How To: Cutting Curves
ByI know many of you have seen this done before but I think there are as many who haven’t seen this technique. How to cut a curved line. Simple all you need is some string or heavy thread. Essentially the thread takes the place of a coping saw blade. I start by drawing the line I need to follow on the model. Then a tape the mode to the bench so it overhangs the edge to allow you to hold the length of thread above and below the object being cut.
By running the thread up and down you cut the plastic. Be careful not to use too much pressure or too much speed, this creates heat and will cause the plastic to melt and thread to snap. I cut through both halves of this helicopter in just a couple of minutes. It’s easy and it is fun. I was able to keep the tail boom and engines intact so it can be reused. Give it a try yourself.
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What a cool tip! It makes sense, but never dawned on me. Thanks Gerald!
Hey there Gerald!
I’ve tried about as many (unsuccessful) methods and decided to give this string method a chance and guess what? Bingo! Heard the string idea mentioned before but never really thought it would work. My first go-around was a little aggressive I guess and ended up with some crap/crud along the cut line but got it down now- Thanks for sharing!
First thought “you got to be kidding”. Tried it out and after a couple of tries got the hang of it. Next step, put the string in a jeweler’s saw (small coping saw) frame just like a regular saw blade. This works even better; one hand for sawing, one hand for holding parts. In plastic it works better than a small saw blade; it can turn very small corners or even right angles and doesn’t bind and break in the process.
I’ve seen this done in the model car mags before for opening doors and such but haven’t gotten around to trying it…yet. Nice to see it’s making a resurgence of sorts!
What a terrifically simple solution to a frustrating problem!! I’ll definitely try it in the near future.
But what kind of “string” are we to use, Gerald; a guitar string?
Sewing thread. What ever you’d use to sew a button back onto your shirt.
Gerald,
Great idea! One question though. I want to cut open the clamshell doors on my Revell EC-135 helicopter. They feature both straight and curved lines. “Can you use a few layers of masking tape to guide your cut?” Just a thought… Thanks.
David
That sounds plausible. Anything that will keep you inside the line or closely along it is good.
One note, you want to use polyester thread, works much better than other types.
I find that a cotton polyester blend is good. Pure polyester builds up too much heat. Cotton seems to not too and cuts more aggressively on harder plastics.
Brilliant!
I’ll be dipped!…been using string forever to cut PVC pipe…thanks for bringing the light into my hobby room.