Glass Fabrication

[szw21]

I know a few here also fab glass so I wanted to ask a question on that.

I want to take a sheet of glass (not thicker than about 1/4") and route it to a circle about 46" in diamater. What would be the best method to do that using hand fab method. For stone I would say either use a router coupled to a circle cutting jig or rough cut and and finish with a z-wheel. But for glass - are there simiar bits for doing such things.

As far as safety - compared to stone is the glass dust dangerous in terms of causing cuts. Any special protective gear required? I assume the correct way to cut and shape glass is with water - just like for stone.

[Joshua Hopkins]

You need a circle cutter.

http://www.crlaurence.com/apps/sitesear ... e%20cutter

[Joshua Hopkins]

You will adjust the cutting handle to the size you want then suction down to the surface of the glass for 1/4" glass leave your clearance about 1 1/2" since you are new at this for example if you want to cut 24 " circle cut a 27"sqare mark center then align cutter. Put a little three in one oil on the cutter. Use a downward steady just under medium pressure on the glass.

Call me for more instructions if you need them my cell is in my sig.

[szw21]

Thanks Joshua - that's easier than I thought. It seems like the link you posted requires the opening of a acocunt with the company to purchase but I looked online and there are other sources where you can buy these without having to do that. I will contact you if I need any further advice but as you say it is probably a good idea to experiment first and cut a larger circle and then fine tune the size to the correct one.

[szw21]

Joshua - had a quick followup question - are you supposed to use the tool to simply score the glass and then break it or are you supposed to go round and round with the cutter until it goes fully through the glass. All the info I've found online suggest that you only use the tool for scoring the glass and you break the glass. So I'm unclear about the correct method.

[Joshua Hopkins]

Score it one time then lightly tap directly under the score until you see the score start to run then tap the run all the way around the score from underneath.

[szw21]

Thanks

[Stuart Gill]

Good article for you to look at in Glass Magazine this month. It has just what you are looking for.

STU

[szw21]

Thanks Stu - nice article with pics and very relevant to what I'm doing.

[Stuart Gill]

Heavy plate is a bit harder to work with than what you are talking about. 1/4" will be a bit harder than cutting the thin stuff that local hardware places have for garage window but not a huge problem. A circle cutter will really help out even if you are only doing one as it is going to give you a proper diameter to start with.

What is the application? If it is a table cover you may want to drop by a local glass shop and ask for some clear desk buttons. They will help to keep moisture from skacking out the finish on the top you are covering.

CRL does require an account to purchase but they do have local stores that will accept walk in traffic. Even for the big boys, money talks.

Just as a side note: glass will not take near the amount of heat that stone will, so if you intend on polishing the edge by hand go easy on it. You will heat stress the glass surprisingly fast if you get on it to aggressively. Keep the edge cool and your pad or belt wet with water or a polishing oil. This also goes a long way to keeping the glass dust down.

Where are you located, if you are close I bring a cutter by.

STU

[szw21]

The application is for an outdoor firepit cover. I thought of glass as it will reveal the colored fireglass inside as well as the outer ring made of Costa Esmerelda which I fabricated. My plan was to glue some legs on it so that it would rest on the outer stone ring and overhang so that rainwater will not drain into the fireput during the rainy season. It will also allow the firepit to function as a table when not being used as a firepit. I will post up a pic tomorrow just to show the application. 1/4" was just a guess on my part - it could be thinner.

I'm located in San Diego. I'm probably about a couple of weeks away from actually doing the job - I was just thinking about what supplies are needed to do this and to get some background info.

Can you use regular stone pads to polish the edges of glass.

[Joshua Hopkins]

I have not tried those but DavidL said they would work fine.

[Stuart Gill]

We always had super simple rules to guide customers choice in glass thickness.

12/24 rule: If the glass is hanging 12" over an edge or has more than a 24" span between supports, think about thicker glass.
Replacement rule: Can you replace what you are putting on this glass shelf? Think about thicker glass.

At 47" sitting on legs I would suggest not going below 1/4". If you are only going to have it sit on the outside edge of your fire pit it would be nice to get up to 3/8" glass. 1/4" will work, most patio tables are tempered 3/16" and last just fine. With no frame and legs glued to the outside edge I would use thicker glass. That's just me.

Is this going to be at your place or a customer? You need to be careful about putting non-tempered glass outside at a customer.

The stone pads should work fine but as I said play with a test piece and get used to the pressure so you do not heat stress your finished diameter. I know this sounds funny but my brother lives in San Diego and used to work with me at the glass shop. He might be able to help you out with polishing the edge if you need it. Let me know if you want his number.

STU

[DavidL]

We have used wet pads on glass with no problems. Just watch your pressure and make sure you keep it wet. You can actually polish it with a belt sander if you wanted but it would be a very dark finish. Use your grinder,low, slow, wet. Before you begin polishing though, go ahead and put a slight aris on the top and bottom edge as this will help to avoid chipping during the polishing process. Then re-aris again when complete.

I am assuming you are only going to use this when the pit is off, correct? Heck for as cheap as glass is, other than the "do it yourself" factor (which I know you like) it is certainly cheaper to just buy a polished circle from a glass shop. Even in 3/8" if you wanted to go thicker.

[szw21]

Here's a pic of the application.



I'm still finishing up the entire project and the firepit is still undergoing some finishing touches. You cannot see the fireglass in the middle as I had to put down the plastic to catch excess mortar while seating the ring pieces.

The ides is to have legs on the glass in a circle so that it sits on the stone ring. Yes this is just a cover which will be removed when the firepit is lit. I naturally assumed it would be very costly to have a glass shop make this - if the cost is not great it may make sense to have them make it. I will look into that.

Since posting this while looking aorund for glass cutting supplies I came across supplies for doing stained glass. I've never done anything with stained glass but I thought a stained glass disc in the middle of the plain glass with a picture of flames may be cool. No idea what's involved in making something like that.

[Stuart Gill]

Cool fire pit! You may be surprised at how affordable a 1/4" or 3/8" diameter can be. You could just put the legs on yourself and it would be done. The cost you are going to have in tools and materials will be close to what a shop will charge, not to say anything for time and headaches on your part.

Stained glass inserts are supercool but do not hold up well outside and horizontal like this. The last few we did were put inside a sealed window unit to keep it from the elements, grabby hands and baseballs. Typically this is in the art glass department and prices can go up quickly when you get artsy folks involved.

STU

[szw21]

Okay thanks - yes I will price out having this done vs doing it myself and see how the numbers stack up. Pity about the stained glass - sounds like a nice idea - but if it looks bad after a while there would be no point making it in the first place.