Sandblasting

[Clemens]

Could some of you share how to sandblast a turning with a prominent grain pattern. I would like to create texture by removing the softer portion of the grain, and leave the harder portion. I'm thinking of ash, for example, but I'm sure there are other, perhaps better, woods for this purpose. I'm not even sure what equipment I would need. I'd appreciate any discussion of general sandblasting in woodturning. Many thanks.
Dale

 

[John Jordan]

Ash is ideal for this, as is any ring porous wood. You might start experimenting with wire brushes, first. A lot of similarities in the effect, and way cheaper to start. Sand, brush, sand etc.

Clean dry air with a good sized compressor is a start for blasting. Not sand, but crushed glass, aluminum oxide, glass beads and others can be used but all are different to some degree.

TPtools.com used to be a good resource on requirements and equipment, plumbing etc.

John

 

[Robert Raess]

My experience,has been that you need a 2 stage compressor,and they are big and pricey.Waiting for the compressor to recover can be a pain+peak power may only be a few seconds.I talked with a friend of mine that has at least a 60 gal single stage.He said he just has more volume but his peak is also short lived.I agree with John,wire brush is low tech and quite effective.where it falls short, is if you wanted to plant some rubber cut-outs on the turned pc. and blast all around the uncovered areas..harder to achieve with a wire brush...Rob

 

[Dick Sowa]

Not quite what you were asking, but I had some really good results with a different approach. Although it was with some flatwork I was doing. I used a propane torch, and singed the entire surface pretty heavily. Then took a wire brush to it (like John suggests) and the burnt soft parts disappeared in an instant. What was left was a gorgeous surface with highly accented grain. I was working with redwood, but the same result can be achieved with a lot of hardwoods as well.

 

[Clemens]

Many thanks. As suggested by John and Robert, I need to try the wire brushing first. I have small cheap brass, steel, and bristlle brushes, sold in a pack. Do I need something bigger and of what metal? I also have a single stage compressor with a 60 gallon tank, but from what has been said, it won't really do the job (if I understand the "peak" comments). I thought perhaps I could buy an inexpensive cabinet, but I suppose I'd be throwing my money away. I want to try Dick's scorching technique. I do know that in scorching a hollow vessel that too much heat will cause it to crack. Experimenting with all ideas seems to be my best bet. Again, thanks, and if you or anyone has any suggestions they would be most welcome, helpful, and appreciated.
Dale

 

[Robert Raess]

Wire brush

I prefer to use the little pack of three:steel,brass,plastic.Altho all can be used, it is the little 4" steel that i like for affect+texture..as well has if i'm holding a pc. in my hand a big 12" long wire brush is too unwieldy and the gauge of bristle is too stiff.I also have an assortment of steel wire wheels i put on my drill press..tho i caution you that it does grab but with anything you develop a technique and it gets easier.As far as the compressed air.."peak" to me , is those few seconds where your compressor is putting out peak pressure of say 100-120psi..but it's all down hill from there.The sandblaster uses up alot of volume of air and when that drops so does the peak air pressure.Scorching is fun,and you can sneek up on the effect..almost using it like a paint brush,every time you make a pass a little darker.....Rob

 

[john lucas]

I have used the burn and wire brush method. It works well but is different than sandblasting. Practice first. you get different results based on the grain direction and which way you brush. Now hard the bristles are and even the size of the brush to some extent. I probably have the same 3 brushes you have. Bought them at Harbour Freight. They are somewhat soft and tend to just clean up the surface and add a slight texture.
I have a steel brush like you buy at the hardware. It tends to cut too much and leave scratches in the hard wood. I clean those up with a softer brush.
Wire wheels work well but it's hard to describe how hard or soft the bristles need to be. After seeing John Jordan's demo many years ago I stared buying them whenever I see a good sale. I probably have 6 or 8. 2 of them work really well.
I have only done sandblasting once. I bough a gun from HF for $20. I used some white sand I already had. I took it outside and put the piece in the open end of a plastic garbage bag. I have one of the 30 gallon cheapie compressors. It works. You have to squirt a little and let the compressor recycle. You need lots of protective clothing and of course a mask. My gun clogged often but wasn't too hard to clean out. for a one off piece it worked. If I was going to do it often I would definitly get some info from the pros and buy a better system.

 

[John Jordan]

The Harbor Freight brushes aren't very good-not much wire in them. You can buy small stainless and brass brushes from Enco, McMaster Carr, local welding suppliers would have them. The small stainless are about right for ash, some brass brushes may work on some woods. I have dozens of brushes of all types bought all over the world-I'm always looking. I have bought plenty that aren't much good. Look around and experiment on scraps or junk bowls.

You could do some blasting with that compressor, but you have to have DRY air-I did a fair amount with one of those before I got my current, large one. Let it rest, too. I only use 50-60 psi most of the time.

John

 

[Clemens]

Thanks, John. I've admired your work for years. I just put a Sears in-line filter on my compressed air system. Not sure how well it works yet, but hopefully it will keep the air dry enough. To try sanblasting without a cabinet, and working out doors, would anyone recommend an abrasive. I live in the "Sandhills Area" of NC so there is plenty of plain sand, and whatever abrasive I use won't harm the field behind my shop.
Dale

 

[John Jordan]

Sand is dangerous-the abrasive media suppliers won't even sell it, and you would have to figure ways to sift/screen it etc.

John