The Murphy Builders Site

Posted: **Fri Feb 17, 2012 10:37 pm**

Nearly the last cut and I cracked it!!! About 1.5 inches long on the top where it sits on the cabin top, about a third of the way across. I stop drilled it out to 5/32. Don't ask me why. That size just looked right. I plan to fill the stop drill hole with some kind of flexible sealant. Probably whatever I use to seal the entire windshield. It this an acceptable practice? I guess I should put something on the crack itself since water is insidious and will find a way through even the tight fitting crack. Otherwise, the windshield is a perfect fit. Sure don't want to throw it away and start over!

Mike Kimball
SR#044

Posted: **Fri Feb 17, 2012 10:37 pm**

Mike, ain't that a bummer!! Make sure that the hole you drilled is really beyond the crack and not short of the end. It's hard to tell where the crack stops in acrylic and it's better to guess a little long and let the crack come to the hole. I have to be a pesimist though and say that even stop drilled it will only get bigger with time, but it might last a few years. The only thing is you will have to pull all your retainers at that time, make a mess and install a new windshield before it becomes unsafe.

Take a large sheet of " butchers" paper, or similar, and make yourself a pattern of the windshield now before you install it, as you will probably break it removing it. That way when the time comes, if you decide to use this windshield, you can have the replacement already cut and ready to install for a quick "pit stop".

To make the pattern I clamp the paper to one edge and then take it across and clamp to the center of the other edge. Then you have to gather "darts" along the bottom and various other places to take up the slack and tape them off, until you have the paper sitting fairly smooth across the contour of the windshield.

Put some clear bathroom sealant in the hole and a smear along the crack. This stuff won't turn green like some will as it has a fungiside in it.

What are you cutting the windshield with???? I only paid attention to L&P's bandsaw recommendations once and that was expensive!! I only use a dremel with a 2" abrasive cutwheel in it. I find this works great and smooths and blends the edge as you go along.

Wayne

----- Original Message -----
From: Mike Kimball (mkimball@gci.net)
To: murphy-rebel@dcsol.com (murphy-rebel@dcsol.com)
Sent: Sunday, December 15, 2002 1:09 AM
Subject: Windshield crack!

Nearly the last cut and I cracked it!!! About 1.5 inches long on the top where it sits on the cabin top, about a third of the way across. I stop drilled it out to 5/32. Don't ask me why. That size just looked right. I plan to fill the stop drill hole with some kind of flexible sealant. Probably whatever I use to seal the entire windshield. It this an acceptable practice? I guess I should put something on the crack itself since water is insidious and will find a way through even the tight fitting crack. Otherwise, the windshield is a perfect fit. Sure don't want to throw it away and start over!

Mike Kimball
SR#044

Posted: **Fri Feb 17, 2012 10:37 pm**

I took my friends advice since it worked for him and used a 3-3/8 diameter cordless circular saw with carbide tips of all things. He actually used a full size circular saw! Sounds funny, but it actually worked beautifully for the entire windshield until it kicked back on the cut across the top for some reason. I'm guessing that I must have angled the blade slightly as I moved it and it just caught the one time. A drum sander in the air drill took care of the final fitting along with a small drum sander in the Dremel. That little drum in the Dremel was actually amazing! It was phenomenal how fast that little tiny drum removed material.

I did place the stop drilled hole just a tad past the barely visible end of the crack. Thanks.

Mike

----- Original Message -----
From: Wayne G. O'Shea (oifa@irishfield.on.ca)
To: murphy-rebel@dcsol.com (murphy-rebel@dcsol.com)
Sent: Saturday, December 14, 2002 2:07 PM
Subject: Re: Windshield crack!

Mike, ain't that a bummer!! Make sure that the hole you drilled is really beyond the crack and not short of the end. It's hard to tell where the crack stops in acrylic and it's better to guess a little long and let the crack come to the hole. I have to be a pesimist though and say that even stop drilled it will only get bigger with time, but it might last a few years. The only thing is you will have to pull all your retainers at that time, make a mess and install a new windshield before it becomes unsafe.

Take a large sheet of " butchers" paper, or similar, and make yourself a pattern of the windshield now before you install it, as you will probably break it removing it. That way when the time comes, if you decide to use this windshield, you can have the replacement already cut and ready to install for a quick "pit stop".

To make the pattern I clamp the paper to one edge and then take it across and clamp to the center of the other edge. Then you have to gather "darts" along the bottom and various other places to take up the slack and tape them off, until you have the paper sitting fairly smooth across the contour of the windshield.

