Flite Test - Hot Wire Foam Cutting

[@BJbear2001]

Thank you for interviewing David! He seemed shy to begin, but near the end his wisdom shown through like something out of this world! David seems very experienced beyond his years! Great interview!

[@TactiColt]

Thank you so much for this video, guys. My father used to build balsa gliders way back when he was in the Navy. He and I are beginning to explore the RC hobby together, but so much has changed since his day. It would be a tragedy to build a big balsa craft and wreck it on first flight, but building is what he loves. Showing how to use foam core as a medium lets him build a much more durable aircraft. This makes a big difference for both of us getting into things.

They are to scale. Just downloaded them of the site and they are still correct. The wingspan says 700mm so that's a scale you can use.

[@wx9dx]

BTW I use a number 10 Dulcimer string " like a guitar string" hooked to my Weller Soldering gun as a transformer " tip removed and wires hook there" and run the gun from a light dimmer. Has always worked on projects for me. The biggest foam we can get around here is from Lowes or Menards for house walls. 73 Jimmy, ARRL TS, WX9DX

[@RCHobbyist463]

That is just plane epic. I have never seen a solution that simple but sophisticated enough to replace a professional soldering jig. You could literally save $100 just by choosing this simplistic yet sturdy design. I could see a whole new revolution in DIY!

[@AndrewWorkshop]

You could also use an AC transformer and a light dimmer to control the heat of the wire.

[@jezjezman9487]

Health and safety bit: **Wear an M3 Vapor mask**, Gloves, Goggles

[@wutangclams3203]

and do it outside! i was thinking the same thing, boy i bet those vapors have all kinds of carcinogens in them

[@TheStonehammerFiles]

Cutting it is safe, burning it is not.

[@vince38curious2]

The good thing about the templates is if you are like me and hopeless with all things electrical you can make your templates out of thin steel or aluminium and use a sanding block / Blocks to sand down to the template after cutting the excess foam away with a small saw or knife.. Thanks Dave and Josh this gives me more confidence to try new shapes that I wouln't have thought possible before.. Regards Vince.

[@frogsoda]

I have a hot foam cutter that is configured like a bandsaw. It has a table, the wire comes out of the table vertically to a frame that goes back to the table. I haven't used it but I loaned it to a friend who uses a handheld cutter and she liked it a whole lot better. Also, we have no trouble getting foam in Miami. In fact we're 30 miles from Miami and that's where we go to get foam.

[@user-ik7bl4yg2t]

"what was it, Vegan?" "Viggen" "Alright, the Vegan..."

[@nilsolsson880]

its a swedish plane

[@nilsolsson880]

David is from Sweden i things

[@afrog2666]

Saab 37 Viggen ;) Saab also made a car called Viggen.. Little factoid for ya ;)

[@johnlight5388]

Jan Christian Frodahl m

[@fenderstratguy]

He kept saying vegan lol

[@eastcarolinadroneshelispla6635]

Building one of these now. Can not wait to try it out. HUGE THANKS TO FLITE TEST GUYS!!

[@mnovo]

Ohm's Law is V=I*R (Voltage=Current*Resistance) Joule's Law is P=V*I (Watts=Voltage*Current) Nichrome wire with a diameter of .010 is roughly sitting at 7 Ohms resistance per linear foot. You can measure the 2 contact points on the bow with a DMM or use this as a rough calculation entry point for your R value. What current value are you attempting to achieve while you vary the voltage? Great video btw! M~

[@mnovo]

hotwirefoamcutterinfo.com/__SupplyCalc.html Nevermind. I found it. 6.2v @ .92A = 5.7watts and 400F and 8.0v @ 1.19A = 9.52 watts and 600F

[@shotintel]

Mmm, brings back my unregulated vape mod days. I would turn my own coils.

[@Mad-Duk_Machine_Werkes]

We need a laser-cut set of the plywood templates avail in the FT Store right away!! (for this and OTHER planes)

[@mattivirta]

and if have laser who can cut plywood can cut laser all foam too easy.

[@thebunkreport]

You can buy a whole hot wire cutting set for around $25. However, the one that you made works great as well!

