Is it possible to cut down my existing side windows?

[Jeremy]

One of the features I really like about my bus is the large side windows. I want to retain as much glass as I can, and in fact the front pair of windows are going to stay exactly as they are. I also want other windows further back as well, but the existing ones are just too big to fit in with the conversion. The problem is that the windows on my coach are all double-glazed, tinted, and worst of all, curved. I just know that fitting a set of RV-style windows is going to look awful, and no doubt cost me a fortune too.

What I really want to do is to get a couple of my existing windows cut down to a smaller size, so that when refitted they match the original windows further forward. Is this feasible? I'm hoping that the double glazed units could be disassembled, each pane cut, and then reassembled again by a glass specialist. I have a nagging feeling though that I've heard that old glass becomes brittle and very difficult to cut, and I'm not sure as well whether coach side windows are regular glass or toughened or something else special that cannot be worked.

Anyone got any experience of this?

Thanks

Jeremy

[NewbeeMC9]

You could just Black out the inside area of the window that you want to cover up.  It'll still look like a bus on the out side.   A couple layers  of dark limo tint should work.  Check out MAKs MotorCabins.

DIYW

[Jeremy]

Hi

Yes, I have seen people do that - unfortunately though, due to reasons too complcated to explain, I'm actually altering the steelwork of the window frames, so the existing windows won't fit unless they are physically smaller

Thanks anyway

Jeremy

[belfert]

This would be very difficult or impossible with sealed double pane units unless you don't care about the seal.  I can't imagine being able to reseal double pane glass after cutting it.

The glass is probably tempered which means it is very difficult to cut.  You'll need to find a glass shop willing to cut tempered glass, but even then there is a good chance of breaking the glass.  When tempered glass is made, they cut the glass to size before tempering it.

Tempered glass is often cut on Prevost Lemirages simply because it is so expensive to get curved sliding windows for that model bus.  Even then, it is not unusual for some of the windows to break while cutting.  Usually some of th windows are covered so there will be spare glass.

Brian Elfert

[gumpy]

Are those windows tempered safety glass?  That might create a problem.

I've heard, but have no experience with it, that you can use a sandblaster to cut windows down. You mask off the line you want to cut to, and blast through the glass. Again, very second hand, no experience. I suggest you consult with some custom glass shops that do hotrod glass work.

[Len Silva]

Jeremy,

I am far from expert but do have some experience working with glass.

If it is tempered glass it cannot be cut, even a deep scratch can cause it to shatter.  I do sandblast engraving and will only do a very light dusting on tempered where I can engrave very deeply, even all the way through regular glass.  Some colleagues of mine have reported engraving tempered glass only to have it shatter days or weeks later.

Tempered glass can be annealed, then cut and retempered but finding a shop that can do that will be a challenge.

Len

[Jeremy]

Thanks for the replies

Breaking down then reassembling the double glazed units doesn't worry me (I've seen it done with domestic windows, and it is straightforward), but I think the tempered glass issue is going to make the idea a non-starter. I am pretty certain the windows will be termpered glass as a couple of them are actually labeled as emergency exits, and having done some Googling it is clear that cutting tempered glass is impossible, and re-annealing is probably impractical.

The only other option that occurs to me is to make up my replica 'smaller' windows in acrylic or Perspex sheet (to allow me to get the necessary curve etc), and then maybe apply tinting film to the outside to try to match the appearance and make the windows more scratch-resistant (I believe the only real disadvantage of acrylic over glass is that it scratches much more easily).

I really don't want to fit RV windows!

Jeremy

[Stan]

Here is a suggestion out of left field. If you make the windows out of acrylic. can you hard coat them with the material they use on plastic eye glass lens? 

[Kristinsgrandpa]

Jeremy, 

I replaced a small section of a two piece window using a cut down piece from one of  my take outs.

After checking the local glass shops to no avail, I decided to try it myself. I went to Lowes and bought a 4" diamond saw blade for my Metabo. It was about $12.

I laid the smaller window down on the one to be cut and marked with felt tip marker, which made it a little larger,and proceded to make light cuts in the glass till I reached the innner plastic lamination, then I flipped it over and started on the other side, cutting all the way thru this time.

The corners were radiused about 8" but it worked fine. I was going to make the first one for practice but it came out so good I used it.

The edges were a little ragged but the rubber gasket around the glass hid all of it.  If you cut it a little big then you could take it to a glass shop and have them sand it down to exact dimensions and it would smooth out the ragged edge.

  A smooth steady hand with a good rest is the key to a smooth edge.

I used a pair of my sandblasting goggles, but I would suggest useing a pair of SCUBA gear goggles, and a very good particle mask or a respirator.

HTH Ed

[prevost82]

Wouldn't you also have to change the radius of the 2nd pc of glass?

Ron

[Jeremy]

Jeremy, 

I replaced a small section of a two piece window using a cut down piece from one of  my take outs.

After checking the local glass shops to no avail, I decided to try it myself. I went to Lowes and bought a 4" diamond saw blade for my Metabo. It was about $12.

I laid the smaller window down on the one to be cut and marked with felt tip marker, which made it a little larger,and proceded to make light cuts in the glass till I reached the innner plastic lamination, then I flipped it over and started on the other side, cutting all the way thru this time.

The corners were radiused about 8" but it worked fine. I was going to make the first one for practice but it came out so good I used it.

The edges were a little ragged but the rubber gasket around the glass hid all of it.  If you cut it a little big then you could take it to a glass shop and have them sand it down to exact dimensions and it would smooth out the ragged edge.

  A smooth steady hand with a good rest is the key to a smooth edge.

I used a pair of my sandblasting goggles, but I would suggest useing a pair of SCUBA gear goggles, and a very good particle mask or a respirator.

HTH Ed

Interesting - I've never heard of cutting glass with a power tool before (other than lasers and waterjets which are now used in industry apparently). Sounds like you were cutting laminated glass though - by all accounts tempered glass will shatter as soon as the surface is cut (something to do with the internal tensions in the glass introduced by the tempering process)

Jeremy

[Len Silva]

Laminated glass is a whole 'nuther animal from tempered.  It can be cut using conventioal methods.  One trick is to cut each side with a glass cutter, just a normal score. Apply pressure with your thumbs to the score until you hare a glass crack.  Do the same on the other side.  It is very important that the scores be directly over each other.

After both side have been "cracked" put a little lighter fluid along the crack and ingite it. This will soften up the plastic and allow it to seaprate.

I'm not sure what type of glass you have.  Most auto glass these days is tempered except for the windshield.

If it's laminated and not tempered, you might find a pro glass shop to cut it.

Len