Cutting windows

[NetDoc]

I contacted a glass shop down here in Key Largo to put in some panes into my '68 Fibra boat about a week ago. They were going to call me to come in for them to cut and install for about $300. So far they have not called. Phhhhhhhhhhht.

So, when I was in Lowes, I saw some Lexan and feel that I could spend about $150 in lexan and do the same thing. What I don't understand is how to affix the lexan into the frame. Silicone caulk??? Any hints, ideas or directions?

 

[Woodonglass]

Re: Cutting windows

I'd use this...

 

[BWT]

Re: Cutting windows

If you're working with plastic, silicone based caulking is reallyyour best option (although for any other application I DO NOT recommend silicone ) Most other caulks do not bond with plastic (read the fine print of the caulking labels) The product I like is made by Dow-Corning (their 791 caulking, or 795). It's a structural silicone that has good working time before it skins over. IMO as far as silicone's go, it's the best I've come across...

Hope this helps!

~BWT

 

[NetDoc]

Re: Cutting windows

After I cut the windows, should I lay a bead on the frame and then put the window in on top of that. After that sets, I feel I should Run a filler bead around the frame as well. Do I need to worry about the initial set?

 

[NetDoc]

Re: Cutting windows

Also, I plan to mark and cut the lexan with the protective cover on using a fine jig saw blade like 14tpm. Is this too fine? Will it cause the plastic to melt? I want to use a fine blade so it won't craze?

 

[RandyJ]

Re: Cutting windows

Another good source for lexan and possibly much cheaper is a sign shop that molds vacuum formed faces or a plastics shop. I used to work in a sign manufacturing company and discovered LOTS of materials that I frequently use when working on boats. The internally illuminated sign business uses lots of plastics and aluminum...and wires!

 

[phillyg]

Re: Cutting windows

Have a variety of blades on hand and use the one that gives you the best cut. Also, use a variable speed jigsaw and get the "feel" for the best cutting speed. It's worth the effort to practice a bit first. Make sure your jigsaw foot is clean and has no sharp edges. I recommend putting some masking tape over the protective sheets, top and bottom, to lay out your cutting lines, and it also helps provide some extra protection.

 

[Woodonglass]

Re: Cutting windows

phillyg is spot on. Speed is all important when cutting lexan or plexiglass. Tape is great. I also mix up a liquid soap and water mixture, heavy on the soap, and brush it on the glass prior to cutting. I doublesided taped a piece of felt on my VS Jigsaw to ensure not scratches.

 

[NetDoc]

Re: Cutting windows

I have a Bosch jig saw and I just put on the plastic foot. I learned the hard way when cutting out the hole for my stereo. The marks cleaned up nicely, and the weather cover did the rest. Still, I figured out real quickly what it was there for! Using another layer of tape is a GREAT idea. Now if it would stop drizzling so I can work.

Woodonglass, looking at your sig line, you might appreciate one of the custom smilies I made for ScubaBoard:

The code: [img]http://www.scubaboard.com/forums/images/smilies/ijs1.gif[/img]​

 

[BWT]

Re: Cutting windows

A source I use for the polycarbonate is Plastics International http://www.plasticsintl.com/ They carry anything you would want. Best pricing I've found. I've found that there is a HUGE price difference between distributors.

Lexan is a trade name, and there are many out there but generally they are all referred to as polycarbonate (some just have protective films to add scratch resistance and UV protection. The brand that I typically use is Makrolon GP (no scratch resistance but is UV stabilized). You can get the scratch film with any brand but IMO unless they are going to be mounted on deck where they can get foot traffic I don't know that it's worth the additional cost.

Also depending on the install lately I've been using an 1/8" VHB (very high bond) tape made by 3M. I use this to seal the glass to the frames and then a regular compound (4200 or 4000) to seal the frames to the boat. BUT, this isn't necessary for every application. If there is a caulking seam to trim off the exterior side of the glass and frame use a silicone. If you have a chance post some pics of your situation. If the glass is transparent (visible where it mounts onto the frame) the tape gives a nice clean appearance rather than using a caulk which may leave some "bare" spots allowing the frame to be seen through the glass after install (hint-hint). This is how many of the manufacturers do it giving a nice clean, trimmed off look. I live in north wisconsin where we get a huge swing in temps over a year and have never had an issue with bonding failure of the tape. Works very well, but I've always had to special order the tape direct from 3M to get this thickness and in black.

As far as cutting the material, I use a standard wood blade that cuts on the down stroke. Leave the protective film on the glass and run a piece of masking tape along the bottom feet of the jig-saw. I've done quite a few of these and have always had great results.

Hope this helps!

~BWT

 

[BWT]

Re: Cutting windows

I doublesided taped a piece of felt on my VS Jigsaw to ensure not scratches.

Great Idea! Have to try that one

 

[RandyJ]

Re: Cutting windows

One of the problems I've had cutting plastics with a jig saw is that it will get hot and melt around the blade. Plexiglas is brittle and will easily fracture/crack. Polycarbonate (Lexan) is really nice to work with though over time it may get cloudy. We used it in vacuum forming and it is hygroscopic so has to be dried before heating. Not that that will matter to you. My best results in cutting about any plastic was to use a router with a board set up for a fence to guide the cutting. One thing I really like about polycarbonate is that I've been able to bend it in a sheet metal brake.