# Cutting tool for plastic structures



## babu2 (Jun 8, 2015)

Can someone please give me advice on cutting tools for plastic? I have some cast parts I need to cut that are about 1/4 inch thick plastic and the cutting area is about 1 inch by 1 inch.
I am also looking for some good advice on how to burrow out some windows. I have cast a number of building flats but in some cases when the plastic was poured it covered some of the windows and now I need to cut or burrow out the plastic where the window are. The windows are small and I do not wish to ruin them by cutting too close to them. I have been using a dremel drill but the result have been less than satisfactory.


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## wvgca (Jan 21, 2013)

i use a band saw for some, and an ordinary dril for others,but at slow speed so that it cuts, but doesnt melt...a nibbler also works for material under 1/8" thick


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## babu2 (Jun 8, 2015)

What is a nibbler? Where can I find one?


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## wvgca (Jan 21, 2013)

nibblers cut a slit or notch in thin metal or plastic, industrial ones are electric or air powered, hobby ones are hand tools ... some cut slits, some cut round half circles out, most common is the 3/16 square size, cuts up to 3/16 by 1/16 each squeeze, needs side access or 3/16 hole to start ..
here is a link to a standard square hand tool on ebay
http://www.ebay.ca/itm/Hand-Nibbler...382?pt=LH_DefaultDomain_0&hash=item2eb9c33bb6

finish with a razor knife or file to final size...


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## CTValleyRR (Jul 26, 2014)

I have found the best choice for specialized hobby tools to be Micromark (www.micromark.com). They sell nibblers, razor saws, miter boxes, and much much more. Some folks complain about their prices, but I've always found their quality and customer service to be worth it. Even if you don't buy from them, a trip through their catalog is an eye-opening experience.


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## DonR (Oct 18, 2012)

Unfortunately the Dremel slowest speed is far to fast to cut
plastic.

Am I reading that you are saying you have windows in a plastic sheet but they
are too small and you need to enlarge them? If that is the case, the safest is
to use a file unless the undesired thickness is too great. Else, a sharp hobby
knife against a straight edge would be helpful. Likely, you will need to
do several passes of the knife blade. In any case, be sure to mark
the exact lines of the windows.

Don


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## Cycleops (Dec 6, 2014)

DonR said:


> Unfortunately the Dremel slowest speed is far to fast to cut
> plastic.Don


You maybe able to get one which has rheostat which can infinitely control the speed. I have one which I bought for just a few pounds.


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## T-Man (May 16, 2008)

Maybe a scroll saw is what you need. Motorized of course. I have Xacto saws and blades, but I do prefer the dremel cutting wheel.


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## CTValleyRR (Jul 26, 2014)

A cutoff wheel in a motor tool is a great choice for a lot of cutting jobs, but generally not where a very straight cut is required, and especially not window and door openings where you need not only a straight cut, but a precise stopping point as well.

In woodworking, we say, "The right tool for the job." That's true here as well.


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## DonR (Oct 18, 2012)

Cycleops said:


> You maybe able to get one which has rheostat which can infinitely control the speed. I have one which I bought for just a few pounds.


It would be my guess that to safely cut plastic with
the Dremel cutting wheel the RPM would need to
be less than 1 or 2 hundred. Maybe at that speed it
would cut evenly without melting the plastic.

I have seen various Dremel models advertised that claim slow
speeds but I don't know how slow they claim is slow.
200 RPM? 2000?

Don


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## wvgca (Jan 21, 2013)

most 'dremel' type tools are high speed, 25,000 or better, a genuine dremel 3000 variable speed will only go down to 5000 rpm ....an alternative for light duty plastic removal tat i have used in the past is a jigsaw held upside down, with fine blades, i have also used a multi saw rotary cutter bit in a jigsaw, with the shank ground flat so it would clamp in, does a nice shaving , gentle on thin plastic or hydrocal / resin castings as well ... depending on the job, a mini table saw will work well also..


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## traction fan (Oct 5, 2014)

*Cutting plastic*

BaBu2;

There are many methods and tools to cut plastic. The simplest, and the one I use most, is an Xacto knife with a #11 blade. This will trim away the plastic molding "flash" you found on your model windows. Combined with the model railroader's other favorite tool, a steel scale ruler, you can do most of the cutting you'll ever need to. BY running the knife along the ruler; starting with light pressure, and then increasing pressure on subsequent strokes, you can scribe a straight line in the plastic. The plastic can then be broken along this line leaving a perfectly straight and clean edge.

Regards;

Traction Fan


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## CTValleyRR (Jul 26, 2014)

traction fan said:


> BaBu2;
> 
> There are many methods and tools to cut plastic. The simplest, and the one I use most, is an Xacto knife with a #11 blade. This will trim away the plastic molding "flash" you found on your model windows. Combined with the model railroader's other favorite tool, a steel scale ruler, you can do most of the cutting you'll ever need to. BY running the knife along the ruler; starting with light pressure, and then increasing pressure on subsequent strokes, you can scribe a straight line in the plastic. The plastic can then be broken along this line leaving a perfectly straight and clean edge.
> 
> ...


