UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > General Vintage Technology > Cabinet and Chassis Restoration and Refinishing

Notices

Cabinet and Chassis Restoration and Refinishing For help with cabinet or chassis restoration (non-electrical), please leave a message here.

Closed Thread
 
Thread Tools
Old 27th Jan 2020, 8:02 pm   #1
Al (astral highway)
Dekatron
 
Al (astral highway)'s Avatar
 
Join Date: Nov 2006
Location: London, UK.
Posts: 3,496
Default Cutting perfect circle in acrylic

Hi folks,

I have limited workshop facilities and although in the past I’ve used a home made cutter with nichrome wire and a hefty current at low volts , I want this one perfect without having to spend ages cleaning up the edges.

Alternatively , if anyone knows where (specifically ) I could get this done or if ok with mods/ forum rules , is up for doing it for a reasonable amount , please let me know by PM.

It’s only about 14 cm diameter.

Thank you
__________________
Al
Al (astral highway) is offline  
Old 27th Jan 2020, 8:39 pm   #2
Radio Wrangler
Moderator
 
Radio Wrangler's Avatar
 
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,799
Default Re: Cutting perfect circle in acrylic

To clear up ambiguity, do you want a perfectly circular hole in a piece of perspex, or do you want a perfectly circular disc of perspex?

Perspex can me machined, but needs care over speeds and feeds to avoid chipping the edges or shattering everything.

A local machine shop could turn you a disc. If a centre hole is wanted, then things are easier, if not then it's a double-sided tape job. I can do 12 or 13 inches in the gap bed of my lathe. If you want a circular hole, then a router on a trammel is a possibility but revs need to be controlled and feeding has to be very steady. A shallow cut from each side and then a deeper cut etc until the disc breaks out. Tidy up with abrasive paper then rubbing compound and perspex polish.

David
__________________
Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done
Radio Wrangler is online now  
Old 27th Jan 2020, 9:16 pm   #3
Al (astral highway)
Dekatron
 
Al (astral highway)'s Avatar
 
Join Date: Nov 2006
Location: London, UK.
Posts: 3,496
Default Re: Cutting perfect circle in acrylic

Hi David ,

It’s the positive , a circular disc, that I’m after.

Sadly, any kind of conventional workshops have long been squeezed out of my area by gentrification. I used to go to a local collective with shared kit, including lathes and a laser cutter, but it closed 5 years ago .

If you’re potentially up for doing this for me in exchange for an appropriate fee , can you let me know and i’ll DM you and we can see if it can work.

Thank you for your really informative reply, as usual

Or if a
__________________
Al
Al (astral highway) is offline  
Old 27th Jan 2020, 9:19 pm   #4
yesnaby
Octode
 
yesnaby's Avatar
 
Join Date: Jul 2005
Location: Newport, Gwent, UK.
Posts: 1,623
Default Re: Cutting perfect circle in acrylic

Plenty custom ones on eBay, e.g.

https://www.ebay.co.uk/itm/Glass-Eff...xNKP4DtGLrU51w
yesnaby is offline  
Old 27th Jan 2020, 9:47 pm   #5
Al (astral highway)
Dekatron
 
Al (astral highway)'s Avatar
 
Join Date: Nov 2006
Location: London, UK.
Posts: 3,496
Default Re: Cutting perfect circle in acrylic

Thank you , Yesnaby! That’s great to know and solves this problem for me .

Mods close thread if you like ?
__________________
Al
Al (astral highway) is offline  
Old 27th Jan 2020, 11:43 pm   #6
Tim
Dekatron
 
Tim's Avatar
 
Join Date: Jan 2003
Location: Bradford on Avon, Wiltshire, UK.
Posts: 3,301
Default Re: Cutting perfect circle in acrylic

If you are handy with( or know someone) with a router( the woodworking type) it’s a fairly simple job.
I’ve used a router a couple of times, and they make a good job of acrylic provided the cutter is sharp.
__________________
"Nothing is as dangerous as being too modern;one is apt to grow old fashioned quite suddenly."
Tim is offline  
Old 28th Jan 2020, 2:13 pm   #7
Al (astral highway)
Dekatron
 
