Glass Cutting

[Onoff]

Any tips on glass cutting?

I can jump in the car this morning and take a trip to my friendly glass man in Dartford. I need a bit of 4mm glass with excellent light transmission properties.

On the other hand I've a stack of old greenhouse glass...4mm...I'll have to check.

Then I need some black, glass paint though thinking some black Gorilla tape might be better as it'd cushion the glass where it sits on the lip of the steel case.

(Got to print some TPU feet too and maybe repaint the case).

So back to glass cutting, vaguely remember Dad having a cutter, in fact all the local dads did along with putty and linseed oil etc. Back in the days before double glazing! I'm going to need another bit of bigger glass when I make my A4 unit.

Safety concerns me. If I went to the proper shop I dare say he could give be a piece of toughened. I've visions of my (getting on) brother, tripping in his shed and putting his hand through a bit of dodgy greenhouse glass.

Thinking I'm talking myself into a trip to Dartford...

 

[ajlelectronics]

Any tips on glass cutting?

I can jump in the car this morning and take a trip to my friendly glass man in Dartford. I need a bit of 4mm glass with excellent light transmission properties.

On the other hand I've a stack of old greenhouse glass...4mm...I'll have to check.

View attachment 481184

Then I need some black, glass paint though thinking some black Gorilla tape might be better as it'd cushion the glass where it sits on the lip of the steel case.

(Got to print some TPU feet too and maybe repaint the case).

So back to glass cutting, vaguely remember Dad having a cutter, in fact all the local dads did along with putty and linseed oil etc. Back in the days before double glazing! I'm going to need another bit of bigger glass when I make my A4 unit.

Safety concerns me. If I went to the proper shop I dare say he could give be a piece of toughened. I've visions of my (getting on) brother, tripping in his shed and putting his hand through a bit of dodgy greenhouse glass.

Thinking I'm talking myself into a trip to Dartford...

Toughened glass is cut to size and then sent away to be toughened, when purchased in our local emporiums. A quicker job would be to go for laminated. They can do that while you wait and may be cheaper too. Minimum thickness is 4mm I believe.

Masking; how about cutting it from some black craft paper / card?

 

[Onoff]

Drove to the glass place, web says they open at 9am on a Saturday as does the sign on the door.

They're shut!

 

[Redsailor]

Greenhouse glass is usually very thin and of dubious quality and trying to cut aged glass is more problematic than fresh new glass. Laminated can be cut to size whereas trying to cut already toughened glass will result in some rather spectacular moments when it shatters into a gazillion pieces!

 

[ajlelectronics]

Another option of course is clear acrylic sheet.

 

[Misterg]

Any tips on glass cutting?

You need a glass cutter (or you could try a wet tile saw if you have one).

Old, weathered glass is much harder to cut than new glass.

Keep the thickness to a minimum, as 'normal' (window / greenhouse / picture) glass starts losing transmission in the UVA region.

I wouldn't bother with laminated (it will be quite thick). Toughened is probably a non-starter (as it needs to be done after cutting, and requires a certain minimum thickness). You could put some safety film over it if you were worried, but beware UV blocking films.

Mask the edges with tape, but wrap it around the edge to cover the sharp bits (top and bottom).

Anywhere near you selling cheap picture frames with glass in?

 

[The_Yellow_Ardvark]

Green house glass is a bugger to cut. Thin, stressed and of mixed quality.

Get a NEW glass cutter. With spare wheels. A wax pencil.

Lay the glass sheet down on a old blanket, making sure the under surface a CLEAN.

Lay the glass down, so the first longest cut is on your right hand side. Lift up the glass so it rests on one edge. Using the ball end of the cutter, tap the glass it should ring, if not there may be micro cracks.

Mark the Longest cut line with the wax pencil. Drop the cutter into white spirit. Start with the wheel over the edge and make ONE clean pull of the cutter towards you and off the end of the sheet.

Lift up and tap the underside of the scored line. It should start to crack. If the crack does not go full length, tap the end of the crack.
It should go.

Or lay the cut onto match sticks and give one gentle, but firm push.

Practise is good.

 

[nickk]

Polycarbonate sheet? I use 4mm,hellish tough.

 

[jsf55]

Old glass never likes being cut, i'm sure they used a lubricant too, might have been 3 in1 ... long time since i watched it being done !

 

[JohnH]

Glue it back together.

 

[Dcal]

A proper glass cutter will make the job far easier, but as has been said, old glass has a mind of it's own.

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[Onoff]

I cheated and had a very nice man at a glazing place in Northfleet cut me a bit whilst I waited. £12.50, 4.4mm laminate after comparing the sample broken piece against it on a white paper background. Could have had a bit of 4mm, ordinary glass for £4.

Fascinating to watch. He scored it, sprayed it with meths and set fire to it, then snapped it along the line.

 

[Cobbler]

Old glass never likes being cut, i'm sure they used a lubricant too, might have been 3 in1 ... long time since i watched it being done !

When I cut glass years ago, we kept a jar of white spirit on the glass table to dip the cutter in, also added a few drops of 3 in 1 oil to lubricate it. Last cut glass in about 1973, once you’ve got the knack it’s quite easy. Often the customer wanted to watch, we would get a sheet of glass, about 6 foot x 3 foot, lift it onto the table on its edge & stand back, the air trapped would let down gently flat, the customer’s face was always a picture when you did it.