[@azgarogly]

Great! Actually, I was expecting a long time, when David'd share the knowledge on hotwire foam cutting. I have some (working) idea on how to power hotwire with simple components from electric store. Now, I guess, I have to write an article for flitetest

[@carmatic]

also, how about adding mirrors to the sides of the bow so you can see how far along you are cutting on both sides without having to turn the piece over the awesome thing about having the plans made in foam sections is that each of these sections are small enough to be 3d printed ... you could add pins and holes, or slots and tabs, and make it much easier to assemble and give it some added structural rigidity as well

[@masoncayaban9790]

Add Springs to tension the wire. You'll get a better finish and you can turn up the voltage, which will produce more heat and will also allow you to cut faster.

[@lululock]

If you put more voltage, more heat, yes. But the heat will "melt" more foam than your template. With a friend, we made that mistake while cutting foam cores for our glider's wings.

[@daveroche689]

I have have miles of Nicrome wire if you would like some. However you can use fine piano wire but unlike Davids bow you need more tension to get a good cut. Use a high current transformer and a light dimer or you will just get a fire. The best bows are made of wood and Aluminium, and have an H shape. You use 2 pieces Aluminium at the ends and timber to separate and insulate. Tension with shock cord or a spring & cord/rope. $20 and your cutting. Don't use PVC and don't burn the house down.

[@techsmith6818]

You could use a turnbuckle half way up the arms to keep the wire taught,

[@whatelseison8970]

It's usually better to just use the flex of the bow or a tension spring.

[@Brian_Boxtruck]

You can get big blocks of the blue foam from aircraft spruce and other aircraft/fibeglass supply places. It's not expensive but can be to ship due to size.

[@ballwizz23]

I just made one today. I didn't use the esc or the dimmer. Just some nichrome, wood, and screws. I used a simple 9 volt on 12 inches of 28 guage wire. I plan to step it up to 12 volt as 9 was a little slow. Idk about the AC/DC part though. You can buy Nichrome on Amazon for a few dollars.

[@h78i23jjy]

Hobby King still sells Brushed ESCs. But they only have two of them. A 20a and a 30a. You have to search "brushed" if you want to find them quickly.

[@sato4kaiba]

For those who don't know: I squared R is the power P that is produce and is not necessarily the amount of heat. There is a formula to calculate the amount heat that will be produced.

[@gasparreis303]

Great video, congratulations, but what are the measurements in centimeters of the saw and Nichrome wire ?

[@poobertop]

You can also use an adjustable light dimmer to have control over the current to the wire.

[@3duckit]

Miss this young man. Great video.

[@MAYERMAKES]

If you construct the bow like a spanend woodworking saw and use a string spring between the hotwire and frame you will get much better tension.

[@ytubesucksazznow]

I don't even do this hobby, probably due to the fact my first real plane blew up on maiden voyage as a kid lol, that's another story all in itself haha, yet I learn a lot of tricks for other things and strangely I keep watching your vids anyway knowing I could never build the awesomeness you guys do ^^ i love watching you guys and keep up good work.

[@RCHobbyist463]

One of my favourite channels, other than Flite Test, did that and it was amazing.

[@MrJoseJasso]

did you laser cut the formers? what if i don't have a laser cutter? how do i cut formers? Great plane!!!

[@splendoremmanuel9091]

Nice one bro, thank you very much. But what is the thickness of the Nichrome wire?

[@robinbeckford]

3M77 works, too. Spray both faces, leave until it's only just tacky then press together. Holds well, and the wire goes through the joint no problem. (I learnt that from Phil Barnes dvd on vacuum bagging.)

[@MrROTD]

If you have any experience with 3-d modelling on computers this is a piece of cake, its a similar concept to skinning between two polygons, in fact I've modelled planes in 3-d doing exactly that

[@maxfig4167]

good places to find good foam, craft stores, they have a foam that is excellent for hot wire cutting and it's also very light.

[@carmatic]

2:53 you can use a 3 phase brushless ESC if you make a rectifier out of diodes ... you will need to hook up a motor in parallel so that it gives a feedback voltage so that the ESC will work

[@heaanlasai866]

Thank you for your great video! Will you be making a video about fibreglass coating the foam?

