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Paint on the plexiglass
- Thread starter togaflyer
- Start date
rocketman1988
Well Known Member
Paint
Don't use any acetone based solvent...
Don't use any acetone based solvent...
Start with denatured alcohol (the sooner after painting the better).
Soak with a saturated rag for a bit, then try and rub it off.
Soak with a saturated rag for a bit, then try and rub it off.
cajunwings
Well Known Member
Overspray
Some of the pro paint shops use Mothers aluminum polish and similar products to remove paint overspray from various surfaces including plex. This probably works better a day after vs a week after. I would start in a inconspicuous place.
Don Broussard
RV9 Rebuild in Progress
57 Pacer
Some of the pro paint shops use Mothers aluminum polish and similar products to remove paint overspray from various surfaces including plex. This probably works better a day after vs a week after. I would start in a inconspicuous place.
Don Broussard
RV9 Rebuild in Progress
57 Pacer
DougZetting
Member
Overspray
I would suggest doing some more research on what to use, maybe check with a plexiglass manufacturer on what to use. I used simple green to clean overspray off a plexiglass skylight and the damage took 6 months to a year to really be visible. Cost my insurance company 17 grand. It was a huge skylight!
I would suggest doing some more research on what to use, maybe check with a plexiglass manufacturer on what to use. I used simple green to clean overspray off a plexiglass skylight and the damage took 6 months to a year to really be visible. Cost my insurance company 17 grand. It was a huge skylight!
rocketman1988
Well Known Member
Simple Green...
Beware...some versions of this product do not react well with aluminum...
Beware...some versions of this product do not react well with aluminum...
I have also had to do this.
First tape off the good paint so you dont damage it. Blue painters tape or black elevtrical tape both work well for this
You can try the alcohol first. I always start with isopropol alcohol and then denatured alcohol if the first doesnt work.
If you still need something more, try Novus plexi polish.
Novus 1 is like milk and mainly cleans and polishes.
Novus 2 is for removing minor scratches and should remove any paint. Then follow that up with the Novus 1 if you want.
I use the Novus 1 as an everyday plexi cleaner and it works quite well for me.
Good luck.
First tape off the good paint so you dont damage it. Blue painters tape or black elevtrical tape both work well for this
You can try the alcohol first. I always start with isopropol alcohol and then denatured alcohol if the first doesnt work.
If you still need something more, try Novus plexi polish.
Novus 1 is like milk and mainly cleans and polishes.
Novus 2 is for removing minor scratches and should remove any paint. Then follow that up with the Novus 1 if you want.
I use the Novus 1 as an everyday plexi cleaner and it works quite well for me.
Good luck.
Auburntsts
Well Known Member
What method did you end up using?
rocketman1988
Well Known Member
Really?
That is odd, have never come across any acrylic that was resistant to acetone...
Right from the Plexiglass website:
"Do not use: Window cleaning fluids, scouring compounds, gritty cloths, leaded or ethyl gasoline or solvents such as alcohol, acetone, carbon tetrachloride, etc."
"Use a hydrocarbon solvent such as VM&P naphtha, kerosene, or mineral spirits. Follow with a detergent-water wash and a CLEAN water* rinse.."
That is odd, have never come across any acrylic that was resistant to acetone...
Right from the Plexiglass website:
"Do not use: Window cleaning fluids, scouring compounds, gritty cloths, leaded or ethyl gasoline or solvents such as alcohol, acetone, carbon tetrachloride, etc."
"Use a hydrocarbon solvent such as VM&P naphtha, kerosene, or mineral spirits. Follow with a detergent-water wash and a CLEAN water* rinse.."
Because my tape lifted just enough I had 3 coats of color and clear. I wiped the area with denatured alcohol, then used an exacto knife with a rounded edge to scrape the clear and most of the paint, then came back with the alcohol to finish the clean. The round edge did not have a corner edge to possibly dig into the plexigass, and I scraped the paint like it was a newly discovered Picasso being restored. Did not leave a scratch.
Captain Avgas
Well Known Member
Very bad advice.
Plexi is most certainly NOT resistant to acetone.
Acetone is a very strong solvent and will readily attack the surface of acrylic and dissolve the polymer chains. This leads to microscopic stress cracking which in turn leads to larger cracks by "work of fracture".
