Cutting the Canopy -Method

It's my turn to try my hand at cutting the canopy. I'm going with a tip-up. I laid the canopy as it came from Van's over the top of the fuselage. I was wondering if anyone had tried cutting the canopy by just leaving it up there and possibly using cleats between the fuselage and the canopy to keep the cutting wheel clear of the skins etc. it almost looks doable.

Anyone?? What was your method?

I think you're taking an unnecessary risk if you use a cutting wheel with it just over the skins. Of course, there's more than one way to skin a cat. But the way Vans described is tried and true. If it were me, I'd be asking if the benefits outweigh the risk. I'm just sayin'...

By all means, follow the instructions! Trim down the perimeter until the gap over the roll bar is close. If you don't, then a gap will occur as the ends are high and the center drops. I used an angle head die grinder for the big cut. When making the big cut, a frame to keep it from spreading and/or dropping is good to prevent stress on the cut as it progresses. I also taped behind the cut periodically.

After the big cut, I made a cradle to hold the canopy upside down in order to use the various tools for fitting. I made three hoops from 2X4's then feet with carpet for the cradle. Kinda like a boat trailer, only with more contacts. A diamond wheel in a dremel makes nice precision cuts for trimming. I sanded with a belt sander for part, but used a 18" board with sand paper for the hoop edge to keep it planar. Get a number of grits of sand paper on blocks ready, so you can keep the edges relatively smooth thus avoiding a crack.

Good Luck, it is a lot more talk than action with the big cut. It only took about an hour. Fitting is much longer.

Temperature is a big factor in cutting the canopy
Some of what I did.
Placed the canopy on the fuselage and marked the centerline as well as on the forward fuselage skin
Used the shipping crate and made blocks to hold the canopy in place on the top of the shipping container.. I used 4 pieces of 2x4 padded that would allow the canopy to nest between them
I made a center support of old pillows and towels to hold up the center section as I made the cuts.
Put electric heater to blow under the canopy until it's temp was above 90 degrees.
I used a Dremel tool with the newer 1 1/2 cutoff wheel in the thinnest Profile they come in different thickness.
I taped the canopy on the fuselage and marked the center of the roll bar. Then I used electrical tape to space me a cut line for the cut, Two runs across the top of the canopy spaced a a tad less than a 1/16 th apart. Then put the canopy back on the crate.
I practice cutting off some of the excess plastic and then went for the big piece
I scribed ,using the Drexel, a line across the entire canopy then came back and made repeated passes until I cut through 4 inch to 6 inch sections separated by 1 in uncut across the canopy
Then had my wife support the front end and pack the pillows under then cut the remaining 1 inch spaces leaving the top spaces for last.
Before doing anything else I belt sanded the edge with 120 then used an orbital sander and worked up to 320 grit on the edge. then wet dry sanded the edge to 600 grit.. No marks left
Now since you marked the center lines you can place the canopy back on the fuselage and sit back and call it a day.
Pretty close to what I did. For me the cutting wheel supplied by Vans was to big
Jack

Okay, I took the advice of not trying to cut the canopy on the fuselage.

I began cutting today. Took wood crate turned upside down on some saw horses. Draped carpet scraps over the crate and piled an old sleeping bag, pillow, and blankets on top to support the curve of the canopy. The crate is about 2/3 of the width of the canopy. the sides of the canopy hang over the sides of the crate. It is supported very well.

I found the cutoff wheel supplied by Van's had less than stellar performance because my compressor could not keep up with the die grinder. Switched to a Dremel tool with a carbide cutting wheel and it works amazing. Cuts fast and cuts much cleaner with more control than what I could get with the cutoff wheel. Likewise, as the compressor would fall behind the die grinder, the cutting wheel would bind and I was afraid of creating a crack. The Dremel never threatened a bind. The feel is much more natural to me and being electric, my cutting power and speed did not vary like with my compressor. Made several large cuts and think I'll be sticking with the Dremel. I'm using 100 grit between cuts to smooth the edges. I'll go finer grit once this thing gets to final shape.

More cutting tomorrow! I think I've got my technique figured out. The 95 degree weather is also helping.