Template modelling material.

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jonjo

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I am looking for a fairly rigid sheet material to create a 3d template for a boat project. The project is to create a rigid coachroof screen as seen on Malos and HRs.

The material I have in mind would be cutable like polystyrene but not as messy or brittle. I intend to join sections of the template with gaffer tape. A tricky part of the project will be shaping the plinth (on which the final alloy screen will sit) to the curves of the coachroof. So the ability to file and shape this mystery material of no name would be useful.

This will be an expensive project if I go ahead so I do not mind spending ££ on the templating sheet. Any suggestions as what I could use?
 
Assuming you need something fairly rigid, I'd be inclined to get some thin ply or, provided it won't get soaked, mdf. You'll need a jigsaw to cut it, rather than a stanley knife, and a belt sander for fine adjustments, but that'd the only problem I can see.

If flexibility isn't a problem but damp is, how about the stuff estate agents use for their For Sale boards? I'm sure a local one would be happy to tell you who makes their signs and the sign maker would be able to sell you a sheet
 
Stemar said:
Assuming you need something fairly rigid, I'd be inclined to get some thin ply or, provided it won't get soaked, mdf. You'll need a jigsaw to cut it, rather than a stanley knife, and a belt sander for fine adjustments, but that'd the only problem I can see.

If flexibility isn't a problem but damp is, how about the stuff estate agents use for their For Sale boards? I'm sure a local one would be happy to tell you who makes their signs and the sign maker would be able to sell you a sheet
Click to expand...

The plastic cardboard stuff is corex, or was when I was at school :)
 
I take it you're doing this by hand? If so, one way you might be able to do it is to paint plenty of release agent on to the coachroof (maybe even cover it with parcel tape) and make a rough cardboard "dam" round the area, then pour expanding foam into it. You can then shape that very easily with just about anything - bread knife, surform, etc.

Without seeing the area, it's hard to recommend something suitable. If there's not much curvature (and that which there is, only contains single plane curves), you might be better off making something out of MDF / plywood / hardboard and do the detail bits with car body filler (which will stick to the above pretty well). For creating the recess, there are various thicknesses of self-adhesive sheet wax products that can be stuck to your master to help with that:

http://www.ecfibreglasssupplies.co.uk/p-2222-5mm-sheet-wax.aspx
 
Mdf.6 or 10mm inexpensive but with beautiful smooth surface.

Be careful using thin ply as there will be voids internally, thus when you bend it there will be hard spots( ridges). In fact the lack of voids is what mostly in part defines 'marine' plywood and it's fancy £.

Mdf can be worked and sanded with power and hand tools( eg planes and spoke shaves or a compass plane if you are lucky enough to own one, for shaping the concave bevels that meet the camber of the coach roof.

Car body filler as stated, applied with lolly and tongue depressor/epixy mixing sticks, will give you the right internal radii .

This is all of course just IME.
 
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Avocet said:
I take it you're doing this by hand? If so, one way you might be able to do it is to paint plenty of release agent on to the coachroof (maybe even cover it with parcel tape) and make a rough cardboard "dam" round the area, then pour expanding foam into it. You can then shape that very easily with just about anything - bread knife, surform, etc.
Click to expand...
You have just eliminated a lot of uncertainty from stage 2 of project, this sounds ideal for modelling the coachroof contours for the actual GRP mould.

Avocet said:
Without seeing the area, it's hard to recommend something suitable. If there's not much curvature (and that which there is, only contains single plane curves)
Click to expand...
very curvy.

http://adriaservice-yachting.com/sl/wp-content/uploads/bavaria-35-match-titel.jpg

http://www.sailingnetworks.com/images/photo/571206.jpg?1217245849
 
Stemar said:
If flexibility isn't a problem but damp is, how about the stuff estate agents use for their For Sale boards?
Click to expand...
Brilliant, this is just the sort of lateral thinking I was hoping for.

Stage one is a rough mock-up to assess the aesthetics, helming sight-lines and ergonomics and also see if it is possible to merge this into an overhead mainsheet gantry as per a Malo.
 
OK, photos look pretty curvy, but you might be lucky and find that in the precise areas you want to put your edges, they're actually all in one plane. Worth assessing when you make your rough one to assess the sight lines. I can't over-stress the importance of stopping this foam from sticking to the decks though - it really is VERY sticky!

http://www.cfsnet.co.uk/acatalog/CFS_Catalogue__2_Part_Polyurethane_Foam_Liquid_415.html

Also noticed this:

http://www.cfsnet.co.uk/acatalog/CFS_Catalogue__Ethafoam_Sheet_418.html

I've never used it but it might be worth talking to them to see if it's the sort of stuff you could at least use for your mockup.

One thing to mention about the expanding foam is that if you paint resin on it, to make a hard surface, the resin attacks it to a certain extent, so it wil lsink a bit. There's not much that can be done about this - other than filling it and fairing it with car bodyfiller afterwards.
 
The plastic they use for soffit boards might be suitable but not sure if it's available in larger sheets. Maybe a visit to a local firm that supplies the contractors who do that sort of work and get the name of the product and Google it?
 
Stemar said:
how about the stuff estate agents use for their For Sale boards? I'm sure a local one would be happy to tell you who makes their signs and the sign maker would be able to sell you a sheet
Click to expand...

I have used Foamex for quite a few jobs on the boat. It comes in different thicknesses and is the stuff signwriters mount vinyl artwork on.
Can be cut with a craft-knife and snapped, better and less messy than sawing. It can also be welded with adhesive.
 
Source of cardboard in big sheets?

I've also got some template work to do this summer but l was thinking of using cardboard just because it's lightweight and easy to cut. Can anyone tell me where it can be obtained in 8x4 sheets like mdf & the foam boards etc?

Thanks,

Boo2
 
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