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Ben Halop
08-21-2012, 4:35 PM
Hi guys,

Long time reader, first time poster.

My question regards etching with an Epilog 75 watt Helix on Borosilicate glass. I have successfully etched onto this material before but the result was not the normal frosted look I achieve with glass. The etching itself was more clear. I was wondering if their are any tips or tricks to gettings better frosted results with this type of glass. The wooden display I made for the same guy came out great, cutout the harder shapes with the vector laser and etched a family crest :)

Thanks,

-Ben

Mike Null
08-21-2012, 5:51 PM
Ben

Welcome to SMC. I believe there have been some recent threads on engraving glass so a little research might turn up what you want.

Gary Hair
08-21-2012, 5:52 PM
Borosilicate glass has the property of being resistant to thermal shock - that's the mechanism that a laser "etches" glass. It doesn't cut it, mark it, engrave it, etc., it heats it up to a very high temp in a very small area and the difference in temperature of this spot and the cool glass surrounding the heated area causes the glass to crack. Really, the only way to etch glass is sandcarving, especially with borosilicate glass - if you want consistent results anyway.

Gary

Here is a link to the wiki entry: http://en.wikipedia.org/wiki/Borosilicate_glass

Ben Halop
08-21-2012, 6:42 PM
Borosilicate glass has the property of being resistant to thermal shock - that's the mechanism that a laser "etches" glass. It doesn't cut it, mark it, engrave it, etc., it heats it up to a very high temp in a very small area and the difference in temperature of this spot and the cool glass surrounding the heated area causes the glass to crack. Really, the only way to etch glass is sandcarving, especially with borosilicate glass - if you want consistent results anyway.

Gary

Here is a link to the wiki entry: http://en.wikipedia.org/wiki/Borosilicate_glass

Ok thanks for the reply! So no way to get frosted etchings with a CO2 laser on borosilicate. I guess my next option would be vector cut the stencils out of adhesive vinyl, apply to glass, and buy a small sandblaster huh?

Mike - I am still searching around but haven't found anything yet regarding laser-etching borosilicate, posted this when I couldn't find anything earlier. Will continue looking though

Gary Hair
08-21-2012, 8:00 PM
Ok thanks for the reply! So no way to get frosted etchings with a CO2 laser on borosilicate. I guess my next option would be vector cut the stencils out of adhesive vinyl, apply to glass, and buy a small sandblaster huh?

Mike - I am still searching around but haven't found anything yet regarding laser-etching borosilicate, posted this when I couldn't find anything earlier. Will continue looking though

I wouldn't say there is no way to laser it, but I would say that the results are not going to be stellar. Don't laser vinyl, it's nasty for your laser and anyone that breathes air... Anchor sandblast stencil is laser friendly as well as Ikonics laser tape, I use laser tape often. If you have a compressor already it would be beneficial to add sandblasting but don't over-tax your compressor with a large setup, start with a pencil blaster or something similar.

Gary

Chuck Stone
08-22-2012, 8:03 AM
laser mask an acid etch?

Ben Halop
08-22-2012, 12:51 PM
I wouldn't say there is no way to laser it, but I would say that the results are not going to be stellar. Don't laser vinyl, it's nasty for your laser and anyone that breathes air... Anchor sandblast stencil is laser friendly as well as Ikonics laser tape, I use laser tape often. If you have a compressor already it would be beneficial to add sandblasting but don't over-tax your compressor with a large setup, start with a pencil blaster or something similar.

Gary

Yikes thanks for letting me know about the vinyl, further research showed it as very harmful to my laser, so thanks for stopping me one that haha.

So Ikonics laser tape is basically a substitute for that? Say I would tape the borosilicate cylinder, put it on the rotary, etch my design, then go over it again with a small sandblaster? I'm fairly new to decorating, and have only been using my Epilog for about a year, though I am not new to graphics and pick stuff up very quickly. The compressor I use is pretty large, and I have ran the piping to about 10 access points in the woodshop, one by the laser to blow stuff off, and another into the air assist. Even when I have friends helping in the woodshop we have not overtaxed the compressor yet. I'm pretty sure it's an industrial size :)

What would you recommend for a small sandblaster? I don't want to spend too much as I have one project right now that requires it, then if it works out I would like to upgrade to something better.

Ben Halop
08-22-2012, 12:52 PM
laser mask an acid etch?

Never done acid etching before and have only heard of it once. Is it hard to do? or is there a lot of equipment/supplies needed to get started?

Michael Hunter
08-22-2012, 1:08 PM
There seem to be two ways of acid etching on glass.

The "professional" methods use hydroflouric acid - very nasty stuff so you would need lots of safety wear, goggles etc., the antidote and a safe way of disposing of used solution.

The "safe" methods (used for etching anti-theft IDs onto car windscreens etc.) are rather slow, but are presumably really safe since they are sold directly to the general public. No idea what is in these etchants.

Seems to me that investing in sandblasting kit would be safer and much more versatile.

Gary Hair
08-22-2012, 2:17 PM
Yikes thanks for letting me know about the vinyl, further research showed it as very harmful to my laser, so thanks for stopping me one that haha. You'll find various opinions about this, some people will laser vinyl and swear it's ok to do small pieces, minor cuts, etc., I say, "it's your $25k machine, do what you want. I won't do it in mine".


