OK, this might seem a bit out of sequence in the overall scheme of things, but for me when I'm starting a really big project it sometimes helps to figure out what is the one thing that I
least look forward to...and just jump on that first. (ie: If I get all the dreaded stuff out of the way then the project just seems to move along with less foreboding/excess head stress?)
Well, I seemed to remember that when the Dual turntable was relegated (with dust cover unprotected) to the basement when I first moved to CDs as my primary music source...and while down there the grit from some cylinder head porting + papers being put on top of it gave the Dual's dust cover a bunch of tiny scratches -- some refer to the resulting look as 'cobwebs'. When I discovered what had happened during move #6 of #11, needless to say I was not happy with the fruit of my carelessness. (Eff it, I'll deal with it later if/when I ever drag it out someday in the distant future! :0)
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( 20+ years pass )
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Sure enough, when I recently unwrapped the turntable the day after Christmas, the cover looked, if anything, even
worse than I remembered. Way too scratched to be fixed with just polish & a cloth -- it was going to take wet-sanding first, followed by a good buffing.
Without further ado, here's what I did to bring back my old Dual turntable to a serviceable condition. Not perfect, but certainly plenty good enough to be pressed into service when I need to check out a phono stage after a preamp rebuild. (Or brought out for some live music on vinyl while feeding friends some tasty BBQ.)
1) For starters, here's the reflection of the dining room lights on the turntable cover, as found, after being put out to pasture incorrectly:
2) One more 'pre - repair' photo, reflection of single straight light source:
3) For comparison, here's the cover with the same light, post-fix:
4) If you are now curious as how the plexiglass was de-scratched & polished, in this photo you will see the 3 grits I used to remove the cobwebs. (scratches) 1500 / 2000 /2500 grit:
5) Starting with a 1/2 sheet of 1500 grit & a small container of lukewarm water with a couple of drops of dish soap. (For lubricity, to help minimize the wet sandpaper from sticking while trying to evenly cover the dust cover surface. Keep working the plexiglass until the entire surface is evenly
dull.
Here is what it looks like when you are halfway through switching to the finest paper. (2500 grit)
Once you have evenly covered the dust cover with the 2500 grit, now it's time to switch to the polish & work through those three levels, coarsest to finest. (
Follow this link & go to the last picture if you need a refresher of what I used on the RCA line meter.)
Yes, it can be done by hand, but you'll need some time & effort. Budget a couple quarters of a football game. NOTE: If you want to utilize a force multiplier, the entry level of chucking up a foam polishing pad (~$10 from Harbor Freight) to a variable-speed drill is completely legit.
Since I routinely correct paint on vehicles, I cheated & used a variable-speed Makita 9227C polisher with a fine foam polishing pad, light pressure, and increasing speed as the polish breaks down from aggressive to ever-finer finishing slurry:
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OK, if you are still with me, here's a photo of the Shure V15 Type IV cartridge as installed:
And finally, here's a beauty shot of the turntable powered up & holding a steady strobe. (no flash + f18 for good depth of field = 2 second exposure)
I am particularly happy to have the turntable all cleaned up & ready for use, for I have been dreading this little subroutine for far longer than I've been a member of this forum. And I'm sure that busting the rust off of my wet-sanding chops will pay off when it comes time to restore the used test equipment heading my way to their former glory.
Hopefully the above will help anyone living with a scratched turntable dust cover made of unobtainium & would like to return it to it's original beauty.
Cheers --
