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  #1  
Old 06-13-2017, 06:31 PM
JDA_BTR JDA_BTR is offline
 
Join Date: Dec 2013
Location: Baton Rouge, LA
Posts: 415
Default Canopy Trimming

I'm working on the rear window and marked the "sigma" distance off the front edge. About to make the trim cuts for the rear aft window, then will trim the front once I get the tape line on.

What are best practices for making the aft relief cuts? Drill holes in the corners and then dremel/smooth the actual cuts?

What's the best way to shape the forward edge? 80 grit paper and sand to shape with a palm sander? Then a finer series to 400 last run?

I've read so much I don't know a nice clean way to do it right the first time.
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  #2  
Old 06-13-2017, 08:22 PM
cajunwings cajunwings is offline
 
Join Date: Jun 2007
Location: new iberia la
Posts: 470
Default Plex edges

For me 400 grit finish sanding on the edges is a minimum. I did 600 then wet sanded with 1000. A bit of overkill but no scratches.

Don Broussard
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  #3  
Old 06-13-2017, 08:52 PM
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wjb wjb is offline
 
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Location: Half Moon Bay, CA
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Quote:
Originally Posted by JDA_BTR View Post

What's the best way to shape the forward edge? 80 grit paper and sand to shape with a palm sander? Then a finer series to 400 last run?
On my -7 tipper canopy, I used a 12 inch block with 80 grit to fine tune the edges a the roll bar, then progressively finer grits up to 600 to polish it. I needed to take off about 3/16" to get the forward canopy it to size, and didn't want to use any power tools and risk the chance of overdoing it. Worked out really well .. 20 mins and done. The long block helped to keep the edge in a nice plane (no wavies!)
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  #4  
Old 06-29-2017, 12:53 PM
Rteem Rteem is offline
 
Join Date: Jan 2017
Location: Charleston, SC
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I recently cut my window and had to trim a little off the back of the canopy as well, had fantastic results following recommendations on the forum to use a dremel multi-max
https://www.dremel.com/en_US/product...multi-max-mm40

For the aft trim cuts on the window, I simply cut in using this, and then snipped the center out with a standard dremel. To radius the corners just used sand paper until the desired radius was achieved.

For all major cuts, I used the multimax with a steady hand and I was able to take off even small slivers. If you keep it moving smoothly it cuts straight and leaves a decent edge. I used a scraper on the edge to take out most tool marks, then used sandpaper as needed to bring to a polish.
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  #5  
Old 06-29-2017, 01:21 PM
Nova RV Nova RV is offline
 
Join Date: Aug 2015
Location: Leesburg, VA
Posts: 123
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For the relief notches in the rear I used a Dremel tool with the round sanding drum bit and then dressed the edges with fine and finer grits of sandpaper. The sanding drum allows you to make nice gentle corners to the notches so there are no sharp angles.
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  #6  
Old 06-29-2017, 03:26 PM
Tom Martin Tom Martin is offline
 
Join Date: Jan 2005
Location: Ontario, Canada
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I wish I could get one of you guys to try a cabinet scrapper. It really is the bomb for fine finishing plexiglass. Do a google search on cabinet scrapers. I use an old box plane blade. You turn the blade edge backwards and pull it towards yourself. You can make a perfectly round edge with no sanding required. It takes minutes to fine finish an edge. Over twenty years, no cracks, no sandpaper. Give it a try!
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  #7  
Old 06-29-2017, 06:37 PM
Tom Martin Tom Martin is offline
 
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Here is a nice little article on scrappers.

http://woodgears.ca/scraper/

It deals with wood but the principles are the same for plexiglass except there are no worries about the "grain" of the wood.
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Tom Martin RV1 pilot 4.6hours!
CPL & IFR rated
EVO F1 Rocket 1000 hours,
2010 SARL Rocket 100 race, average speed of 238.6 knots/274.6mph
RV4, RV7, RV10, two HRIIs and five F1 Rockets
RV14 Tail dragger under construction #153

Fairlea Field
St.Thomas, Ontario Canada, CYQS
fairleafield@gmail.com
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  #8  
Old 07-02-2017, 02:52 PM
Tom023 Tom023 is offline
 
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Location: Cypress, TX
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Ok Tom, took your advice and bought a cabinet scraper on Amazon. Are you kidding? This tool made it so ridiculously easy to precisely finish the edges with no sanding. I only needed to do small sections in the lower corners but the scraper is just the tool.
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  #9  
Old 07-02-2017, 05:54 PM
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Tilford Tilford is offline
 
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Location: KY
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Tom,

Could you post a picture or a link to the type of scraper you're referring to? I did a general search of cabinet scrapers and was surprised at the number of options. Sadly, I'm not very of woodworking and have very little knowledge of the tools of the trade.

Thanks,

Greg
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  #10  
Old 07-02-2017, 07:10 PM
Tom Martin Tom Martin is offline
 
Join Date: Jan 2005
Location: Ontario, Canada
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Here is some copy from a previous attempt to get folks to try a scraper. I use an old hand plane blade pulled backwards, or you can buy a real scraper, both work.
Note the little youtube video at the bottom that I did at the time.

Guys, finishing the edges of plexiglass to a smooth finish can be very time consuming but necessary. The method I use involves the use of a sharp blade from a wood plane. Hold the blade with the angle away from you, using a slight angle draw the blade towards yourself. Once you get the hang of it you will really enjoy the process. A few passes can make a nice rounded edges with no sharp nicks. If the edge had a slight wave caused by the initial saw you may need to use a sanding bloc for a couple of light passes or the blade will chatter. I typically use no sandpaper on the final canopy edges and if you get the knack of the scrapper, neither will you!
This idea is from woodworking where cabinet scrappers are often used for the final finish. The following short video will give you an idea of how it works.
This is just an alternative, use it at your own risk, and of course practice on some scraps first. Unfortunately the RV14 does not come with enough material to make scraps!


http://www.youtube.com/watch?v=XwW4gCdfmA4
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Tom Martin RV1 pilot 4.6hours!
CPL & IFR rated
EVO F1 Rocket 1000 hours,
2010 SARL Rocket 100 race, average speed of 238.6 knots/274.6mph
RV4, RV7, RV10, two HRIIs and five F1 Rockets
RV14 Tail dragger under construction #153

Fairlea Field
St.Thomas, Ontario Canada, CYQS
fairleafield@gmail.com
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