So Ikonics laser tape is basically a substitute for that? exactly. It's not as cheap as vinyl, but it works really well and is very easy to use.

Say I would tape the borosilicate cylinder, put it on the rotary, etch my design, then go over it again with a small sandblaster? exactly

The compressor I use is pretty large...I'm pretty sure it's an industrial size It would likely work fine for small runs of etching glass. Check out the CFM rating, if it's 10 or more then you should be fine for light stuff. Heavy stuff, including rocks, pavers, bricks, etc., would need 20 or more. I have a diesel powered compressor that puts out 125 CFM, it can handle anything I could ever throw at it!

What would you recommend for a small sandblaster? I don't want to spend too much as I have one project right now that requires it, then if it works out I would like to upgrade to something better. I would get this cabinet from Harbor Freight, http://www.harborfreight.com/40-lb-capacity-floor-blast-cabinet-93608.html, and a pencil blaster like this, http://blasters.com/pencil.htm. The cabinet will work fine for glass and lots of other stuff. The pencil blaster will only really work well for glass, but it's fairly inexpensive and easy to use. I used one for several years before I built a larger setup using a 20lb blaster like this,http://www.harborfreight.com/20-lb-pressurized-abrasive-blaster-68994.html. It's not difficult to convert the 20lb blaster to use for glass, but if you want something you can use right away then go with the pencil blaster. I use 180 grit silicon carbide for glass but you could use anything from 120 to 220. SMC is a great resource for anything, in general, but if you want specific info on sandcarving then I would recommend you check out cuttingedgesandcarving.com.

Gary

Bill Cunningham
08-22-2012, 7:28 PM
I would get this cabinet from Harbor Freight, http://www.harborfreight.com/40-lb-capacity-floor-blast-cabinet-93608.html, and a pencil blaster like this, http://blasters.com/pencil.htm. The cabinet will work fine for glass and lots of other stuff. The pencil blaster will only really work well for glass, but it's fairly inexpensive and easy to use. I used one for several years before I built a larger setup using a 20lb blaster like this,http://www.harborfreight.com/20-lb-pressurized-abrasive-blaster-68994.html. It's not difficult to convert the 20lb blaster to use for glass, but if you want something you can use right away then go with the pencil blaster. I use 180 grit silicon carbide for glass but you could use anything from 120 to 220. SMC is a great resource for anything, in general, but if you want specific info on sandcarving then I would recommend you check out cuttingedgesandcarving.com.

Gary

I have the floor blast cabinet in Gary's link, in Canada they are sold by Princess Auto. If you buy this, as you assemble it make sure you run a bead of silicone caulking on every surface before you screw it together or the blast medium will leak out. I learned the hard way, mine was leaking 80 grit. Using 140 or finer for glass, it would run out like water..

Michael Hunter
08-23-2012, 8:00 AM
Update to my previous post about acid etching -

It seems that most of the hobby glass engraving kits available use "Armour Etching Creme" which DOES contain hydrofloric acid.

Moreover, Armour say that the product will not etch Pyrex (borosilicate glass), so again, sandblastings looks the best bet.

David Rust
09-04-2012, 9:41 PM
It would likely work fine for small runs of etching glass. Check out the CFM rating, if it's 10 or more then you should be fine for light stuff. Heavy stuff, including rocks, pavers, bricks, etc., would need 20 or more.

Gary,
A quick look at 20cfm compressors show that they are going for $1200-$5500... There seems to be a lot of lesser cfm models out there. Can we get away with less cfm's for pavers? Does less cfm's mean a job will take longer?

Thanks,
Dave

Gary Hair
09-04-2012, 10:01 PM
Gary,
A quick look at 20cfm compressors show that they are going for $1200-$5500... There seems to be a lot of lesser cfm models out there. Can we get away with less cfm's? Does less cfm's mean a job will take longer?

Thanks,
Dave

You pay for CFM's, they are like gold! More cfm's mean two things - 1. You can use a larger nozzle which could equate to shorter blasting time. 2. Even with a smaller nozzle your compressor won't have to run as much/often because it puts out more air and refills the tank in a shorter period of time.

If you are trying to use more air than your compressor puts out then you will end up with lower psi and your compressor will run often/continuously.

Here is a great chart that shows the relationships between cfm/psi/nozzle size. http://azglassclasses.com/Reference/CFM-PSI.htm Notice how quickly your cfm requirments jump on a 1/8" nozzle - 10 cfm will only get you 30 psi.

Check your compressor for two things - the cfm@psi rating and the duty cycle - chances are the duty cycle is NOT continuous and you WILL burn it up if you run it continuously at anywhere near the max.

FYI - I bought my diesel powered rotary screw compressor for $1,200 and put another $500 into to get it in good shape - so for $1,700 I have 125 cfm at 125 psi - according to that chart I can run a 1/4" nozzle at 120 psi, that's way more than I'll ever need. I typically use a 1/8" nozzle and even at 90 psi it barely runs above idle...

Check craigslist for "diesel compressor" "rotary compressor" "gas compressor" and you'll find something. Just recently I sold my 25 cfm gas compressor for $850, it worked fine but I wanted more air!!!

Gary