Old Fool.. Polishing Ebonite

[old foolParticipant @old-fool]

I have a small sheet of ebonite, which I wish to use in an up coming vintage radio project. I know it can be polished to a mirror finish, mine is mat grey. Anyone know how to polish it up? I only have just enough so haven’t got any to experiment on.

Help welcome

Bob

 

[Michael GilliganParticipant @michaelgilligan61133]

Autosol metal polish [previously Solvol Autosol] is about the right grade of abrasive … apply with a clean, soft, cloth.

Alternatively there is [was?] a dedicated ‘Perspex’ polish available.

MichaelG.

[Mark EasingwoodParticipant @markeasingwood33578]

Hello,

I can’t help with the Ebonite, but  “The Polishing shop” sells a range of Autosol and other polishing compounds.

Mark.

[EmgeeParticipant @emgee]

T Cut works well for Perspex, polished out scratches on my camper windows quite quickly.

Emgee

[Alan CharlestonParticipant @alancharleston78882]

Hi Bob,

I use Brasso on perspex and it seems to work well.

Regards,

Alan

[JasonBModerator @jasonb]

Not tried iton Ebonite but have done various plastics and clear acrylic using Micro-mesh which are a range of cloth backed abrasives down to 12000grit and then a final liquid polish which is a lot finer than metal polish. Said to have originally been designed for removing marks from fighter jet canopies. My kit (KR70) goes down to 6000g which has been been enough for my uses. Uses water to stop the mesh clogging so nothing else to stain the material.

As machined

Polished mostly inside and the curved bottom

[DiogenesParticipant @diogenes]

If it’s ‘matt’ to start with and you really do want a mirror finish, probably best to work down through the grades with wet (‘wet & dry’) papers first – maybe start with 320 or 400, and then 800 and onwards to remove any scratches still visible from that, taking care not to finish with a particular grade until you have removed all traces of the finish left by the previous one.

Wash the panel thoroughly between grades and take great care to avoid contamination, also try and keep the paper wet and not let it ‘pick up’.

For a ‘mirror finish’ I’d go down to at least 2400 before I got the polish out for a trial. Finer grades are available if needed.

The work will go better and more quickly if you are strict with the process; don’t be tempted to skip a grade..

Patience and cleanliness are the key to success.

Crossed with Jason’s, I see..

[Michael GilliganParticipant @michaelgilligan61133]

Assuming the sheet really is Ebonite … These two links might be of interest:

https://en.wikipedia.org/wiki/Ebonite

https://www.vintage-radio.net/forum/showthread.php?t=15337

MichaelG.

[SillyOldDufferModerator @sillyoldduffer]

Unfortunately my mate who restored old radios died a few years back so I can’t ask him.

From memory, I think Bob’s assumption that Ebonite can be restored by polishing is wrong.  I believe ageing can cause it to lose colour throughout, not just on the surface.

I’d try polishing as described by colleagues first, but if it fails to get a ‘good enough’ result, this photo is an example of my mate’s work.

The camera does a poor job of capturing the colour of the panel edge, in real life it’s a medium grey.  The black splashes on the edge show my mate restored the panel by painting and buffing on a wheel.  Don’t know if my radio was done with the black dye used to restore shoe leather and black boot polish, but he mentioned that as a possibility.  His work looks OK from a distance.

His efforts were in vain!  After recreating a working 1920’s wireless receiver from an original wooden chassis plus period parts, he sent it off to a proper auction-house hoping to make big money.   Nope, the auctioneer’s expert denounced it as a fake, and it came back with a letter saying he should never contact them again!    Restoration work is controversial because the genuine article in good condition is worth serious money, and fraud is a major problem.

Dave

 

 

[JohnFParticipant @johnf59703]

Bob, I have used lots of Ebonite over the years but never flat !  My ideas gun stock extensions of butt plates.

As far as finishing goes it’s pretty much all been said. Just work your way down the grades of abrasive and finish with metal polish.  I also used a buff on occasions but it must be slow speed and light pressure or you will burn/melt the material!
I used wet & dry and no lubricant, do use a mask the dust is very fine.
John

[DalboyParticipant @dalboy]

I use THESE on acrylic pen blanks along with THIS. and get a finish like the photo. As it is a flat panel it will take a lot longer as when doing the pens the acrylic is rotating.

 

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