Author Topic: Sanding, Buffing & Polishing Plastic to a Mirror Finish  (Read 49201 times)

Offline AE_Collector

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Re: How to Sand Plastic to a Mirror Finish?
« Reply #15 on: December 22, 2012, 02:13:55 AM »
Ray:

I thought your clear phones were not supposed to yellow with age? Something has happened to the one in your avatar. I think it could be related to the Mayan Calendar but don't want to mention it in case people here on the forum begin to panic.

Terry

Offline kleenax

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Re: How to Sand Plastic to a Mirror Finish?
« Reply #16 on: December 22, 2012, 10:04:45 AM »
Oh Terry, you don't know how close you are to the truth! Bad time with a naughty batch of resin yellowing on some of the 200-series GPO based projects in the UK!

On this thread, there are some very good buffing systems (for phones!) at www.eastwood.com. The photo below shows my "Dream System"; a dual-speed, 1-HP long-stuff buffing motor. 1,750RPM for plastics, and 3,450RPM for bakelite!  If you are even thinking of investing in a buffing set-up, check out Eastwood; there are many other set-ups available on their website.
Ray Kotke
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Offline kleenax

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Re: How to Sand Plastic to a Mirror Finish?
« Reply #17 on: December 22, 2012, 10:08:42 AM »
That is one outstanding restoration, Ray. It looks like NOS, but better.

Thank you John, and Happy Christmas!
Ray Kotke
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Offline kleenax

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Re: How to Sand Plastic to a Mirror Finish?
« Reply #18 on: December 22, 2012, 10:09:27 AM »
Beautiful, Ray!  Thanks for posting this information and photos.

Thanks Dennis; most appreciated :D
Ray Kotke
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Offline AE_Collector

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Re: How to Sand Plastic to a Mirror Finish?
« Reply #19 on: December 22, 2012, 09:31:17 PM »
I keep dreaming of getting a buffer so I took a look at Eastwood per Ray's suggestion.

The Two Speed 1HP unit he mentions is $159. This is just the buffer motor, I don't think it comes with any wheels or compound. The picture that Ray posted is the buffer motor with a stand and a kit of wheels, compound and protective equipment. That kit is $339. Or the same kit but without the stand is $289.

I also see that the Eastwood site says all orders over $50 have free shipping which would be a fair bit of cash for an item like this.

They also have single speed motors and 1/2HP motors which are likely all that is really needed for plastic buffing. The single speed motors always seem to be 3450 RPM rather then the preferable for plastic 1725 RPM. A 1/2 HP kit with 6" buff wheels is avalable for $109 including a couple of wheels and some compound.

This is usually where I get overwhelmed and do nothing further about it. I think that Ray suggested 6" wheels for phone parts.

If I stumbled upon a 1/2 HP kit with a 1725 RPM motor and with 6" wheels for a good price along with free shipping I would probably click "Buy it Now" but I never see just what I want. This dual speed motor solves the speed problem but says it is for 10" wheels although maybe it is as simple as buying 6" wheels to go with it.

Terry
« Last Edit: November 19, 2016, 10:59:17 AM by AE_Collector »

Offline TelePlay

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Re: How to Sand Plastic to a Mirror Finish?
« Reply #20 on: December 22, 2012, 10:10:37 PM »
Getting into the details, the speed of the buffing wheel on the item being buffed is interesting. A 10 inch wheel at 1,725 is about the same as a 6 inch wheel at 3,450. I can see why a 6 inch wheel at 1,725 3,450 is preferable in that it is slower and would create heat less quickly.

I wonder if it's too late to write a letter to Santa?

RPM     1,725                 3,450
      
6"      2,709 fpm          5,419 fpm
      
8"      3,665 fpm          7,225 fpm
      
10"    4,515 fpm          9,032 fpm
« Last Edit: December 22, 2012, 10:57:19 PM by TelePlay »
            John . . .

              

Offline AE_Collector

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Re: How to Sand Plastic to a Mirror Finish?
« Reply #21 on: December 22, 2012, 10:32:29 PM »
So having different diameter buffing wheels would simulate different speeds on the buffer motor. A 3450 RPM 1/2 HP buffer with 6" wheels may be reasonable for plastic. Does that sound correct Ray or is it still on the edge for plastic? I know that you use a 3450 buffer but have lots of experience with it so you are able to carefully buff plastic without melting it! What size wheels do you usually use?

Terry
« Last Edit: November 19, 2016, 10:56:35 AM by AE_Collector »

Offline kleenax

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Re: How to Sand Plastic to a Mirror Finish?
« Reply #22 on: December 22, 2012, 10:52:58 PM »
So maybe having different diameter buffing wheels would simulate different speeds on the buffer motor. A 3450 RPM 1/2 HP buffer wit h6" wheels may be reasonable for plastic. Does that sound reasonable Ray or is it still on the edge for plastic? I know that you use a 3450 buffer but have lots of experience with it so you are able to carefully buff plastic ithout melting it! Wha tsoze wheels do you usually use?

