I have been thinking about how to get certain wear, chipping, fading and weathering effects for my small scale boat project.....this reminded me of a discussion years ago with Chuck Doan who had tried sandblasting to age and grain his wood, and a recent discussion on the Terrrapin group re. etching the surface of certain materials with an "air eraser" to get better paint adhesion...........
Sunday I was wandering through my local "Harbor Freight" tool outlet, when I came across their "Air Eraser", on sale for $29 (Paasche also makes one that is around $60).....I couldn't resist. (the box also includes an air hose with moisture trap, a wrench, and a holder)
(https://www.finescalerr.com/smf/proxy.php?request=http%3A%2F%2Fhome.earthlink.net%2F%7Erbadesign%2FAirEraser.jpg&hash=f46788523a37f38694b749aee949731e4f326c64)
Just to see how the eraser functioned I decided to give it a quick test run (I had no specific look or effect in mind when I did these.....just playing around). Instead of using the "sand" they sell for the eraser, I used common Arm & Hammer baking soda.
These are 3 pieces of scrap stripwood that were originally stained with silverwood, and painted with Tamiya acrylics (for scale, the middle board is about 5mm wide).
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This is a 1/35 Opel Blitz cab roof, the white was painted over a layer of Dunkelgrau, and hairspray (this was a left-over test piece for experimenting with the hairspray method).
(https://www.finescalerr.com/smf/proxy.php?request=http%3A%2F%2Fhome.earthlink.net%2F%7Erbadesign%2FErasedRoof2.jpg&hash=3a4525686b77c513b0b9ee34379ef58fea718c0e)
Another view of the entire cab roof.....on the green side you can see where the air eraser was used to fade/wear through the green paint which had been applied over the white (you can also see where I held it too long and the plastic base shows through)
(https://www.finescalerr.com/smf/proxy.php?request=http%3A%2F%2Fhome.earthlink.net%2F%7Erbadesign%2FErasedRoof1.jpg&hash=4d19d363f4b825560b093a2318e50be310752506)
...anyway....far from perfected...but maybe something to think about or possibly try as another tool in the weathering arsenal.
NOTE: When using this tool....do it outside...it's messy...and wear glasses.
Marc
One interesting thing to point out on the last image of the roof. Note the difference in the chipping/wear effect. The white paint at the right was applied over a layer of hairspray, while the green was painted directly over the white (and the white under the green was agian over hairspray). You can see that the [aint over the hairspray has a different, more flakey, wear/chip while the paint-on-paint gives a more subtle faded transition/wear/chip.
On the picture with the wood, the effect will vary depending on how thick the layer of paint is. The top piece had the thickest application, and thus appears more peeling and flakey....the wide board had a fairly thin/washed coat this the wear pattern is different, and more paint stays in the grain.
The borrom piece had about a med amount of paint....but I used high pressure and wirked real close, as I wanted to see if what would happen......could one make the wood look rotten/decaying.
Marc
Marc , on the wood parts how long did the paint dry before you did the erasing?
Gordon Birrell
Gordon,
Those came out of my scrap box, so they were probably painted over a year ago.
Marc
AWESOME!!!!!!!!!!!!
what kind of pressure(s) were you using?
-Mj
Marty,
I think it was around 50-55 lbs........I didnt really look too hard.
Marc
I've had one of those for years but it sits in an unopened box. After seeing the results you have gotten Marc, I will be digging it out to experiment with. Thanks for the motivation. Some very nice effects.
Cool effects. I'll have to look into one of those.
John
I acquired an industrial bead blast cabinet some years ago. It's been interesting experimenting with different media to achieve textures and paint wear. Very fine glass beads will make a machined brass scale part look like it was sand-cast. Walnut shells (yes, those are commercially available for cleaning delicate parts) will burnish painted surfaces making them look worn, but not worn through. The only drawback to the cabinet is holding on to small parts with the heavy rubber gloves. If I lose my grip, and the part can pass through the 1/2" holes of the cabinet's working surface, it gets sucked through the dust extraction blower's impeller. They're often a bit worse for the wear!
Mark
I picked up one Saturday - mine was only $25.00!!!!
;D ;D ;D ;D ;D
Can't wait to use it!
Thanks for the tip Marc.
-Marty
Mark, when blasting small parts, tape a piece of woman's stocking over the exhaust to catch them when they go flying.
The trick is to get the stocking off the woman. I'm sure Uncle Russ will help.
