Making Cut Outs

 There is a good consensus here !

 This is an aside . I have a coping saw that takes the rounded , any direction blades like I use in my Scroll - Saw . They work very good !

Devil Dawg

Here is another way to cut out irregular-shaped holes without messing up the immediate area around said holes (yes, I have actually seen this performed during a demo at a club meeting a while back):

As previously mentioned, mark your areas to be cut with a pencil of some kind; drill a small hole somewhere along that line; then, insert either some dental floss in the hole, or some very strong thread, and use that as your saw. A curved piece of springy metal, or a Flex-I-File U-shaped sanding handle, with both ends of the thread/floss secured to the handle (think of something horseshoe-shaped to hold the floss/thread), will work great handling the thread/floss while you saw with it. Won't overheat anything, and cuts curves very, very easily.

Gary Mason

 

 

 

There are coping saw blades that are flexible and grit covered. Slightly larger diameter than floss or thread.

Here is another way to cut out irregular-shaped holes without messing up the immediate area around said holes (yes, I have actually seen this performed during a demo at a club meeting a while back):

As previously mentioned, mark your areas to be cut with a pencil of some kind; drill a small hole somewhere along that line; then, insert either some dental floss in the hole, or some very strong thread, and use that as your saw. A curved piece of springy metal, or a Flex-I-File U-shaped sanding handle, with both ends of the thread/floss secured to the handle (think of something horseshoe-shaped to hold the floss/thread), will work great handling the thread/floss while you saw with it. Won't overheat anything, and cuts curves very, very easily.

Gary Mason

I second GMorrison--I would not use a rotary tool for this operation, I would use a pin vise to drill out small holes and remove material, till you can fit a razor saw into the cut.  I find that even at the slowest possible speeds, a rotary tool is too fast and it is too easy to slip and damage the piece, the tool and blade, and yourself.

Dremel hand grinders, even the variable speed models, vary in how slow a minimum speed they have.  There are, however, Dremel models that do have quite good speed control, though they tend to be the more expensive models. If you are able to buy one of these more expensive models, I find them an excellent modeling tool.

this drill by tamiya is far superior for plastic

http://www.ebay.com.au/itm/Tamiya-74041-Electric-Handy-Drill-Craft-Tools-No-41-For-Plastic-Wood-Model-/201279909525

Dremels have little to no use on plastic.

There are cutting bits for the dremel, rather than disks. Carbide ones for tile which might be overkill and ones that look like a drill bit but a sharp edge in the spiral to cut. Of course you need enough depth to use, but moving up and down helps keep things cooler.

However I have not tried this with plastic, so test on some scrap first.

Hi Lightfoot !

   I see a problem , but not one that cannot be overcome . Usually I lay out areas to be removed , Before , assembling the model , after dry fitting as many components as I can safely .

   Then take a grease pencil and mark out the areas you want removed in a small or large flowing " Cloud " shape . These " Clouds " can then be created by using a drill bit of 1/8 " size at the perimeter of your " Holes " .

 Now carefully cut between the holes you've drilled , smooth and there you have it . Now in Armor I believe it's best to leave very Blunt edges to give the effect of armor thickness .

 On Planes and Ships I usually chamfer the edges inward so the exterior edge is a scale thickness or close without losing any strength . There you have my way . Good Luck .

   Oh , by the way .Do NOT use a DREMEL to do this ! Even at the slowest speed , even on the rechargeable one it's too high in R.P.M.s for plastic ! I bought a small Hand sized re-chargeable drill . I believe it's a Black and Decker and the R.P.M. Is controlleable two ways . By the switch setting to slow and then the trigger pressure . This works best for me .

I haven't tried the Dremel saw disk. I'll look and see if they have one with a fine enough blade. Usually the problem with the Dremel is even at low speeds it tends to generate to much heat for a clean cut. I do have some exacto saw blades and am going to test them on some scrap. In the past I have found the saw blades to be a little difficult to get through plastic without damaging it.

Part of problem is most of the tank is assembled so I can tell what parts would need to be cut to give the maximum view without destroying important parts of the model. Some areas of this tank like the drive shafts just are to deeply buried to expose without destroying the model. The other choice is to leave the top areas unglued so the interior can be viewed by just lifting off the top. I would prefer cutaways so it is always visible. I have been researching what others have done but noticed some of the cutaways are quite complicated cuts which I am not sure the tools I have can do without damaging the tank.

have you ever tried a razor saw by CMK , very fine tooth , excellent cut , hand use .

If I get the drift, you want to have openings that are soft shapes.

I do that kind of thing by drilling (by hand) a close row of holes.

Then clean up with a sharp knife and a file.

Dremel has a saw blade that I have used in the past to do this very delicate surgery. It didnt leave much "slag" on the edge ( and what was there I easily snapped off with my fingers ) I finished with an X-acto sawblade all the stuff that I couldnt reach with the dremel.( There the same size as a regular  #11 blade they just have teeth.

C A U T I O N !!!!! Keep your fingers well clear of the blade if using the  Dremel sawblade !!!!

And if possable use the slowest setting you have.