Homemade cnc hotwire cutter

General Discussion
1

This is an interesting link - a homemade cnc hotwire cutter.

http://www.8linx.com/cnc/cnc.htm

This ones for model glider wing sections - it looks good, but x and y axis are short, maybe 500 mm. Has anyone tried to make something like this for surfboard blanks?

2

Foam core fins perhaps, looks really interesting…

3

Yes we’ve done it. The Y axis was never a problem, but a 9’+ X axis creates other problems. It’s still possible though.

Now we cut EPS blanks in Europe. http://www.atuacores.com/english/index.php (the english version is very new and still under construction)

4

Hi Pierre,

With the long x axis could you use the same construction method as the one used in the link? ie could you use a larger diameter threaded rod for the x-axis so it could span the 9’ or does the distance make this method impractical?

Checked the English version of the atuacores website - apart with something funny happening with a mouseover event on some links, it looks good. That’s a neat trick you’ve got there for attaching rails:

http://www.atuacores.com/english/constructionsandwichsousvide2.php

5

Hi Pinhead,

A larger diameter threaded rod won’t do the trick because it would still flex with the distance and be impossible to turn, expecially with low power stepper motors (and even by hand), that’s why the length makes it more difficult. We started by trying what you said, with 12 MM (about 1/2 inch) threaded rods and this wouldn’t work at all.

6

Thanks Pierre,

Yes I can see now there’d be a few problems to solve - It’d be more hassle than it’s worth unless you were doing a lot of boards.

7

Pinhead, you’d have to use a rack and pinion setup to cover a distance such as 9’ on the x axis. http://www.mcmaster.com/ (search for: gear rack) Or a belt drive would probably be more reasonable for a setup such as a foam cutter. (try searching for timing belt on mcmaster.) -Carl

8

I think you are all going for way too complicated, if this is the far end of design, go for a full CNC cut, start to finish. The simplicity of hot wire is low tech, profile temps and a hot wire, finish from there. A good hotwiring looks like it came off a machine anyway. Don’t take a $19.99 job and push it into the thousands

9

That’s the conclusion I’ve come to - except I can’t think of a quick and simple way to make the profile guides for the hotwire so I guess I’ll just continue using the cnc hotwire service my eps supplier offers.

10

The profile guides are so simple to make, tempered masonite, paired up, so that exacting duplicates can be made at once. Give a little extra at each end for wire run-off. With profile temps, you get to see a side view, cross section of what you want the board to look like. Most of the eps builders I have seen put three nail holes in the temps, nose, middle and tail, them use an 8d nail to afix 6to the billet. Then it is a matter of running the wire down the deck, then the bottom. Doug Wright in Fla. used to cut the deck, drop the temps down about a half inch, lay a piece of paneling about 8" wide, centered along the stringer, then re-wire again. The paneling kept the wire off the center of the blank and let him come up with a pre crowned deck before doing the bottom

11

Jim.

That hotwire crowning method is absolutely elegant. Simple and effective. A fine example of what Swaylocks,as a forum, provides.

12

You can use the same offset hotwire guide technique on the bottom to pre-cut vee into the blank.

Here’s an interesting cnc link:

http://www.astatue.com/index.htm

13

This is a good example of a computer controlled hotwire that can get your blanks as close to finish as possible. They also offer different blades. Only problem is you’ve got to fork out about $10K to get one. Not exactly the average shapers budget. But, you can probably make one yourself cheaper if you do your homework.

http://www.demandhotwire.com/c844_.html

Blades:

http://www.demandproducts.com/hotknifehd_blades.html

14

Get Tom Sullivan’s Video to see how they used to do it back when,

Vee, Railbands, Outline, Rocker everything done with just a couple homemade hotwire tools…

Definitely opened my eyes as to waht could be done with out a planer and EPS/XPS foam…

Hotwirefoamfactory also has some clips and they send you a dvd when you order any of their tools but watching what the set designer folks in the movie industry can do with styrofoam and some basic tools is also amazing way more complicated shapes than a surfboard…

15

does anyone have Tom Sullivan’s video. Every link I’ve seen in the archives to is is dead or the web page no longer has teh video.

thanks!

Archive Scounger

(it is lonely in here)

16

I have it, sent to me by another Swaylocker. PM your address to me and I’ll mail it to you. Or you can pick it up if you’re going to be nearby anytime soon.

17

But can you cut concave?