Cutting styrene sheets (big ones)

[Southwest Chief]

I'll be cutting up a lot of styrene sheets soon for my next G scale project.  I'm familiar with the old X-Acto and ruler method, but when it comes to thicker plastic sheeting this method isn't always as easy as it sounds.

The last project I made out of thicker sheet styrene (1/8) was a G scale Silver Vista.  As I recall it was very difficult to cut this styrene.  I ended up using a Dremel cutting tool, but of course this will never give a perfect straight edge.

Now I'm building a structure, so I need a very good starting box.  Straight cuts are a necessity.  And I have to use thick material for the walls because this structure will be used outdoors, and handled at least two times a year when I bring it out for the summer and then back inside for the winter.

So after all that, now my question...

Are there any special tools or combination of tools that will help me get nice straight cuts in very thick sheet styrene?  I know of the Cutter II, etc... but this won't help me with sheet styrene.  The smaller stuff is so easy to scribe/bend/break.  What can be done with the large stuff? 

[Trekkie]

I've not done this, but just thinking aloud, but if you put some kind of hard stencil (poster paper, something that would keep you in line) around the area on both sides you wanted to cut would it be possible to use a hot wire cutter or are we talking a foot thick or something?

[mikesmowers]

   Not sure how big is big here, but I use a band saw to cut mine. You could use the band saw and cut a little larger than what you want then use a belt sander to get the perfect size. Is this what you are looking for?     Mike

[Don Z]

Matt,

If you have access to a table saw you could cut the styrene very easily provided you use the correct blade for the material. I would suggest you use a laminate or acrylic cutting blade. You might need to use a piece of sheet metal or wood as an auxiliary fence to keep the thin styrene from sliding under the table saw fence.

Don Z.

[dehusman]

Ditto on the band saw, with sanding to get the edge smooth.

Dave H.

[on30francisco]

Although I mostly work with wood (board by board construction) in modeling Large Scale, the only method I'm familiar with that will make perfectly straight cuts in large thick sheets of styrene is Micro-Mark's variable speed tablesaw. A bandsaw with a guide will also work if used carefully. For smaller pieces less than around four inches in width, a miter box and fine-tooth razor saw will work.

[warhammerdriver]

I've used a coping saw with a fine tooth blade.  You'd still need to sand it afterwards, but works pretty well for rough cutting.

[doctorwayne]

If you have access to a table saw you could cut the styrene very easily provided you use the correct blade for the material. I would suggest you use a laminate or acrylic cutting blade. You might need to use a piece of sheet metal or wood as an auxiliary fence to keep the thin styrene from sliding under the table saw fence.

This sounds like a good idea.  You could also ask at the plastics supplier where you get your sheets, as I'm sure they must have to cut the stuff all the time.  Even if they use a sophisticated piece of machinery for this task, they might have some useful suggestions for home users.  I purchase my .060" styrene in 4'x8' sheets, and cut it with a utility knife.  I model in HO, so small structures don't need bracing, while I use .125" square strip for medium-size ones.  For larger buildings, 2' or 3' long, or more, I cut 1" wide strips from the .060" sheets, then cement it, on edge, on the interior of the walls, using lacquer thinner.  It's also useful for making triangular gussets on the inside of corners.

Wayne

[engineerjoey]

Believe it or not, I pencil on a straight line then follow the line with a good pair of scissors. You'd think the styrene would crack or warp, but it doesn't and seems to come out well enough.

[Southwest Chief]

Good suggestions.

I'm looking at 1/8" thick.  Not that thick, but thick enough for what I need, and large enough that an X-Acto + bend + snap doesn't work too well.

With it only being 1/8 thick I'm not sure a table saw would be safe.  I like the idea of a coping saw.  In fact I think I used one for cutting the styrene sides for the Silver Vista, but it has been a while and I can't remember the exact techniques used.

[mls1621]

If you intend to use some corner detail, you could use 1/4" X 1/4" styrene for interior support at the corners, then use flat strips for the exterior trim.  The strips at the corners would hide any irregularity in the wall edges.

Just a thought.

[sunsetbeachry]

Hi,

i used to cut plastic all sizes and types for a living and used only a good table saw and a plastic saw blade [made solely for cutting plastic] and to finish the edges a torch to smooth the edge. Be careful don't melt the edge just clean it up. when finished with edge it should look like clear, with no saw marks.

                 chuck 

[warhammerdriver]

finish the edges a torch to smooth the edge. Be careful don't melt the edge just clean it up. when finished with edge it should look like clear, with no saw marks.

Never thought of using a torch.  With a light touch I can see how it would work well.

[MisterBeasley]

A utility knife with a brand new blade will work wonders.  Score it once and then go deeper with successive passes.  With 1/8th inch thick, you can probably score-and-snap if you can get halfway through.  Put it on a table edge so you can get a good 90 degree bend down to snap it.  If you score-and-snap, you'll probably need to sand the final edge smooth, but it should be pretty straight.

[fire5506]

You can also buy a tool made for scoring plastic to snap. I have seen them at Lowes, Home Deot and also in Micro Marks catalog. At the Hardware stores look for it in the area where they have lexan/plexiglass.

  Richard
 

[larak]

I've done 1/8" two ways.

1) Sheetrock knife and metal straightedge. New blade.

2) Table saw with very fine toothed plywood blade. Sometimes works best if the blade is installed backwards (it will snag and kick less). Feed carefully to avoid melting. Also use a zero clearance insert on the table.

Karl 

[Tom O-Scale]

Matt:

Scoring is an old Al Armitage (the master of styrene, wrote loads of MR articles back in the 60's) trick.  I actually knew Al before he moved to California to work for Athern?  This would be the easiest without buying any additional tooling.  You may need to score quite deep for 1/8" styrene?

