still thinking about a large scale balsa kit. they come with vacuform cowlings and spinner. obviously I will need a clean cut around the base of those parts. I've never touched vacuform before. I know its thin and most likely unforgiving to an errant cutting blade.
How to get a smooth, straight, etc cut with this stuff?
thx much - Craig
Shalom Craig.
One way is to cut out vac-formed parts, using light pressure, to scribe the plastic over and over again with the back of a #11 knife blade and then snap the excess plastic off. Then using a sanding block sand the part to the exact dimensions.
Cheers from Peter
thx. what bugs me about the vac for balsa kits is that there is no real clean line to cut. for the pieces I mentioned, I need to cut perfect circles at the base and hope I get it right.
Craig
Hi Craig.
For cutting perfect circles you can put a temporary plug in any existing hole and then use a pair of dividers or a compass with the pencil lead replace by a small sharpened nail. You center the compass in the plug and just turn the compass or hold the compass still and turn the part if that is easier and scribe the circle until you can snap it off or until the point starts to come through in spots. That is how I make styrene discs for my scratch-building.
Cheers from Peter
Mark the cut. Rough trim with scissors, medium trim with an X-acto knife (as someone else says, repeated scoring and bending is a good method), then fine trim with sandpaper.
As someone showed me long ago here.
Paint the part/sheet in question. Than scribe around the part. Than sand away until no more white (or whatever color they molded the part sheet in) shows anymore.
You now have the part ready to use.
The side of the sheet the part sticks out of.
Jack Bohn wrote: : OM wrote: : :>On Sat, 09 Jan 2010 10:38:24 -0500, AM wrote: :>
:>>Paint the part/sheet in question. :>
:>...Point of clarification: which side of the sheet? : : The side of the sheet the part sticks out of. : I have heard of this technique before, but doesn't it make a difference if the vac was pulled over a male or into a female mold?
This technique seems to assume a female mold.
Bruce
No.
Because either way, you want to get rid of the excess sheet.
If you always paint the raised part of the sheet, cut and then sand down, it does not matter at all. The result will always be the same.
All painting the sheet does is show you the thickness of said sheet, and how far you have to go before the excess plastic is gone and you're down the the part.
It is soo much easier to show this to someone than describe it.
It really works that well !
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