[@davidkelly4598]

I've done this w a dimmer switch wired upstream of a 12 volt car charger. Great temp control.

[@theartofflying3108]

Dimmer switch from room light switch?? And how did you force car battery charger to flow current if it is with electronic processor prevents from overload and so..??

[@TytanPuzzles]

At around 13 minutes, is the type of foam you are talking about insulation polystyrene? Also, now I know that I can get foam very easily.

[@Kerberosfish]

the guy in the red woodsman shirt is mad smart

[@colinmaguire3273]

David windestal?

[@colinmaguire3273]

David windestal?

[@calebsmedia]

You guys should sell the templates for the Viggen. That would cut down the build time a lot. Thanks!

[@VictorHugoRC1111]

You can get it from an old heater heating element. Usually it comes in a coil shape.

[@johnlandbeckjr3736]

What an amazing young man!!! Very well done. John in MD

[@getcartercarpark.]

Hi David, Great quoting the formula for power, I2 x R. We can measure the resistance of the wire in the bow of any length we intend to use, but how much current are you having flowing through the wire of the bow? Fantastic model, second to none! TIA. Kay.

[@HuylerBrooks]

Hey, sorry for the completely unrelated comment, but could y'all do an episode/walk-around of David's "Quadrone"?? I was looking at it on David's website, and by golly, that design is wonderful! Would love to hear the designer comments on how he came up with the design and how it performs! Thanks!

[@itsgr82bl8]

Thanks for the info guys, I built a foam cutter using a computer power supply which had WAY more than enough power. I will have to revisit that adventure and see if I can't refine it a little bit!

[@antecboy]

It's when you're cutting the foam and the wire isn't hot enough to cut it with proper speed, so you push it a little harder and the wire starts to flex a little. That is bowing. Like when you pull back the string of a bow, bowing.

[@WCPAGEL]

The pink foam in made by Owens Corning witch is in Toledo, OH.

[@britblad]

I am not into planes anymore but making a smaller ver of you wire former would save me alot of time with my model Railroad!

[@chrisleech1565]

You can still get a brushed ESC at Hobby King. Check it out. Just type in search for them at the top of page and you'll find 20 and 30A there.

[@cowcar87]

did you guys think about keeping the wire cutter stationary and moving the form only. it may be easier with these small pieces.

[@hyzenthlay7151]

What amperage is the brushed ESC you are using in this video? As you say, they are getting hard to get your hands on, and I wanted to know what would be the minimum needed.

[@bridgendesar]

Could you make an aerofoil shaped hot wire cutter and cut the foam side to side instead of a long wire across the width? I think you'd need thicker wire to hold aerofoil shape and more power, but it could the cutting process much simpler!

[@josephmolinari1]

please please please do a flite tip episode about how to extend the flight time of an existing air frame. thanks and keep the episodes coming!

[@chrisleech1565]

Thanks for the heads-up VH, that's what I call team work. Now that I have sorted my first Tricopter build and the associated Firm Ware issues.Whew! I can now try my hand at making an airframe from inexpensive, readily available, easy to cut Foam. BTW I am looking for the "How To Make Inexpensive Hot Wire Templates" ? Or is there another link you found with actual template designs that I can print and cut out?

[@XxXAUTOXxX]

You shouldn't need more than 10amp I use a PWM controller instead of an esc, it has a rheostat and will take up to 40V. I use 28gauge nichrome wire (stainless fishing leader also works) and up to 24v (2 car batteries in series) for wings up to 10 feet long. Any longer than that and you have to go really slow or your wire will bend too much (but that can be useful for adding reflex).

[@FPVREVIEWS]

i know those are not, but why cut the whole plane out of blue foam with very close to ideal shapes, and then just use flat wings? that only works well for small park flyers. i like to use real naca 4 digit foils for low reynolds numbers. would love to see a good tutorial on how to cut real airfoil wing sections from foam.

[@BaconRanch]

does the hot wire not cut/burn into the PVC? I do not see any insulator on it?