John
Ha ha... yeah ;)
I've had one of the Paasche units for years... great little tool. I've also been using a bead blast cabinet for many years. It's a great way to remove paint from previously painted brass models and prep finished models for new paint. I've also found it very useful for cleaning up 1:1 motorcycle parts for finishing or powder-coating though you do need a fairly high-capacity compressor to be productive. Can't imagine being without it in the shop now.
Paul
Don't see many woman wearing stockings any more. Slacks seem to be the uniform these days! :-\
With a 2 hp blower motor, the air flow is too great for a fine stocking, but Chester's suggestion got me thinking about lying a sheet of fine screen on top of the perforated work plate. That will keep wee parts from falling through the plate to the bottom where the dust extraction hose connects. I have a 25 hp air compressor to run the 175# pneumatic forging hammer, so feeding the blast cabinet is a cinch. Can airbrush all evening without the compressor running once!
Mark
I ordered one. $25 from Harbor Freight. Ordered three different kinds of media so I can experiment. I think it also might be good for cleaning up soldered parts.
John
I do believe you're going to love this tool John. It can do a super job cleaning up soldered parts and assemblies. It does have a very small cutting area though so it's not very practical for cleaning up large parts or areas. As far as media, there are 3 different I use for different applications. In all cases, your air supply has to be absolutely dry for the eraser to work, especially with the finer compounds. I generally run 3 moisture traps in line whenever I use the eraser.
For fast-cutting work and "chipping" I use the Paasche AEX compound (Aluminum Oxide). I usually just shoot it into a large bucket so I can recover the majority of the media. I've had the same 6 oz. jar for over 10 years now, so that just shows you how much of a cheap-skate I am :D
For cleaning up brass parts and assemblies I use regular old Arm & Hammer Baking Soda. It has enough grit to clean and brighten brass parts without peaning any edges. Your air has to be absolutely dry though since it absorbs moisture. The slightest moisture and it will clump in the eraser. I don't bother to try and recover the baking soda (I'm not that cheap ;)). I just shoot the baking soda straight into my city trash can so there's no messy cleanup and I have the added benefit of a fresh-smelling garbage can :D :D
The third product I use is Rottenstone (It's sometimes, I think erroneously, called tripoli.) It's a fine powder (finer than pumice) made of powdered limestone and silica or diatomaceous earth. Mixed with oil or water, it's used as a final rubbing compound in fine finishing of varnished or painted surfaces. Properly used it can make varnish look like glass. Used in the air eraser it will put a very fine buffed-like finish on brass and paint. Once again your air supply has to be absolutely dry. I generally don't bother trying to recover it, it's too fine. It usually costs between $7-$8/lb and is available at woodworking or finishing specialty shops or online. I also use it as a weathering powder. Being medium gray in color (looks basically like dust) it's great for representing dust buildup on horizontal surfaces. There are several brands available. I have both Rainbow and Bondex which both work perfectly well.
Have fun with it John. I expect you'll find it a useful addition to your shop and will probably come up with some other applications for us.
Paul
Thank you muchly Paul. From Harbor Freight the things they had that sounded good for us was fine walnut shells and spark plug cleaner. I'll have my housekeeper pick me up some baking soda at the market. I think I'll also contact my old boss at North-South Machinery and see if I can get some garnet from him. N/S is a major player in water jets and those are actually abrasive cutters, they do not cut with water. Let me clarify this; they have a very high speed water jet (faster than the speed of sound) that they introduce a fine grit (usually garnet) that does the actual cutting. Since I'm every bit the cheapskate you claim to be, the chance of free abrasive sounds way too tempting.
I also contacted Mac McCalla (Mr. Airbrush) and he has never used, or even heard of one of these things, so I'm going to get his wrinkled old ass over here and get him playing with it. I'll bet he comes up with some great uses.
Uncle Russ, are you listening? This might be a very good 'how to' for your magazines.
John
That's cool John. I'm looking forward to seeing what you think of the tool and what uses you come up with for it. I think you'll find it a lot of fun.
Paul
I've now got the grit that comes with the brush (whatever it is), spark plug cleaner, 180 and 220 grit garnet (from a waterjet) and walnut shells. I've been using the 220 garnet at about 45 to 60 lbs air pressure to clean my soldered brass fabricated parts and it is doing quite well. Gets in there and cleans out the flux and leaves a satin surface that is very good for paint. Just finished the paint on the wood gondola and will play with it next week. Also want to see what it does to the plastic one.
I think I'm going to like this tool.
John
I'm betting you'll find it to be very useful John.
Paul
ill be going to harbor freight tommorow and see if i can get a air eraser!! I learn something new every-time i log in 8) lots of info on this fourm. Craig Mt. Clemens. Mich