Author Topic: Sanding, Buffing & Polishing Plastic to a Mirror Finish  (Read 48550 times)

Offline twocvbloke

  • Hero Member
  • *****
  • Posts: 4466
  • W.E. 500 DM
Re: Sanding, Buffing & Polishing Plastic to a Mirror Finish
« Reply #30 on: December 24, 2012, 11:05:07 PM »
I have a Black & decker dremel-type tool, and it has a speed control on it so you can go for low & slow RPMs for polishing and hard & fast RPMs for cutting & grinding... :)

I think the B&D tool is called the "Wizard"... ???

Offline kleenax

  • TelephoneCreations.com
  • Hero Member
  • *****
  • Posts: 638
  • Worlds Fair - 302
    • TelephoneCreations.com
Re: Sanding, Buffing & Polishing Plastic to a Mirror Finish
« Reply #31 on: December 24, 2012, 11:14:53 PM »
I have a home made polisher. 

Dennis Hallworth

Dennis;

this is exactly what I will build when my 3450rpm buffer bites the dust. It would be easy as pie to adjust the different pulleys to get various RPMs, and finding a 1HP electric motor shouldn't take much since I have a couple in my garage right now that I scrounged somewhere! Put a 3-tier pulley on each end (like most drill-presses are equipped with), and it would work well in varying the speeds. Get a nice long shaft of the correct size, and you're in business! You can mount the pillow-blocks right on a modified grinder stand and go from there.
Ray Kotke
Recumbent Casting, LLC

Offline dencins

  • ****
  • Posts: 373
Re: Sanding, Buffing & Polishing Plastic to a Mirror Finish
« Reply #32 on: December 25, 2012, 12:04:05 AM »
Ray

One thing I would do different the next time is to make this vertical rather than horizontal.  First it would take less space and second I could use the weight of the motor to maintain the belt tension.  Now I force the motor back away from the mandrel when the belt starts to slip.  I figure I could fasten a rod to the base of the motor and then hinge it to whatever I use as a stand.

Dennis Hallworth

Offline DavePEI

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 4005
  • Telephone Museum of Prince Edward Island
    • The Telephone Museum of Prince Edward Island
Re: Sanding, Buffing & Polishing Plastic to a Mirror Finish
« Reply #33 on: December 25, 2012, 05:53:45 AM »
Exactly what I have been using for the past ten years or more....It is a gas pump motor and it is mounted on hinges - the weight of the motor keeps the belt tight, and should clothing or anything become engaged in the belt, it can be quickly pulled forward to release the belt tension. I chose the motor because it runs 1250 RPM, brought down even further to close to 1000 RPM by the pulley ratio.

Dave

http://www.islandregister.com/phones/buffing.html
« Last Edit: December 25, 2012, 03:19:58 PM by DavePEI »
The Telephone Museum of Prince Edward Island:
http://www.islandregister.com/phones/museum.html
Free Admission - Call (902) 651-2762 to arrange a visit!
C*NET 1-651-0001

Offline JorgeAmely

  • Hero Member
  • *****
  • Posts: 2162
  • SC from 1973
Re: Sanding, Buffing & Polishing Plastic to a Mirror Finish
« Reply #34 on: December 25, 2012, 02:01:48 PM »
...  I have been using this for several years waiting for the motor to burn out.

Dennis Hallworth


That old motor looks like it could take a direct nuclear blast and keep on spinning.
Jorge

Offline kleenax

  • TelephoneCreations.com
  • Hero Member
  • *****
  • Posts: 638
  • Worlds Fair - 302
    • TelephoneCreations.com
Re: Sanding, Buffing & Polishing Plastic to a Mirror Finish
« Reply #35 on: December 25, 2012, 02:52:19 PM »
Ray

One thing I would do different the next time is to make this vertical rather than horizontal.  First it would take less space and second I could use the weight of the motor to maintain the belt tension.  Now I force the motor back away from the mandrel when the belt starts to slip.  I figure I could fasten a rod to the base of the motor and then hinge it to whatever I use as a stand.

Dennis Hallworth

Yep; vertical is the way to go for sure. In fact, if you are handy with a welder, it's easy to use a big door hinge on one side of the motor-mount, and then you can use a piece of threaded rod to adjust tension. All of this can be mounted right on the stand.
Ray Kotke
Recumbent Casting, LLC

Offline WesternElectricBen

  • Hero Member
  • *****
  • Posts: 2875
Sanding plastic
« Reply #36 on: January 05, 2013, 10:33:02 AM »
Mine is about the same method, go from 120 grit to 400 to 800 and 1000-1500(for polishing). You can use dermal tool to speed up process.
Ben

Offline kleenax

  • TelephoneCreations.com
  • Hero Member
  • *****
  • Posts: 638
  • Worlds Fair - 302
    • TelephoneCreations.com
Re: Sanding plastic
« Reply #37 on: January 27, 2013, 05:35:50 PM »
Mine is about the same method, go from 120 grit to 400 to 800 and 1000-1500(for polishing). You can use dermal tool to speed up process.
Ben

I really wouldn't recommend using a Dremel. They are WAY too fast for anything other than drilling holes and grinding metal in my opinion, and they just cover way too small an area at a time causing streaking.
Ray Kotke
Recumbent Casting, LLC

Offline Phonesrfun

  • Hero Member
  • *****
  • Posts: 4867
  • "Number Please"
Re: Sanding, Buffing & Polishing Plastic to a Mirror Finish
« Reply #38 on: January 27, 2013, 06:31:24 PM »
The once or twice that  I ever let a Dremel near my phones, I instantly created a parts phone.  Not good for plastics in my book.
-Bill G

Offline EbayJay

  • *
  • Posts: 6
    • Jay's Treasureshed
Re: Sanding, Buffing & Polishing Plastic to a Mirror Finish
« Reply #39 on: March 04, 2013, 11:09:50 AM »
So... w/o using a Dremel-type tool, how do you get into the small areas, (headset cradle, etc.) using a 6" bonnet on the RB60?

