I have a customer with a mirror he wants to sandblast. He already has someone to do the blasting, he just wants me to cut the mask. I don't think he really knows what he needs because he's telling me he wants it cut in reverse so they can apply it to the "backside" of the mirror. I'm new to blasting mirrors......is this right? If he blasts the backside of the mirror he's actually removing the mirror and just leaving glass. Maybe they want to paint the background or something leaving the artwork the only thing mirrored.
My real (probably dumb) question is "Aren't mirrors usually blasted from the front"???
I'm going to call him back and see if I can talk to whoever is doing the blasting.....they should know what effect he's after.
Any tips?
Posted by Dave Grundy (Member # 103) on :
Tony..Blasting the back side will remove the mirroring and will also leave the glass with an "etched" appearance, with the surface still smooth as I guess they would wish.
I use paintmask for the resist on blasting mirrors, no need for any heavy resist since it doesn't require much pressure to blast a mirror.
ALSO, a tip from Don Coplen, who has done many a mirror.... leave the resist on the back side after blasting. That way you retain a clean edge. Removing the resist can result in a jagged edge.
Posted by Joey Madden (Member # 1192) on :
My sign is on mirror, sandblasted in the back. The mirror slides into a lightbox. I've only seen mirrors done this way, with or without a lightbox.
Posted by Tony McDonald (Member # 1158) on :
Thanks Dave and Joey....I wasn't exactly sure how it was done. I've applied quite a bit of frosted vinyl but this was something new to me.
Thanks again....Tony
Posted by Jeff Ogden (Member # 3184) on :
You can use that thin rubber if you want, but I have found that just a little too much pressure(or time) on a particular area will cause little spots to appear under the mask, kind of like "pinging", where tiny pieces of the mirror pop off. You got to look close to see it, but it's enough to be annoying. I like to use something heavier ,so I just use 153 cause I already have it in stock.
Yes, blast from the back, and yes, you can paint it or even gild or bronze it after blasting. Posted by Starr Bright (Member # 3166) on :
Hey Dave, What's Paintmask? I've been doing sandblast glass for 27 years and haven't heard of it...I use tuffback mask for mirror and glass...it can be removed witout chipping....but the MOST important thing Tony needs to find out is WHAT grit his sandblaster is using....that determines his mask. 120 aluminum oxide requires a heavier mask than let's say 220...Tony... find out what the blaster is using and I'll tell you what to use...you also have to be very careful with your cutting...you can't cut past any intersection or miss cut, or you will have scored the silver and it will show. In addition, if it will be painted, the blast has to be deep enough to have a slight edge to hold the paint. Just removing the silver isn't good enough. Let me know. Starr
Posted by Dave Grundy (Member # 103) on :
Starr..Paintmask is a thick vinyl with a less aggressive adhesive and is used for cutting masks for spraying. I use it for mirrors because I keep it in stock and it works just fine for me. I use a pressure pot/125 psi/and silica sand for blasting mirrors BTW.
Posted by Tony Vickio (Member # 2265) on :
Tony, you have picked up some good info here! I find that when you blast the front of a mirror, you get the reflection of the blast in the mirror, make the lettering look "blurry". I would blast the back side !
Posted by Steve Carter (Member # 494) on :
Tony,
Just another process for back etching mirrors!
After etching and before placing into light box or hanging in window, colors can be applied to the area etched.
Use Stained Glass paints or use colored Mylar - the effects are great! Use your imagination.
Stained Glass paints can be applied to regular etched glass and get the effects of stained glass without the leading!
Steve Carter
LOGIN Name Formerly: atog254 Posted by Don Coplen (Member # 127) on :
OK, I suppose y'all were expectin me to show up here. lol
Good advice all the way so far. I prefer high tack anchor continental or hartco. As Dave said, I don't remove the stencil after blasting...which is one of the reasons that I prefer high tack. Another is that the high tack is less likely to fail on smaller details.
Cover the front of the glass with vinly paper premask. One grain of sand on that side can ruin your day.
For color, the best is to airbrush One shot pearlescent enamel. It gives you vivid color, plus sprays on translucent, so that it can be backlighted.
Of course, pretty much all of this is irrelevent, since all you're doing is providing the stencil.
(By the way, any lettering on it? you'll want to remember to cut everything in reverse.)
Question: Why would you not do the mirror yourself? Seems there's alotta money bein let out the door.
Posted by Tony McDonald (Member # 1158) on :
Thanks for all the help....this is great and I'm going to print and save all these tips.
This is a guy I've done quite a bit of work for. He and his buddies have Harleys. He has a big bus (to haul their bikes) with a mirror on it that measures 21" x 141" I think they was probably sittin' round havn' a beer and decided they needed to blast the mirror before they go somewhere next week. One of them has the blaster and is doing that part but he didn't have a way to cut the mask. This is where I came in. It involves some lettering with barbed wire runnin around the border. I've never cut the sandblast mask but it's probably about like cutting the the cadcut t-shirt material which is a lot of fun. They want it done by this weekend and it's in the artwork approval stage right now.
I have a blast setup (kind of) but havn't had time to try it yet. I don't think I'd want this job to be my first blasting experience.
Posted by Don Coplen (Member # 127) on :
Blasting the mirror is the easy part. Just protect the front with premask or whatever, then blast the back till you see white. No depth is necessary...it's like spray painting the graphics white. Virtually no chance of blasting thru the glass...just keep the blaster moving.
The "hard" part is the design. A bad or so-so layout will look 100 times worse when it's lit up.
Posted by Steve Carter (Member # 494) on :
Bear with me alittle here as I am visiting my son at Univ. of Md for the Georgia Tech game which Ga lost badly and we are partying a little too much!
I do alot of mirrors and have designed and built a sandblasting cabinet with a light on the back for etching desings. When the light shines thru you know the desing is complete. If anyone would like information on this cabinet E-mail me and I'll get it back to you asap.
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