Making new windows tomorrow - any tips for cutting/sanding/drilling please

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Trevelyan

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Hi all,
I've taken my windows off today, with the intention to reseal them - only to realise they are cracked as well as crazed. I've got some 6mm replacement sheet today and intend to make and fit them tomorrow. Any tips for cutting and then sanding/curving edges and drilling please, as I haven't much time to do any homework!

At the moment I'm intending to use a jigsaw to cut the sheet, 1/3 sheet sander to sand, and normal steel drills to drill....

All pointers appreciated!

Best wishes,
Trev
 
Trevelyan said:
Hi all,
I've taken my windows off today, with the intention to reseal them - only to realise they are cracked as well as crazed. I've got some 6mm replacement sheet today and intend to make and fit them tomorrow. Any tips for cutting and then sanding/curving edges and drilling please, as I haven't much time to do any homework!

At the moment I'm intending to use a jigsaw to cut the sheet, 1/3 sheet sander to sand, and normal steel drills to drill....

All pointers appreciated!

Best wishes,
Trev
Click to expand...

I did a couple of windows while in Norway last summer. My sheet was trimmed to about 25mm over sized rectangles initially. I used an ink marker around the old window - on top of the new sheet, making best use of long edges to reduce cutting. The sheet had protective film both sides- to mark on.
The saw I used was a fine cut hand saw ( 2 for £10 -B and Q), so it was new and sharp. That avoided the "chattering/shattering/chipping" issues with a jigsaw, which tend to also heat up and clog. I cut the corners as little straight segments -neatly, then finished them off by hand with 100grit wet and dry *wet*. Then 400 WD to tidy up .
Drilling holes was more tricky. I did 2 each end to pin the pattern (4 small bolts) , then worked my way round the rest.
I was pleased with the result. See outside without looking through crazing and scratches ... Yeeha!
There are still 2 more to do this season.
 
As I've a similar job to do at the moment...not a boat job...I'll be interested in this topic. I'm using Lexan polycarbonate....I'm just wondering if it's this material or perhaps acrylic or other material that the above windows are being cut from?
 
Throw an old towel over bench before putting the sheet down, but away from the edge of the bench.

A router will cut and put a rounded edge on without chipping, just don't push the too hard.

Running tape over the area and marking your cut line on it can help reduce chipping if you use a jigsaw.

Do not remove any protective coatings till ready to install, and only then if you must just prior to adding sealant.

Make sealant is compatible with all surfaces.

Use disposable gloves to avoid finger marks.

Good luck and fair winds. :)
 
As Oldsaltoz says, use masking tape round the perimeter and mark the profile on there if using a jig saw, plus take it slow with the jigsaw. I would also put masking tape on the base of the jigsaw to minimise risk of scratching the acrylic, although it has the protective film, this can easily be accidentally damaged.

Drilling holes with conventional steel bits is no problem, but again take it easy to minimise heat. As always a sharp drill helps and presumably the original window can be used as a pattern if clamped firmly to new piece.
 
if it's not too late I would consider using closed cell foam tape instead of sealant. It's neat, non-messy and it worked first time for me after several unsuccessful (leaking) attempts with sealant. I was using the correct type BTW. If you do use tape be very careful about screwing the windows down too tight especially if you have to countersink. 6mm is very thin and I would go for 8 or 10mm even though it's probably 3x the price. Sorry if you've already bought all this stuff! If you have, check the data sheet for your chosen sealant carefully with regard to the thickness of the layer you should have between window and boat. I thought it was best to screw down as tight as possible to get a good seal, but I was wrong. The materials expand/ contract in heat/cold but at different rates so you need a much thicker sealant boundary than you'd think. This is just what I discovered with the materials I used, yours may be different of course.
 
Small tooth handsaw or circular saw is best for straight edges, single speed jigsaw blade will heat up and clog. Coarse file or rasp good on corners used along the length. Standard drill bits can be used with care but can break out the plastic on the underside. Any old drill bits can be ground to suit plastic if you don't want to buy new dedicated ones see - http://www.instructables.com/id/Foolproof-Easy-Drill-Bit-Sharpening-for-Acrylic/

I used Arbo 1096 for bedding into frames about 7 years ago and no leaks so far in hot sunny area and, closed cell foam tape (sticky side to frame) for frames to coach roof.
 
Before you do anything, make sure that your old windows fit properly and are the correct size, I replaced mine last year as crazed and leaking, thought it was the sealant but no, the previous owner had made a right mess in his measurement. We're 10mm shy off what they should have been, got new rubber seals from Seals Direct. No problem with them.Buy the tool with the rubber to install much better than the end of a spoon.
 
Thanks all for your tips and advice. I tried using a jigsaw and found this difficult, melting the perspex. I then dug out a diamond blade wet cutter I'd used previously for cutting tiles - worked a treat! I used Sikaflex 295 in the end (but not the expensive primer that they recommend)... hopefully this will hold! Trev
 
I used a jigsaw with out any problems but you need to make sure you are using a blade for plastic, not any old blade, I also cut down the screen on my motor bike, so the saying goes right tools for the job, I laid my window plastic down on some 3/4 ply on two trestles, used G Cramps to hold the plastic down, when cut I used a small hand plane and run it lightly around the edge on both sides.
 
trthebees said:
I'm using Lexan polycarbonate....
Click to expand...

I am led to understand that polycarbonate is not ideal for windows .... although it is shatterproof, unless it is the really expensive specially UV coated stuff, it goes misty quickly in the sunlight. Acrylic is much more resistant which is why it is used more commonly

jr
 
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