Plasticard working tips?

[steampig]

I need to make a cylinder for a Faller locomotive which arrived short of one - I have drawn up a plan on the computer for the shapes to imitate an original, and made one out of cardboard to verify it -



I now have a couple of issues I'd be glad of guidance on when I try to make one out of plasticard - mostly 1.5mm thick to match how the original is constructed

1) How to transfer the parts to be cut from paper to black plasticard. I thought of sticking a paper pattern to the sheet with pva glue and then washing off after cutting, but it looks like the adhesion may be minimal. Is there a better adhesive that won't damage the sheet? Print onto a self-adhesive label? Double-side selotape?

2) cutting the card - it's thick and cut edges will be on display. Is there some clever way to get a smooth cut edge? Otherwise it will be fine-toothed piercing- and hack-saws, cleaned up with a file or knife.

Grateful for any guidance

[Big Jim]

I use pva or prittstick if I need to stick a paper pattern to plastic sheet. Both will rub off with no damage to the plastic. A nice soft, such as a 2B or 4B, pencil will also mark plasticard well (even black).

I use a sharp scalpel to cut the stuff and clean up with fine wet and dry paper. I never have much luck with fret saws or the like.

[Peter Butler]

If the fact of using black Plasticard is causing you problems, why not just use white? When you try to smooth joins on the black card you will inevitably have different colour finishes so you will probably end up painting it black anyway!

[steampig]

I have already bought the card and black seemed like a good idea at the time ... seems I might be expecting too much of what can be achieved cosmetically without resorting to a touch of paint.

I'll give the prittstick a go and try a knife, but I think the 1.5mm stuff may be too heavy for any I have.

Thanks for the help.

[Enginehouse]

I have already bought the card and black seemed like a good idea at the time ... seems I might be expecting too much of what can be achieved cosmetically without resorting to a touch of paint.

I'll give the prittstick a go and try a knife, but I think the 1.5mm stuff may be too heavy for any I have.

Thanks for the help.

I never ever advise anyone to use a surgical scalpel for cutting Plasticard as it is extremely easy to flex and break the blade by using even reasonable pressure. I always use an Olfa cutter to mark, score, snap or corner-bend plasticard. The tools (there are two different sizes) are designed for the job. New Plasticard snaps cleanly and extremely easily once scored deeply enough. Old Plasticard is another matter?? It is quite possible to cut right through thick 2mm Plasticard with an Olfa cutter BUT allowance must be made for the thickness of the blade. Cut on a line and the width of the blade as it slices deeper through the plastic will undersize your work by half the thickness of the blade. So allow for that with your first light drawn cut. Drawing an Olfa cutter across the work will slice out a very narrow slot as deep as light pressure will allow. Continue drawing the blade through the same narrow slot until three quarters through and then snap cleanly over a hard edge. It's very easy to do and very little chance of getting cut forcing a thin blade through the material. I used to construct clinker built boat hulls using an Olfa cutter and Plasticard which requires very precise cutting and never experienced any problems. It just a matter of practice. Cutting out loco windows is also quite easy with an Olfa cutter.

Whoops! I almost forgot. The tool you are looking for is an Olfa P-450 scriber and is the correct tool for the job.

[GTB]

I'll give the prittstick a go and try a knife, but I think the 1.5mm stuff may be too heavy for any I have.

At least with black sheet, it won't matter if handling wears some of the black paint off the high points.....

The trick with cutting polystyrene sheet is to not try and cut all the way through with a knife.

The technique commonly used is called score and snap. Make a light cut with a sharp blade along a steel rule then bend along the cut line starting at one edge and the sheet will snap cleanly along the line of the cut. Make sure you use a sharp blade, as a blunt blade requires more force to cut. If the blade breaks, you are pressing too hard. As in the kitchen, it's a blunt blade that slips and cuts you........

The other thing to be careful about is to make sure the part being cut can't move under the knife, as polystyrene sheet is a bit slippery on a smooth surface.

