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View Full Version : Best material for window in blast cabinet???



winchman
07-16-2008, 04:13 AM
The blast cabinet at the school is pretty old, and someone replaced the window with some sort of plastic. Now the window gets foggy with fine particles as soon as you start working. It's almost impossible to see what you're doing. It's not as bad around the outer edges, but you can't always see well from there.

It looks like there's some sort of electrostatic attraction going on, but wiping the inside doesn't remove enough of the dust film to help much.

I want to get the instructor to replace the window with something that'll work better, but don't know what to suggest.

Roger

Davek0974
07-16-2008, 04:47 AM
I would probably go for a bit of laminated glass. This would stop the static problem and is shatterproof.

Dave

Chipslinger
07-16-2008, 06:20 AM
Plexi glass is fine But buy some mylar clear thingies from Harbor freight to stick on, it makes it last longer/

torker
07-16-2008, 07:57 AM
The "used" (homemade) blastcabinet I'm just getting to work... it has glass windows but he had clear plastic "tearoffs" inside to protect the glass.
I'd like to know where he got those, they look pretty handy.

Steve Steven
07-16-2008, 09:11 AM
TP Tools sells the clear plastic stickons....
http://www.tptools.com/p/238,23_Inner-Lens-Protectors.html

Steve

Evan
07-16-2008, 09:14 AM
Go to a supplier of windows that also does heavy equipment repairs. The ROPS canopies are glazed using heavy Lexan sheet that has a super hard protective layer. One brand name is Mar-Guard (Lexan). The coating is so hard that it can be scrubbed with a brass brush without scratching and it doesn't seem to develop a static charge. I pick up 1/2" thick pieces of this for free from a local glass shop since pieces smaller that several square feet are of no other use as they aren't big enough to repair a machine window and there isn't a big business making vent windows for armored limos around here. Note that regular Lexan isn't suitable as it scratches very easily.

torker
07-16-2008, 09:34 AM
Evan.. That Mar-Guard... here it is very expensive.
They want a fortune for even little scrap pieces.

Evan
07-16-2008, 09:43 AM
Yeah, the local guy has given me what would normally cost maybe $500 or more. I made a few engravings on some of it for him including a Harley. He's happy. :D Since Roger needs some for a school he might find somebody willing to make a donation.

Dunc
07-16-2008, 09:55 AM
PM has a 16 vol set (give or take a few) that reprints some of their old info ( guessing 1950s, '60s, maybe early '70s).

Build it yourself uses a couple of galvanized tubs - clamshell - to form the cabinet. Suggests a shield of plastic/nylon window screen on the inside of the glass porthole. It should be spaced about 3/4 inch from the glass.

Bruce Griffing
07-16-2008, 10:15 AM
The tear off idea is the way to go. I bought a roll of acetate from an art supply house and cut the whole roll to the right width on the table saw. I then just cut the right length whenever I need another piece. I use clear packing tape to put it on the glass. Works fine.

Patch
07-16-2008, 10:18 AM
I've been using clear window tinting near 20 years now. Sandblast cabinet windows, lathe and mill guards get a film as well.

Mar-gard and like products ususally run about $wow'sq.

Tear-offs? $8.00'sq.

Window tint runs in less at about $0.50'sq. for 4mil. You can also double the thickness for longer use time.
The 8 or 10 mill film is great if you wish not to double the 4mil.

Below:Not the same type as what I use but it is a start for you all. Look for the type that best suits you.
I have found that the amber works great if you haven't a dust recovery system on your blast cabinet. Amber is about like a fog light lens.

http://cgi.ebay.com/ebaymotors/SECURITY-SAFETY-FILM-WINDOW-TINT-ROLL-24x100-4MIL-SS-20_W0QQcmdZViewItemQQ_trksidZp3286Q2em14Q2el1318QQ hashZitem280244666098QQitemZ280244666098


Patch

Roy Andrews
07-16-2008, 05:03 PM
when i built my cabinet i used a chevy truck back window. easy and cheap to replace and has lasted 7 years now.

ERBenoit
07-16-2008, 05:38 PM
The OE window in the Skat Blast at work is tempered glass. I also use the peel away films others have mentioned. I WOULD ADVISE AGAINST THE USE FLOAT OR PLATE GLASS. I'll suspect you would know why.

pcarpenter
07-16-2008, 05:40 PM
Evan-- Aluminum oxide is a lot harder than a brass brush:D If I had an expensive piece of Lexan, I would want to protect it with the tear-offs.

I run an old shop vac dedicated to the task of keeping a negative pressure on the cabinet to deal with the dust problem. Of course you have to watch where you are pointing the gun, too or it will start sucking up a lot of your abraisive.

Paul

Ernie
07-16-2008, 05:52 PM
There must be as many answers as there are posters. I made my cabinet using one of the glass shelves from a refrigerator I trashed. It's 14 X 24 inches and I figured if it stands up to glass jars etc. beeing dumped on it, it should work for a sandblast cabinet. I just use a soft bench brush to clean off the dust. I made the cabinet to fit the glass. If you need to fit the glass to an existing cabinet, I don't know if that tempered glass can be cut.

