Lofting Problems...

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Treadhead
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Lofting Problems...

Post by Treadhead »

When scratchbuilding a complex shape I use the lofting technique -- basically assembling a styrene framework with formers that follow the contour of the object attached to a keel.

Now when using A&B putty to cover the framework, I sometimes wind up with undulations where the putty meets the styrene. Beveling the cross-sections helps somewhat, but I still end up getting those annoying lines where the cross-pieces lie. I end up using a ton of Mr Surfacer, but I know that there must be an easier way.

Can anyone help? :)

Thanks in advance
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Arklan
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Post by Arklan »

haven't tried it yet myself, as i've had no need on current projects (yet...)

but i've heard people mention taking strip styrene and gluing it over the formers to give the putty more of a solid guide, if that makes any sense.

...someone who has done it can explain better i'm sure.
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Treadhead
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Post by Treadhead »

Arklan wrote:haven't tried it yet myself, as i've had no need on current projects (yet...)

but i've heard people mention taking strip styrene and gluing it over the formers to give the putty more of a solid guide, if that makes any sense.

...someone who has done it can explain better i'm sure.
Arklan, it seems brilliant minds think alike :) I was thinking of doing just that. Basically the strip gives the putty a contour line. It also gives a constant 'height' so the putty remains at a somewhat uniform depth throughout the shape.
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Post by TER-OR »

And after that, you can roll out the epoxy putty like pie dough, using talc or corn starch. Drape it over the structure and work into place. If you want it to stick right away, rinse the lubricant from the surface to mate to the model.

You will want to let it partially cure before lifting and moving the putty - about a third of the way cured is about right.


Polypropylene rolling pins available at confectionary supply stores are great for this. Michael's sells them here in the US.
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Post by Lt. Z0mBe »

The way I avoid it is to add more putty after the first round of sanding and forming like Terry suggested Sounds simple, but it's way less frustrating than filling with primer.

Sculpt, sand, check against template. Repeat. Takes time, but it is worth it.

Works great for any depressions in a scratchbuild.

I hope this helps.

Kenny

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Post by Migmaker »

this may be a little tough to explain but when you make your loftings(bulkheads). make sure that your top edge is the hightest point of the contour line. Then as you sand down to it, you will only sand to edge using this technique which I've used for years. You can pretty much do away with epoxy putty and the like if you just make a series of lofts in a thicker material, say balsa or basswood, and stack em, using same technique as above. just thought. I get very difficult compound curves and odd contours to come out great using this method.
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