Cutting Body Panels

[FLHCAHZ]

What are you guys using to cut body panel (like holes in the hood for the engine to stick through or wheel arch relocation)  Xacto knife?  What blade and what technique do you use?  

[crazyjim]

Razor saw.

[NOBLNG]

For a hole in a hood I would drill a hole in each corner to get a radius then connect them by either drilling a series of holes and then filing the inside edge smooth. Or I would connect them with a razor saw. These photo etch saws require a very light touch, but make a very thin cut.

[TarheelRick]

For radiusing wheelwells I use a small sanding drum on my Dremel, for other straight lines I use my t(rusty) razor saw.

[Russell C]

I use paper (or thin cardboard) ... and a motortool. It's strictly for doing big brutal fast cuts, a trick I learned from one of the legends of the model kit world, Bob Paeth. Basically, if you rub into plastic fast enough, it starts to melt away, so the idea here is to have a stiff paper or cardboard circle bolted into a screw mandrel that's chucked into a Dremel or other type of motor tool. (I must say that inflexible steel circular blades scare the willies out of me). What I do to make the paper/cardboard circles is first cut a square a little bigger than the size I need, then punch or drill a hole the size of the mandrel's screw threads, then bolt the square into the mandrel, chuck it into the motor tool, turn in on and use a pencil to draw a circle border onto the square. Turn it off and use a scissors to cut around the circle perimeter line.

As long as you aren't too brutal with the cuts, even a stiff piece of paper will last quite a while. If it bends or shreds, well, just cut out a new one. Saves quite a bit of time compared to the more tedious effort of razor-sawing big chunks of plastic. Top photo here shows it turned off, since I had nobody available to take the photo as I was cutting.

Edited December 31, 2022 by Russell C
fixed busted link

[peteski]

57 minutes ago, Russell C said:

I use paper (or thin cardboard) ... and a motortool. It's strictly for doing big brutal fast cuts, a trick I learned from one of the legends of the model kit world, Bob Paeth. Basically, if you rub into plastic fast enough, it starts to melt away, so the idea here is to have a stiff paper or cardboard circle bolted into a screw mandrel that's chucked into a Dremel or other type of motor tool. (I must say that inflexible steel circular blades scare the willies out of me). What I do to make the paper/cardboard circles is first cut a square a little bigger than the size I need, then punch or drill a hole the size of the mandrel's screw threads, then bolt the square into the mandrel, chuck it into the motor tool, turn in on and use a pencil to draw a circle border onto the square. Turn it off and use a scissors to cut around the circle perimeter line.

As long as you aren't too brutal with the cuts, even a stiff piece of paper will last quite a while. If it bends or shreds, well, just cut out a new one. Saves quite a bit of time compared to the more tedious effort of razor-sawing big chunks of plastic. Top photo here shows it turned off, since I had nobody available to take the photo as I was cutting.

 

Wow, that is clever.  Gives it a new meaning to a "paper cut"!    Just like rubbing 2 pieces of dry wood hard enough can ignite them, heat generated from the friction of paper against plastic heats it enough to melt it.  Nice!

And I can't help commenting on your rotary tool.  I think I have done that in the past. Instead of the ubiquitous Dremel tool most modelers use, you still have one of those Weller (or Craftsman) rotary tool.  I think you and me are the only2  members of this forum that still have one of those. But mine is put away - I now use a Dremel too.

[Russell C]

14 minutes ago, peteski said:

Wow, that is clever. ...can't help commenting on your rotary tool. ... Instead of the ubiquitous Dremel tool most modelers use, you still have one of those Weller (or Craftsman) rotary tool. ...

A JC Penny Micro Workshop, actually, from sometime in the mid 1980s. I swiped it from my dad back then, hasn't let me down since. Replaced one set of brushes for the motor, and lubed it once.

[peteski]

15 minutes ago, Russell C said:

A JC Penny Micro Workshop, actually, from sometime in the mid 1980s. I swiped it from my dad back then, hasn't let me down since. Replaced one set of brushes for the motor, and lubed it once.

Ah yes, JC Penny. Now  I remember seeing that photo. I got confused with Craftsman.  Mine is Weller (I believe it was the original manufacturer, and JC Panny is just rebadged Weller). Mine was also purchased in the '80s.  But we digress. . .

I do like the paper cut method. I have to try it next time I'm making cuts in plastic.

[FLHCAHZ]

7 hours ago, Russell C said:

I use paper (or thin cardboard) ... and a motortool. It's strictly for doing big brutal fast cuts, a trick I learned from one of the legends of the model kit world, Bob Paeth. Basically, if you rub into plastic fast enough, it starts to melt away, so the idea here is to have a stiff paper or cardboard circle bolted into a screw mandrel that's chucked into a Dremel or other type of motor tool. (I must say that inflexible steel circular blades scare the willies out of me). What I do to make the paper/cardboard circles is first cut a square a little bigger than the size I need, then punch or drill a hole the size of the mandrel's screw threads, then bolt the square into the mandrel, chuck it into the motor tool, turn in on and use a pencil to draw a circle border onto the square. Turn it off and use a scissors to cut around the circle perimeter line.

As long as you aren't too brutal with the cuts, even a stiff piece of paper will last quite a while. If it bends or shreds, well, just cut out a new one. Saves quite a bit of time compared to the more tedious effort of razor-sawing big chunks of plastic. Top photo here shows it turned off, since I had nobody available to take the photo as I was cutting.

Geat tip!  Thank you

[Rocking Rodney Rat]

I find a sledgehammer useful... -RRR

[89AKurt]

The paper disk is something I'll have to try!

My favorite tool is a hot-wire, intended for cutting foam insulation for train layouts.  For cutting straight lines, I go against a steel ruler.  I do a sawing motion.  There are times keeping the cut edges looks like welds.  Has it's limitations, but that's when I determine if keeping the offcut is important.