Ernie B

ERBenoit
07-16-2008, 05:53 PM
I don't know if that tempered glass can be cut. Ernie B

You'll only cut it once. Into very small pieces. :D

gnm109
07-16-2008, 06:55 PM
I went to a glass company and had a piece of tempered glass cut to fit the drop-in window area in my blast cabinet. I also got a sheet of clear 1/8" polycarbonate from a plastic store and made several pieces that drop into the area before the glass. They will last almost a year before they get too scuffed up to see through. Then I just unscrew the mount and replace the plastic behind the glass and go all over again.

It sounds like everyone has a different method.

Evan
07-16-2008, 10:10 PM
Evan-- Aluminum oxide is a lot harder than a brass brush

Ok. Since Roger asked what would be the best material there is one that wins hands down.

Aluminum oxynitride (ALON). It's almost as hard as diamond and a thin piece can withstand 50 cal fire. It water clear and bombproof. The military is using it as transparent armor. It also costs about $1500 per sq foot. :D :eek:


I went to a glass company and had a piece of tempered glass cut to fit the drop-in window area in my blast cabinet.

You must mean laminated safety glass. Tempered glass cannot be cut by any method after it is made.

Your Old Dog
07-16-2008, 10:15 PM
I'm using clear acetate sheets as used for document protectors found at Office Max and Office Depot. They are cheap and work for my needs. I cut them in two and tape them to the inside of the lexan window.

gnm109
07-16-2008, 10:27 PM
Ok. Since Roger asked what would be the best material there is one that wins hands down.

Aluminum oxynitride (ALON). It's almost as hard as diamond and a thin piece can withstand 50 cal fire. It water clear and bombproof. The military is using it as transparent armor. It also costs about $1500 per sq foot. :D :eek:



You must mean laminated safety glass. Tempered glass cannot be cut by any method after it is made.


I guess I bette go look at it. I ordered tempered glass.....I will have to remove it and take a look.

Mike of the North
07-16-2008, 10:47 PM
If you want to stop the build up of static, wipe the plastic with a dryer sheet.

Dragons_fire
07-16-2008, 11:40 PM
ive just been using a sheet of 1/8" plexi with the clear protector on each side. the stuff that comes on it when you buy it. used if for about a year, flipped it over and pulled off the scratched one, then used it for another year... now its pretty scratched up, and i need to find something new to protect the plexi...

JRouche
07-17-2008, 01:51 AM
If you want to stop the build up of static, wipe the plastic with a dryer sheet.

Now this is one Im gonna try. I seem to have alot of static attraction and have to carefully brush the grit off the window. I use disposable plastic sheets from HF because they are cheap and they fit. But still, I would like to get some life outta those too. More consumables...

I worked at a place though that had a pretty nice cabinet and after so many guys went to wiping the inside glass we had to say hands off!! They were ruining the glass by wiping it. And the foreman wasnt knowledgeable about the peel off films. JR

malbenbut
07-17-2008, 03:55 AM
I used to order a material called bexoid film in rolls which was placed in behind the glass. the shotblast was used approx four hours per day and the film was changed once a week. Bexoid may have a different name in the USA.
MBB

Evan
07-17-2008, 08:58 AM
Make an air curtain to keep the dust away from the glass. A tube with a linear series of small holes like a sprinkler hose will release jets of air that if placed along the edge of the glass will produce a laminar flow boundary layer of air. It will prevent most dust from attaching to the surface.

Orrin
07-17-2008, 09:34 AM
I got tired of buying the expensive stuff from TP Tools and bought some Warp's Flex-o-Glass at a local farm supply outfit. It is a tough, flexible clear film made of what appears to be vinyl. It is cheap and easy to handle. Its optical performance isn't as good as that of harder, smoother plastics; but, it is plenty good for a blast cabinet.

Of course, what one saves in money the wind up paying for in inconvenience. It takes a bit of time to cut to size, apply the double-stick tape, etc.

I use double-stick tape because that way the adhesive goes only onto the glass and it can be cleaned off easily.

Regards,

Orrin

Scishopguy
07-17-2008, 03:49 PM
We had a Trinco Dry Blast cabinet at work, about 2'x2'x4', with a sloped front that hinged upward. There was a 1'x2' piece of laminated glass that was held in a frame on the outside by 4 studs with wing nuts. We used acetate film from the bookstore, taped to the inside surface. It lasted about a year, unless we had a big bunch of jobs for the cabinet and then it was about once a month. There was always some student that had to look at the nozzle, straight on, to see if sand was coming out, no matter how much we told them not to. :( The acetate was something like $0.50 for a 2'x2' sheet so that wasn't so bad. The unit had a vacuum hose attached to a vent in the top of the cabinet, to the right of the light fixture, to take out all the dust. It didn't come close to removing it all. The higher the pressure the worse the dust was. The instruction booklet said to keep the pressure down below 30 psi but some folks had to turn it up to 125 psi to "speed up" the process. This was especially bad with glass beads. The coarse bead worked best at about 15 psi and didn't break down that much. I had read about using fiberglass window screen with standoffs, to protect the glass but never had time enough to try it. I will as soon as I buy or make a cabinet. Also, that is a great idea about the dryer sheats!!!

john hobdeclipe
07-17-2008, 06:36 PM
The blast cabinet in the saw shop where I once worked simply had a layer of plain old window glass facing the inside, and a layer of 1/8" acrylic facing the outside. The window glass would need to be replaced about once a year, the plexi protected the operator from any accidents. Cheap and functional.