Foam Wing Cutter

[alex nicol]

I'm hopeing somebody can give me a steer on a suitable foam wing cutter set up.

I have a variable 9 - 24vdc/3a/72w PSU and was wondering if this would be adequate and what cutting wire would be recommended

Cut length will be in the 0.75m to 1m range.

Thanks

Alex

[kevin b]

There seems to be a fair bit of information on YouTube, but little on the forum and all the links are out of date.

I too would be interested in any advice.

[Alan Hilton]

The most up to date power supply is to use a 3 or 4 cell lipo and an esc with a nichrome wire bow .I have no experience with this setup but if you go onto the RCMF forum a member PDR is expert on this .I use a 240 to 25 volt transformer and a big series wound variable resistor in series.This works well but I scrounged the hardware ,I think the cost of ‘this ser upwould be far too high if bought new

Alan

[sticky fingers]

Your power supply could be a 12 volt battery , an electric fire element straightened and a simple bow assembly , experimentation is the key as the length of wire and power input all dependent on wing span. Wing panels can be made in sections and joined.

[Chris Freeman 3]

My set up uses a transformer with a light dimmer switch so you can adjust the power needed for the foam that is being cut and the length. The denser the foam and the longer the foam requires more heat. If you cut with a wire that is too hot you get a ripple effect and the wire can stretch so you loose accuracy, too cold means a slow cut. My transfomer also has an amp meter so you can see where you are when switching on heat wise. The bow design is also important as you need to tension the cutting wire. This is how mine looks. I was given this set up and am not the best to describe electronics.

[Edgeflyer]

You need nichrome wire which is high resistance good for heat elements. The longer the wire the more volts you need to give the current needed to get the temp right. Wire available in cheap coils search or go to flea Bay.

[Edgeflyer]

I know a guy who uses metal guitar strings about 3 foot long, probably the top E string! He gets the right tension by tuning it! He can play status quo songs while it's warming up! 😜

[Rob Ashley]

Posted by Phil B on 15/11/2019 08:13:34:

I know a guy who uses metal guitar strings about 3 foot long, probably the top E string! He gets the right tension by tuning it! He can play status quo songs while it's warming up! 😜

- Phil that made me laugh for ages.....

[David Hall 9]

The next time that I try foam core cutting, I'll try this wire...

here

[Ken Lighten]

Available here Wire

[Torsten Spitzner]

Posted by Phil B on 15/11/2019 08:13:34:

I know a guy who uses metal guitar strings about 3 foot long, probably the top E string! He gets the right tension by tuning it! He can play status quo songs while it's warming up! 😜

I have used guitar strings successfully. The thinnest one there is. Simply connected to a 12V battery. Worked well enough over 700mm span.

[Mark Kettle 1]

Hi Alex,

I use nichrome wire see link. ( 80//20 nickel-chrome alloy resistance wire )  Web site for hot wire

I too have used the above wire from broken electric heaters, however it can be ordered on a 60m length bobbin, your power supply is adequate, however I tend to use a 12V DC battery charger with a 12v car battery in parallel.

The wire has a outer diameter of - 0.71mm - which is like a guitar ( note g-string ) which I've also used many years ago.

I've got bows from 15" to 50 " in length.

Here's a auto- slicing cut going on :-

 

 

 

Edited By Mark Kettle 1 on 18/11/2019 22:30:32

[alex nicol]

Quick Update,

I bought a 24v 3a laptop type power supply with an adjustable output of 9 to 24v (about £8 on ebay)

The current bow is circa 33"with 0.5mm nichrome wire giving a resistance value of 7.8 ohms and giving a nice cut at about 15v. Next step is to extend the bow to around 44" and try again.

One question I do have, is what material do you find works best for cutting template

Thanks

Alex

[FlyinFlynn]

glass fibre sheet... or SRBP if you can find some uncoated

[bert baker]

I’ve been told the iron on kitchen worktop edging is good,,,

But I rather fancy the newer stuff is probably not as hardy as it used to be

[Martin McIntosh]

My simple bow is a length of polypipe with wooden arms at each end extending up and down from the wire which is tensioned with a couple of lengths of strimmer line and a turniquet ( how do you spell that?) of piano wire in the centre which is held in position by the pipe once wound up to tension. The cutting wire came from Nexus. Power is from a huge 24V transformer which I sort of obtained and the temperature of the wire is set by winding the ends round the wooden arms until just right. Sounds more complex than it actually is.

[leccyflyer]

It's spelled windlass.

Some years ago we made a few very simple, effective foam cutting bows with three pieces of 2x1" PAR, with tension applied by a windlass on a stout nylon cord across the two arms at the top. Make up a set of asymettrical "rugby posts" with a notch cut in the upper section on each side, fix the cord across between this, then use a stout stick through the cord, winding this up to tension the cord.

Power supply varied between a couple of car batteries, a Minicraft minidrill power supply and an MCA foam cutter power supply. Something between 12v and 24v worked well, depending on the length of bow, which varied from 12" -42".

[Bert]

Don’t buy wire from amazon or RS, far too expensive.

Get it fromThe Crazy Wire Company

Bert

[alex nicol]

Just made and quickly tested a 48" bow, it cut nicely about the 20v mark, the set up is a bit crude but so far so good.

Unfortunately lack of foam stops play for now. I've ordered a 1200 x 600 x 300mm block. I've scaled up Mike D's Big Easy to 82" span and will give the wings and tail a bash once foam arrives.

I'll stick some plcs up shortly

Cheers

Alex

[Edgeflyer]

How do folks veneer the cut foam wings?

[Ken Lighten]

Posted by Bert on 24/11/2019 10:48:20:

Don’t buy wire from amazon or RS, far too expensive.

Get it fromThe Crazy Wire Company

Bert

the flat wire they do could be good for rigging wires for smaller scale WW1 modellers

Ken

[Nigel R]

On another forum, the common practice seems now to be

veneer of choice (balsa, obechi, etc)

very thin spread of gorilla glue (or other foaming PU glue) on the veneer

line it all up

put the wing back into the offcuts and weight it all down for 24 hrs

disclaimer - I've never veneered a pair of foam wings

[Martin McIntosh]

Having once tried veneer, which is prone to splitting, I now only use 1/16th balsa. The joined and sanded sheets and one side of the core are coated with slightly thinned Copydex, left to dry completely then the core carefully rolled over the balsa. You only get one go at this so maybe epoxy is a better bet, using the shutts (offcuts) and weights (sand bags).

[bert baker]

Contact adhesive on both bits,,,, leave the laminate on the bench and roll the foam onto it and use the offcuts of the blank to support if required.

a alternative was years ago to use paper...

think the Mick Reeves Disco fun plane was paper covered

[chris meek 1]

What foam do you use and where's best to get it from in the UK?

Thanks

Chris