# Cutting plastics....best way?



## Cap'nBill (Dec 27, 2008)

O.k., so I have 2 Bachmann cars I want to cut in two. Actually they're two coal tenders I want to make into one large water tender. Seems as though it's hard to get a good cut in plastic...at least for me. It wants to' burr' up and bind with whatever saw I seem to try. Anyone have some good solutions? Obviously, I want a good square cut. Thought about using my electric miter saw but I've cut shedule 40 pipe and had it break the plastic. Bill


----------



## peter bunce (Dec 29, 2007)

Hi Bill

The 'burr' you talk about is melted plastic from the saw doing its work it melts when cutting plastic as basically it is running too fast, so the crumbs produced by the blade fuse together = burrs.

Cutting a (pre) made body is always difficult as it is possibly large, and/or difficult to hold and is in effect a 3D shape, and not flat sheet.

The best I can suggest is hand held saws, used to a cut line that has been pre-marked on the two bodies; I would also say that the line that you saw to should really be a tiny bit 'into the waste' of them the two bodies and they are filed down to the pre-cut lines. 

It is unlikely that you could cut a totally perpendicular line twice, in at least two directions at once, so they fit together with no gaps. 

Long winded I agree, being done with a hand saw you will have much more control then a power saw, slower an thus more accuracy. 

Done like that with care the join should be invisible, after some 'possible' filling is done, and sanded down to the level, with a flat plate, or block, wrapped with fine 'wet & dry' paper, used wet.


----------



## Dr G (Jan 16, 2008)

Bill, 

I agree with Peter. I use a hand miter saw (the one that had the rod on top and is stabilized by two upright posts). Even with the guides the saw is not totally true. So I cut "into the waste" and file to the line. Now if you had a band saw, many have had great sucess with such a tool--but you will get some melted plastic with just about any power tool. It really isn't all that hard, just go slow and plan on some filing to get a good fit (and in my case a bit of body putty--hides a myriad of mistakes!!!). 

Regards, 

Matt


----------



## Les (Feb 11, 2008)

Cap,

Another option is to put a speed controller on your bandsaw--provided the type of motor on it will accept one. Some won't. And provided you have a bandsaw.







And don't run it slow very long, those motors overheat fast!

For cutting cast plastic, like on train stuff I generally use a hacksaw with a fine-tooth blade, and some soap. Then file to suit.

Les


----------



## dltrains (Jan 2, 2008)

They've been making a zona saw for years.X-acto has a couple miter sawblades. Both these have a rigid back to keep the thin blade straight, and they give a very fine cut. 

Dave


----------



## San Juan (Jan 3, 2008)

Zona hand saws work great for cutting plastic. The finer the blade, the better.


The big problem with them though is the straight blade (like a dove tail blade) is never tall enough to go all the way through most G scale cars. At one point in your cut, the blade holder hits the top of your cut and you can't cut any lower. 


I had to cut through very tough LGB plastic to make two pipe gondolas. Here is a link with photos showing the progress:

Pipe Cars 

I used this 4-In-1 Zona saw for cutting the ends off of the gondolas. I used the large thin blade for most of the cut until the blade holder hit the top of my cut and then I used the thicker jagged triangular end blade for the rest. I had less fine control with the jagged blade, but it cut through without hitting the top of the cut since it doesn't have a holder.

The saw I used looks like this:


----------



## pimanjc (Jan 2, 2008)

To do these cuts, I uses a harbor Freight minature table saw for the sides and a pneumatic automotive pannel saw for the bottom.










Jim Carter


----------



## Cap'nBill (Dec 27, 2008)

I thought about this and decided to give the electric saw a try. Figured I'd make a cut ahead of where I wanted to go and see how it came out. I thought I'd at least get a good 'square' cut all the way through. As it turned out, if one goes very slow, the cut comes out very clean with just a tiny bit of burr....which brushed off.


----------



## Totalwrecker (Feb 26, 2009)

I recently cut the end and the dome off an Aristo shorty tank. 

I used a seperating disc in my Foredom (Dremel with slow speed) I did raise a few melted burrs, but they came off with a fingernail. I used a disc aprox 0.010 " I get my discs from jewelry supply stores. There are many better than Dremel's thick discs. I have some .009" for gold work, can cut a paper thin kerf in 16 ga metal! 

I sanded the cuts true on a water cooled flat lapper, the water reduces the dust from sanding. you could use a piece of sand paper taped to a flat surface, even wet n dry and spray with water. 600 grit. 

Now how to put it back together? 

John


----------



## Cap'nBill (Dec 27, 2008)

Yep! Wrestlin' that question too! Guess I'll try some pieces of the cast off parts with the 'usual suspects': MEK, CA, think I may try the "all purpose' CPV pipe cement. Glue up plumbing pipe with that and it's welded!


----------



## barnmichael (Jan 2, 2008)

Use one of those Japanese woodworking saws. Very thin, very fine teeth on both sides, cuts on the pull stroke. Although quite flexible, with a little practice you can cut a fairly accurate straight line.


----------

