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Canopy Trimming

JDA_BTR

Well Known Member
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.
 
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
 
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!)
 
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/products/-/show-product/tools/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.
 
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.
 
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!
 
Picture or Link

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
 
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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Chair scrapes work well on plexiglass edges as well.

3-Veritas-scraper-shave.jpg
 
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