Put some clear bathroom sealant in the hole and a smear along the crack. This stuff won't turn green like some will as it has a fungiside in it.

What are you cutting the windshield with???? I only paid attention to L&P's bandsaw recommendations once and that was expensive!! I only use a dremel with a 2" abrasive cutwheel in it. I find this works great and smooths and blends the edge as you go along.

Wayne

----- Original Message -----
From: Mike Kimball (mkimball@gci.net)
To: murphy-rebel@dcsol.com (murphy-rebel@dcsol.com)
Sent: Sunday, December 15, 2002 1:09 AM
Subject: Windshield crack!

Nearly the last cut and I cracked it!!! About 1.5 inches long on the top where it sits on the cabin top, about a third of the way across. I stop drilled it out to 5/32. Don't ask me why. That size just looked right. I plan to fill the stop drill hole with some kind of flexible sealant. Probably whatever I use to seal the entire windshield. It this an acceptable practice? I guess I should put something on the crack itself since water is insidious and will find a way through even the tight fitting crack. Otherwise, the windshield is a perfect fit. Sure don't want to throw it away and start over!

Mike Kimball
SR#044

Posted: **Fri Feb 17, 2012 10:37 pm**

I've heard of cutting plexiglas with a saw blade, but the blade was to be reversed to prevent kickback.

I don't know how this next one fits into the Murphy Digest but maybe someone will need a perfect circle for a cowl template.

Another weird one for you wood workers is the only way to cut a perfect circular on a large area such as a table is to use a table saw.
Find centre and mark acurate radius, trim to within about 3/8" of final. Set blade below table. Mount piece on surface using nail at true centre point so it can spin.
Raise blade into piece and slowly spin into blade. you will wnd up with a perfect circle although cut is slightly concave.

I've used this to make 48" round picnic tables and it works great.

Warren
Moose 029

Mike Kimball wrote:

I took my friends advice since it worked for him and used a 3-3/8 diameter cordless circular saw with carbide tips of all things. He actually used a full size circular saw! Sounds funny, but it actually worked beautifully for the entire windshield until it kicked back on the cut across the top for some reason.

Posted: **Fri Feb 17, 2012 10:37 pm**

Mike: You know for about $75 you in make a mold and form your own wind screen that is stronger and requires no center brace. It did take about a day and a half to conplete. Ed R109

----- Original Message -----
From: Mike Kimball (mkimball@gci.net)
To: murphy-rebel@dcsol.com (murphy-rebel@dcsol.com)
Sent: Tuesday, December 17, 2002 7:40 PM
Subject: Re: Windshield crack!

I took my friends advice since it worked for him and used a 3-3/8 diameter cordless circular saw with carbide tips of all things. He actually used a full size circular saw! Sounds funny, but it actually worked beautifully for the entire windshield until it kicked back on the cut across the top for some reason. I'm guessing that I must have angled the blade slightly as I moved it and it just caught the one time. A drum sander in the air drill took care of the final fitting along with a small drum sander in the Dremel. That little drum in the Dremel was actually amazing! It was phenomenal how fast that little tiny drum removed material.

I did place the stop drilled hole just a tad past the barely visible end of the crack. Thanks.

Mike
----- Original Message -----
From: Wayne G. O'Shea (oifa@irishfield.on.ca)
To: murphy-rebel@dcsol.com (murphy-rebel@dcsol.com)
Sent: Saturday, December 14, 2002 2:07 PM
Subject: Re: Windshield crack!

Mike, ain't that a bummer!! Make sure that the hole you drilled is really beyond the crack and not short of the end. It's hard to tell where the crack stops in acrylic and it's better to guess a little long and let the crack come to the hole. I have to be a pesimist though and say that even stop drilled it will only get bigger with time, but it might last a few years. The only thing is you will have to pull all your retainers at that time, make a mess and install a new windshield before it becomes unsafe.

Take a large sheet of " butchers" paper, or similar, and make yourself a pattern of the windshield now before you install it, as you will probably break it removing it. That way when the time comes, if you decide to use this windshield, you can have the replacement already cut and ready to install for a quick "pit stop".

To make the pattern I clamp the paper to one edge and then take it across and clamp to the center of the other edge. Then you have to gather "darts" along the bottom and various other places to take up the slack and tape them off, until you have the paper sitting fairly smooth across the contour of the windshield.

