pewe
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| posted on 8/1/09 at 06:55 PM |
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Cutting perspex/acrylic
Finally got round to fitting the aeroscreen but reckon it's 60mm too high.
Cut the bottom to match the scuttle but the Dremel cut-off discs leave it slightly opaque.
Anyone know how to achieve a good transparent edge? It's going to be easier to cut straight across the top off than re-profile the bottom edge
so needs to be a good finish.
Thanks in anticipation, Pewe 
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blakep82
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| posted on 8/1/09 at 06:59 PM |
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hmmm, not sure. try on a scrap bit first, but jig saw with a fine metal blade perhaps?
i remember we had to do it at school many many years ago, and i forget how it was done
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McLannahan
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| posted on 8/1/09 at 06:59 PM |
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I used to use an old sharpened hacksaw blade as a metal scraper. Sharpened off the teeth and cut a standard blade into 3.
Scrape it along the sawn/cut edge holding the blade with both hands.
Once there's no more teeth/cutting marks in the acrylic I then used to use Brasso to polish and buff it up.
Worked really well but a little labour intensive!
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Humbug
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| posted on 8/1/09 at 07:01 PM |
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When cutting Lexan previously I have left the film on or covered up the surfaces with masking tape to avoid scratches, then cut it with a jigsaw (same
blade as for ali sheet) at slow to medium pace (to avoid it melting and sticking back together!). Once cut, I used a surform to even out any wobbles
in the "straight" line  , ran a metal ruler along the flat edge, then at an angle on the "corners".
Worked for me, but others might have other methods.
Cheers
Simon
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Humbug
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| posted on 8/1/09 at 07:05 PM |
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quote:
Originally posted by McLannahan
I used to use an old sharpened hacksaw blade as a metal scraper. Sharpened off the teeth and cut a standard blade into 3.
Scrape it along the sawn/cut edge holding the blade with both hands.
Once there's no more teeth/cutting marks in the acrylic I then used to use Brasso to polish and buff it up.
Worked really well but a little labour intensive!
It would take a long time to scrape off 60mm
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McLannahan
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| posted on 8/1/09 at 07:10 PM |
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quote:
Originally posted by Humbug
quote:
Originally posted by McLannahan
I used to use an old sharpened hacksaw blade as a metal scraper. Sharpened off the teeth and cut a standard blade into 3.
Scrape it along the sawn/cut edge holding the blade with both hands.
Once there's no more teeth/cutting marks in the acrylic I then used to use Brasso to polish and buff it up.
Worked really well but a little labour intensive!
It would take a long time to scrape off 60mm
You think? Obviously my method is suggested to clean the edge up after cutting!
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myke pocock
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| posted on 8/1/09 at 07:11 PM |
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Once you have cut and polished the edge with fine wet and dry, try flame polishing if you have oxy/acetylene. Put your finest nozle in (No 1 or 2 if
pos) and run along the edge with your flame at right angles to it fairly quickly. Try not to let the flame go across the face of the acrylic or you
could get shadows on the face. Flame polishing is preferably done with a very fine jewellers torch but I have done it this way a few times and make
sure it is acrylic and not polycarbonate or similar.
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jacko
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| posted on 8/1/09 at 07:12 PM |
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Masking tape mark your line cut with jigsaw then finish of with a sharp spoke shave
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splitrivet
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| posted on 8/1/09 at 07:22 PM |
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I cut mine the same as Humbug, Jigsaw slow speed, do it with the material at room temperature. Then used a small block plane to finish.
At the top edge I used a round over in a router with a plywood sheet backing to take off the edge, the lexan I used though was 6mm thick.
Cheers,
Bob
I used to be a Werewolf but I'm alright nowwoooooooooooooo
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trextr7monkey
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| posted on 8/1/09 at 07:32 PM |
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I'd cut it on a bandsaw (for straight edge and speed) don't use your dad's finest cabinet making gear though, or jigsaw with fine
blade, then draw file, sand, wet and dry then buff or Brasso /G3 . You will achieve a factory finish if you work at it guaranteed!!
Wear goggles gfor the sawing as the chips are very damaging to eyes
If using a jigsaw make sure it doesnt scratch the face of the screen - either leave on protective coating or get it covered with card etc
hth
Mike
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pewe
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| posted on 8/1/09 at 08:29 PM |
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Thanks guys. I think I'll mask it up first with masking tape and try the fine jigsaw blade first and then scrape & polish.
Cheers, Pewe
PS Sorry Bob what was that you were saying????
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mr henderson
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| posted on 8/1/09 at 09:15 PM |
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Scrape the edge. Stanley knife blade held vertically will do it if nothing more suitable handy.
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jlparsons
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| posted on 8/1/09 at 10:12 PM |
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I used to work with acrylic/poly sheet occasionally, i used a router. It gives a very fine edge and you can then rub it to a glass finish if
you're patient. Cock it up and it'll crack though, go slow.
Any resemblance to real persons, living or dead is purely coincidental. Some assembly required. Batteries not included. Contents may settle during
shipment. Use only as directed. No other warranty expressed or implied. Do not use while operating a motor vehicle or heavy equipment. Subject to
approval, terms and conditions apply. Apply only to affected area. For recreational use only. All models over 18 years of age. No user-serviceable
parts inside. Subject to change. As seen on TV. One size fits all. May contain nuts. Slippery when wet. For office use only. Edited for television.
Keep cool; process promptly.
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splitrivet
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| posted on 9/1/09 at 08:46 AM |
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Sorry didnt explain too well, the lexan I used was 6mm thick rather than having a sharp edge along the top of the screen I used a round over bit in a
router to give it a uniform edge, the lexan was clamped onto ply as I did this.
As said above I have used a router to cut Lexan this gives a superior edge but its mighty scary unless your a router whizz kid.
Cheers,
Bob
[Edited on 9/1/09 by splitrivet]
I used to be a Werewolf but I'm alright nowwoooooooooooooo
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pewe
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| posted on 9/1/09 at 09:14 AM |
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Bob, explanation was fine it was the wobbly bits that were distracting me. Cheers, Pewe
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splitrivet
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| posted on 9/1/09 at 09:52 AM |
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Oh right, I keep dribbling every time I see em.
Cheers,
Bob
I used to be a Werewolf but I'm alright nowwoooooooooooooo
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