I've been using scalpels as modeling knives for 30+ years without cutting myself and the only time a blade has broken is when changing out a worn one. To change them I grip the blade with pair of pliers.

Before scalpel handles and blades became easily available locally, I used Xacto modelling knives. If scalpels worry you these work OK, but are less comfortable to grip and the blades go blunt faster. The round handles are a less obvious menace, as they easily roll off the bench and they always seem to land point down......

I usually use a scalpel for marking out cut lines on polystyrene. The line is very narrow and unlike pencil, handling the part doesn't remove the marking out.

Cutting curves in polystyrene is a bit more of a problem than cutting straight lines. Score and snap works, but the break tends to wander around a bit and needs more cleanup. I'm more likely to use a piercing saw, but sometimes I use a pair of flush cutting nippers to nibble the part down to the line.

Only thing I use a P-cutter for is scribing planking, panel lines, door lines, etc. into the surface of polystyrene sheet. Probably why I've never had to change the blade in the 30+ years I've owned it.

Regards,
Graeme

[steampig]

Many thanks for the words of accumulated wisdom so far! Score-and-break had not occurred to me. In this case however the parts are quite small compared with the sheet thickness, and not all convex, so it's looking like sawing followed by filing or paring with a knife. A nibbler for final trimming might be the answer, if I had one.

[GTB]

A nibbler for final trimming might be the answer, if I had one.

Good hobby shops that sell plastic kits should have them. The plastic kit modellers use them for cleanly cutting parts off the fret.

From memory Tamiya sell them to the hobby trade, labelled as 'side cutters for plastic'. They also sell a badge engineered version of the Olfa P-cutter, labelled as a 'plastic scriber'.

I usually get mine from a local electronic shop that has a good range of small hand tools. They call them transistor nippers, good for brass and copper wire, as well as plastic, but not for hard wire.

Polystyrene sheet is a bit unpredictable for paring with a knife. I'd stick with the files for final shaping. A 4" warding file with a handle is good for roughing down blocks of polystyrene held in a small bench vice.

Regards,
Graeme

[Big Jim]

Treated myself to a olfa type cutter from The Range yesterday. Three quid well spent! Works very well on plastic and the slice I have across my finger is lovely and straight!
(note to self, don't sneeze while cutting plastic)

[Lonsdaler]

Treated myself to a olfa type cutter from The Range yesterday. Three quid well spent! Works very well on plastic and the slice I have across my finger is lovely and straight!
(note to self, don't sneeze while cutting plastic)

Lol So much for being safer than using a sharp blade! Hope it's not serious, however neat…

[steampig]

Had an experimental run using the 1mm matt-black card of which I have a fair bit ...

Major problem was that pva glue failed to stick the patterns to the card - they just fell off when the glue dried. Stuck it on again and tried cutting (to snap) while still damp and adhering and clamped under a steel edge, but that tore and distorted the now weakened pattern. Chopped things out as best I could, but the 1/2mm accuracy and right-angles of the computer-printed patterns were lost. Will have to try Prittstick, or printing to self-adhesive labels (if white spirit - excellent for clearing S-H glue - doesn't damage the card)

Cleaned up the bits as best I could with knife and file (some now under-size) and tried to assemble with EMK plastic weld. This seemed very reluctant to dissolve the card face and snapped edges, but attacked filed edges more readily - roughing up edges to be joined seems indicated. The EMK evaporated very fast from the bottle - during a total lid-off time of some 5 minutes while painting edges to be joined, I reckon I lost about 1cc.

Very hard to assemble the pieces, as the edges were now poor straights and the corners iffy right-angles, and just using fingers and failing eyes. Definitely need some sort of right-angle jig to line things up while a weld sets.

Further attempts await sorting the pattern fixing problem, I think I'm cured of my desire to make a less Germanic-looking steam-outline top to go on the Faller chassis.

[Peter Butler]

It seems you have more problems than you deserve as a newcomer to the use of plasticard.... it is a wonderful material to work with but some experience is always useful.
I would remind you of my suggestion to use white plasticard as a starter, even if you don't use the finished item it will show you how successful you can be and who knows where it will lead?

