Removing scratches in plexi

[madk]

I'm starting a new thread that will focus on removing scratches in plexi-glass or other acrylics.  As many of you know I have a nice scratch on my new control and was looking for advice here - http://www.arcadecontrols.org/yabbse/index.php?board=1;action=display;threadid=2654

I've done a small bit of research online and found some descent info...

Scratch Removal: In the event that, after taking meticulous steps to prevent it, your fine piece of acrylic becomes scratched, HAVE NO FEAR. Fine scratches can be removed with a mild abrasive polish such as Novus #2, or Novus #3. Heavier scratches, such that you can feel with your fingernail, will require some elbow effort to remove with a bit of sanding and buffing. A series of grits (150,400,600) followed by a buffing wheel and available buffing compound, will restore the luster of your acrylic!

I would like others to post an info they have regarding removing scratches.  I'll post more as I find it.

Thanks,
mad-k

[Grasshopper]

I once bought some glue called "Loctite Glass Bond". Not surprisingly this is used for sticking glass to glass, or glass to metal.

It's a bit of a long shot, but it occurs to me that this stuff may be suitable for filling in the scratches on your panel.

[John IV [MameUI64]]

Hmm, the Novus polish solution would interest me as I have some very fine scratches from sanding a corner of my Lexan.  I'll see if I can find some tomorrow and report back here.

I'm starting a new thread that will focus on removing scratches in plexi-glass or other acrylics.  As many of you know I have a nice scratch on my new control and was looking for advice here - http://www.arcadecontrols.org/yabbse/index.php?board=1;action=display;threadid=2654

I've done a small bit of research online and found some descent info...

Scratch Removal: In the event that, after taking meticulous steps to prevent it, your fine piece of acrylic becomes scratched, HAVE NO FEAR. Fine scratches can be removed with a mild abrasive polish such as Novus #2, or Novus #3. Heavier scratches, such that you can feel with your fingernail, will require some elbow effort to remove with a bit of sanding and buffing. A series of grits (150,400,600) followed by a buffing wheel and available buffing compound, will restore the luster of your acrylic!

I would like others to post an info they have regarding removing scratches.  I'll post more as I find it.

Thanks,
mad-k

[1UP]

I actually removed some pretty bad scratches from my red coin reject buttons by wet sanding with fine grit paper, then buffing with a dremel buffing wheel and some toothpaste.  Works like a charm!

[rampy]

I did a quick search on RVGAC to see how the "pro" restorers deal with it... looks like the novus stuff is the way to go...

goofle usenet news thread 1

google usenet thread 2

*shrug* thought that'd help...

rampy

*modded* fixed daft url

[Keith O]

I bought Novus to take the scratches out of my arcade laserdics and it works great. I haven't had anything too deep but I imagine you could use a dremel buff in addition to the novus and it would work well.

[madk]

Well after searching around it does look like this Novus stuff is the best around.  I order a bottle of  Novus 3 and Novus 2 from http://www.pinballusa.com.  Hopefully I'll get my order by the end of this week and I can post back with results.

Thanks for the help and info so far.  I'd still like to hear from others if you have some info.

-mad k

[John IV [MameUI64]]

Were you unable to locate it locally?  Does Home Depot carry it? Perhaps one of the auto parts stores.. Hmm.

Well after searching around it does look like this Novus stuff is the best around.  I order a bottle of  Novus 3 and Novus 2 from http://www.pinballusa.com.  Hopefully I'll get my order by the end of this week and I can post back with results.

Thanks for the help and info so far.  I'd still like to hear from others if you have some info.

-mad k

[madk]

I actually didn't check anywhere locally.  Most of my attempts to find things locally fail.  Even tho I do have a Home Depot and a Lowes nearby.  I'll check there sites and report back...

UPDATE - I just checked both of the websites and didn't find anything.  Tomorrow I may run to Ace Hardware and see if they have anything.  I've had good luck with them in the past.  I'll keep you updated.

[Keith O]

check here:

http://www.spadepot.com/products/005novus.htm

You also might be able to find it at a local spa shop.

[Lilwolf]

if you get those CD scratch removers (that look like the scrap robot transport from starwars one with the little guys in it)...

then hack it so it will take a full sheet of plexi..  Then hook the crank arm up to a 2cc gasoline engine

and your set..


(btw... jk)

[rampy]

OT:

they were called jawa's...  (oops, I let my star wars geek side show...)

rampy

[John IV [MameUI64]]

Amusingly, your local Novus windshield repairer should carry it.  I'm picking up a bottle of Novus #2 today from them.

[madk]

Report back with the results.

[John IV [MameUI64]]

The number #2 did nothing to help.  Could not notice a difference in the Lexan even after a third application.  Guess I'll return it and try the #3 next.

