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Chubber
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This sounds unlikely, but recently on another forum a female lady modeller of the opposite sex advocated the use of hard cardboard under plasticard instead of the ubiquitous cutting mat.

As I have recently started to bodge some NG shunting diesel locos, I am new to plastic, and the first took some struggling and swearing with lots of up-cocks.

This time, using card underneath, much easier, less effort and to date no up-cocks. [I know I shouldn't tempt fate.]

Doug

allan downes
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Well Chubber, I've been cutting plasticard over both card and cutting matts for years and just really can't see the advantage of one over the other apart from the cutting matt lasting much longer.

If you use the 'score and snap' method it doesn't matter what you have underneath - even the dining room table ! (( in the abscence of any female authority of course...)

However, and given the choice, I would use a cutting matt for its durability alone if nothing else - oh, and if you're cutting through 40 thou upward, forget all about that silly little scapel, ditch it for a Stanley knife loaded with a heavy duty blade and you can hack your way through anything, even MDF and ply with equal accuracy.


Allan

Last edited on Thu Jul 14th, 2016 02:15 pm by allan downes

Brossard
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Never bother much with silly scalpels apart from home appendectomies.  I like something with heft - the Olfa cutter works for me.  I like that I can get a fresh blade by snapping off the old one.  Mind you they don't their edge very long.

So Doug, what is "female lady modeller of the opposite sex" anyway.  Trying to get my brain around that.

John

 

 

BCDR
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Hi Doug,

I can see why it would make a difference, although the quality/heft of the knife and the cutting guide probably make more of a impact. Cutting mats have a slight give to the surface (deliberate, the surface is "self healing"), and I can see where cutting thin (5 thou' or less) styrene sheet would give rise to a very small give that could influence the cut.

The advantage of cutting mats is that are relatively non-slip compared to thick craft cardboard (which from memory has a very smooth and slippery surface). Plus all those guidelines come in useful.

I susepct the methods of measurement/drawing have more of an impact on the precision than the cutting mat. I doubt any of us work to more than ±0.1mm precision when scratch building (I can eyeball 0.05mm on the manual micrometer, diameter of a male human hair, those with electronic ones will go to 0.01mm or less). Over 10cm that's an error of ±1/1000. Most commercial brass or nickel-silver etches don't get that precise. For comparison current 3D printers can have a vertical resolution of 0.02mm (layers) and spot resolutions of 0.14mm.

Easiest method I found for getting more precise cuts was to stop using an HB pencil and go to a 4H, or even better a metal scribe. That and an engineer's steel square rather than a ruler. All this of course counts for nothing when doing compound curves. Or cutting thick (20 thou' or greater) lumps of styrene. Rather than cutting to the exact dimension (good luck with that) it pays to cut longer and file/sand back to the required dimension using the line and appropriate measuring stick. Plus do any of us account for the effect of plastic solvent when gluing up?

Alternatively draw the shape on the computer (I use CorelDraw) and print it out with the thinnest line possible (hairline) after checking that the printer gives a true 100% image, and use that as the template (on styrene or brass). Precision is about 0.001cm on the screen, a bit less than that on the printout and even less on the cut. Still better than drawing lines by hand. and avoids drawing lines or true squares/rectangles/curves on styrene or brass. Goodnuff for modeling in N-scale and up.

Like John I'm also wondering - who's this lady who's modeling the opposite sex in styrene? How does she measure or is she just eyeballing?

Nigel

 

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Or go the whole hog and use a plotter cutter; also difficult to cut a finger with one of them.

allan downes
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When building castles and such I have the luxury of being able to work to a plus or minus a mil or two tolerance  without any noticeable effect on the finished model and when you consider the prototypes can be anything up to a foot or more out in any direction then that ain't bad - which also helps explain why I don't build loco's !

Allan.

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Hi Allan,

Rare indeed was the locomotive model (at 12" to the foot) where all the members of a class had identical dimensions, frame and driving gear excluded. Even then the grinder was often taken to the frame to get the hornblocks to fit properly. Couple of inches here or there made not a jot of differences to the bodywork. And especially after a few major overhauls.

My experience in scratch building is measure twice, cut once, then proceed to fettle to get it to fit. Looks OK from 3 feet though.

 Nigel


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BCDR wrote:

Like John I'm also wondering - who's this lady who's modeling the opposite sex in styrene? How does she measure or is she just eyeballing?

Nigel

Oh the joys of the English language...
Is she on the catwalk dressed as a man?
Is she wrapped in plastic?

Should we be worried about Chubber?


                 

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