Here is a circular from Vans Aircraft on hints for fabricating plexi (acrylic) canopies. It very specifically advises not to use acetone.
https://www.vansaircraft.com/pdf/Acrylic_Canopy_and_Lexan_Window_Hints.pdf
I would suggest that if you have cleaned your canopy with acetone you have already irreversibly damaged it at the microscopic level and that there will be a high likelihood of visible cracking eventually.
Plexi is most certainly NOT resistant to acetone.
Acetone is a very strong solvent and will readily attack the surface of acrylic and dissolve the polymer chains. This leads to microscopic stress cracking which in turn leads to larger cracks by "work of fracture".
Here is a circular from Vans Aircraft on hints for fabricating plexi (acrylic) canopies. It very specifically advises not to use acetone.
https://www.vansaircraft.com/pdf/Acrylic_Canopy_and_Lexan_Window_Hints.pdf
I would suggest that if you have cleaned your canopy with acetone you have already irreversibly damaged it at the microscopic level and that there will be a high likelihood of visible cracking eventually.
Kyle Boatright
Well Known Member
Agree. I had a bad experience when I applied acetone to a Plexiglas wingtip lens.
flyboy1963
Well Known Member
a cautionary tale
ok, I wasn't going to comment, but since over 1,000 people have viewed this, some general advice might not hurt.
Not a criticism at all of the poster, he asked for advice, and got it, and did what he found worked....perhaps with some risks!
Plexi is funny stuff, and most haven't much experience with it.
the face is much tougher than the edge, often treated to be UV or scratch-resistant after processing, ( more common with Lexan). As others have said, use the manufacturer's recommendations, if you can get them.
whenever you get a scratch or paint or dirt on it, always start with the most simple, and benign solution possible.
warm water is good, soap and water likely better as it carries away impurities that could stick to the surface.
if the paint or sap or whatever is really stuck on there, something like peanut butter, ( hey, gets dried paint off my hands!) or mild solvents like mineral spirits ( plain paint thinner) or the 'alcohol's recommended, though most of those evaporate long before any effect on the stuff stuck to the plexi.
Caution: orange ( limonene) solvents can be harsher than the strongest petroleum based solvent!)
certainly, high level hydrocarbons like acetone, toluene, both components of lacquer thinner, are 'high-risk'.
Acetone ( as methyl methacrylate) is a component of most plexi GLUES, which dissolve the acrylic, thus welding parts together!
..... you may get away with them on new, soft, warm, non-stressed acrylic sheet, but as the material ages, UV reduces the plasticizers, or they are stressed by age, bending, or hot vacuum-forming ( gee, a canopy !) they are much more subject to damage such as the tiny stress cracks or risers that you hear about.
I've washed large sheets of plexi with lacquer thinner to remove paint, successfully, but eventually fresh thinner on old weathered plexi with numerous cuts and chips in it would craze and turn almost opaque, or crack into a thousand pieces.
I just don't want to hear of anything bad happening to your $1000 canopy.
ok, I wasn't going to comment, but since over 1,000 people have viewed this, some general advice might not hurt.
Not a criticism at all of the poster, he asked for advice, and got it, and did what he found worked....perhaps with some risks!
Plexi is funny stuff, and most haven't much experience with it.
the face is much tougher than the edge, often treated to be UV or scratch-resistant after processing, ( more common with Lexan). As others have said, use the manufacturer's recommendations, if you can get them.
whenever you get a scratch or paint or dirt on it, always start with the most simple, and benign solution possible.
warm water is good, soap and water likely better as it carries away impurities that could stick to the surface.
if the paint or sap or whatever is really stuck on there, something like peanut butter, ( hey, gets dried paint off my hands!) or mild solvents like mineral spirits ( plain paint thinner) or the 'alcohol's recommended, though most of those evaporate long before any effect on the stuff stuck to the plexi.
Caution: orange ( limonene) solvents can be harsher than the strongest petroleum based solvent!)
certainly, high level hydrocarbons like acetone, toluene, both components of lacquer thinner, are 'high-risk'.
Acetone ( as methyl methacrylate) is a component of most plexi GLUES, which dissolve the acrylic, thus welding parts together!
..... you may get away with them on new, soft, warm, non-stressed acrylic sheet, but as the material ages, UV reduces the plasticizers, or they are stressed by age, bending, or hot vacuum-forming ( gee, a canopy !) they are much more subject to damage such as the tiny stress cracks or risers that you hear about.
