Polishing Gray Sheet PVC

[PVC]

Hello, new to this forum, and I see this will be of great help to me over time.

Both my Dad and I work with Acrylic, making various products. I recently got the idea to substitute gray PVC Type-I sheeting (same as schedule-40 pipe) in place of black acrylic.

What I'm running into is that the PVC sheeting does not come paper-coated, and since it is softer, there are scratches all over it. While acrylic can be flame-polished, PVC cannot, it just turns black and melts.

I have used a plastic polishing compound, a 3-stitch buffing wheel, and a drill to polish it to a mirror shine, however this takes quite a bit of time. It's a 4 or 5 inch wheel, and I run it at full speed (3000 RPM?) and when I get the consistency of the polish just right (I have some experience with using this polish) it will shine up to a perfect mirror shine in about 5-10 seconds, but that's holding the wheel in one spot, about 1 square inch. So when I want to polish a finished product, or individual pieces prior to welding, this will take much longer than I wish it to take.

Is there a better way to quickly and easily polish PVC?

Is there a chemical that can be applied to this type of PVC that will get rid of the scratches?

Any insight would be greatly appreciated.

Thanks

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[RomanLini]

I think it's a really bad material to try to polish (or keep polished for that matter!).

Have you considered just coating it with a thick hard clear coat like an epoxy clear coat?

[PVC]

Up to this point, I haven't cared so much about it getting scratched up after it is sold. The way the product is used, it is generally not in plain view, and will receive a fair amount of wear & tear over time. So regardless of whether it is made of black acrylic or gray PVC, it will get damaged. The PVC appears more flexible and durable for the application.

I haven't looked into an epoxy clear coat, but that certainly is a possibility. The PVC would still have to be buffed before applying that however. Would such a clear coat yellow and crack over time though, especially if it's used in a high humidity environment?

I found a 6" buffing wheel, but haven't tried it yet. 50% higher speed, so maybe that will help. I also considered getting a bench grinder (3600 RPM), that way I can buff the individual pieces before assembly and use both hands. They also make those with 8" wheels so that would go much faster also.

I think the chemical polish (like a dip or something) isn't an option. At least, no one has presented me with that option, and it looks like anything that would do that would actually melt the product and it wouldn't return to it's original state.

[Geof]

...The PVC appears more flexible and durable for the application.....

.....I think the chemical polish (like a dip or something) isn't an option. At least, no one has presented me with that option, and it looks like anything that would do that would actually melt the product and it wouldn't return to it's original state.

"PVC appears more...." Sometimes 'appears' is the keyword. Certainly new PVC is more flexible and impact resistant than acrylic but over time the plasticizers leach out of PVC and it becomes brittle. So it may not be more durable over a period of time.


Have you looked into 'vapor polishing'? This does not use a dip procedure it just exposes the plastic to concentrated solvent vapors which can have the effect of smoothing the surface. Google 'vapor polishing PVC' and you will get many hits.

[PVC]

"PVC appears more...." Sometimes 'appears' is the keyword. Certainly new PVC is more flexible and impact resistant than acrylic but over time the plasticizers leach out of PVC and it becomes brittle. So it may not be more durable over a period of time.

This is the same at Schedule 40 PVC, and in the environment it will be used in, people used PVC pipe almost exclusively, and I haven't ever heard of problems. For my application I will be making the product out of 1/4" Type-I gray industrial PVC. Does this change your comment about durability over time at all?

Have you looked into 'vapor polishing'? This does not use a dip procedure it just exposes the plastic to concentrated solvent vapors which can have the effect of smoothing the surface. Google 'vapor polishing PVC' and you will get many hits.

That's very interesting, in fact that's exactly what I was looking for! Unfortunately, it doesn't look like anything I will be able to do at home by myself. But at least I know what to ask for when I call my local businesses.

Thank you very much for your answer!!