[@jeffv2074]

Excellent 👍 video, it is a great help since it will be my first time working with a foam cutter. I'm into RC cars and drones so I am very familiar with the components utilized, the heat for the wire was my biggest concern and you guys clarified that for me, thanks

[@balafayam9175]

this is awesome...... but how do people in countries like Nigeria get foams like the ones u use? hv tried a couple of places n hv only seen d soft foams from electric appliance packaging...

[@leonmurray7570]

try it out man, you can make anything fly from most foam

[@snugglylovemuffin]

maybe we can get a demonstration on urethane foam casting?

[@parisipsilantis6142]

Hi guys great job.were you get the former! You design them?

[@1985cjjeeper]

NiChrome wire is the stuff you need for this. It's the same stuff they put in hair driers and heaters. Get it from a hair drier without breaking it and a few sticks from the yard later you have a foam cutter if you plug it in to a rheostat like a light dimmer.

[@Harlanmote]

+1985cjjeeper Nicrome wire brakes to easy i use stainless steal or a guitar string.... Even mig welding wire works good.

[@davidb4557]

what size mig wire and what kind? SS or Fluxcore?

[@1985cjjeeper]

David B, you'd want to use SS not flux core. Probably any thickness since it doesn't get very hot. I used Nicrome in a textile mill to cut 5 10 inch rolls of 150 denier polyester at a time on a machine we built. I can't remember the gauge but you can buy it at supply shops. I can see how stainless or a guitar string would work fine on foam though. Our wire had to be a higher temperature or it would melt the tube ends of the rolls together. In that application other wires would sag/break. I admit we only used a hair dryer wire to prove the concept them moved on to thicker stuff. I still have a roll somewhere, maybe 12 gauge or 14.

[@davidb4557]

Thank you for the reply. I have plenty of SS .025in Dia. wire I can try first. I will give that a try first. If it works, I'll let you know. Once again, Thanks.

[@1985cjjeeper]

That should be fine as it won't need to be very hot for most things. Just make sure you never touch it when it's plugged in and you won't die.

[@chrisleech1565]

I think you can use a guitar string Try the smaller ones like high E or B strings if they are long enough. Easy to get in any music store or from a from a friend who has old ones. Give her a shot!

[@ChrisHewittMedia]

Great video. What should the template be made of so the wire doesn't damage it? Thanks.

[@shotintel]

I have a lot of spare kanthol wire around, will that work, or is nichrom a must?

[@FPVav8tr]

1:20 JOSH: "My bow is huge, you're bow is little" Remember Josh it's not the size of the bow, it's how you use it. :)

[@nordemoniac]

So how would you cut a hatch f.ex? I have a plane where the pilot door is cut in an angle, this means that you can't push the door through, and is an excellent for hatches, as they can only open outwards. But how would you cut that with a good looking result?

[@Femmpaws]

You use a real sharp Exacto knife and make the cut in a number of cut passes. Glue some stiff paper or Balsa inside to act as a stop for the hatch.

[@aviah11]

Can you cut 2 sections together? Meaning the piece you cut but twice as thick

[@vwing7332]

can use tungstun wire which can be easily found in electric iron

[@Mrdaddydaze1]

Thank u guys I always wanted to see a edf jet on your channel

[@davidharrison1572]

The Nichrome wire dosnt stretch when its heated so i make my bow as tight as I can especially for wing panels

[@kmatusik73]

how about figuring out templates for the versa wing, so i can hot wire wings for that. maybe you could lazor cut them and we could buy them from flitetest. you could start a new series on aircraft with cut wings.. that would be awesome.. thanks Kevin

[@NarcizoJE]

Electronic Dimmer used to control lights do the same job and is cheaper. Thumbs up for the great idea of PVC tubes for the bow.

[@simon-gabrielgervais7262]

a foot pedal like a tig welder would be great for start and restart and speed control

[@sergeyafonin2596]

I couldn't catch. What wire temperature should be like? Does it smell while cutting?

[@guloguloguy]

THANK YOU, FOR THIS GREAT DEMO!!

[@tylermcgonigal6031]

you said in the video you would show a diagram of how to make the hot wire bow

[@robfrydryck127]

Crazy good cutting skills for hand held

[@jorbedo]

Better to work with high density foam? Recommended?

