Model Boat Mayhem

Mess Deck: General Section => Model Boating => Topic started by: sinjon on March 29, 2007, 06:11:55 pm

Title: Cutting small clear plastic discs
Post by: sinjon on March 29, 2007, 06:11:55 pm
I need to cut some small clear discs for portholes, ( I worked in the aircraft industry building flying boats - don't ask - we called them port lights) I have tried using 'Kristal Klear' but the dia. is just a bit too big, I need about a 1/4'' dia +
Has anyone got a good system for cutting out small dia. discs from clear plastic?

Colin
Title: Re: Cutting small clear plastic discs
Post by: John W E on March 29, 2007, 06:18:45 pm
Sinjon - you know the paperpunches that you can punch holes in paper with - for loose leaf folders - well, if the clear plastic you are trying to punch isn't too thick, you could use this method. 

Or, some brass tubing 1/4 inch bore, with theouter edge sharpened like a chisel, soft wooden block, place your plastic on the wooden block, place the sharpened brass tube on the top of the plastic and with a sharp belt you should have cut a clear disc out.

 ;D

aye
John e
bluebird
Title: Re: Cutting small clear plastic discs
Post by: Colin Bishop on March 29, 2007, 06:22:59 pm
Best thing to use is a hollow steel punch. They usually come in sets. Squires do two sets. One is  2-10mm 8 pieces ,the other is Imperial 3/16th to 1/2 6 pieces. Both sets cost £10.99 each. I have a 9 piece set which goes up from 3/32-1/2 and which I picked up at a show or stall somewhere for around £6.

Revolving punch pliers are also handy but usually only go up to about 5mm. Try Googling "hollow hole punch" and see what you can find.

Just seen Bluebird's post - the paper punches work well too and are just over 1/4" in diameter - what you are looking for!

Colin (the other one!)
Title: Re: Cutting small clear plastic discs
Post by: HS93 (RIP) on March 29, 2007, 06:27:27 pm
Ive started to use perspex rod cut it of I use a lath but a razor saw does as well and then use 600/1500/2000 wet and dry it does where the end of your fingers away though but you get a nice piece of glass and if you make it a tight fit no glue , you can leave it a bit longer if you are using lights, it picks it up better.  Peter
Title: Re: Cutting small clear plastic discs
Post by: Bunkerbarge on March 29, 2007, 07:07:40 pm
This is an idea if you have a lathe.

The last time I did it I machined a steel tube of the diameter I wanted, cut it in half and squared up both ends in the lathe.  I put one end in the headstock and the other in the three jaw in the tailstock.

The perspex sheet I cut into small squares just slightly bigger than the finished size and then I clamped the peices of perspex between the two ends of the tube by using the tailstock feed.

Then I filed the edges of the perspex down to the diameter of the tube making small circular peices of perspex.  It sounds a bit of a fiddle but once I had got into the swing of it I produced eight fairly quickly.  The advantage with this was that I could use fairly thick perspex that I could then glue into a brass tube giving a nice realistic depth to the port and it's hole.
Title: Re: Cutting small clear plastic discs
Post by: HS93 (RIP) on March 29, 2007, 10:40:07 pm
 A picture of finished portholes and the type of rod used ,I could not find the rod I used for these but this is the same rod. Peter
Title: Re: Cutting small clear plastic discs
Post by: Bryan Young on March 29, 2007, 10:51:18 pm
I need to cut some small clear discs for portholes, ( I worked in the aircraft industry building flying boats - don't ask - we called them port lights) I have tried using 'Kristal Klear' but the dia. is just a bit too big, I need about a 1/4'' dia +
Has anyone got a good system for cutting out small dia. discs from clear plastic?

Colin
Just thought I may add another method. If your scuttles (portholes) have a brass surround, then why not place the brass "tubes" on to a bit of perspex and fill them with clear casting resin. They can be easily removed from the perspex and trimmed off.
"Works for me"  BY.
Title: Re: Cutting small clear plastic discs
Post by: sinjon on March 30, 2007, 07:52:10 am
I was attempting to scribe round the inside of a circle template with a compass point - it didn't work, my thanks to you all, I can now go and play, I hope with some real success.

Colin