Al (astral highway)'s Avatar
 
Join Date: Nov 2006
Location: London, UK.
Posts: 3,496
Default Re: Cutting perfect circle in acrylic

Hi Tim, thank you

I don’t have more than very basic workshop equipment but this of course is a good solution for someone who does.
__________________
Al
Al (astral highway) is offline  
Old 28th Jan 2020, 4:36 pm   #8
paulsherwin
Moderator
 
paulsherwin's Avatar
 
Join Date: Jun 2003
Location: Oxford, UK
Posts: 27,786
Default Re: Cutting perfect circle in acrylic

It does depend on your definition of a 'perfect circle', but a decent glass merchant should be able to sort you out.
paulsherwin is online now  
Old 28th Jan 2020, 5:25 pm   #9
Bazz4CQJ
Dekatron
 
Bazz4CQJ's Avatar
 
Join Date: Apr 2009
Location: Oxfordshire, UK.
Posts: 4,923
Default Re: Cutting perfect circle in acrylic

You'll probably find greater willingness if you buy the material and ask them to cut it, rather than just walk in with the material in your hand .

B
__________________
Saturn V had 6 million pounds of fuel. It would take thirty thousand strong men to lift it an inch.
Bazz4CQJ is offline  
Old 29th Jan 2020, 11:44 am   #10
mike_newcomb
Rest in Peace
 
Join Date: Apr 2012
Location: West London, UK.
Posts: 665
Default Re: Cutting perfect circle in acrylic

Hi,
The places to cut perspex/acrylic sheets these days are Sign makers.
Virtually any shape can be produced as Computerised Cutters are used.

eg. I can think of a number of places in Park Royal that do this.
Regards - Mike
mike_newcomb is offline  
Old 29th Jan 2020, 1:09 pm   #11
Al (astral highway)
Dekatron
 
Al (astral highway)'s Avatar
 
Join Date: Nov 2006
Location: London, UK.
Posts: 3,496
Default Re: Cutting perfect circle in acrylic

Quote:
Originally Posted by paulsherwin View Post
It does depend on your definition of a 'perfect circle', ....
I’m rehearsing walking into the glass shop!

‘Morning, please cut this acrylic on a line defining a closed loop with every contiguous point at exactly the same distance (140mm) from the centre. Thanks , I’ll be back in twenty mins.’
__________________
Al
Al (astral highway) is offline  
Old 29th Jan 2020, 1:28 pm   #12
David G4EBT
Dekatron
 
David G4EBT's Avatar
 
Join Date: Feb 2003
Location: Cottingham, East Yorkshire, UK.
Posts: 5,737
Default Re: Cutting perfect circle in acrylic

The ones at the link in post #4 above by Yesnaby seem to fit the bill perfectly.

I've got a lathe, routers, bandsaws, and acrylic sheet, but I wouldn't dream of faffing about to make a disc, given that I could get a laser-cut perfectly round 14cm disc (or any other diameter) for a little over £3.00 post free. There are other suppliers on eBay who can supply more of less any sized acrylic disc in any colour, in a wide range of thicknesses for little cost.

No need to even get off the chair - two mouse clicks and it's on it's way!

Why look for complex solutions to simple problems?
__________________
David.
BVWS Member.
G-QRP Club member 1339.
David G4EBT is offline  
Old 29th Jan 2020, 2:15 pm   #13
Radio Wrangler
Moderator
 
Radio Wrangler's Avatar
 
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,799
Default Re: Cutting perfect circle in acrylic

I'd likely go through a lot more than £3 worth of perspex in breakages before getting my first usable disc.

