How to buff out acetone on plastic window?

Nov 15, 2015
268
J J/30 Seward, AK
This is a ridiculous question, but if there is even the slightest chance to avoid the obvious work of ripping out 5200, I will pursue it.

has anyone figured out a way to buff out or clear up the erosive affect of acetone on plexiglass? See attached photo.
 

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Jan 11, 2014
12,774
Sabre 362 113 Fair Haven, NY
Not really. Once the outer surface of plexiglass degrades due to age, UV exposure or chemical exposure it is a forever chore polishing it. It will shine and be clear for a few days and then begin to cloud again.

There are polishing compounds for plastic often used on car headlights. You might pick up a small piece of plexiglass at the hardware store, spill some acetone on it and try polishing it. If it works, leave the plexiglass out in the sun for a while to see what happens.

Most likely the port will need to be replaced. Check out Boatworks Today YouTube site. Andy has did a video on replacing those ports a few years ago.
 
Nov 15, 2015
268
J J/30 Seward, AK
Funny thing is, we just fabricated and replaced these windows. The 5200 fast cure is two days old.
 

dmax

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Jul 29, 2018
1,163
Telstar 28 Buzzards Bay
I would try one of plexiglass polishes that airplane owners use on their windshields - since your plexiglass is new, you should be able to polish it out.
 
Mar 26, 2011
3,681
Corsair F-24 MK I Deale, MD
The damage probably has some depth to it. You will have to sand first, going up through the grits. Replacement will probably be easier. We're sorry!

Marine De-Bond is good for removing 5200... which is not recommended for glazing BTW. There is a high probability that the UV will weaken the bond within a few years. Use DOW 795.
 
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Jan 19, 2010
12,553
Hobie 16 & Rhodes 22 Skeeter Charleston
I've had very good luck using the auto lens cleaner.

I posted the results in this thread a few years ago... take a look

 
Sep 25, 2008
7,356
Alden 50 Sarasota, Florida
Depends on how deep the acetone permeated into the plexiglas - guessing is a fun game sometimes but you won’t know the answer until you try polishing
 
Mar 26, 2011
3,681
Corsair F-24 MK I Deale, MD
Depends on how deep the acetone permeated into the plexiglas - guessing is a fun game sometimes but you won’t know the answer until you try polishing
This is the thing. I've had mixed results with compounding. Sometimes it worked very well, sometimes nothing.

You may want to get cheap buffer if you don't have one. This is horrible by hand.
 
Jun 8, 2004
10,385
-na -NA Anywhere USA
as a former dealer, alot depends on the depth. First I used a compound called Finess It by 3 M using a buffer no more than 1000 rpm going back and forth rinsing it afterwards. The key here is not to let the buffer be pressed long in any spot or you will melt the plastic which is one reason no more than 1000 rpm. Sometimes it took 4-5 times but that generally took care of it. Others would wet sand only and then compound to finish the job.. Again it all depends and if the above does not work, replace it. For rebedding windows, use DOW 795, NEVER 5200.
 
Nov 15, 2015
268
J J/30 Seward, AK
as a former dealer, alot depends on the depth. First I used a compound called Finess It by 3 M using a buffer no more than 1000 rpm going back and forth rinsing it afterwards. The key here is not to let the buffer be pressed long in any spot or you will melt the plastic which is one reason no more than 1000 rpm. Sometimes it took 4-5 times but that generally took care of it. Others would wet sand only and then compound to finish the job.. Again it all depends and if the above does not work, replace it. For rebedding windows, use DOW 795, NEVER 5200.
Why DOW 795? Isn't that silicone?
 
Jan 11, 2014
12,774
Sabre 362 113 Fair Haven, NY
Dow 795 is silicone, but not all silicones are the same. Dow 795 and Silpruf are designed as glazing compounds for buildings and hanging plate glass windows. The curing process is different and it is not as susceptible to penetrating the gelcoat.

The Marine and household silicones we all love to hate (just about as much as 5200) does penetrate the gelcoat and it has a strong acetic acid odor. 795 and Silpruf do not have the same odor and the viscosity of the caulk is much different.

 

Mr Fox

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Aug 31, 2017
204
Marshall 22 Portland, ME
5200 is an incredibly strong adhesive, but it’s not compatible with acrylic, (as the acrylic off-gases, the bond/seal with the non-porous polyurethane 5200 will fail, and water will find its way into the boat) so as a sealant for a porthole it’s not the right choice. Use it to put things together that you never ever want to take apart, just not on acrylic (Plexiglass) or polycarbonate (Lexan), neither are compatible with polyurethane (5200) for different reasons.

As dlochner correctly stated both the 795 and Silpruf products are excellent above waterline marine adhesive sealants and are compatible with acrylic. Butyl tape is excellent as well if you have the correct frame on the portlight. Edit- disregard the tape in your case, I see from dlochner your's are frameless.

If you have any concerns about UV damage, you can sand the area of the plexiglass that will be in contact with the sealant/adhesive to make it more opaque, this will reduce UV exposure (and obviously you won't see the sanded area).

You can buff the acrylic/Plexiglas using a headlight polishing kit, definitely use a power tool to make life easier. I hope you can remove the plexiglass without destroying it.

Good luck!
 
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Sep 24, 2018
3,299
Catalina 30 MKIII Chicago
+1 for Butyl tape if you have the frame for it. Cleans up with Goo Gone which also doesnt harm Plexi. At least on mine it didn't affect it
 
Jan 11, 2014
12,774
Sabre 362 113 Fair Haven, NY
Butyl tape is a good sealant, however, it does not have good adhesive properties. The J30 has frameless ports that require the sealant to also have good adhesive properties. Silpruf and Dow 795 meet that criteria. 3M's Very High Bonding Tape also works.

 
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