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bkthomps

Well Known Member
When you are trimming excess away from the canopy, do you have to support the canopy ends like some have done with a flat surface and two pieces of wood at each end to prevent it from bulging?

I'm trying to figure out what order I am going to do this in, and it seems to me that everyone advocates supporting the canopy with either straps, duct tape, string, or a wooden cradle to maintain shape and reduce stress while drilling the canopy latch hole, having said that, I planned to remove some of the excess first before i drilled the hole- do I need to come up with a support system before trimming excess material around the edges??
 
Brian,

Although it may not be "necessary," it certainly doesn't hurt to have a mechanism for holding the canopy in shape when working on it. Less stress = less likelihood of a problem.

My two cents.

Greg
 
i'm also trying to figure out the best way to trim excess from the canopy, flip it upside down and trim along the sides? lay it up on the fuselage and trim while it's sitting quasi in place?
 
What worked for me

I made initial cuts with some duct tape to keep the plastic from spreading out - progressive cuts until done. As you cut away the excess, the canopy gets pretty flexible. Secure it well before making the "big cut."

Dan
 
Here is my no cost solution. I used some saw horses. Laid down the end pieces of the finish kit box on the saw horses and then clamped some wood pieces down to hold the canopy bubble from trying to splay outward. I would just hang the canopy over the edge of the platform as needed to trim with the die grinder abrasive wheel provided in the kit. A piece of foam in the center was used for support when the canopy would get flipped over while sanding the edges after trimming. I would not try to do this with the canopy on the fuselage. The acrylic dust is nasty and gets everywhere.

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Canopy

I just did this last week and it's much easier than most advertise. :):):)

I set the temp to 70-75 for a few hours then flipped the canopy upside down, as I cut the sides I would install duct tape on both sides every 10 inches or so for support. I made all initial cuts in about.

For the so called big cut I flipped it back over in the upright position and ran duct tape from the front, middle and aft section side to side to keep from spreading, again as I cut I installed duct tape every 10 inches or so on both sides reducing stress. This cut was completed within 20 min.

I did not use the supplied cut off wheels, I used a vibrating cut off tool, hardly any mess and great control. If ya need pictures let me know.
 
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I did it exactly ...

....like Ed just described. Had no trouble whatsoever. IMO, the vibrating cutoff tool is PURRfect for cutting plexi and fiberglass.
 
Which kind of "vibrating tool"?

Hello Ed and Therry

I have to do this soon, so I'm interested in more specific information about the "vibration tool". Do you have any pics or a brand name? Type of blade?

Thanks alot,

Dominik
 
Canopy cutting tips

I found the canopy on my -8 was not difficult to do, albeit unnerving. Here's what I learned:

I cut and trimmed with it sitting in the natural position on a large area workbench. As the sides curve a bit, I was able to position it so the area I was working on was hanging over the edge of the worktable allowing me to get my cutter in position.

I used a dremel to cut it, but the abrasive blade bogged down so much it slightly overheated my dremel motor and now it runs slow; however, I bought a diamond blade and it cuts the canopy (and fiberglass) like butter. The blade is also very thin and leaves a nice edge. I highly recommend it.

The only scarey moment was when a helper and I picked it up at the ends and turned it over. The sides bulged outward as we lowered it down to a blanket---yikes!!

I put it on and off the airplane canopy frame and roll bar a couple of dozen times by myself... here's how.

From the workbench, I lifted the canopy at the rear, slipped a hand underneath, and walked my hand forward to the neutral balance point. I then lifted the canopy from the single point inside and walked it to the aircraft, then reversed the process.

I found that method allowed me to move it without any adverse stress on the flimsy sides. Lifting it from the inside top lets it "hang" in a natural way with no stresses. I did the big cut in place on the frame and roll bar.

After the big cut, the canopy portion is much more flimsy. When I moved it to the workbench after that I would use a couple of clamps on either side of the cut end to keep it from spreading out while I dressed the edges.

Worked for me, and I am glad that part is over!

Don
 
Blocking the canopy is most helpful during the big cut to prevent it from splaying out and cracking. A short piece of 2x4 screwed to the table top in 4 places is all you need to do. I set mine on old towels during the trimming stages and often reset it on the fuselage for fitting. Make the big cut in 2 inch dots 1 inch apart and then connect the dots to complete it. Cut the bottom dots by the bottom edges first while the canopy is still mainly intact. I used a dremmel tool with 1/2" sanding drums to clean up the edges followed by a sanding block with fine emery paper for a nice polished edge.

Roberta
 
Pictures for the tool

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The tool cuts and sands for ya, you can get them at Menards, Home Depot, Lowes, Sears maybe even Wally Mart. I got mine at Menards, this tool has many uses and is inexpensive to purchase. Make three or four top cuts then make the plunge cut.
 