Terry

You remember correctly Terry.  Yes, I use a 3450rpm buffing motor only, basically because I'm cheap and got it for replacing the boards on an elderly gentleman's deck! I use this with 6" wheels.

You can alter the speed somewhat by using smaller wheels, but the size of the wheels is usually determined by the HP of the buffer. A 1/2HP buffer usually is equipped with nothing larger than 6", and a 1HP buffer is usually equipped with 8" wheels. I just like the 6" wheel for getting into various areas of a phone. It still leaves some places that you have to do by hand though, like around the cradle, etc.

On buffing wheels, if you have a little more powerful buffing motor, (3/4HP or more), you can "stack" your buffing wheels (put 2 or 3 of them together as long as they are EXACTLY the same) so you end up with a buffing surface about 3" wide. Works great when you are buffing a LOT of phones; especially bakelite.

I will tell you though that when you get smaller than 6" on your buffing motor, your stuff ends up getting in the way too much, and that is when you want to have the flexible stuff on your drillpress for using the smaller (3") buffing wheels for tight places.
Ray Kotke
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Offline AE_Collector

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Re: How to Sand Plastic to a Mirror Finish?
« Reply #23 on: December 22, 2012, 11:16:10 PM »
So bottom line for plastic is, even with 6" wheels you ideally want a 1725 RPM motor rather than 3450. Or the dual speed motor.

Or the 1100 RPM that Caswel Plating has but it is $259. Caswell used to have a 1725 RPM and when they got the 1100 RPM models in they cleared out the 1725 RPM's for $99. When I saw the sale I was about a day too late. They were still showing as available but when I tried to order one they got back to me saying the last one was gone.

Terry
« Last Edit: November 19, 2016, 11:02:55 AM by AE_Collector »

Offline TelePlay

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Re: How to Sand Plastic to a Mirror Finish?
« Reply #24 on: December 22, 2012, 11:46:31 PM »
I also see that the Eastwood site says all orders over $50 have free shipping which would be a fair bit of cash for an item like this.

If you read the fine print, the free shipping does not apply to kits or heavy weight items so the $109 buffer kit will cost an additional $33 or so in ground shipping. If you went with just the motor, it's $109 with free shipping but then you would have to buy the wheels and compounds and rake. So, the kit supplies are $33 if you think of it as free shipping. They say the kit and motor list at $182 so it's still a deal. Sneaky, aren't they?
« Last Edit: December 22, 2012, 11:59:43 PM by TelePlay »
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Offline Nick in Manitou

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Re: How to Sand Plastic to a Mirror Finish?
« Reply #25 on: December 24, 2012, 01:51:46 PM »
I have a question about polishing with Dremel-type tools.

I have never used one, but assumed that they would be good for polishing in the tight spots.     

Are they good for this purpose?  Anyone have any experience trying to use them for polishing where a buffing wheel won't reach?

Any thoughts, experience, suggestions?

Thanks,
Nick

Offline Dennis Markham

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Re: How to Sand Plastic to a Mirror Finish?
« Reply #26 on: December 24, 2012, 02:44:41 PM »
I've burned plastic with a Dremmel tool.  I was using an accessory that was pretty hard.  The high RPM burned the plastic.  Never tried that again.

Offline TelePlay

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Re: How to Sand Plastic to a Mirror Finish?
« Reply #27 on: December 24, 2012, 03:48:52 PM »
I've burned plastic with a Dremmel tool.  I was using an accessory that was pretty hard.  The high RPM burned the plastic.  Never tried that again.

Oh, yeah. Nothing related to Dremel is good for polishing plastic. Drilling and cutting, yes. Polishing or sanding, no. Way to fast and too small of a surface area. I don't let my Dremel anywhere near anything plastic or bakelite.

But, the Dremel wire brush does work well for polishing small unpainted metal parts.
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Offline Phonesrfun

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Re: How to Sand Plastic to a Mirror Finish?
« Reply #28 on: December 24, 2012, 04:16:25 PM »
oooohhh, Dremel and plastics, a big NO!

Been there and done that.  No speed on the variable spedd Dremel is slow enough.  Don't go there.
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Offline dencins

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Re: Sanding, Buffing & Polishing Plastic to a Mirror Finish
« Reply #29 on: December 24, 2012, 09:52:11 PM »
I have a home made polisher.  I got the mandrel from Ace Hardware for $30 and the belt from an auto store for $4.  The motor is a 1 hp 1800 RPM very old Sears table saw motor.  The pulley reduction (motor pulley is smaller than mandrel pulley) brings the speed down to about 1400 RPM. 

I use the brass brush side to clean up steel like footpad plates and the buffer side for plastic and brass (different wheels).  I have been using this for several years waiting for the motor to burn out.

Dennis Hallworth