Flash, yes. Cutting out window openings, no. You can't use the score and snap method because all the cuts are interior, and it takes a heck of a long time to cut through a thick piece of plastic with a #11 hobby knife.


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## SBRacing (Mar 11, 2015)

My dremal at slow speeds hardy does anything. For windows MicroMark sells an L shaped punch. You can use a hammer the puch it out or it can be used in a drill press (dont trun on the press on) just using the telescoping part.

5/16 http://www.micromark.com/5and16-inch-corner-punch,7805.html

3/16 http://www.micromark.com/3and16-inch-corner-punch,8013.html


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## traction fan (Oct 5, 2014)

*My bad*

BaBu2;

Sorry for giving bad advice. I was thinking of the thin(1/16" or less) plastic from which most railroad models are built. The scribe and break method I described would not be suitable for the 1/4" plastic you are cutting. I am curious about what you are building that requires such thick plastic?
I have cut 1/4" plexiglass plastic on a table saw. (I don't know if you have one.) I used a fine tooth, plywood blade mounted with the teeth backwards. This helps prevent cracking the brittle plexiglass. As mentioned earlier, a band saw with a fine tooth blade is another option. If you have a choice between the two power tools, the circular blade table saw will be easier to cut straight lines with. Either tool will produce lots of little plastic bits; some "welded" along the cut edge. These can be removed by running a file along the cut. Of course wear protective goggles(or better yet a full face shield) and work gloves while cutting. The little flying bits of plastic are hot and can do great damage to your eyes.
These tools will only help with outside cuts. Inside cuts, such as window openings, will need something else. Traditionally window openings have been made by drilling small holes just inside the corners, and cutting between the holes. This can be done with a scroll saw or by drilling more holes in the center areas and using larger drill bits to expand the opening until most of the plastic in the window area is removed. Final shaping is then done with small files.

Good Luck;

Traction Fan



CTValleyRR said:


> Flash, yes. Cutting out window openings, no. You can't use the score and snap method because all the cuts are interior, and it takes a heck of a long time to cut through a thick piece of plastic with a #11 hobby knife.


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## CTValleyRR (Jul 26, 2014)

The nibbling cutters are designed to avoid having to drill all those holes. Unfortunately, I don't know of one that cuts 1/4" styrene. As someone else pointed out, though, that is really thick stuff, and I'm betting it's overkill. I generally use much thinner stuff, reinforced with strip or a second layer of sheet if necessary.


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## babu2 (Jun 8, 2015)

*Every picture telles a story*

This is the project I am working on. As you can see some of the windows are covered with plastic that I need to remove.


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## SBRacing (Mar 11, 2015)

This may be a stretch but what about a jig saw with a fine plastic blade?


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## DonR (Oct 18, 2012)

Hard to tell from your pics, but the errant plastic appears
to be similar to 'flash' which can be easily cut off with a
good hobby knife.

I have a razor saw with a choice of several blades. One
is very slender and would be right to remove the 'flash'
even if thick. It could easily get into tight spaces.

Don


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## wvgca (Jan 21, 2013)

if you just want to get 'most' of the excess plastic off, and file to finish size...i have used a small fine tooth jig [sabre] saw blade..to make it easier to hold i sawed a notch into the end of a piece of wood doweling for a handle, hot glue or hose clamp tight...


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## CTValleyRR (Jul 26, 2014)

Did you cast those yourself? Some of them look pretty rough.

Anyway, for that job, I think a hobby knife and mill file would be your best bet.


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## tr1 (Mar 9, 2013)

*Save our work surface area from wear and tear*

I agree, a sharp hobby knife. and a very fine mini file along with patience. The casting should be placed on some spare wood to take most of the punishment from the sharp pointed blade. That, I believe, will save your work surface from showing it's age. Regard's,tr1


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## CTValleyRR (Jul 26, 2014)

Or use a self healing mat.


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## JoeG (Feb 3, 2013)

I found this product which might help for cutting windows. I might even buy once for the same reason. 

http://www.micromark.com/7-piece-11-size-micro-saw-set,6567.html


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## thedoc (Oct 15, 2015)

If you mount a carbide tipped blade on the Dremel table saw, it makes a very good tool for cutting small items. I have even used one for cutting hard woods over 1/2" thick.


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## CTValleyRR (Jul 26, 2014)

Well, no saw with a continuous blade is going to help you cut out a window, unless you're willing to cut through your wall and patch it up. 

My choice is a nibbler, like this one.


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## thedoc (Oct 15, 2015)

CTValleyRR said:


> Well, no saw with a continuous blade is going to help you cut out a window, unless you're willing to cut through your wall and patch it up.
> 
> My choice is a nibbler, like this one.


Yep, you need to use the correct tool for the job, and a Dremel with a carbide blade is good for long straight cuts, A nibbler is good for cutting out holes larger than the nibbler blade.


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