Ed, I noticed you made "the big cut" before you drilled for your latch handle hole, how were you able to determine the positioning of the canopy frame structure to line up where the cut would be??
 
forgot this

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I got this polish kit at Farm & Fleet, it also comes with a platic polish. After sanding the edges I attached this wheel to my die grinder using a lower pressure and polished all edges. The polished edges are like glass when your done. I think I only paid 15 bucks for this.
 
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Don

Just a note on your dremel, just drop over to lowe's and get a new set of brushes, clean the armature and drop them in and your dremel will be like new again. Been doing that to mine for 20years now.

bird
 
Latch

Hey Brian, the canopy latch hole was drilled before the cut.
Just cant see it in the picture.
 
any tips to determining the centerline of the canopy? I have tried a string, stretched from bottom left to bottom right, remove it, bend in half, mark a dot, stretch it back, mark the dot on the canopy, etc

it appears that when done, the line down the center, is not down the center, could be parallax error, etc, curious to see what others have done

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yes, that's safety wire holding the insulation panels on the garage door
 
Finding the longitudinal centerline ...

... of the canopy is as much art as science. My canopy had a mark at the center point of the nose and the very tail, but when I tried to use a chalkline between them, it did NOT end up on the visual centerline of the canopy. I fudged between the chalkline and a good visual centerline, and went on from there. In the process I also measured around from the side edges to the apparent CL ... IIRC, that didn't work perfectly cuz the canopy had more waste on one side than the other. ...like I said, more art than science. :eek:
 
Forgot to mention ...

...the vibrating cutters like Ed showed are available today from Harbor Freight, Rockwell, Sears, and a couple other mfgrs. From what I can see, they all operate about the same and are equally effective in cutting Plexi and FG. (They're all a knock-off of the original Fein Multi tool, a German gem that cost $300+. HF sells 'em underr $40. :D)
 
I bought one from HF for 20 bucks on their sale. It worked really nice, but it is a basic throwaway if it conks out. The brushes are made in such a way they can't be replaced or repaired. The wire pulled out of one brush on mine. They are crimped in and it was just not feasible to repair. The brush holder was a bear to remove and broke in the process. I replaced it with a Ridgid, but I think the HF cheapo worked more smoothly. These types of tools are a must have.

Roberta:)
 
second question, the canopy latch hole- i drilled to 5/8 and sanded smooth, but it seems that it needs to be just a bit larger for the powder coated canopy frame portion to stick out through it- is that normal? i realize i can elongate it to help with the fit, but can I enlarge the hole?
 
canopy angst

I worked with mine on the floor on a piece of plywood with blocks nailed on it to keep it from spreading. I had the temp at about 75 (max i could get) I kneeled with my knees between the sides from the back. I thought I would make a slit at the top, tape it all up to support it and then extend the big cut down the sides. I used the HF vibrating tool which works great by the way.

I got the top third cut, moved a bit to grab a tool, bumped the side with my knee and heard this click. Sure enough i cracked that sucker extending from the end of the cut. bottom line I started over with a new one.

Lessons:
temp needs to be higher. 2nd time around I heated the area I was cutting with a heat gun, monitored with an IR heat sensor. i did not cut or drill unless the material was 90F.

support needs to be different. sorry, this really needs pictures but i was not in a mood to take them if you know what i mean. One of the problems with just blocking on a table or something is that the aft section of the canopy is not supported. Using some scrap shipping carton plywood, I roughly cut out a shape that was about halfway down the canopy, then taped foam at points that even when the big cut was made, both the front and back would be supported. I put this support on some blocks to provide ground clearance. This worked good both for the big cut and subsequent work.

probably the biggest mistake I made was to cut just a slit. I should have scored the cut from one edge to the other. You have to make multiple depth passes any how. the crack I had started from the end of a slit I made on the top of the big cut. If I had scored it from one end to the other, if a crack did start, it may have followed the scoring.

This happened over a year ago, and I can talk about it now without crying. :eek: Hope you can learn from my oopsy.
 
my big cut is complete, crack free

thanks everyone for the tips, now for trimming and final fitment, and then I will come in with sika questions galore!
 
Thanks for the pictures!

Hello ed and Therry

Thank you for the pictures and information about the vibrating tool. I thought it will be one that you showed in the picture.

Here in Switzerland, Feintool is extreem expensive and difficult to get a "cheap one" but I try to find.

As it is barely visible in the pictures, you where using a blade with small tooth on it right?

Regards,

Dominik
 
Dominik, yes the blade that came with my tool is a fine tooth. Maybe you can buy one on the Internet and have it shipped
 
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