[MDLR]

Major problem was that pva glue failed to stick the patterns to the card - they just fell off when the glue dried.

It would do - the best bet is either your self-adhesive labels (and turps WON'T affect the surface: thinners will) or Evo-Stik which will again clean off the glue. As an aside, when I built my beer wagon with cast-iron pipes as a load (made from Steradent tubes) the hardest job of the lot (having persuaded to print yellow letters on a black background) was to glue the labels to the pipes - this is where the Evo-Stik came in!

[steampig]

It would do - the best bet is either your self-adhesive labels (and turps WON'T affect the surface: thinners will) or Evo-Stik which will again clean off the glue. ...

Tell me more about Evostick - I thought it was a brand of a range of adhesives, and I'm pretty sure some of them do plasticard no good at all.

PB - I agree I could at least see what I had drawn if I used white plasticard, but at the moment I don't want to draw on it at all, but let the computer do it. I'm sure I can't do it as accurately.

I wasn't expecting things to work too well first time, that's why I went for a dry run. Might go for another on the 1mm again - worth exploring the weld surface preparation some more, and it cuts with my kitchen scissors if it comes to roughing out and filing down everything.

[Big Jim]

Not wishing to muddy the waters even further but I ruined a Tenmille TR coach kit (styrene sheet) with Evostick. It melted the plastic. This was, however 20 years ago and Evostick impact adhesive may not be the same stuff any more.

[MDLR]

evo-Stik IS a range, but most of the ones sold for domestic use don't attack Plasticard. I use Timebond...................... but you need to make the tin is properly sealed after each use, as the solvents otherwise evaporate away.

[Big Jim]

Ahhhhhhhh.
Bet it doesn't smell as nice as the impact stuff though! (Snort, sniff, dribble)

Thanks for putting me right Brian. I shall have a look at their stuff again in a new light.

[steampig]

Just found a packet of SH computer address labels I forgot I had. There's 21 to an A4 sheet at 63mm x 38mm each which is rather small, but they are contiguous and separated by micro-perforations, so it may be possible just to ignore the boundaries entirely.

Tomorrow is another day.

[Peter Butler]

Evo-Stik do make a range of adhesives for a multitude of uses but I think the one Brian means is the impact type which is available in a tube for small jobs. Apply to both surfaces and wait for a while to set before putting the two surfaces together..... remember it is an impact adhesive which means you must get it right first time.
The good news is that it will not affect the Plasticard so can be rubbed off by finger pressure afterwards. (White spirit works too).
The bad news is that you will need to be accompanied by your great grandchildren before being served with the stuff as some people do strange things with it.

[GTB]

The simplest way to use printed paper templates to mark out polystyrene is to cut the shape out first, then glue it in place with a glue stick (the local newsagent stocks Pritt, but there are other brands). I use it to stick printed templates to steel for cutting frames with no problems. PVA only sticks to porous surfaces.

No idea why MEK didn't work to join the polystyrene parts, unless the sheet you were sold is ABS. If you use MEK on ABS, it appears to work, but the joint is very weak.

There are two varieties of contact cement (called impact cement in the UK I think). The water based ones won't attack polystyrene, but the solvent based ones will. I use the solvent based one for fixing metal parts to polystyrene and wood as it retains a little flexibility when cured. I stopped using the water based stuff as it was going off in the tube within a week or two of first opening the tube. Pliobond was the best contact cement, but very hard to find locally now..... sigh.

There is turps and then there is turps..... Real mineral turpentine attacks polystyrene. In the 'good' old days, when the local model shop only sold Britfix 77 and Artmil balsa cement, I used to use some of Dad's supply of mineral turps for assembling Airfix kits. The stuff I use now for cleaning paintbrushes is labelled 'Turps Substitute Low Odour' and can barely clean enamel paint out of a brush. It's sad when we now have to use a substitute for a substitute.....

Graeme