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Getting Overspray Off of Canopy Lexan

rockitdoc

rockitdoc

Well Known Member
Sponsor
I screwed up.....again.

I didn't mask my canopy well enough while attaching it to the frame and got some urethane primer on the clear Lexan.

Does anyone know of a solvent that will dissolve the urethane but not the Lexan? Or, any other technique, short of rebuilding the whole assembly?

Worse comes to worse, I will extend the paint to cover the goof.

Canopy Overspray on Lexan 2.jpg
 
ELO works if the paint is fresh. The paint remover, not the musical group.

Are you sure you have Lexan? I do not know if the ELO eats Plexiglass.

Amazon has it.

BTDT
 
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Aircraftspruce.com has plastic polishing kit. You can wet sand down the overpray with 1200 grit and progressively use the polishing compound to polish the sanded part
 
Mike S said:
ELO works if the paint is fresh. The paint remover, not the musical group.

Are you sure you have Lexan? I do not know if the ELO eats Plexiglass.

Amazon has it.

BTDT
Click to expand...

I was thinking the music vibrated it off or some such.
What is ELO?
Not sure what the canopy is made of. I was guessing Lexan.
 
PhatRV said:
Aircraftspruce.com has plastic polishing kit. You can wet sand down the overpray with 1200 grit and progressively use the polishing compound to polish the sanded part
Click to expand...

That’s probably what Ill do unless the solvents work.
 
Overspray

Try Goo Gone first. Orange oil based. I like to start with it. Rarely causes damage.
Then Lighter fluid.
Then Goof Off or solvents starting with paint thinner and working up toward acetone. Goof Off is acetone so it will definitely cause some damage.

Then if nothing else works, light the match. :D
Sorry. Scott gets my sense of humor.
He's put up with it quite a while.
 
rockitdoc said:
I screwed up.....again.

I didn't mask my canopy well enough while attaching it to the frame and got some urethane primer on the clear Lexan.

Does anyone know of a solvent that will dissolve the urethane but not the Lexan? Or, any other technique, short of rebuilding the whole assembly?

Worse comes to worse, I will extend the paint to cover the goof.

View attachment 51923
Click to expand...

If all came from Vans, not another vendor, this is Vans supplier site for cleaning. If dried, not sure how effective… maybe a soaked rag laid in place. I recommend ALWAYS pulling masking after painting. Fresher the Paint the easier to remove. I just replaced my windscreen, all over spray cleaned off with mineral spirits. Works, no damage.

“ How should I clean my canopy?

Use cleaners specifically for acrylic. A damp cloth or an air blast will clean the dust away. To achieve the best results use fore and aft motion instead of a circular motion. To clean dirty acrylics use plenty of water and non-abrasive soap or detergent. All-cotton flannel can be used for drying. Never use aromatic solvents such as acetone, benzene, carbon tetrachloride, lighter fluid, lacquer thinners, gasoline, window sprays, concentrated alcohol, ketones or scouring compounds. Avoid using cleaners with ammonia, such as 409. Grease, oil or tape residue may be removed with kerosene, white gasoline, naphtha or isopropyl alcohol (Do not use isopropyl alcohol on extruded acrylic). Mineral spirits is our favorite. Wash approved solvents off of canopy with Dawn dishwashing liquid or equivalent and water followed by a clear water rinse. To prevent water spots, blow dry with compressed air or wipe dry with soft cotton flannel.”
 
Plastic razor blades
Paint doesn’t stick well to unscuffed acrylic.
The plastic blade is soft enough that it will not scratch if you use some care.
Finish the job with one of the approved solvents and some light polishing if needed.
 
Some of these answers may be better than mine.
I like the clay bar or plastic razor blade ideas.
However, I made a mess of my canopy while building. Van's said without approval to try MEK.
I went slow but eventually got it all removed with MEK.

This was ten years ago and no damage has appeared yet.

I also am not giving approval so I suggest a test coupon.
 
clay bar works well for VERY light overspray, as in tiny little specks. A clay bar will not help with a solid coating of paint, as that is what is apparently in the pic. My vote is for a plastic scraper and follow up with sanding / polish to get rid of any scratches created. Adhesion to shinny acrylic should be minimal.

Larry
 
Progress Report

Here's what I have tried, so far.

