Author Topic: New hotwire rail and bevel cutter  (Read 928 times)

surfcowboy

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New hotwire rail and bevel cutter
« on: April 04, 2020, 12:22:29 PM »
Made this up last night and finished it this am. Really works great.

Proud that I actually soldered up a cable too instead of my usual twist and go method.

Can and will probably improve the tension mechanism from it's current Gilligan's Island mode but this and some guides should make rail bands and bevels much easier and faster.



Ebay 12 volt 5 amp PSU about $12. Works great and will heat 30Ē of 22 gauge nichrome wire to juuuust about hot enough. Anything shorter is easy.


« Last Edit: April 04, 2020, 12:26:12 PM by surfcowboy »

jrandy

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Re: New hotwire rail and bevel cutter
« Reply #1 on: April 29, 2020, 11:20:28 AM »
Nice S'cowboy.
I have about 4-5 different homemade hot wire tools.
My favorite is one inspired by Dave Daum. It rides on the bottom of the blank and makes a beveled cut on the top rail. Works good for the start from scratch EPS stuff I do.
http://pushheretosavealife.com/
Be safe, have fun. -J

TallDude

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Re: New hotwire rail and bevel cutter
« Reply #2 on: April 29, 2020, 12:14:38 PM »
Only use it in a well ventilated area and a fan. You'll be breathing Hydrogen cyanide, which is used in EPS foam and will turn to gas when heated or burned. 
That's why I started cutting my foam with a course hand saw. 
It's not overhead to me!
8'8" L-41 ST and a whole pile of boards I don't use.

jrandy

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Re: New hotwire rail and bevel cutter
« Reply #3 on: April 29, 2020, 05:46:15 PM »
I was under the impression that the cyanates are from PU products not EPS.
So no cutting PU foam or PU glue either...
Regardless: fumes bad, fresh air good, TallDude advice good.

http://pushheretosavealife.com/
Be safe, have fun. -J

TallDude

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Re: New hotwire rail and bevel cutter
« Reply #4 on: April 29, 2020, 06:24:41 PM »
I built a shaped hotwire rig to make the rail curve. I got it from the company that makes my architectural foam shapes. The problem is you have to move fast and at the exact same speed and you CAN NOT STOP! Otherwise you get this big melted groove in your rail. I just about ruined my blank on the first try. It was fine with my short test pieces, but the length of the board was a whole different story.
It's not overhead to me!
8'8" L-41 ST and a whole pile of boards I don't use.

surfcowboy

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Re: New hotwire rail and bevel cutter
« Reply #5 on: April 29, 2020, 07:40:50 PM »
Thx guys. Yes, Iím big on masks and ventilation either way. Itís all nasty.

And yes, you have to learn to move it right and also really, I only do it with guides so you just pull as fast as it goes. Super clean.

blackeye

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Re: New hotwire rail and bevel cutter
« Reply #6 on: April 30, 2020, 11:57:25 AM »
Nice S'cowboy.
I have about 4-5 different homemade hot wire tools.
My favorite is one inspired by Dave Daum. It rides on the bottom of the blank and makes a beveled cut on the top rail. Works good for the start from scratch EPS stuff I do.

It would be awesome to see these tools.

My single successful tool is a cobbled together contraption in an H shape with a tensioning spring between the top posts and the hot wire on the bottom. I use stainless fishing leader as the wire.

I tried to make a tool to cut a corrugated shape, but it didn't work out. Soon as it got hot enough it sagged despite using heavy wire.

TallDude

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Re: New hotwire rail and bevel cutter
« Reply #7 on: April 30, 2020, 12:13:48 PM »
Nice S'cowboy.
I have about 4-5 different homemade hot wire tools.
My favorite is one inspired by Dave Daum. It rides on the bottom of the blank and makes a beveled cut on the top rail. Works good for the start from scratch EPS stuff I do.

I tried to make a tool to cut a corrugated shape, but it didn't work out. Soon as it got hot enough it sagged despite using heavy wire.
https://hotwirefoamfactory.com/018_Freehand_Router.html
It's not overhead to me!
8'8" L-41 ST and a whole pile of boards I don't use.

surfcowboy

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Re: New hotwire rail and bevel cutter
« Reply #8 on: April 30, 2020, 07:32:04 PM »
Blackeye you have to have a way to tighten it up on it heats, or maintain tension. My big one uses a heavy rubber truck bungee. The smaller one I just twist tighten. But Iím looking for some old guitar tuning pegs for my next rig.

blackeye

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Re: New hotwire rail and bevel cutter
« Reply #9 on: May 01, 2020, 12:16:46 PM »
Blackeye you have to have a way to tighten it up on it heats, or maintain tension.

Sorry, my post was a bit vague. My straight line cutter is tensioned well with a coil spring between the top uprights. That works well.

For the sag, I was referring to the ~~~~ shape I made in heavier gauge nichrome wire. Ockam's Razor took over in my attempt to be succinct. The shape doesn't allow it to be tensioned. The real problem was inconsistent cuts using the shape. That was a from many variables: It took alot of voltage to get it hot enough (which made me apprehensive), lower cutting power caused drag and misshapen cuts, and I didn't have a good guide system. I ran out of patience and lost interest in the project.

My intention was to recreate corrugated cardboard, but in carbon top, bottom and middle and foam in the voids. I figured that would make a great standing area composite and for an unrelated secret project (dormant for now). Also, honeycomb does this already.

Talldude - I have one of those. It didn't work for my needs.

jrandy

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Re: New hotwire rail and bevel cutter
« Reply #10 on: May 02, 2020, 05:45:00 AM »
Blackeye, here are the tools I could find this morning.

PS is a borrowed variac which comes with a set of warnings about non-isolated AC voltage. If I used these more often I would add an isolation transformer and a remote on/off switch or I would switch to a DC lab supply. All the tools have insulated connectors to a shared extension cord.

I forget the gauge of wire I am using, something thin the 20's...26?
I use the wire and calcs from https://jacobs-online.biz/

The bigger bows were made first, starting with the PVC one.
Then I went with the all scrap wood approach. I have though about re-doing them with CAD-drawn and CNC-cut pieces but that has yet to happen...

The Daum* hot wire rail cutter and my other bevel tool are shown.
The Daum* comes apart and the middle C-shaped part get re-configured to make cuts at 90 degrees such as starting with an EPS sled cut and cutting the plan shape rail straight down from the deck or bottom.

The one with the guitar tuners is just a 45 degree chamfer tool. Anything longer than a few inches of wire and I use a spring of some sort. The ones off the cheap architects' lamps are pretty good. A collection of screw eyes, eye bolts, and wing nuts helps for putting these together. I am only making straight cuts, nothing with a formed wire.

*Dave Daum has a router with an attachment for doing the same/simiimar thing (cutting a bevel into a rail indexed to bottom) so that is why I call it that. With some googling and digging a person can find a picture of his device.
http://pushheretosavealife.com/
Be safe, have fun. -J