblasting them takes no time at all. Actually it is so good that it will save me a lot of time in the future.