1. Isopropyl 99% - no effect
2. Plastic razors (blue and orange) - no effect
3. Lacquer thinner - doesn't soften the plexiglass so, I tried removing the primer with it. No joy by itself.....but,
4. Lacquer thinner to soften the primer a bit, then the plastic razor to scrape it off. This works! It's agonizingly slow, but, it works.
5. Polish the little scratches resulting from step 4 with Novus
6. Nice, clean result!

My advice. Don't get any primer or paint on your canopy like I did! Masking is cheap insurance. Take your time and do it thoroughly! This will cost me at least 1 day.

Oh, I have a call in to the manufacturer of the canopy to see what they recommend and will post the answer. But, in the meantime, unless there is a quicker solution, steps 4 and 5 above will be my process.

Oh, and that primer (Sherwin Williams Urethane) sticks to the plexiglass like frickin GLUE!! Getting it off requires lots of chisling with the little 'razors'. If this is any indication of how well the paint will stick to the aluminum, this airplane will never need a repaint.

Here's the place on the canopy I tested the process above:
Canopy Paint Removal Trial.jpg

And, this is what it looks like after and before polishing:
Canopy Paint Removed before polish.jpg

Then, after polishing: (don't judge my crappy paint job, it hasn't been cut and buffed, yet.)
Canopy Paint Removed and Polished.jpg

Lacquer thinner was runofthemill Ace hardware
LAcquer Thinner.jpg

Novus polish is three stages
Novus Polishes.jpg

Make sure to use the Novus Polish Mates. They are spendy, but work very well, an remember...it's your airplane we're talking about. I have tried to poor-boy this part with microfiber cloths and not been happy. So I bought the bulk pack of Novus Mates. They work.
Novus Polish Mates.jpg

The plastic 'razor' blades were from Grainger. Orange and blue varieties. I bought them both cause I didn't know the which was better for this process, but in the end I could find no difference. I think the materials they are made from are different and may matter for some purposes, but not this one.
Paint Removal Mini scraper orange.jpg

Paint Removal Miniscraper Blue.jpg
 
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Canopy

Glad you found a process.
If there is still some fogging, try this on some scrap.
Try cut & buff process then Meguires on a scrap piece. I tried it just to see if I could do it if needed later.
 
After reading this thread the curiosity is killing me so I just ordered a clay bar just to see what it does. :cool:
 
Pilot135pd said:
After reading this thread the curiosity is killing me so I just ordered a clay bar just to see what it does. :cool:
Click to expand...

I thought a clay bar was one of those "over the top" things that we seem to get on the market regularly, but they work really well. Clean an area very well with your normal method. I'm talking about painted areas, not the canopy. Thread drift alert! Then, spray lots of detailer liquid or other lubricant, and slide your hand across the paint. No matter how clean you thought it was, you will feel little bumps. After using the clay bar, these little bumps will be gone. At least that's what I have experienced. I've only used it on paint, not the canopy.

Sure, it's over the top, but wow, what a nice finish it leaves.
 
rockitdoc said:
Here's what I have tried, so far.

1. Isopropyl 99% - no effect
2. Plastic razors (blue and orange) - no effect
3. Lacquer thinner - doesn't soften the plexiglass so, I tried removing the primer with it. No joy by itself.....but,
4. Lacquer thinner to soften the primer a bit, then the plastic razor to scrape it off. This works! It's agonizingly slow, but, it works.
5. Polish the little scratches resulting from step 4 with Novus
6. Nice, clean result!

My advice. Don't get any primer or paint on your canopy like I did! Masking is cheap insurance. Take your time and do it thoroughly! This will cost me at least 1 day.

Oh, I have a call in to the manufacturer of the canopy to see what they recommend and will post the answer. But, in the meantime, unless there is a quicker solution, steps 4 and 5 above will be my process.

Oh, and that primer (Sherwin Williams Urethane) sticks to the plexiglass like frickin GLUE!! Getting it off requires lots of chisling with the little 'razors'. If this is any indication of how well the paint will stick to the aluminum, this airplane will never need a repaint.

Here's the place on the canopy I tested the process above:
View attachment 51973

And, this is what it looks like after and before polishing:
View attachment 51975

Then, after polishing: (don't judge my crappy paint job, it hasn't been cut and buffed, yet.)
View attachment 51974

Lacquer thinner was runofthemill Ace hardware
View attachment 51976

Novus polish is three stages
View attachment 51980

Make sure to use the Novus Polish Mates. They are spendy, but work very well, an remember...it's your airplane we're talking about. I have tried to poor-boy this part with microfiber cloths and not been happy. So I bought the bulk pack of Novus Mates. They work.
View attachment 51977

The plastic 'razor' blades were from Grainger. Orange and blue varieties. I bought them both cause I didn't know the which was better for this process, but in the end I could find no difference. I think the materials they are made from are different and may matter for some purposes, but not this one.
View attachment 51978

View attachment 51979
Click to expand...

