cyclone3350
Master member
Oh, that's gonna be a toughie. With the choices that can only be measured in light years, which one to pick? What ever U decide on, I will be looking forward to seeing your build. My $0 .02, Pick from a Golden Age Era.
Fellow hot wire foam cutters, please feel free to weigh in.
- Thread starter cyclone3350
- Start date
Oh, that's gonna be a toughie. With the choices that can only be measured in light years, which one to pick? What ever U decide on, I will be looking forward to seeing your build. My $0 .02, Pick from a Golden Age Era.
Bo123
Elite member
I shall take a look.
Bo123
Elite member
OK so I have started my hotwire build.
I I found some hanging wire that wasnt being used, took a single strand, and cut it to length. I then found a power plug that wasnt being used, cut off the end, and stripped both ends. for a quick test, I hooked both ends up to the wire, and the other to a 2 cell battery. the first thing I noticed was that the wire started to glow very brightly. I think the voltage was too much. Does anyone know the right voltage for a hotwire, or is it supposed to glow?
I also started thinking about what plane to make first. I was thinking something like a Cessna 195 would be nice.
I I found some hanging wire that wasnt being used, took a single strand, and cut it to length. I then found a power plug that wasnt being used, cut off the end, and stripped both ends. for a quick test, I hooked both ends up to the wire, and the other to a 2 cell battery. the first thing I noticed was that the wire started to glow very brightly. I think the voltage was too much. Does anyone know the right voltage for a hotwire, or is it supposed to glow?
I also started thinking about what plane to make first. I was thinking something like a Cessna 195 would be nice.
Ligbaer
50 Percenter
i know @Taildragger used a brushed esc and a servo tester then hung it on the foam while turning up voltage
cyclone3350
Master member
A 195 is an excellent choice. For the volts required, it depends on the length, resistance and gauge of the wire. For nichrome 28 gauge, it is about .6 volts per inch. 7.4/.6=12.33". A 12" bow length. U can buy the nichrome 60 28 gauge here https://jacobs-online.biz/nichrome_wire.htm I have also used a heavy guitar E string (.012 dia.) with about the same results.
NM156
Member
I have been cutting EPS and XPS for several years now and wanted to share what has worked for me.
If you are not electrically inclined DO NOT attempt this. The 24V supply requires connecting to mains AC voltage.
I have found that Rene cutting wire works best. I use 27 gauge.
You can find it at https://jacobs-online.biz/rene_wire.htm
The best way to maintain temperature of the wire is through constant current regulation.
I use the variable power supply listed below in constant current mode.
https://www.amazon.com/gp/product/B0861LGM15/?tag=lstir-20
It is connected a 24V 10A power supply
https://www.amazon.com/gp/product/B07QMLFMRH/?tag=lstir-20
Set the voltage upper limit on the UCTRONICS device to around 16V, and adjust the CURRENT until gravity cuts through the foam.
The display will show the Wattage. (Around 16-18W is normal cutting for my setup depending on the wire length)
NM156 aka Captain Foul
If you are not electrically inclined DO NOT attempt this. The 24V supply requires connecting to mains AC voltage.
I have found that Rene cutting wire works best. I use 27 gauge.
You can find it at https://jacobs-online.biz/rene_wire.htm
The best way to maintain temperature of the wire is through constant current regulation.
I use the variable power supply listed below in constant current mode.
https://www.amazon.com/gp/product/B0861LGM15/?tag=lstir-20
It is connected a 24V 10A power supply
https://www.amazon.com/gp/product/B07QMLFMRH/?tag=lstir-20
Set the voltage upper limit on the UCTRONICS device to around 16V, and adjust the CURRENT until gravity cuts through the foam.
The display will show the Wattage. (Around 16-18W is normal cutting for my setup depending on the wire length)
NM156 aka Captain Foul
Last edited:
cyclone3350
Master member
Thanks @NM156. I have this set up I built from Jacobs Video tutorial using the 24v 9a transformer. I am controlling the power through a dimmer. Would it be better to use the regulator U listed? I am not very electrically smart and don't know much about it. I built this one from a monkey see and do using the video. As U stated, I wouldn't recommend doing it this way without doing some self education. Fortunately, my hair is still laying flat & didn't burn the house down in the process.
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cyclone3350
Master member
Thanks for weighing in. I am hoping that this thread ends as a source to go to for foam cutting.
Bo123
Elite member
I am using a single strand from some hanging wire.
Off-topic jes
Elite member
danskis
Master member
I've been wanting to build a foam cutter for years - just never go around to it. I've got a project in mind where I want to cut either wing cores or ribs to put inside a foldover foam core wing to make a symmetrical airfoil. What I know about electricity I can write on my thumbnail. So....realizing that the following look all about the same (to me) which of the below power supplies should I use?
cyclone3350
Master member
Contact @NM156 & see what he has to offer. My electrical knowledge is not much more than a thumbnail either. Based on my experience, I would say that to cut a 24" wing panel, U would need a 30" bow. That would take about 18v-20v would be my guess. The Pwr+ with the 19.7v probably is the one. As far as setting it up, that I would not be able to tell U.
danskis
Master member
Thanks to @NM156 I went to Jacobs online and found this table. I can use it to figure out which of the above transformers I can use.
Buy Transformers (jacobs-online.biz)
Buy Transformers (jacobs-online.biz)
cyclone3350
Master member
Fantastic. I'm glad to hear he was able to help. I did my cutter using their video.
cyclone3350
Master member
Made good use of the table cutter this past week. I need these very large wing fillets & found this to be a challenge that was done very well with pink foam. I made a pattern of the side view that fitted perfectly to the top airfoil. Once I cut that out, it was rough carved using an X-Acto #26 long blade. Sanded to final shape & sheeted it with 1/16th balsa. Now I am working on the cowling. This is being done with 1/32" balsa which will be glassed. After making some poster board patterns, I dry fitted it & once satisfied, I made a pink foam core. This was then cover in wax paper using 3M-77 spray. I wrapped the cowl around that, glued it where the ends meet @ the bottom of the centerline & sanded that down smooth. This was dry fitted to the plane & the fit was perfect. slid it back over the form & 4oz FG clothed it. I used BSI 15min thinned down with rubbing alcohol. I did this as I wanted some structural strength out this. That is the theory any way. So far it is working as far as the application. The next step is to 1oz cloth with BSI finish cure . Brushing it on & credit card squeegee the excess worked out great. The nose block, also carved from pink foam, should finish this off.
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Taildragger
Legendary member
so how do we do hinges on all foam hotwired planes? @cyclone3350
Off-topic jes
Elite member
well the way I do it I know you weren’t asking me but I’m gonna answer anyway is when you have a tail surface or ailerons, line the tail surface or aileron with a piece of balsa wood the thickness of the foam and sand it to be flush with the foam it’s just like hinging a Balsawood plane but only strips on the tail surfaces flush with the foam
FlyingTyger
Elite member
This is the best way I have heard of as well. Some of the old foam Byron Originals kits had you crimp a 2" piece of brass or aluminum tubing onto the ends of a Robart hinge point. Then glue that into the foam. The extra tubing extended the glueing area. I did it this way on my Byron T-34 and it worked. But I can't say I felt very confident with it.
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