Put some clear bathroom sealant in the hole and a smear along the crack. This stuff won't turn green like some will as it has a fungiside in it.

What are you cutting the windshield with???? I only paid attention to L&P's bandsaw recommendations once and that was expensive!! I only use a dremel with a 2" abrasive cutwheel in it. I find this works great and smooths and blends the edge as you go along.

Wayne

----- Original Message -----
From: Mike Kimball (mkimball@gci.net)
To: murphy-rebel@dcsol.com (murphy-rebel@dcsol.com)
Sent: Sunday, December 15, 2002 1:09 AM
Subject: Windshield crack!

Nearly the last cut and I cracked it!!! About 1.5 inches long on the top where it sits on the cabin top, about a third of the way across. I stop drilled it out to 5/32. Don't ask me why. That size just looked right. I plan to fill the stop drill hole with some kind of flexible sealant. Probably whatever I use to seal the entire windshield. It this an acceptable practice? I guess I should put something on the crack itself since water is insidious and will find a way through even the tight fitting crack. Otherwise, the windshield is a perfect fit. Sure don't want to throw it away and start over!

Mike Kimball
SR#044

Posted: **Fri Feb 17, 2012 10:37 pm**

I used a small wood plane to shave down the edges on my windsheild. It
works way faster than you'd imagine and I was able to put a radius on each
edge.
Drew

At 06:40 PM 12/17/2002 -0900, you wrote:

It was phenomenal how fast that little tiny drum removed
material. Thanks. Mike ----- Original Message ----- From:
Wayne G. O'Shea To: murphy-rebel@dcsol.com Sent: Saturday,
December 14, 2002 2:07 PM Subject: Re: Windshield crack!
Mike, ain't that a bummer!! Make sure that the hole you drilled is
really beyond the crack and not short of the end. It's hard to tell
where the crack stops in acrylic and it pesimist though and say that even
stop drilled it will only get bigger with time, but it might last a few
years. The only thing is you will have to pull all your retainers at
that time, make a mess and install a new windshield before it becomes
unsafe. Take a large sheet of " butchers" paper, or similar, and
make yourself a pattern of the windshield now before you install it, as
you will probably break it removing it. That way when the time comes, if
you decide to use this windshield, you can have the replacement already cut
and ready to install for a quick "pit stop". until you have the
paper sitting fairly smooth across the contour of the windshield.
Put some clear bathroom sealant in the hole and a smear along the crack.
This stuff won't turn green like some will as it has a fungiside in it.
& and that was expensive!! I only use a dremel with a 2" abrasive
cutwheel in it. I find this works great and smooths and blends the edge
as you go along. Wayne ----- Original Message -----
From: Mike Kimball To: murphy-rebel@dcsol.com Sent:
Sunday, December 15, 2002 1:09 AM Subject: Windshield crack!
Sure don't want to throw it away and start over!
Mike Kimball SR#044

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Posted: **Fri Feb 17, 2012 10:37 pm**

Mr. Kimball,
My condolences; I cracked the windshield for my helicopter and cried for
a day. Then a fellow homebuilder called and assured me I was not the first
nor the last, the company included. Anyhows; I stop drilled and also
applied a little super glue to the length of the crack. The thin model
builders type flowed in nicely by capilary action. I have since heard of
something similar being widely used by homebuilders but this has served me
well for three years now.
Jim Goodwin SR179

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Posted: **Fri Feb 17, 2012 10:37 pm**

Jim, Group

Is the window Acrylic (Plexiglas TM) or Polycarbonate (PC, Lexan TM)? If it is
PC then methylene chloride is just the ticket to "weld" the crack. It is a
solvent for the PC and will weld it almost as good as new but two things to
watch for, first it is quite nasty so use very good ventilation, like outside,
and be careful how you apply it because it is watery thin & will run if too much
is applied. The effect is like model cement on the polystyrene of the models we
built as kids.

If the window is acrylic then there should be solvents to bond it as well. In
both cases a small patch covering the crack will add a great deal of strength
although it will be noticeable.

Cheers,

Dave
elite583.cjb.net

goody wrote:

Mr. Kimball,
My condolences; I cracked the windshield for my helicopter and cried for
a day. Then a fellow homebuilder called and assured me I was not the first
nor the last, the company included. Anyhows; I stop drilled and also
applied a little super glue to the length of the crack. The thin model
builders type flowed in nicely by capilary action. I have since heard of
something similar being widely used by homebuilders but this has served me
well for three years now.
Jim Goodwin SR179

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