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Die Grinder vs. Oscillating Saw for Canopy?

Mark Dickens

Well Known Member
Patron
My die grinder is small, cheap and uses a lot of air for what it gets done. As I approach cutting the canopy, I will need to either buy a new die grinder, or find another way to get the job done. I was thinking about using something like a Fein Multimaster Oscillating Tool to do the work. Any experience or thoughts on this?
 
NO SAW

Get a 90 degree die grinder from Harbor Freight and some thin discs. IMHO a saw is a recipe for failure in this area.
 
My die grinder is small, cheap and uses a lot of air for what it gets done. As I approach cutting the canopy, I will need to either buy a new die grinder, or find another way to get the job done. I was thinking about using something like a Fein Multimaster Oscillating Tool to do the work. Any experience or thoughts on this?

I used an oscillating tool - it worked great. It's not a saw in the traditional sense. It was slow going, however - it was perhaps 10 or more passes along the cut path, deepening the groove a little bit more each time.

The best tool, after the big cut, was a small belt sander. I used coarse grit belts to grind the edges to the approximate size, then progressively finer belts to finish it, followed by hand sanding down to 1500 grit paper.

Edit-to-add: Look for reports here on the Harbor Freight version - much cheaper than the Fein tool. I used a Dremel version, but they all work on the same principle.
 
Done it both ways

I have cut my canopy with the die grinder (straight shaft) with Van's cutoff disks and helped a friend cut his canopy with an oscillating saw. Both worked. However I would use the die grinder over the oscillating saw any day of the week.

Since there is a lot of progressive trimming involved the die grinder is much faster to cut with then the other. You have to be careful and support your hands against the canopy when cutting with either one so the tool cuts where you want it to. When making the big cut put extra layers of masking/duct tape on either side of the cut line, just in case you wander by accident.

BTW the oscillating saw was from HF. It did the job and is cheap.
 
Plexiglas Cutting

I used an electric drill with a 3 in. disk fitted in the arbor. Worked great and I didn't run out of electricity!
 
My Bosch 6.4A model uses very little air. Well, I don't know how much is consumed at the power plant, but I never see it coming out of the outlet... ;)

I like that idea...my compressor is 25 gallons, so I'm sure it would be kicking on all the time.
 
Believe it or not. By the time I neared the end of all my canopy work I found that a cordless drill and the Van's disks worked the best. You do not need the speed of the die-grinder and having the weight of the drill helped.
 
I used an old electric (110 volt plug in) drill and chucked the cut off disk provided by Van's in that.

With the cutoff disk you aren't so much cutting as you are melting your way through the canopy.

Remember to tape it back together as you cut it. That will help keep it from cracking.
 
Electric

My Bosch 6.4A model uses very little air. Well, I don't know how much is consumed at the power plant, but I never see it coming out of the outlet... ;)

+1
Buy an electric. I rarely use that air grinder except for deburring.
HF sells one and the thin disks. I've cut 1/8" steel with it.
 
All die grinders use a lot of air!

They do use a lot of air. Air drills do not. I put the cutoff wheel in the arbor and used the air drill with very good success. I think I had better control of the drill than I would have had with the die grinder and the cutting speed was slower. Go light with several passes.

Dan
 
Not recommending using an electric drill

I cut my RV4 canopy with an electric drill (2500 rpm). I cut my RV-7A canopy with a die grinder (air). Both using Van's cutoff disks. I would never use the electric drill again. Way to slow a speed to properly cut with the cutoff disk.

One comment made is that the die grinder is too fast and will melt the plastic rather then cut it. That is not exactly accurate. If you don't move the cutting wheel with either a drill or die grinder you will develop heat which you want to avoid. So keep the disk moving and don't do a plung cut.

Your milage may vary, don't take if you are............bleeding may occur.
 
Believe it or not. By the time I neared the end of all my canopy work I found that a cordless drill and the Van's disks worked the best. You do not need the speed of the die-grinder and having the weight of the drill helped.

+1 on the cordless drill. I did mine this way and know of at least 3 or 4 other builders locally who did the same . It makes it very non-scary as you can control the speed much easier than a die grinder.
 
It makes it very non-scary as you can control the speed much easier than a die grinder.

Yep, my little die grinder goes from 0-whatever in a split second and I find it hard to control. Thinking of cutting an expensive canopy with that thing gives me nightmares.
 
Devil's Advocate

To counter the drill recommendations -- I used a die grinder and found it very easy to control due to it's weight and the fact that the high RPMs and a light touch kept it from getting caught in the cut. I can't imagine accurately controlling a heavy drill during the cut.

My compressor is also on the smaller side (33 gallon I think), but I augment it's capacity with an auxiliary 10 gallon tank. I no longer lack air in grinding tasks.

Good luck. It's really not a difficult task, though very messy. I did mine one very hot fourth of July and was soon covered in sweat and lots of plastic dust.
 
When we did ours, back in 2007, we used the air drill not die grinder, as a result of advice from VAF (I think).

The theory, IIRC, was the drill is slower but more torque, and would "cut" the plexi, rather than "melt" it. Heating the plexi is undesirable since it leaves residual stresses. As a consequence also make long cuts and only return to continue that area after time has allowed it to cool.

No idea if it is true, but sounded good and we followed it...
 
dremel works

My old Dremel 100 died on some of the first practice cuts. So I bought a new Dremel 4000. Much more powerful, and made the big cut without any problem. Small and very manageable. I wasn't worried about it getting away from me. And the thin disks did not remove much kerf.
 
Big Cut

Clean up the not perfect cut with a 80 grit
Belt sander. Then work your way down to 220 wet or dry. What ever you use to cut.
 
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An electric die grinder will pay for itself in not wearing out compressors, not to mention not blowing oil every where. After cutting I draw filed the edges smooth and polished them with a buffing wheel and white rouge. They look like glass. I practiced the edge polishing on some scrap first. It makes a very "finished'' looking job.
 
Mark, I used a Harbor Freight vibrating saw. It is not fast but it the unit that is easy to hold and control, Just follow your line and make a few passes. simple.
Dave
:)
 
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