Making Cab Roofs From Plasticard

[jason clarke]

Hi All,

Firstly , Im new here so please excuse me if this is a stupid question!. I am looking at scratchbuilding and was wondering what would be the prefered method of building cab roofs with compound curves (ie class 56 cab roof etc) . I have noticed that some modeller make them from laminates of styrene sheet which seems to make sence but , I was wondering , is it best to make the laminates slightly under size for the profile of the roof then fill them ( I am guessing with something like miliput) or to make them over size and file the plastic back to the corect profile.
Many thanks in advance .

Jason

 

[iploffy]

Hello and welcome, I remember reading somewhere a fella built a load of AC electrics he laminated the roofs with alternate colours so he could get the profile the same on both sides of the loco roof. I can't remember where I saw it perhaps someone else will know

Ian

 

[28ten]

Crude sketch, but this is what I would do, the arc being the desired profile. slap the filler on and as soon as you start seeing plastic you are on the correct profile. it also helps if you use black plasticard and white filler.

 

[Dog Star]

it helps if you use black plasticard and white filler...

nice thinking about the use of black sheet and white filler.

Taking the idea further.... decrease the thickness of the sheet moving to the top ought to assist in having filler "strips" visible as roughly similar widths.

 

[jason clarke]

Thanks guys,

Just the kind of advice I was looking for, Especially like the point about Black plasticard and white filler.

Thanks again guys, Now back to the bench!

Jason

 

[Steph Dale]

Funny one that - I'd always think that 'solid' plasticard was better than plasticard and filler. So I'd use a good quality adhesive (ZAP SheetZap is good), and key the layers well before gluing. Make a template and file/polish back the layered plasticard to the shape you want. The layering of different colours is a good idea - it'll be easier to see you've got the shape consistent/symmetrical, etc.

You can always subsequently use a thin skin of plasticard over the top., if you need to.

You may find this note on the Southwark Bridge website useful: http://www.sbmodels.org/sbm_toptips.html

As regards tools I'd get a decent sized (8" or 10") flat rough or bastard cut file and you'll find roughing the shape very quick. I'd then make up a few sanding pads using different grades of wet and dry superglued to 1"x2" styrene sheet - and using wet, working down the grades you'll find it a synch to get a good finish too...

Steph

 

[jason clarke]

Thanks Steph, very usefull link there.

I think the best thing I can do for now is to try both methods and see which I find easiest to produce a good result.

Again thanks to everyone for taking the time to reply, lots of very usefull info to get stuck into now.

Cheers guys

Jason

 

[JimG]

Thanks Steph, very usefull link there.

I think the best thing I can do for now is to try both methods and see which I find easiest to produce a good result.

Again thanks to everyone for taking the time to reply, lots of very usefull info to get stuck into now.

Jason,

Another method I have used to shape Plastikard for roofs is to use formers to the shape of the roof and curve the sheet over the formers. I found it better to use thicker sheets on formers and it helps to make these sheets more flexible by scoring grooves close together along the lemgth of the sheet. Use something like an Olfa cutter which actually cuts a groove, rather than split the plastic like a knife blade, to get the best results. Once the thicker sheet is laid over the formers with the grooves to the outside and stuck down, sand the grooved surface smooth and cover with a sheet of thin Plastikard to get a smooth finish. When making the formers you obviously have to allow for whatever thismnesses of sheet you are going to use.

Jim.

 

[jason clarke]

Thanks for the reply Jim, Im not sure how I would manage that on the dome shaped roof ends though (probably me being stupid and not following your sugestion correctly), Do you have any images that would illustrate the idea that I could see please.
Sorry if I am being a bit thick here ,but well, I am .

Thanks again

Jason

 

[Wagonman]

Thanks for the reply Jim, Im not sure how I would manage that on the dome shaped roof ends though (probably me being stupid and not following your sugestion correctly), Do you have any images that would illustrate the idea that I could see please.
Sorry if I am being a bit thick here ,but well, I am .

Thanks again

Jason

There is always the possibility of heat forming the styrene over a wooden former.

 

[JimG]

Thanks for the reply Jim, Im not sure how I would manage that on the dome shaped roof ends though (probably me being stupid and not following your sugestion correctly), Do you have any images that would illustrate the idea that I could see please.
Sorry if I am being a bit thick here ,but well, I am .

You're not being thick - I didn't read the thread properly. My suggestion really only works along the length of a roof, not round complex curves at the ends. Blame the time that I responded - should have been in bed.

Jim.

 

[jason clarke]

I know the feeling well Jim