Gnawing at Wood with an Air Eraser…

[RoughboyModelworks]

I did an experiment earlier today with the air eraser. I'm finding this tool to be of great use in the shop for cleaning up parts prior to painting and for weathering painted finishes creating an oxidized effect. It occurred to me that by using the eraser with an appropriate grit it might be possible wear away scale lumber to resemble wood that had been eaten away by rot. The piece I tested was a scrap of basswood, 1/4" W. x .040" T. I used Paasché's AEX Aluminum Oxide grit for the test. It worked a treat. By keeping the pressure low and blasting in close proximity to the wood, it was possible to quickly eat away the wood in a controlled fashion. As in real life, the softer portions of the wood wore away first leaving the harder strands. A few quick coats of SilverWood and some dirty Diosol followed by a gentle soda blast to reveal some highlights finished the job. Now only if it were as easy to get a good photograph of it. It was hard (with the rainy weather today) to get lighting that was strong enough to reveal the texture but not so strong as to create a lot of harsh contrast. Oh well, you should be able to get the general idea...





Paul

[Mobilgas]

Looks like rotted wood to me       Craig

[DaKra]

Good stuff! Very convincing miniature wood rot.   What sort of set up do you have and where does the spent abrasive go?   I'm considering getting an air eraser.   

[RoughboyModelworks]

Dave, I'm willing to bet that once you add an air eraser to your arsenal you'll wonder how you got along without it. I've found it to be a very useful tool and am always experimenting with it on different materials.

To the best of my knowledge there are several air erasers on the market. I have used two of them, the Paasché (which I believe is the original) and the Harbor Freight knock-off. The Paasché is by far the better of the two (no surprise there), but the Harbor Freight version works surprisingly well. (I normally don't recommend anything from Harbor Freight apart from zip-ties and storage boxes. Most of their stuff is just crap.)  I use two different grits: the Paasché AEX Aluminum Oxide grit and Baking Soda. I don't worry about capturing the spent baking soda. I just blast outdoors, outside the shop door and let the excess blast blow away. The advantages of baking soda are: it is very cheap, available at any grocery store and is a very fine grit, much finer than the AEX. I'm not quite as wasteful with the aluminum oxide. I hold the part to be blasted inside a large bucket and blast away. The bucket catches the bulk of the excess grit which I can then reuse. You're using very little at a time, so a container of grit lasts a long while. The reservoir holds around 4 teaspoons full. It's definitely not a tool for working on large areas but is perfect for detail work.

The most important thing with the air eraser (especially if you're blasting baking soda) is that your air supply has to be absolutely dry. When I'm blasting, I run three moisture traps in line and have never had a problem, even when blasting in wet weather. The erasers work anywhere from 20-65 psi, though I usually blast at the lower end of the range to avoid cutting too quickly. For blasting work on decals or when oxidizing paint, I usually blast the soda at around 20 psi. Varying the distance between the air eraser and the object gives very good control over the blast effect.

Paul

[finescalerr]

You've achieved a 1:16 Chuck Doan finish in 1:48 scale. Most satisfactory. -- Russ

[TRAINS1941]

Yes the air eraser is a nice add on tool to have.  Great for taking paint off the wood and giving it the CD look.

Jerry

[JohnP]

My gosh another superior technique I've seen on this forum. Superbly weathered and rotted wood appearance. Thanks for sharing!

Another tool for the ultimate modeling workshop. Someday...

John

[eTraxx]

The Harbor Freight air eraser is $19.99 .. which I picked up the last time I was at HF. Now .. I need the abrasive .. and it's a LOOONNNGG drive there. Dang.

[lab-dad]

Ed, mine came with a small container of aluminum oxide.
Also you can use baking soda for finer blasting.
I have heard of walnut shells, wonder if I put them in my coffee grinder if they would then be useful?......
-Marty

[RoughboyModelworks]

Thanks guys... I believe it does show some promise.

Not sure about the walnut shells Marty... you'd have to get them very fine, finer than what's commercially available as a blast media. The blast opening in the air eraser is pretty tiny. Just for the heck of it, I tried some glass beads from my media blaster and they are too coarse for the air eraser. I believe you can also use corn starch for a fine finish. I've also blasted Rottenstone which, in addition to creating a great cloud of dust, does impart a very fine finish.

Paul

[DaKra]

Got my cheapo HFT mini blaster on the way, thanks for the tip, Paul!   Besides the scale model applications, I'll try using it on glass, something I'd been meaning to try for a while.    I've been directly lasering designs into glass, but sandblasting creates a frosting effect with much more contrast.   I suppose I can laser cut masks, and proceed as per airbrushing paint.    If it looks promising, I'll upgrade to the Pasche.

  Dave

[jim s-w]

Hi all

Can you sculpt with this tool?  I am looking for ideas on how to approach something like this?

. The thingie above the gates?

Cheers

Jim

[DaKra]

Wrong tool for that job.   It would be sort of like trying to make that by building up layers of paint in an airbrush, but in reverse!   

Dave