sanding lexan bodies

[littleVETTE]

has anyone tried this on the outside of a lexan body? i have a couple of bodies i would like to get started on, but they have scratches on them. what grade of sandpaper would anyone start with, since it's on the outside of the body? what about wet sanding with a finer grit? i'm a little iffy on it. i would think it would blur up the body. making any paint job look bad.

[Eau Rouge]

Why do you want to sand the outside of the body? Do you want to paint the outside? Are you trying to remove scratches or intentionally make more?

Bad idea, on all counts. I have never gotten good results from scuffing the inside before painting, and sanding the outside for any reason will really make a mess. Unless you are spraying the outside for a "matte look" flat hot rod paint job, I can't see any reason to waste a perfectly good body putting sandpaper anywhere near it.

If you want to take the scuffs out, try the Novus polishing system (use all three courseness polishes) made specifically for plastic. That stuff works really well with a little elbow grease and a soft cloth.

[shodog]

I've polished the outside of some scuffed up shells by using a buffing wheel and some metal polish. You have to be oh so light on the touch as you can easily put a burn mark in the body from the spinning buffing wheel.

[Brandon G]

3m Perfect it does well on plastics.

[Lonestar]

I have never gotten good results from scuffing the inside before painting

interesting... I have. I don't do ultra fancy paint jobs like the pros (3 or 4 colors with tape is plenty enough for me), but if I don't scuff the inside, the paint sticks much less... I've tried both techniques. I usually race the bodies I paint, and I race them a year or so, running about 3 times a month, so that tells you that my paintjobs last, no flaking (I'm an ok driver but no pro, I do crash).

I mean, to each his own, but most body manufacturers recomment a light scuffing before painting, I guess there's a reason to this

Paul

[ROH73]

I've never tried scuffing for good paint adhesion; I personally don't think it's necessary as the proper paint is designed to bond to the lexan no matter if it's perfectly smooth or scuffed. I think the absolute key is to make sure the surface to be painted is very clean; no fingerprints, oils, mold release, dust, etc.

As for polishing scuffs, etc off the outside, I second the Novus products. They can work wonders.

Regards,

Robert

[Eau Rouge]

Since 1984, I have painted more Lexan than you can possibly imagine. There was a summer in the easrly 90s that I painted over 300 bodies. There was a small time where I scuffed the insides of bodies before painting (using a red 3M pad), and every single body that was done to gave poor results with color appearance—fades, especially. Some colors even showed the scratches/scuffs in the finish.

If you are not getting good paint adhesion, you aren't cleaning the new body well enough before masking and paint. The only times I have EVER had paint come off of a Lexan body was the very first one I painted in 1984—with Testors model enamels—and a touring car body about 8 years ago, using Pactra's new-at-the-time water-based acrylic fluorescents. It wound up being a problem with the paint, itself.

Twice in 26 years of painting Lexan. And no other paint adhesion problems ever without scuffing.

[GJW]

ive used novas polishing system with good results also. took some time though so be prepared.

[littleVETTE]

this isn't for the paint. i have some bodies that have scratches on the outside of the body. i know i've heard a couple of guys talking about sanding the outside, can't remember if it was wet sanding or not, but they got good results from it. i wanted hear a couple ideas from anyone that has tried it.

this is just to make the body a lot more enjoyable to look at. especially the window areas.

[Lonestar]

Since 1984, I have painted more Lexan than you can possibly imagine. There was a summer in the easrly 90s that I painted over 300 bodies. There was a small time where I scuffed the insides of bodies before painting (using a red 3M pad), and every single body that was done to gave poor results with color appearance—fades, especially. Some colors even showed the scratches/scuffs in the finish.

If you are not getting good paint adhesion, you aren't cleaning the new body well enough before masking and paint. The only times I have EVER had paint come off of a Lexan body was the very first one I painted in 1984—with Testors model enamels—and a touring car body about 8 years ago, using Pactra's new-at-the-time water-based acrylic fluorescents. It wound up being a problem with the paint, itself.

Twice in 26 years of painting Lexan. And no other paint adhesion problems ever without scuffing.

That's an interesting perspective... I certainly haven't done 300 bodies a year, but I've done a good, say, 75 or so since I started in 1984... but I respect your experience

paul

[RedScampi]

There are plastic polishing kits available such as this one that will give spectacular results if you do it right. The key here is patience and following the instructions to the letter. My question is whether or not it's worth it unless the shell is very rare or special for some other reason. Very labor intensive.
http://www.hobbylinc.com/htm/dtm/dtm9040.htm?source=froogle

Also - not sure of the results on Lexan as these are made for styrene plastic. I use PlastX on my bodies and they come out pretty nice.