I've washed large sheets of plexi with lacquer thinner to remove paint, successfully, but eventually fresh thinner on old weathered plexi with numerous cuts and chips in it would craze and turn almost opaque, or crack into a thousand pieces.
I just don't want to hear of anything bad happening to your $1000 canopy.
Captain Avgas
Well Known Member
There has been so much dubious advice given on this thread that it is truly frightening. It's no wonder that so many builders end up with cracks in their canopies.
"Denatured alcohol" is more commonly called methylated spirits and consists mainly of ethyl alcohol with a very small percentage of methyl alcohol. And I can assure you that methylated spirits is extremely dangerous to use on Plexiglass and can cause instantaneous crazing.
It MAY be safe to use isopropyl alcohol on Plexiglass but I wouldn't advise anybody to use any alcohol because, as the post above shows, it is too easy to get confused between the various alcohols and truly stuff your canopy.
If a cleaning agent is required I would recommend Kerosene only, and then not more than is truly required. And I would avoid using it at drilled holes and cut edges to be on the safe side.
The truth is that acrylic sheet or poly methyl methacrylate (or Plexiglass brand name) is susceptible by degree to virtually all solvents.
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Thank you for the correction. I should have just posted a link to Section 5 of the manual which says.....
Grease, oil, tape residue, etc. may best be removed with mineral spirits, refined kerosene, white gasoline, naphtha, or isopropyl alcohol.
What did you end up using to successfully remove the paint?
Captain Avgas
Well Known Member
As per my post #19, denatured alcohol (methylated spirits) can be quite catastrophic on Plexiglass. In particular, formed single and double curvature surfaces tend to be even more susceptible to solvents than flat sheet due to the fact that they can contain additional residual stresses from the forming process.
I had a friend who used methylated spirits to clean his landing and taxi light leading edge lenses and they both cracked extensively.
How much damage you have done and whether you will have visible cracking in the future will depend on a number of factors including the quantity of methylated spirits you used, the duration of the application, the proximity to any existing flaws or discontinuities in the acrylic (e.g. scratches), and the curvature of the acrylic.
As I said previously on this thread I do not personally recommend that builders use any type of alcohol to clean their canopies. Yes, some types (particularly isopropyl alcohol) are relatively benign, but the trouble is that builders get confused and buy the wrong type (or get confused and give the wrong advice to other builders). It's safer to use (and recommend) kerosene because it's just so much easier to identify.
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Oops..........
Well, it's been well over a year and no ill effects visible. To be clear, I was very careful to just use a damp cloth (not liquid) and clean it off immediately. But no more...............
Captain Avgas
Well Known Member
So..........no Windex? (cleans glass and a whole lot more) ?
Red lights are flashing. Alarm bells are ringing !!!!
The Ammonium Hydroxide in Windex will eat into the surface of your Plexiglass canopy and leave it cloudy. Windex also contains other cleaners including 2-Hexoxyethanol, Isopropanolamine, Sodium Dodecylbenzene Sulfanate, and Lauramine Oxide. God only knows what they may do to your precious canopy.
At any rate if you read the instructions on a bottle of windex you will find that it specifically warns against using the product on acrylic surfaces.
I strongly advise against using ANY commercial cleaners on acrylic (or on polycarbonate in the case of the RV12). You just don't know what's in them or the damage they may do. As I have said previously Acrylic can be irreversibly damaged by an enormously wide range of chemicals. It is frighteningly susceptible to damage at the molecular level.
This is the safe strategy I recommend for cleaning an Acrylic canopy.
1. For normal everyday cleaning use a dedicated and proven Acrylic aircraft windscreen cleaner such as Plexus. Expensive but 100% safe.
2. For more serious cleaning use a mild dish detergent in water and apply with a high quality microfibre cloth to avoid scratching the surface. If that fails move to Kerosene. Remove any Kerosene residual with the mild dish detergent. Don't use more Kerosene than is absolutely necessary and avoid dangerous areas such as drilled holes and cut edges.
3. For more persistent surface soiling (paint overspray etc) I'd use a dedicated acrylic scratch removal kit such as Optica Scratch-off or Micromesh. Once again, expensive but safe.
That's it...I wouldn't use ANYTHING else on my aircraft canopy. No alcohols, no solvents...nothing. And don't even think of going cheap in this area and using general household cleaners. There is probably no worse job on an RV than replacing a windscreen/canopy.
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