Otter
Well-Known Member
Sometimes I bloody love this forum.
And I might just ask a glazier about the laminated idea.
And I might just ask a glazier about the laminated idea.
Just smash it? Removing toughened glass
- Thread starter Otter
- Start date
oldbilbo
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So you didn't think 'out of the box' and acquire a handful of rounds that were NOT in brown paper and plastic wrappers.....?
It's more than likely your sergeant or one of the corporals would have had that 'sorted' for you/him/them, but would not expect to be asked.
Tranona
Well-Known Member
Should be no problem. I had a hole cut in a laminated window pane for an extractor fan.
CelebrityScandel
Well-Known Member
The following from our real experience having panes removed in one piece for resealing and putting them back in again, not from wild imagination as seems most of the advice you are getting is.
If they are Sikaflexed in place (if so then should have likely been with Sikaflex 296) then between the glass and the frame they are bedded on there should be a thickness of sealant if it has been done correctly i.e. the glass should not be hard up against the flange of the frame. One can get the glass out in one piece by running a flexible bladed knife around between the glass and the frame flange. Often this thisckness is quite large as a trick when putting glass in it to bed it on a narrow strip of adhesive foam on the inside at the edge of the frame flange so that when bedding the glass it goes down onto the foam which stops excess sealant squeezing out onto the inside of the glass.
If the glass sits in a recess the gap between the edge of the frame and the frame is likely sealed with Sikaflex 295UV and this is again easyish to cut with a knife.
Be very careful with the laminated glass suggestion. Contrary to popular opinion, unless the laminated panes are toughened before laminating, laminated glass is actually slightly weaker than plain glass of the same thickness, and so very much weaker than toughened. That because part of the thickness is made up of of the plastic between them and that has little tensile strength compared to the glass itself. If you are replacing toughened glass with laminated you will need a much greater thickness of laminated for the same strength. The general recommendation is to use toughened for marine services and holes are no problem as the glass company will cut those before the heat treatment.
In case someone comes along soon and recommends polycarbonate, as they often do, then again be very careful. Contrary to popular opinion polycarbonate has only the same tensile strength as Perspex, it is only more resisistant to impact. However, even when relatively lightly stressed it suffers badly from permanent distortion - creep (which is one mechanism that gives it resistant to impact loads, it absorbs energy by distorting permanently) whereas Perspex can be stressed up close to its ultimate tensile strength with no permanent distortion, but is not so resistant to impact loads - and this creep and its general flexibility leads to sealing and other problems. It is really only effective for very small windows and the only time I have seen it in hatches (Bomar, I think are the only ones) it has had supporting bars under it. Some codes for commercial vessels (e.g. the Canadian one comes to mind if I recall correctly), specifically limit the window size in which polycarbonate may be used.
That will have all those who have used polycarbonate telling me that is a load of rubbish, but if you ask any reputable marine port and hatch manufacturer they will say the same, and they all use cast acrylic which is not a cheap alternative.
If going for perspex (acrylic) then one should use cast acrylic as it is much more resistant to UV than the normal extruded stuff but at a higher cost. It also machines better and sealants adhere to it better.
We have looked at glazing lots of times for our boats and where practical we have always ended up with toughened glass or cast acrylic if using manufactured ports and hatches such as Lewmar, etc. If it were me and the existing was toughened glass I would be replacing with the same again. Any reputable glass company will prepare the glass to the relevant marine standard for you (should come to you with your country's relevant standard emblem fused into one corner), hole and all.
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robertj
Well-Known Member
Don't use a hammer as it often requires three or four large hits before the glass breaks and by that time your catchment system might have moved or fallen.
Use a centre punch (automatic, self-loading type) at a corner of the glass and it will break without any effort at all. That is what car thieves use to get at the laptop on the front seat or the Sat Nav on the dashboard.
+1
the fire brigade use the pre loaded centre punch to gain access to vehicles when in an emergency.
If that's not available a hacksaw blade used in one corner, not on a cutting but impact way.
AntarcticPilot
Well-Known Member
Friend of mine, bought a steel dutch pilot boat & found himself locked out.
Attacked the wheelhouse windows with a lump hammer & still couldn't get them to break.
Best of luck.
It needs a point blow; if you look at the safety hammers carried on things like coaches (I think you can get them to carry in your car), you'll see they have a sharp point. Once the "skin" is broken, the internal tensions of the glass will cause it to disintegrate. A lump hammer probably distributes the blow over too large an area, so the glass can resist it.
AntarcticPilot
Well-Known Member
Nothing new under the sun - my dad told similar stories about sentry duty in the UK during WW2! Issued one or two bullets; had to account for same at end of duty!
You can imagine it: "Who goes there, friend or foe?" "Foe!" "OK, hang on a minute while I load my rifle...."
Mind, his best story was about his army driving test. They had to do a hill start with a Bedford truck, and the sergeant in charge put his expensive watch behind the back tire, and said that any of them that slipped back would be paying for a replacement!
sailorman
Well-Known Member
use a nail punch