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Disclaimer: These aerobatics pages are developed by individual IAC members and do not represent official IAC policy or opinion.
Disclaimer: These IAC pages are developed by individual IAC members and do not represent official IAC policy or opinion.
This weekend, while refueling, a gust of wind caught my canopy. The retaining strap broke and the canopy hit the wing. As a result there are a lot of fine -- and a few not-so-fine -- scratches on the top of the canopy.
Any opinions on the best way to get rid of them? I used a polishing system containing various grades of grit on a Pitts canopy once, and was not that happy with the results. Is that the best way to go, or are there alternatives? Better yet, does anyone know of a professional in the Denver area who is actually good with plexi?
IAC Chapter 12
Rocky Mountain Aerobatic Club
From: "PAUL D READER" (email@example.com)
DJ, I've had some success using WET sanding paper with grit of 2000 followed by the highest available, which is about 4000. Use a rubber block and go with the airstream. DO NOT swirl the sanding pattern. The block is so that you don't just clean out the scratch and leave an optical wiggle after polishing. The block is about 2" x 3" and around 1/4 " thick. I always do this by hand since you can control the pressure easily. Essentially, this is the procedure used to finish small spots on auto finishes. After using a grit around 4000, the normal plexiglas cleaner that you use to remove scratches should clean the very minor haze from the sanding. You might want to try the procedure on a small sample piece to get the technique down pat and see what kind of results you will get.
I also used this method to finish lucite blocks. You might want to go to a trophy place and see if they have plastic finishing methods and materials to recommend.
From: "Matt Wilderman" (firstname.lastname@example.org)
As someone who's used all the mentioned methods, and more, they all work. It's a matter of how much work you want to put into it. My advice: Hire someone to do it. For the $300-500 they'll charge, it's well worth it. There are a number of outfits that do this. Ask your detailer, or local FBO's. If you can't find anyone, let me know and I'll get a name for you. In case you're interested, I just finished doing a canopy for a guy on a mid-wing 300. Canopy, with shipping-$12,500. Installation-$1000. Paint-$1500. Add $1000 for 300L's. The fuzzy gray stuff is a real pain in the ass to apply. Add in the damage to the fabric, the horizontal, and the wing, and you've got a nice little expense of ~$15-18K. Moral to the story...close and lock your canopy, allways, even just for a minute.
I also do a neat little mod where you mount an angle piece of aluminum across the back of the canopy and use two straps. Cheap insurance. Let me know if you want pics.
From: "tailwind" (email@example.com)
DJ, After using the various grit sand paper system up though 6000 grit wet, follow with the Dupont 1500 and 2000 polish system designed for the clear coat paint system. Use a a foam pad attached to a variable speed polisher. Start with a course pad and follow through with a medium and finally a fine pad until all sand scratches disappear. I spent 4 hours removing helmet scratches from the inside of an S-2 canopy a few weeks ago using this method. The canopy looked like new when I finished.
Good Luck, Gary Novack
From: Mike W. (Akrosmith@aol.com)
NOVUS, Inc. has a great polish.
Three step process starting with number #3 and working down to #1.
I had some severe helmet scratches and they are practiaclly gone.
From: Charlie Harrison (K2MZ@aol.com)
Meguires has one of the better systems for refurbishing canopies. It starts with increasingly finer grades of a special quality wet sandpaper and finishes up with increasingly finer grades of polishing compounds.
It takes a while but it is a lot cheaper than a new canopy.
From: "m.gallaway" (firstname.lastname@example.org)
The micromesh kit mis the way to go...but it is a pain in the ass....I do recomend it, I used it on my canopy at it really works.......
From: Bob (email@example.com)
Man what a bummer. As you remember, same thing happened to me. There is an industrial plastics seller in Boulder, called Boulder Plastics. They sell some polishing stuff for plastic. I think they sell multiple grades, I only used the finest 2. The scratches are not completely gone, but they are tolerable. The finest is really only plastic cleaner, not really a polish. The other is a true polishing compound. I don't know what grit level it is, but it reminds me a lot of Meguiers plexiglass polish. I typically use that stuff all the time, even for cleaning, not just for polishing.
My theory is that if I polish the scratches every time I clean the bugs off, I'll eventually put in enough strokes to polish out the scratches, which I think is the same idea behind the micro mesh. The deeper the scratches the tougher the problem, because you really have to thin your canopy down to the depth that the scratches no longer bother you, without thinning it in a way that causes optical distortion, meaning lot's of area. And you have to use progressively finer grit so you don't make more scratches. I'll bet the Micro Mesh system is scary, because the first grit level is going to look like it does more damage then good. Then you are committed to a long process of finer and finer compounds. It's pretty much like doing bondo work on a fender in prep for painting.
So if you look close, you'll see I still have some of the scratches, but they are going away slowly. The worst scratches I have are from my helmet on the inside before I got the seat belts right. I haven't even started working on them, and they are deep!
Good luck. Colorado Plastics is pretty close to Boulder Airport, on Pearl, near 30th.
From: Mike Dupont (MDupont339@aol.com)
I restored the plexi on a Long EZ once. Started with 400 sand paper to get out the deep scratches. DId this by hand with wet paper. Worked my way down to 1000 grit. Then finished it off with compound and a power buffer. It takes a while but you can get it all out. Toothpaste can also work on some scrathches but I had the best luck with the power buffer and rubbing compound
From: "Bob Buckley" (Bwana@PCISys.net)
You talked to Fonfara? He got in on a deal last year to replacing his Extra canopy that "disembarked". Dunno who made it but it was like $6k. Somebody like Phil DeTurck got him into the deal. Just guessing that the maker knows how to work plexiglass. I'll ask around Meadowlake.
How'd it all go? Weather looked pretty shitty today up next to the foothills and south of the Palmer divide. Got my mags back Thursday.
From: "Dr. Guenther Eichhorn"
I had the same happen to me. I fixed the canopy with Micromesh. It is a set of sandpapers with ever fine grit. The finest one is 10,000. You star with using regular sandpaper to smooth out the deepest scratches and the use ever finer grit to end up with a clear canopy. It is a LOT of work,(I spent several days sanding), but eventually (if you follow the instructions), you will get a clear canopy. You can get the Micromesh kit from Sporty's and other aviation supplies store. It is a lot of work, but it (actually you) will achieve amazing results.
I have no relation with Micromesh whatsoever, I am just a very satisfied customer.
If you have any questions about how to use it, let me know, I have been through using it and I would be happy to help anybody who wants to use it.