Hot Foam cutter for RC aircraft

**rckeith** · 11-08-2010

Hi

This is the start of my build after spending a lot of time researching the internet I've taken the plunge. Had some real good advice from this site as well.

My motivation for building a cnc hot wire foam cutter is for two reasons.
1. I'm currently building a Radio controlled Vickers Super VC10 (http://www.rckeith.co.uk/vc10) made from 3 types of foam and the biggest pain with all this is cutting templates out. I'm getting better at it now and have just cut the wings but I'd like to have something that's more accurate and removes the need for all those templates.

2. I recently visited Mike Black who's also buidling a VC10 he runs Green Air Designs and uses CNC both foam and laser cutting and got inspired by his equipment. http://www.greenairdesigns.com/lab/i...d=6&Itemid=112

I've purchased the plan from http://www.drayconstruction.com/foamstuffs/ and have all the MDF cut out. Today I also purchased the motors and electronics from ebay http://cgi.ebay.co.uk/CNC-Kit-4-Axis...item2a0900f6ee

Will get some pictures up soon.

**GeorgeD** · 12-08-2010

Oh dear,don't want to dampen your expectations on that HongKong kit but I read somewhere about the driver boards are not up to scratch ie the chips pop at high peaks,it just miht of been a one off? but the uy who tested one seemed to know what he was doing.

I'll look for the source and you can judge for yourself,might of even been on here?.

http://www.mad-professor.co.uk/Misc/...AHQ%20Chip.jpg

This is not the site I'm lookin for but the info is the same ie popping chips.
http://www.cnczone.com/forums/archiv...p/t-93048.html

**ecat** · 12-08-2010

I had a very quick read through that cnczone thread, so much background noise. It appears the boards may be fine up to about 24v, above that the ice beneath you feet starts to thin.

**irving2008** · 12-08-2010

Originally Posted by GeorgeD

Oh dear,don't want to dampen your expectations on that HongKong kit but I read somewhere about the driver boards are not up to scratch ie the chips pop at high peaks,it just miht of been a one off? but the uy who tested one seemed to know what he was doing.

I'll look for the source and you can judge for yourself,might of even been on here?.

http://www.mad-professor.co.uk/Misc/...AHQ%20Chip.jpg

This is not the site I'm lookin for but the info is the same ie popping chips.
http://www.cnczone.com/forums/archiv...p/t-93048.html

Can we please not send this thread off topic... if you'd used the search facility here you'd have seen the extensive discussions on this subject here and here. Please keep discussions on the OP's original topic - if the subject is important enough then start a new thread in the appropriate section.

**routercnc** · 12-08-2010

Hi rckeith

Nice little machine. If the author of the plan is on iteration 3 is can't be too bad.

What sort of shapes are you looking to cut - foam core wings, 2D formers etc. ? I guess with any 2D work it's fiddly if you want lightening holes, but maybe with foam/depron you don't need them.

Do the towers move apart to handle bigger jobs?

Not into EDF myself, but looking forward to seeing the m/c in action, plus the finished aircraft.

Barry

**rckeith** · 12-08-2010

Hi Barry

I'm looking to wings and fuselages. I have a Priory Models Lancaster which is made of white foam and then covered in balsa. On my website as well http://www.rckeith.co.uk/lanc showing the build. I'm sure I can make a fuselage without too much complication. Unfortunately she's in pieces had a speed controller failure but I have new parts to rebuild her.

This video on youtube shows the same foam cutter in action http://www.youtube.com/watch?v=hV79pjFDdRY and as you can see the towers can be moved to any desired width.

Keith

**rckeith** · 12-08-2010

Here is the start of my machine.

The wood is MDF with a veneer. Some desk were being dumped from my work place and it seemed a same to see them burnt so I saved them for a better life as a cnc machine. All parts are cut to size.

Keith

**irving2008** · 12-08-2010

thats going to be a posh machine then ;)

whats the material you are bulding the VC10 from? I look at the website and the video.... it looks strange stuff....

**GeorgeD** · 12-08-2010

Hi Keith

I have this feelin that the width of this machine can be narrower unless I'm missin somethin that dictates it needs to be wide?

**rckeith** · 12-08-2010

Hi Irving2008

VC10 is built with 3 type of foam Depron which comes in various widths 3 and 6mm being the most popular. Its mainly used for underfloor heating insulation. XPS is the pink/orange looking foam and is similar to blue foam used a lot in RC flying. This stuff is mainly used for wall insulation and I get mine from B&Q. The wings are the usual polystyrene foam which acts as a core and strengthened with a spar ( carbon rod or spruce) and a balsa leading edge. its then covered in brown parcel paper which is glued on with thinned PVA, a bit like wall papering. Amazingly strong once dry.

Keith