Offline kleenax

  • TelephoneCreations.com
  • Hero Member
  • *****
  • Posts: 638
  • Worlds Fair - 302
    • TelephoneCreations.com
Re: Sanding, Buffing & Polishing Plastic to a Mirror Finish
« Reply #40 on: March 04, 2013, 09:10:13 PM »
So... w/o using a Dremel-type tool, how do you get into the small areas, (headset cradle, etc.) using a 6" bonnet on the RB60?

Use a flexible shaft with a small buff and SLOW speed or you can do a pretty good job by hand actually. I bought a flexible shaft with a drill chuck on the end at Harbor Freight for something like $10 US. I'm sure you can find an inexpensive one on eBay. You can chuck it in your power drill, or if you have one (better), mount it to your drill press. I use it with 3M buffing compound. This buffing compound is what professional automotive painters use for "wheeling" out auto paint. Novus could also be used. It's messy though! Gets ALL over if you're not careful.
Ray Kotke
Recumbent Casting, LLC

Offline EbayJay

  • *
  • Posts: 6
    • Jay's Treasureshed
Re: Sanding, Buffing & Polishing Plastic to a Mirror Finish
« Reply #41 on: March 09, 2013, 09:26:51 PM »
Yes, I found that out the hard way. My buffer threw Novus all over the room. Hahaha. Thanks for the tip.

Offline AE40FAN

  • Hero Member
  • *****
  • Posts: 555
Re: Sanding, Buffing & Polishing Plastic to a Mirror Finish
« Reply #42 on: December 03, 2013, 09:04:17 AM »
I have been practicing sanding on a soft plastic 500 case.  Started with 800 and ended at 12000 "micromesh".  Sanded in opposite directions with each change in grit. Sanding until previous sanding marks are no longer visible.  I've spent many hours on this and can't seem to perfect the process.  After polishing there are still these very fine swirly sanding marks that still appear under bright reflective light.   Is there actually a buffing tool that will buff out these very fine marks?   I hear about the Ryobi, as well as, a stationary unit.  Are they messy?  I'm willing to invest if I can get confirmation that it does indeed remove fine sanding marks.  Any feedback would be greatly appreciated. 

-Frank

Offline DavePEI

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 4005
  • Telephone Museum of Prince Edward Island
    • The Telephone Museum of Prince Edward Island
Re: How to Sand Plastic to a Mirror Finish?
« Reply #43 on: January 27, 2014, 10:46:39 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.
Every tool is good at certain things. While I would never use a dremel to polish an entire phone, they do have their uses - in particular when equipped with a flexible shaft, The secret to using a dremel or similar tool is to finesse it, and to not force or manhandle it. Don't expect it to do large areas. It isn't designed for it. But for small areas, cutting, etc. they can be invaluable.

Note, most of the time I refer to a dremel (small c), I am referring to a chinese dremel knock-off I use on occasion, but I also have a true Dremel, as well. I find the quality of the knock-off just as good as the Dremel.

Cracks in shells can be v'ed out so epoxy can be used to repair them using a diamond tipped burr chucked into the dremel. This gives the glue more "tooth" to hold. The powder left after v'ing them out can be mixed with  the epoxy to colour it. I use dental spatulas to force the glue into the cracks, much the same way a dentist forces a filling into a hole in a tooth. The dremel can then be used to grind the glue almost level with the surface, and then a small dremel buffing wheel can be used to polish out the repair using buffing compound.

The reason I prefer to use a flexible shaft with them, is that a hand held dremel will attempt to fight you due to the gyroscopic action of the motor. Using a flexible shaft, this isn't an issue, giving more control....

Example: A photo of an AE34 case I worked on this evening which had had a severe crack extending from the upper right hand of the photo, down through the vent close to the left hand side. The crack was solidified, using crazy glue, then v'ed out and filled as described above, then finished with the dremel. I should have wiped it before taking the photo as some fluff shows in the photo above the vent...

I dare you to tell me where the crack was. I can see one short scratch where part of the crack was, but final buffing should make that impossible to see. You can flip it over and see where the crack was from the inside.

Next step, buffing with my big buffer.

Second photo showing location of original crack, made more visible by lightening up the same photo and running a red line along side the repair to make it more visible. Photos were taken before the final complete buffing. The Dremel portion of this repair took about 2 hours total, and the filling 8 hours to let the epoxy cure.

It takes practice to get results as good as these - practice on a junk piece first.

I have toyed with the idea of using dental epoxy for this (the type which sets up with a UV lamp). It would be interesting to see if it makes it easier to get a smooth finish. It would definitely save on setting up time.

Dave
« Last Edit: January 28, 2014, 05:36:29 AM by DavePEI »
The Telephone Museum of Prince Edward Island:
http://www.islandregister.com/phones/museum.html
Free Admission - Call (902) 651-2762 to arrange a visit!
C*NET 1-651-0001