Report back with the results.

[1UP]

Somebody mentioned using a heat gun before.  How exactly would you remove scratches with this?  May need to take a scratch out of my spinner knob...

[nullb0y]

those cd things remove layers making cds weaker!!!!!!!!!!!!!!!!!!!!!!!

[Beley]

Somebody mentioned using a heat gun before.  How exactly would you remove scratches with this?  May need to take a scratch out of my spinner knob...

I mentioned it on the other post dealing with this, When we were relpacing a windscreen in our boat someone slipped and scratched a peace of wood acoss part of the window. The scratch was probably about the equivelent of someone taking a 1cm x 1cm peace of 40 grit sand paper and dragging it across the plexy while pushing hard.  by applying a lot of concentrated heat to the scratch (holding the heat gun right over it for about 30seconds) it dissepeared almost compleatly.  

if you try this just be carfull not to head the plaxy up so much that it bubbles

[1UP]

I mentioned it on the other post dealing with this, When we were relpacing a windscreen in our boat someone slipped and scratched a peace of wood acoss part of the window. The scratch was probably about the equivelent of someone taking a 1cm x 1cm peace of 40 grit sand paper and dragging it across the plexy while pushing hard.  by applying a lot of concentrated heat to the scratch (holding the heat gun right over it for about 30seconds) it dissepeared almost compleatly.  

if you try this just be carfull not to head the plaxy up so much that it bubbles

So the heat just melts everything back together?  No rubbing or anything else?

[John IV [MameUI64]]

Novus #3 also did not work on the Lexan sanding scratches.  Will investigate the heat gun alternative next.  

The number #2 did nothing to help.  Could not notice a difference in the Lexan even after a third application.  Guess I'll return it and try the #3 next.

Report back with the results.

[rampy]

could the physical characteristics of lexan be a problem here?

Don't most people use lexan 'cuz it's stronger than plexiglass?

Maybe all of these tips are truly for plexiglass with lexan being a slightly different beast?  (more elbow grease required ...  or  mystery buffing agent?)

Just a thought.

rampy

EDIT YAGGT (yet another google groups thread) google link here


Another one... Another one... here  talks about motorcycle helmet shields and windshields... they use Meguiar's Mirror Glaze Plastic Polish and Plastic
Cleaner.... I bet it's just like novus, so no real luck there...

[madk]

I actually removed some pretty bad scratches from my red coin reject buttons by wet sanding with fine grit paper, then buffing with a dremel buffing wheel and some toothpaste.  Works like a charm!

May I ask what grit paper you used?  

[Beley]

So the heat just melts everything back together?  No rubbing or anything else?

no rubbing just heat, you could just barely see where the scratch was if you looked very closley in the right light.  I think it works because it must melt a very thin layer on top whick goes all flat and therefor clear

[Donor]

Your local Spa or Hot tub shop may carry novus and maybe some others alternatives for removing scratches.

[Xiaou2]

I used to use novice at the arcade i worked at.  Its dosnt really work.  its more of for protection, and shine.   All it is, is some creamy substance, and sand.

 Basically, to get rid of a scratch in plexi,  you either have to sand the cracked surface round, or sand past the depth level of the scratch.    When using sand paper, if you use a heavy grit, it will massacure the plastic with tons of new scratches... so you have to use a fine grit paper... but its gona take forever... and even so, will probably look 'frosted'
because you cant get the surface perfectly level.

 The heat gun approach seems the best candidate.  Or maybe even a combination of sanding heavy, then light, then heating it to 'sheen' the surface to a nice smooth finish.



 

[madk]

As an update to all my posts...I recieved my bottle of Novus 2 and 3 the other day and have been doing some tests with it.  I used a spare piece of plexi and ran a few tests.  I first applied the #3 to fill in the larger scratches and then moved up to the #2.  Once done it looked as if nothing had changed...but once I buffed it heavily with my dremel everything came out smooth.  It took a bit of power...but I think buffing is the solution here.  Make sure to apply a lot of pressure and don't stop once you start.  You need to create enough heat to smooth out the plexi.

[Brax]

Heres another solution.

I do alot of plastic modeling. Many modelers perfer a thinner, more "scale" thickness for aircraft canopies. How do they do it? They sand they canopy, starting with a 600 grit sandpaper working their way up to 1000. This leaves the canopy totally white. How do they get it clear again? Future Floor Polish. Future is an acrylic sealing system. In english........ waterbased clearcoat. If you have an airbrush just spray it on and any frosting will dissappear.

