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Old Jan 03, 2013, 09:51 PM
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Watty's Avatar
Somers, CT USA
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Do it Yourself Thin Depron Sheet - A Durobatics Substitute

I have developed a method to machine 1mm (0.039-in) Depron foam sheet to remove one side and reduce thickness to about 0.025-in. Most of the weight of 1mm Depron is in the skins, so the weight reduction is significant. Plus, the thinned Depron will bend to a tight radius as one skin has been removed. The resulting material is very similar to Durobatics, which is no longer available.

In a nutshell, I machine the Depron with a Great Planes Power Plane. This is a rotary plane with a cutter that looks like the cutter in a pencil sharpener. Unfortunately, this useful tool has been discontinued, and I haven't been able to find an equivalent. But, there should be a lot of them out there, or maybe you have one.

A more detailed discription of this method is in my blog.


Watty
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Last edited by Watty; Jan 03, 2013 at 11:37 PM.
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Old Jan 04, 2013, 12:18 AM
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Canada, BC, Whistler
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Interesting technique, i can imagine it would be easier to roll fuselages and make curves, than it would be with a sliced equivalent, since slicing leaves a melted skin.. making it quite a bit stiffer, ive sanded pieces of depron before, but could never get uniform thickness over a large area.
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Old Jan 04, 2013, 05:57 AM
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plantraco have sone durobatics for sale!

I got some durobatics from plantraco a few weeks ago I think thay must have a stockpile or a new maker of it great stuff
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Old Jan 04, 2013, 06:37 AM
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Blacksburg, VA 24060 USA
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Plantraco's Durobatics is the uncoated kind that can't be run through a printer. They are out of stock on the coated stuff.

Jim R.
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Old Jan 04, 2013, 12:43 PM
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Carbondale PA
Joined Aug 2005
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John,

It looks like a good technique for thinning down foam. I would like to try it out. However, I cannot find the Great Planes Power Plane for sale. If anyone has one that they want to sell, I would be interested.

Joe.
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Old Jan 04, 2013, 02:46 PM
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Petem's Avatar
Werribee, Victoria, Australia
Joined Jul 2008
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Alternative tools?

Would a conventional woodworking power plane, set to a very fine cut, do the job?
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Old Jan 04, 2013, 06:30 PM
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USA, ID, Coeur D'Alene
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harbor freight has a small planer that looks like it might work... only $31
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Old Jan 04, 2013, 07:32 PM
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Gordon Johnson's Avatar
Boston, Mass
Joined May 2001
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Another way to obtain "Durobatics" equivalent sheets is to wire cut Depron into thinner sheets, resulting in sheets with a skin on just one side. Do some searching in this forum for techniques on how to do it. For example, EPilot (of the former Indoor Flyer) made IFoam this way, which had virtually identical properties to Durobatics. I have not explored any of these techniques personally because I have not exhausted my stash of Durobatics yet.

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Old Jan 04, 2013, 10:45 PM
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United States, AZ, Yuma
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the key to getting good cuts seems to be taut wire when hot, and feed speed constacy.
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Old Jan 04, 2013, 11:15 PM
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Robster's Avatar
Brentwood, CA
Joined Nov 2002
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Slicing sub millimeter sheets with even planarity at .025" doesn't seem to me like an easy process. Bob definitely knew his stuff!
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Old Jan 05, 2013, 12:22 AM
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Canada, BC, Whistler
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Ive been slicing depron to 025 and thinner.. using my crappy version of the ss foam slicer, i use the foam in my molds, here is the original thread from a few years ago http://www.rcgroups.com/forums/showthread.php?t=1221543

What made Bob's foam unique is he made the stuff himself "apparently".
He was in the foam industry most of his life, and knew the formulations.
His slicing technique was perfect as well.

As i mentioned in my first post, i find the slightly burnt "stringy" skin that's left on the foam after hot wire slicing stiffens the piece, sanding and routing doesn't.

Therefore there is use for both techniques, it is easier to roll the sanded vs sliced. For when i needed slight compound curves in my Durobatics models i sanded the backside to get rid of the"slicing marks" it made it easier to work with without creasing.

Atleast that's what i found.
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Last edited by Heliman420; Jan 05, 2013 at 12:52 AM.
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Old Jan 05, 2013, 07:23 AM
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when i need light foam, i get some 1mm and take some 150 grit to it.
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