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  #1  
Old 11-01-2016, 03:08 PM
bubba bubba is offline
 
Join Date: Dec 2011
Location: Roanoke, Va
Posts: 36
Default Melted canopy

I got a utility lamp to close to the canopy. This caused the canopy to melt causing a concave in the canopy.
I tried pushing the canopy back up after heating it to 200 degrees.the concave got worst.
I turned the canopy upside down, heated up the Plexiglas from the inside of the canopy and was able to remove some of the disfigurement.
I then turned the canopy over, placed utility lamp on the outside of the canopy, heated up to 225 degrees and placed a mold on the inside of the canopy and place 60 pounds of mold and left over night. This got more of the concave out, I still have about a 1/8 inch concave.
In all this stretching and melting I created two nipples on the outside of the Plexiglas about the size of a human nipple. I added heat to 250 degrees to outside of canopy pen pointing the area, but they did not go down.

Help
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  #2  
Old 11-01-2016, 03:15 PM
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Steve Melton Steve Melton is offline
 
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it may be time for some Viagra
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My Artwork is freely given and published and cannot be patented.
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  #3  
Old 11-01-2016, 03:22 PM
bubba bubba is offline
 
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Quote:
Originally Posted by Steve Melton View Post
it may be time for some Viagra
Have some didn't help.
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  #4  
Old 11-01-2016, 03:38 PM
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Steve Melton Steve Melton is offline
 
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leave it. take another look at it in a couple of years.
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Steve Melton
Cincinnati, OH
RV-9A, Tip-up, Superior O-320, roller lifters, 160HP, WW 200RV, dual impulse slick mags, oil pressure = 65 psi, EGT = 1300F, flight hours = 800+ for all

Simplicity is the art in design.
My Artwork is freely given and published and cannot be patented.
www.rvplasticparts.com
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  #5  
Old 11-01-2016, 05:51 PM
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Bob Kuykendall Bob Kuykendall is offline
 
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Location: Douglas Flat, CA
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[partially off-topic]

It's been my experience that plexi does strange things when you heat it up on its own. One of the things I make is sliding windows for bubble canopies, and I've found that you can't just drape heated plexi over the form and expect it to take on the form's shape. Depending on whether the temperature ramp is going up or down, I've found that sometimes the plexi arches up away from the form. I'm pretty sure that this is due to uneven heating through the thickness of the material, but it might also be due to residual stresses from the original forming operation.

Anyhow, what I do is make an edge capture frame that pushes the heated plexi against the form around the perimeter of the shape, and hold it until it cools. That seems to do it.
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  #6  
Old 11-01-2016, 07:41 PM
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Mark33 Mark33 is offline
 
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Location: Baton Rouge, La.
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That sucks!....I thought I was the only one that that happened to. I ended up replacing my entire canopy. 😏

Mark
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  #7  
Old 11-02-2016, 05:29 AM
bubba bubba is offline
 
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thanks, I think I will
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  #8  
Old 11-02-2016, 05:32 AM
bubba bubba is offline
 
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Your Idea is good. I had a concave mold done and used it in the inside after heating it. The shape took place but not completely.
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  #9  
Old 11-23-2016, 07:23 PM
socal socal is offline
 
Join Date: Jan 2006
Location: Bakersfield, CA L45
Posts: 48
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[quote=Bob Kuykendall;1123530][partially off-topic]

It's been my experience that plexi does strange things when you heat it up on its own. One of the things I make is sliding windows for bubble canopies, and I've found that you can't just drape heated plexi over the form and expect it to take on the form's shape. Depending on whether the temperature ramp is going up or down, I've found that sometimes the plexi arches up away from the form. I'm pretty sure that this is due to uneven heating through the thickness of the material, but it might also be due to residual stresses from the original forming operation
Im interested in one of your windows for bubble canopy, I have an RV8A,
More info please
Thx
Al Dilger avdilger@yahoo.com
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