By the sounds of it you guys are being way too gentle to get any scratches out. You used SANDPAPER to put them in. You can't be gentler to get them out! Before you worry about a nice shiney finish you need to get the scratches out. Start with a fine grit sandpaper and move to even finer. Then use your polishing compounds to get the final shine. If its still lacking a shine, the Future will work wonders.
Try it on a test piece. It works. You can't be gentle, go for it! Especially with Lexan..... Some say it's bullet proof!

[Dave Dribin]

Just to add my $0.02.  I spent the day getting some nasty scratches out of my monitor plexi.  Some of the scratches were quite deep: I could feel 'em with my fingernail.

I tried a while ago using Novus #3, #2, and #1.  This didn't work too well.  Today I tried using sandpaper first, and it worked great!  I bought some 600, 800, and 1200 grit at a local boat supply store.  Use the sandpaper starting with 600, to get the scratches out completely.  I used a little water to do a wet sand.  It may take a while to get the scratch out if it is deep.   I wish I had 400 grit paper, too, since one of my deeper scratches took a *lot* of elbow grease with the 600.  The plexi will haze or frost, but this is ok.  That's what the Novus #3 is for.  I actually only used the 800 on one of the scratches.  And one of the scratches I skipped the 1200, too, only using the 600 and it worked out ok.  Using the 1200 seemed to produce a nicer result before going to the Novus,  so I used it on the rest.  I'd be interested to here other's opinions on whether 1200 grit is necessary.

Ok, after the scratch has been completely sanded out, you should be left with a frosty, smooth section on your plexi.  It's now time to take the haze out.  Break out the Novus #3 and keep polishing until the the haze disappears.  In some cases, I had to apply it 3 or 4 times with some heavy elbow grease to get the haze to go away.  This is probably the toughest part of the whole thing and wish I had a power tool to help out.  My arm is killing me!  Note: I've heard using a Dremel for buffing is very bad as the RPM is way to high.  I've heard you want about 2000 or 3000 RPM while buffing or you can melt the plexi and cause it to bubble.  Dremels are 15,000 - 30,000 RPM.  Anyhow, once you get the haze completely out with Novus #3, you can use #2 to take out the fine scratches that are left.  You should have a clear, smooth, scratchless surface.

And after all this, voila!  The scratches are gone.  I successfully removed all my nasty scratches using this method.  It's not perfect.  Removing the scratches seems to create a slight lensing effect in some cases since the plexi is no longer perfectly flat and now curves a bit.  But I'd rather have this than some of the scratches I had.  To reduce this effect, you should sand only as deep as you need to go.  One final obvious piece of advice.... do it on the right side!  I was sanding away for a while on one scratch only to realize it was on the bottom of the plexi!

FWIW, I've heard Lexan is much tougher than plexi and that this method may not work with Lexan.

-Dave

[mw]

A little OT but might be of intrest.  

Plexiglas is a brand name used by Rohm & Hauss, the early developers of the plastic. Lexan is a brand name of GE Plastics and has many specs, thicknesses and properties.

Acrylic is about 8 times clearer than glass.  It has good strength but is breakable. Acrylic is a thermoplastic. Used alot for show cases and displays as glues seams can be nearly undetectable.

Lexan is a polycarbonate, the most famous use is bullet-proof glass but has many other applications. It's main drawback is, it scratches more easily than acrylic. The properties that makes it unbreakable, namely its elasticity and flexibility, give it a softer surface. It is clearer than glass but less clear than Acrylic. It is also porous, therfore absorbing moisture from the air. This moisture will boil when heated causing the sheet to turn white or bubble as the vapors expand, destroying the material. Glueing can cause the same reaction only on a chemical level.

It was informative anyway... wasn't it

[John IV [MameUI64]]

I picked up a heat gun at Home Depot to try on my now un-used first Lexan CP covering.  It had some sanding scratches and it got some more larger scratches as I was fiddling w/ it.

I kicked the heat gun to high and held it over the scratches for about 15-20 seconds.  The scratch itself never got melted over, but the heat did cause the Lexan to start bubbling and warp.  Tried it on another area on the low setting and produced similar results, the scratches would never *fill* presumably like the Plexiglass examples earlier in this thread.

Well, at least I have my new unscratched version.

[ErikRuud]

Yes, lexan will absorb moisture.  Most plastics will to one extent or another, but lexan in particular.

When we vacuform lexan for slot cars, we first put it in the oven at about 100 dgrees for a while to dry it out.

[madk]

The best solution is the sandpaper/buffing method.  I was able to get out some rather large scratches using sandpaper and some buffing with Novus 2.  This seems to be the best method.  I was still left with some very minor imperfections but I got my art printed yesterday and it does an excelent job of masking all my mistakes.  None of my friends could even point out one scratch!

madk