 

[4String.]

I cheated and had a very nice man at a glazing place in Northfleet cut me a bit whilst I waited. £12.50, 4.4mm laminate after comparing the sample broken piece against it on a white paper background. Could have had a bit of 4mm, ordinary glass for £4.

Fascinating to watch. He scored it, sprayed it with meths and set fire to it, then snapped it along the line.

Used to repair overhead cranes in various Solarglass plants around the country back in the late 80's/early 90's.

The guys in there used to handle 8' square sheets of glass as if they were sheets of plywood, no messing about . And the wagons that delivered them were equally fascinating, covered artic trailers from Belgium iirc that used to open the rear door then lower the entire cradle full of glass to the floor before driving forward out of the way.

 

[graffian]

We had a big stack of green house glass.
I turned half the stack into shards trying to make some shields for my welding filter.
Then I turned the other half into shards trying to cut something else.

I was having some glass cut for something and I mentioned the green house glass; I got the impression anything
over a few months old didn't cut reliably, and if I was to find any more old glass I wanted to cut I should stick it next
to out central heating boiler for a few months before trying to cut it.

 

[jmp49]

My wife used to do decorative stained glass for a hobby. Not leaded frame structural stained glass, but cut individual pieces of different colour & texture, cut or wet ground to shape, then foiled with copper foil on the edges and soldered together. She has a cutter with a oil resevoir built into the body of it that feeds the cutter in the cut, and various nipping and grozing pliers. Bit overkill for one cut, and the op had it cut at a shop anyway, but better tooling did make her work a lot easier.
I say used to, because the wet grinder is sitting unused in a shed, and she's more into patchwork etc now, but I'm not complaining as I have access to someone who can cut glass really well, and who can make seats for project vehicles

 

[Morrisman]

Spare glass for my garden shed costs about £3 a piece. Maybe 18’ x 24”.

 

[Muzzer]

FYI - Wickes have a decent selection of polycarbonate (and acrylic) sheet.

 

[DAPPH]

Old glass never likes being cut, i'm sure they used a lubricant too, might have been 3 in1 ... long time since i watched it being done !

Here is how cut old glass .
Pour a line of pure turpentine along the cut line , after putting two lines of tape a few mm apart to stop it sneaking all over the glass , lubricate the cutter wheel with turps & make sure the actual cutter wheel turns , sometimes you'll have to slacken the securing screw a tiny bit get it rotating using turps then retighten but not tighten it dead tight . If you have access to a real diamond cutter or a wheeled cutter with an oil reservoir to lube the score line your fortunate
Select an unused cutter wheel or at least one that's not exposed to daily damage by being exposed. Check it is has a clean un chipped keen edge .

Lay the glass on a doubled thick smoothed out blanket on a stout table , only cut in one direction and only make one cut as multiple strokes tend to cause problems , from the edge away from towards you , along a thickish 1/4" or so straight edge that is lightly clamped to the glass allowing the cut margin to the desired line .
Then in one continuous stroke with the cutter held at about 20 degrees and vertical to the glass draw your line from the just a tad over the far edge to the edge of the glass to score the edge to the edge nearest you using the same pressure all the time . Mess this up and you'll likely get a busted edge . Often any small tags of glass that may happen can be broken off with pliers or pincers held lightly on the cut line and bend down away from the cut line side of the glass.
Don't drop the cutter wheel off this front edge under pressure as it may cause a chip / disasterous cut .

Undo the clamp , put the straight edge under the scratched line 1 mm to the waste /unwanted side of the glass . use gloved hands and press vertically sharply . at the middle of the piece using the your flat palms the glass should brake cleanly .
Use an old chisel sharpening carborundum stone cleaned in white spirit and wiped dry to gently take of the sharp edges .

I've cut loads of old glass like this , having a decent free running cutter wheel , the old glass clean scratch free and turped is the secret get it right and you'll get a nice pleasing gentle grating / cutting sound as you scribe the line .

Old double glazing units are easily separated by using a decent Stanley knife with a new blade and some Turpentine , carefully cut a shallow line right along the glass where the seal is , paint some turps in the cut . Leave it a good 30 seconds for the turps to kill the adhesive , then make another slightly deeper cut . progress like this round one side of the panel till you see the blade on the inside of the panel then gently ease the sheet off . Some times I've use 50 lb fishing line or 60 pound Dacron line on handles to gently pull through the remaining sealant
Remove the sealing & spacing strip off the other sheet exactly the same .
Clean any residues off with a rough dry rag and more Turps .

 

[bricol]

In a previous life we did some work for a glass plant Pontefract way - flippin' 'ot in parts of it. Interesting how the edges of the continually moving sheet of glass was trimmed . . cooled, and smacked - we we involved in the cooling bit. and some other bits in the hot bit.

Bit further up the line it was cut into the big sheets to be loaded into lorries. Quite often the "crack" of the cut turned into the sound of a lot of glass bits hitting the floor . . . swept up and tipped back in at the beginning.