With styrene, the main thing to avoid is heat.  It doesn't take much to melt it and also gum up the cutter.  The softening point of styrene is below the boiling point of water, which is why plastic spoons didtort if exposed to a hot cup of coffee.

We cut a lot of polycarbonate 1/4" sheets, where I work, using a router and a straight-edge.  You clamp a straight edge across the cut and clamp it to the table with the proper overhang.  You calculate the distance from the straight edge to the cut, depending on the tool used.  We ordered a special 1/4" plastic cutting mill bit from MSC that looks a lot like a twist drill, but has a much looser spiral.  It makes a perfect cut with no melting and no finishing to do.

You might experiment with your dremel and a carbide fluted cutter if you have the router plate for your Dremel.  However, be prepared for quite a mess.

Good luck.... 

[Southwest Chief]

Wow, I'm impressed with all of the suggestions.  Thanks everyone so much, this has really got me thinking about this.

I was looking at the Micro-Mark table saws.  Nice machines, but I think they might be too small to cut the biggest sheets I have.

I'm actually using the biggest sheets Evergreen makes (1/8" thick)(12" x 24").

The router is an interesting idea, especially with a Dremel.  Man I never thought of that, but it sound like it will work perfectly...provided the straight edge is good, stable, and thick enough for a router.  I'm going to have to find a really nice straight edge...sort of like the super nice one Norm Abram uses on The New Yankee Workshop.

Since I've cut this stuff with a Dremel cutting disk before I know about melting and the fun little shards you get.  But it's manageable and easily vacuumed up.  You just have to be sure to wear goggles.

The router idea seems like a good one to try out, especially since I won't have to go out and buy an expensive table saw that will likely either be too big or too small.

[Southwest Chief]

...We ordered a special 1/4" plastic cutting mill bit from MSC that looks a lot like a twist drill, but has a much looser spiral.  It makes a perfect cut with no melting and no finishing to do.

Did you mean something like the first bits listed here:

MSC Bits 

And if so, would you recommend a downcut or an upcut spiral?  Also if I want to cut through 1/8" material, what's a good bit length I should be looking for?

 

[bogp40]

Sheets as small as you're working with, using the score and snap should work fine. If it doesn't want to readily snap, just score the other side. This is providing that you don't have a band saw or table saw at your disposal. The power tools with the appropriate blade would do the best job.

I will score and snap small stuff for many jobs, cleaning up the edge is best done by dragging the piece accross fine sand paper on a solid flat surface.

[m sharp]

I bought a 4 x 8 foot sheet of 1/8" styrene several years ago, and have cut sections off using the score and snap method without any problems.  I use an xacto knife (sharp) and make several passes with a steel straight edge.  Next, just place the sheet on a table and line up the score with the edge of the table, and snap!  The edge turns out fairly smooth..not pefect, but a little sanding will correct any flaws.  The only drawback is that if you want, say, a 12" x 20" piece from a much larger piece of styrene sheet, then you would need to snap off a minimum of 12" off the entire width of the sheet, even though you only wanted that 20" length.

Mike

[Tom O-Scale]

Matt:

What we bought was for cutting plastics.  More like this:

http://www1.mscdirect.com/CGI/GSDRVSM?PACACHE=000000038525152

 (I copied the link, as Firefox wouldn't let me cut + paste.  If I typed it incorrectly, look under drill reamer)

I found it under "drill reamer".

The good thing about the finish, is, it leaves you with a machined milled surface.

I would use it in a regular router, as you have better control, power and a clat alignment.

Like I said earlier, that was using 1/4" polycarbonate which you absolutely can't score and break.  It's almost as tough as aluminum. 

But first, it appears that others have had excellent luck with scoring, which is far easier, less messy and inexpensive.

 

Best of luck. 

 

 

 

[tovetune]

 

        Hi, SWC,

                    take a look at  http://www.olfablades.com/  They may have something suitable.

        Mick.

 

 

        

[rdj6737]

I have used both the table saw and score-and-bend methods.

4'x8' sheets were too big and flexible to handle on the table saw so I cut my sheets in half first. I prefer cutting slightly wide as I get a lot of "slag" hanging on the back side of the cut, and then sanding or filing to size.

Scored-and-bent pieces sometimes get a permanent curve near the edge from being overstressed during bending. So make sure to score deep enough and bend from close to the edge, prefering to support one half on the edge of a sharp-cornered table. and using a 2x4 to push the other half over. I've noticed that scored-and-bent pieces have discolored near the bend years later even though never being in the sun. This makes me think that it may be gettting brittle in that over-stressed area although I haven't had trouble yet. Glueing solvents do the same thing when overdoused.

Ultra-Violet Light

For modeling outdoors, one should buy the new black UltraViolet-resistant sheets. The color is likely some carbon black-like compound that blocks UV. UV kills plastics and especially translucent and light-colored styrenes like the white Evergreen by wrecking the plasticisers that keep the plastic tough and slightly flexible. My kids' cheap plastic toys fade quickly outside and then become brittle and weak. I have seen some become so bad that I could crumble them to dust in my bare hand. So make sure that the first layer of paint is very opaque/dark, or use gray/oxide primer to block as much UV as possible. If you can see any light get though, it's probably not protected. Windows will let light inside, so both sides of the plastic must be protected.

Reynold

[Anonymous]

No matter what thickness of styrene you cut, you will find if you take masking tape and mask over the area you need to cut, then mark/cut along the masking tape, you will reduce greatly the frayed edges normally associated with your cuts.  this also works with wood but not as well.

                                                Kofy