Need to Build a Blast Cabinet

[Harry Hagan]

I like Scott’s idea of multiple washer tips. It looks like you have several issues if you decide to use water:

1. Containing the water and blow-back.
2. Having enough water pressure to supply multiple nozzles.
3. Seeing what you’re doing.
4. Handling 1250 signs.

I don’t think you’re going to be able to see what you’re doing with all that water and material flying around so having a view port won’t be of much use.

I propose keeping the nozzles stationary and move the signs past them at the correct distance and speed.

See my drawing for the basic concept. I’m thinking this design will enable you to build a very simple and small blast cabinet. With some experimentation you’ll be able to determine the appropriate offset, angle, distance and number of nozzles. It might be necessary to supply both ends of the supply pipe to achieve even water flow. You’ll hopefully be able to shove signs using the guide rails into the cabinet and out the other side without getting yourself too wet.

Rubber inserts around the entrance and exit holes should help contain the water. I’ve also included a shroud around the spray mechanism to redirect the blast back onto the sign which should help with cleaning, require less water pressure, and further contain the back-blast.



Sign Cleaner 1.jpgSign Cleaner 2.jpgSign Cleaner 3.jpg

[Ken Dolph]

Keith,

Water will be messy. Have you thought of an air knife. It would run off your air compressor. There are many commercially available. I am sure that you could build one easily. Just make sure that you use a tear drop shape for the housing. This will maximize the laminar flow. See http://www.google.com/url?sa=t&rct=j...saMvhnCkDWGGjw

To see a tear drop shape see http://air-knives.com/air-knife-design

Easy to build and no cabinet necessary, except for noise and or dust collection.

I hope this helps.

[Perry Holbrook]

Keith, Cyclone Mfg makes a bench top blast cabinet that is made of tough plastic, I've got the Model E500 (I think) that I use daily as a sand blaster, if that helps any.

Perry

[Keith Outten]

Lots of good ideas in this thread.

I found an old air nozzle that has a siphon connector, the type you use for engine cleaning. Lisa suggested this might work so I will try to round up the fittings I need to connect it to a garden hose and use about 90 psi of air. If it works well the next step would be to get a plastic blast cabinet and install the nozzle. If the combination of city water pressure and air won't do the job then I will have to find a pump that can deliver more pressure. Due to space limitations I really hope that I don't have to use a pressure washer. Even though I know it will do the job the "washing machine" will take up space that I just don't have in the sign shop at CNU.

I am almost convinced that I will have to use water because of the very fine details we engrave in some plaques. The lines are so thin I can't find a brush that will clean them and I have sharpened a pick to the point it looks like a needle. Although it will get into most of the areas it is a very slow process.

I hope to have something working by early next week. We will start engraving AutoCad Drawings that almost always have a lot of very fine lines, the drawings are stairwell signs for Fire Evacuation purposes. I will take some pictures to share with everyone as soon as I have something that works efficiently.

Thanks..........
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[Ken Deckelman]

Keith,
I built mine last year with parts from http://www.tptools.com/ , specifically this kit: http://www.tptools.com/p/335,142_Bui...ed-System.html

There are a bunch of pictures in my Picasa album: https://picasaweb.google.com/1139665...812037/Blaster#

I use this cabinet a lot and it works very well.

Edit: I see that you really are looking for a water base solution and not abrasive, sorry.

[Keith Outten]

We decided to purchase a small electric pressure washer. Since the weather right now is perfect and were running out of time we bought the pressure washer yesterday and started cleaning the signs we had already engraved. It works perfectly, each sign took less than 30 seconds to clean and they air dried in about an hour. Before the cold weather comes back we need to design a cabinet and find a short handle gun so we can move the washing effort inside the shop.

FWIW I tried the engine cleaner gun with 100 pounds of air pressure and water. It wouldn't do the job so I new I had to have a lot of pressure to get the sign blanks clean.

Ken, I built a small plywood sandblast cabinet years ago that worked good, then I gave it to a friend who needed it for a job. I have a commercial blast cabinet now that I got in a trade for some web design work a few years ago. When I get the chance I want to connect my pressure pot to the cabinet so it will not need as much air volume. I have been kicking around the idea of using walnut shells to polish Corian but my early testing didn't go well. The siphon system won't deliver enough shell media to do the job so I am thinking that I can deliver more volume with a pressure delivery system hooked to my blast cabinet.
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