David
__________________
Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done
Radio Wrangler is online now  
Old 29th Jan 2020, 9:07 pm   #14
mole42uk
Nonode
 
mole42uk's Avatar
 
Join Date: Aug 2010
Location: Resolfen, Wales; and Bristol, England
Posts: 2,588
Default Re: Cutting perfect circle in acrylic

I have a piece of 1" Perspex in the workshop, about three feet square. It is ex-BBC when they wanted to film an elephant footsteps, from underneath! I've been wondering what I might do with the Persepex for years.
__________________
Richard

Index:
recursive loop: see recursive loop
mole42uk is online now  
Old 29th Jan 2020, 9:26 pm   #15
Al (astral highway)
Dekatron
 
Al (astral highway)'s Avatar
 
Join Date: Nov 2006
Location: London, UK.
Posts: 3,496
Default Re: Cutting perfect circle in acrylic

David4EBT: yes, I’m all for simplicity!

Richard: ahah, are you saying you now have a plan for that giant bit of Perspex? That sounds like an interesting story about a BBC production ...
__________________
Al
Al (astral highway) is offline  
Old 30th Jan 2020, 9:50 am   #16
Ed_Dinning
Dekatron
 
Join Date: Jan 2004
Location: Newcastle upon Tyne, Tyne & Wear, UK.
Posts: 8,171
Default Re: Cutting perfect circle in acrylic

Hi Al, I think there is a national company, Brisbay Plastics, they supply all sorts of plastic materials to builders, sign makers etc and have all the equipment to do what you require

Ed
Ed_Dinning is offline  
Old 30th Jan 2020, 5:37 pm   #17
Al (astral highway)
Dekatron
 
Al (astral highway)'s Avatar
 
Join Date: Nov 2006
Location: London, UK.
Posts: 3,496
Default Re: Cutting perfect circle in acrylic

Quote:
Originally Posted by Ed_Dinning View Post
... national company, Brisbay Plastics, they supply all sorts of plastic materials to builders, sign makers etc and have all the equipment to do what you require
That looks like a handy contact , thanks Ed!
__________________
Al
Al (astral highway) is offline  
Old 31st Jan 2020, 12:26 am   #18
G0HZU_JMR
Dekatron
 
Join Date: Sep 2010
Location: Cheltenham, Gloucestershire, UK.
Posts: 3,077
Default Re: Cutting perfect circle in acrylic

For ultimate accuracy, I think my PCB mill could do this for thin Perspex, certainly for 3mm but probably up to 5mm thick. However, my previous attempts at cutting plastic haven't been that successful. I think it needs a fairly fast router speed to prevent the plastic from melting. I think my machine can run as fast as 180 inches/min but I rarely run it above 24 inches a minute as this is scarily fast when cutting a series of small arcs for example.

The other issue I found was that the plastic can turn into a hard adhesive when it heats and cools and it gums up and ruins the tool really easily.
I remember milling and engraving a tiny steering wheel for a model boat for my neighbour from hard plastic and that took several attempts and a few tools before I got it right for that particular material.

The specs for my T-Tech 7000S mill are similar to those below and it is impressively accurate. Just draw a 140mm circle shape using the Isopro software and then ask the machine to cut it out using the same software.

https://t-tech.com/shop/product/quick-circuit-qc7000/

I think the best bet is the online vendor. Looking at their other stuff they must be very experienced at cutting Perspex! I think I'd ruin several tools on my mill before I got anything clean and accurate.
__________________
Regards, Jeremy G0HZU
G0HZU_JMR is offline  
Old 31st Jan 2020, 1:01 am   #19
MrBungle
Dekatron
 
MrBungle's Avatar
 
Join Date: Jun 2016
Location: London, UK.
Posts: 3,687
Default Re: Cutting perfect circle in acrylic

You can use a hot wire cutter to cut acrylic. Just need some nichrome wire, some maths and a car battery
MrBungle is offline  
Old 31st Jan 2020, 4:28 pm   #20
Al (astral highway)
Dekatron
 
Al (astral highway)'s Avatar
 
Join Date: Nov 2006
Location: London, UK.
Posts: 3,496
Default Re: Cutting perfect circle in acrylic

Quote:
Originally Posted by MrBungle View Post
You can use a hot wire cutter to cut acrylic. Just need some nichrome wire, some maths and a car battery
Yes, see post #1 ...

I’ve done it many times but it’s not neat enough for show
__________________
Al
Al (astral highway) is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 5:28 pm.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.