So, I finished the paint primer removal today. Worked fantastic! One more tip: rub the lacquer thinner over the paint-primer many times to let the solvent do its thing. Wait about 30 seconds and then scrape with the plastic razor. I found that the paint-primer comes off much easier. Not easy, just easier. Anyway, the photos below show it before, after scraping, and the final finish. I can't tell there was ever any paint-primer or scratches on the surface. Very happy with the result. The whole process took 2 hours today. So, not as bad as I thought it was going to be.

This is the canopy with the primer to be removed.
Canopy Primer Removal Before.jpg

This is what it looked like after scraping the primer off. I know, it looks horrible, but....not to worry.
Canopy Primer Scratched Off.jpg

This is the final result after Novus treatment
Canopy PRimer Removed and Polished.jpg
 
Plexiglass window paint removal

Great that you were able to recover so well!

For anyone else this kind of thing happens to, here are a couple of other approaches. I know that sinking feeling - when I built, my windows came coated with a rubbery protective coating called Spray-Lat, which normally peels off easily. My plane spent tons of time out in the sun while wet sanding and polishing my paint, and I left the coating on the windows for protection. What I didn't know was that exposure to sun/UV hardens the stuff, until it is totally impossible to peel off. And it was all over all my windows!

After great consternation, I found some stunning advice, a liquid that would dissolve the coating (and most paints) and not harm the plexiglass. A solvent is vastly preferable to any mechanical/polishing process, as optical impacts are virtually unavoidable. The liquid is a 25%/75% mixture of toluene and acetone. Strangely enough, while either one will damage plexiglass, in this combination they will not. Some bizarre chemistry goes on there! This was some time ago so off the top of my head I don't remember which was the 25% and which was 75%, so if you get to this point you'll need to test with a sample of the target material, which you should anyway.

The other amazing solvent I've found is Motsenbocker’s Lift Off Spray Paint and Graffiti Remover. It is a latex based product that does an amazing job with no threat of damage that other hydrocarbon solvents pose. In fact, this company makes a bunch of Lift Off products that are useful for a range of applications.
 
☝️Acetone on RV canopy material …… NO NO NO !

From Vans vendor: Never use aromatic solvents such as acetone, benzene, carbon tetrachloride, lighter fluid, lacquer thinners, gasoline, window sprays, concentrated alcohol, ketones or scouring compounds. Avoid using cleaners with ammonia, such as 409. Grease, oil or tape residue may be removed with kerosene, white gasoline, naphtha or isopropyl alcohol (Do not use isopropyl alcohol on extruded acrylic). Mineral spirits is #1 recommendation.
 
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paint on windshield

Avoid chemicals with ammonia and/or isopropyl alcohol. They will cause crazing of the plexiglass. I flew Cessnas in a club that found out the hard way what these chemicals do.

Dave Nellis
RV7-A
95% done, 50% to go.
 
truflite said:
Avoid chemicals with ammonia and/or isopropyl alcohol. They will cause crazing of the plexiglass. I flew Cessnas in a club that found out the hard way what these chemicals do.

Dave Nellis
RV7-A
95% done, 50% to go.
Click to expand...

Really? Isopropyl alcohol is commonly used as a de-icing agent on aircraft. Commonly used, as in I used to have a 45 gallon drum of the stuff for just that purpose!

I've never seen IPA do anything to aircraft transparencies.

If you have a technical reference to support your assertion I would really appreciate reading and learning from it.
 
Isopropyl is commonly used as a de-icing agent on aircraft with glass windows.

For acrylic windows, you'll get somewhere between "slight corrosion and discoloration" up to "severe effect, not recommended for any use," depending on the conditions at the time you've used it.

https://www.industrialspec.com/reso...aka-pmma-chemical-compatiblity-chart-i-j-k-l/

I've spent decades watching people say solvents on plexi are okay due to various expressions of, "it worked well for me." I doubt any of those people will connect that declaration to the discoloration or cracking they'll complain about in 5 or 10 years time.

It's a bit like Sikaflex: We know what that does to acrylic, but it doesn't stop folks posting online about how great it is on their canopy. Very strange.


- mark
 
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