[@rtonce]

Found out I am very allergic to the off gassing of that foam when i used it around a window installed air conditioner years ago. When home, I had non-stop runny nose. We tested our suspicion of the foam being the cause, confirmed it was, and removed it. I have no other known allergies, so can only conclude the chemicals coming off that foam, cannot be good. The takeaway is: Use natural materials and hone your skills of workmanship with other building methods whenever possible. Enjoy lasting health.

[@hieraco]

A good cheap source for wire is your local music store. I picked up a NP017 string (guitar second string) for 10Kr (about $1.20USD) works great with a 4A 12VDC transformer to supply power (wired to a rheostat/potentiometer to adjust the wire temperature.) Also I'd like to ask David if he can recommend any Blue foam core suppliers in Sweden.

[@fullthrottlerc8324]

Does the positive go to one end of the wire and the ground to the other?

[@Mosku94fin]

+Jacob Webb well of course, if you put both wires to the same end it wouldn't work because it won't include the wire in to the circuit itself.

[@fullthrottlerc8324]

That's what my dad thought, both wires to the same side. silly dad.

[@joerandolph7806]

I use a screw attached between the wire and the holder to tighten the wire

[@rva1945]

How many amps are needed for the wire to cut through the foam?

[@sirbow2]

i was gonna built one of these a while back, but im gonna use the 30A Brushed ESC for a RC Power Wheels :D

[@chrisleech1565]

I didn't get it either, or where to buy this Nickel Chromium, and for the majority of us that don't have a brushed ESC , what do we use in its stead. I have seen guys use the little transformer and a dimmer but what kind of transformer. Step down to 12 volt would imply a 10 to 1 ratio.120 in and 12 out, can it be AC or does DC provide better results. And then the application of a cheap selenium dimmer on the input end, the kind you use in a wall switch to dim room lights. Can any help?

[@HugDeeznueces]

That is awesome!!!! What turnigy tester is that? got a model number?

[@SuperArchi2010]

Hi FliteTest this is an awesome piece of work very nice cuts I want to make some shapes cutting a foam but pls tell me what is the name of this foams I know it is a high density foam but there some few other products that are not the best for foam cutting Thank you for your to reply

[@chrisleech1565]

Hey HK still sells a brushed ESC! I don't know how to access templates yet. Are you making your own or have you found a source? I'm so new, I am still working on hand launching my foamcore trainers.I have already destroyed three props and two motors will need new shafts installed. I wanted to use extruded SM styro like in the video. You know there are two diff kind 200 & 300 psi test. Blue and pink.Need templates for flying wing. I'll do a rear motor mount to help keep damage from crash minimal

[@ryanbellyt]

You should sell the cut out templates on the store

[@ecaslimjim]

You guys should sell a template kit.

[@bragr_]

ungratefulmetalpansy What he is saying is that a 2in thick block of foam may turn out to be only 1 and 7/8in thick. It could also be 2 and 1/8in, but you'll never be certain before you get it so buy blocks that are larger than you need and cut them down.

[@epicmcpeplayer]

2 stop wire bending attach a spring because when it gets hot it expands and comes loose.

[@brett8090]

I would really like to see these formers and other formers like them on the store. A C-130 would turn out crazy sharp with this technique.

[@VictorHugoRC1111]

Go to the Flitetest site and they have the templates there, Thanks guys!

[@assamita81]

that servo driver, doesn't need an external power supply or is it powered by internal batteries? I have one that requires to plug in a battery. Does that mean I need one battery for the servo driver and one more for the ESC?

[@nerd1000ify]

The servo tester is powered by the BEC in the speed controller, same way most small receivers are.

[@obRCmania]

Could you please do a review of the Durafly Spitfire.

[@robopony]

I could listen to David say "glue" all day.

[@ARob16x]

im building the hot wire foam cutter from grant thomsons video. With the templates that flite test showed me how to make in their how to make templates video i can make professional scratch built planes like the ft 3d and other planes built by them.

[@EightOneGulf]

Doesn't the PVC pipe melt or burn when you turn the wire on?

[@mtdarus]

hye!guys im using cheap guitar string and a power supply source of 3 amp and 12v to 14v of voltage. i cant get nice surface finish.it is due to the wire type i used or the technique?please help me.