Fellow hot wire foam cutters, please feel free to weigh in.

[cyclone3350]

so how do we do hinges on all foam hotwired planes? @cyclone3350

I have been using balsa with either nylon pin hinges or CA hinges for my foam core wings. On the Gee Bee, I removed 3/16" from the aileron cut out in the wing & the same for the leading edge of the aileron. I then cut that pattern out of the balsa & angle sand them before installation. I also mark a true to center for both pieces. this makes sure the hinges line up as perfect of a straight line as possible to avoid warps in the control surface. To get a good angle cut and maintain that straight line, I use tape. In this case, I used 1/16" pinstriping tape on the edge and painters tape along the center line. With this taped to to bench, I run a sanding block until the sand paper starts to touch both ends of the tape in a straight line. I mark the point for the hinges and carefully run an X-acto knife on the center line eyeballing it horizontal to the flying surface as I cut deeper. I start with # 11 and then make a few paces with a # 2. This will work for either CA hinges or pinned hinges. For the nylon plastic hinge, Formula 560 canopy glue holds them in place. Some folks prefer 30min epoxy. I've found either one to be rock solid. If U R using pink foam on a park flyer size, U might get a good hold with out the wood, hinged directly into the foam, but, I wouldn't do that with beaded foam.

 

[Taildragger]

how do I fix this kind of thing? @cyclone3350

 

[FlamingRCAirplanes]

how do I fix this kind of thing? @cyclone3350
View attachment 222189
View attachment 222190

Wood putty or stucco

 

[cyclone3350]

If this is the rough cut box, I would leave it until the final shape has been hot wired. As long as there is a good glue joint to keep it together for cutting. That Is, I am assuming U R going to put formers on the ends & follow it around with the hot wire. Then U can fill with a light weight spackle like Dap Fast & Final or Hobby Lite filler & sand to finish. If U try to fill it first, it might interfere with the cutting.

 

[Taildragger]

If this is the rough cut box, I would leave it until the final shape has been hot wired. As long as there is a good glue joint to keep it together for cutting. That Is, I am assuming U R going to put formers on the ends & follow it around with the hot wire. Then U can fill with a light weight spackle like Dap Fast & Final or Hobby Lite filler & sand to finish. If U try to fill it first, it might interfere with the cutting.

No this is the final shape (nearly) It's looking pretty good for the most part

 

[cyclone3350]

No this is the final shape (nearly) It's looking pretty good for the most part
View attachment 222206

That looks awesome. I've been using Hobby Lite for filling. I've also used the light weight stuff from Home Depot & find it to work out as well.

 

[Taildragger]

@cyclone3350 on the topic of sealing XPS foam, I've seen that you suggest Modge Podge Hardcoat, but I intend to use the cruiser as a floatplane and I was wondering if that would be a good idea as modege podge is not waterproof

 

[cyclone3350]

@cyclone3350 on the topic of sealing XPS foam, I've seen that you suggest Modge Podge Hardcoat, but I intend to use the cruiser as a floatplane and I was wondering if that would be a good idea as modege podge is not waterproof

I've only began to experiment with MP. I do like it for the protection and the initial quick dry time for handling & sanding. I have found it to allow foam take paints that attack like Krylon. I have tested it with positive results using light fiber glass cloth. If I was going to use it for water ops, I would allow it to cure for @ least 2 weeks ( 4 weeks is MFG recommendation ) & top with a Rust-Oleum or Krylon. Of course there is the tried method of epoxy & fiberglass. It's messy, but U wouldn't have to wait 2-4 weeks for painting. BTW, how is it coming along, the last pics I've seen look very promising.

 

[Taildragger]

I've only began to experiment with MP. I do like it for the protection and the initial quick dry time for handling & sanding. I have found it to allow foam take paints that attack like Krylon. I have tested it with positive results using light fiber glass cloth. If I was going to use it for water ops, I would allow it to cure for @ least 2 weeks ( 4 weeks is MFG recommendation ) & top with a Rust-Oleum or Krylon. Of course there is the tried method of epoxy & fiberglass. It's messy, but U wouldn't have to wait 2-4 weeks for painting. BTW, how is it coming along, the last pics I've seen look very promising.

pretty slow but steady. I don't have pics but I have started on the last tail section and cut the feathers out of dtfb

currently I'm working out how to attach the wing like the arrows husky for portability and a big hatch

 

[Taildragger]

If this is the rough cut box, I would leave it until the final shape has been hot wired. As long as there is a good glue joint to keep it together for cutting. That Is, I am assuming U R going to put formers on the ends & follow it around with the hot wire. Then U can fill with a light weight spackle like Dap Fast & Final or Hobby Lite filler & sand to finish. If U try to fill it first, it might interfere with the cutting.

amazon had some fast n final on sale so the 16oz was about the same price as 8oz. got that now! Haven't updated the forums in a bit, have been posting my progress on facebook. here's how the pa-12 currently sits with wire landing gear and small wheels

 

[cyclone3350]

amazon had some fast n final on sale so the 16oz was about the same price as 8oz. got that now! Haven't updated the forums in a bit, have been posting my progress on facebook. here's how the pa-12 currently sits with wire landing gear and small wheels
View attachment 223436

Like what U did with the windscreen. Will make it very practical for swapping out flight batts.

 

[Taildragger]

Like what U did with the windscreen. Will make it very practical for swapping out flight batts.

I saw the hatch on my friend's Arrows RC husky and had to use the idea

 

[Taildragger]

If this is the rough cut box, I would leave it until the final shape has been hot wired. As long as there is a good glue joint to keep it together for cutting. That Is, I am assuming U R going to put formers on the ends & follow it around with the hot wire. Then U can fill with a light weight spackle like Dap Fast & Final or Hobby Lite filler & sand to finish. If U try to fill it first, it might interfere with the cutting.

yo how long do I wait before I sand it?

 

[cyclone3350]

yo how long do I wait before I sand it?

Yo, good to hear from ya. Whatcha using that U want to sand?

 

[Taildragger]

Yo, good to hear from ya. Whatcha using that U want to sand?

lightweight spackle, fast n final

 

[cyclone3350]

Depends on the depth to fill. 1/32" or less is about 30 min - an hour. For deep fills @ around 1/2", overnight. How's the project coming?

 

[Taildragger]

Depends on the depth to fill. 1/32" or less is about 30 min - an hour. For deep fills @ around 1/2", overnight. How's the project coming?

looking good, just having issues with servos. I might finally start the front end tonight

 

[Taildragger]

@cyclone3350 the pic didn't upload in my last post lol

 

[cyclone3350]

@cyclone3350 the pic didn't upload in my last post lol
View attachment 223704

 

[Taildragger]

half filled and sanded smooth

and cut a hole to start mounting electronics