Foam core fins

[Karl Rocket]

I did an experiment in the hopes of getting a more airfoil-ish profile out of foam core for fins. I cut out some of the foam between the panels and hoped to glue the edges together.

Used wood glue, CA, and liquid plastic cement. Nothing worked! In all cases the seam didn't hold!

I suppose I could expose some of the foam and cut it into a foil... however, how would one seal that? Wood glue, I suppose?

I've also thought of rolling out some Aves Apoxy Sculpt on to the leading edges and shape into a nice leading edge. That adds weight, though.....

Any thoughts?

Thanks

Karl

 

[DaveCombs]

On the last 3 LPR kitbashes I've done (Quest Full Moon converted to 2x18mm, Full Moon 24mm, and Quest Harpoon AGM to 24mm long E), I used foam core for the centering rings, and used Titebond II for gluing it into the airframe. TII is my LPR glue of choice, and I think it would work wonderfully on your fins.

 

[wwattles]

Originally posted by Karl Rocket
I did an experiment in the hopes of getting a more airfoil-ish profile out of foam core for fins. I cut out some of the foam between the panels and hoped to glue the edges together.

Used wood glue, CA, and liquid plastic cement. Nothing worked! In all cases the seam didn't hold!

I suppose I could expose some of the foam and cut it into a foil... however, how would one seal that? Wood glue, I suppose?

I've also thought of rolling out some Aves Apoxy Sculpt on to the leading edges and shape into a nice leading edge. That adds weight, though.....

Any thoughts?

Thanks

Karl

Another option would be to shape the foil you want, and then wrap it with tissue, which is laminated onto both top and bottom surfaces, stretching the tissue to cover the open cells of the foam. If you get an edge you don't like because of the thickness of the tissue, stiffen it with some thin CA and gently sand it down to re-join the foam core surface.

WW

 

[Karl Rocket]

Will pick up some TB2 next time. Thx, Dave.

Would love to hear how your Commanche 3 flies! Flown it yet?

Karl

 

[DaveCombs]

No sir, I have not. And in reality, I'm glad I haven't yet, based on something I had the misfortune to learn at the hands of one of my sons. He had a Custom Aztec, which is a simple little 2-stage 3FNC. He used too much tape to connect the first and second stage motors, and also the coupler was too tight between the stages. End result was that the sustainer lit but the booster stage didn't separate, and the sustainer burned its way through the booster motor case and body tube, leaving 3 gaping holes inbetween the fins. See the attachment on the first post. So, having learned from that, I immediately went to my Comanche and started sanding down the couplers, because they were tight. Also, I had to borrow the streamer out of it (I had not installed it at the time) for my ARV Condor, so it's currently lacking a recovery system.

Titebond II is widely available at Lowes, Home Depot and so on.

 

[Micromeister]

Karl;
You can sand the edges of foamcore and tissue or fill with carpenters yellow glue as well, that's all I did on the 3/16" foamcore wings on my T4 .448" dia. downscale Skydart. Worked pretty well, Tissuing would be a better option on thicker material I believe

 

[Karl Rocket]

NICE Skydart John....

Tissue and diluted white glue, right? I'll experiment...

Thanks for that tip!

Karl

 

[dwinings]

The standard glue for laminating foam core to balsa in model airplanes is fiberglass resin. Use a thin resin like finishining epoxy.

Dan

 

[Micromeister]

Originally posted by Karl Rocket
NICE Skydart John....

Tissue and diluted white glue, right? I'll experiment...

Thanks for that tip!

Karl

Not really that ones kinda clunky. but thanks, it looked much better after I decaled it but it's still way to heavy for unboosted micro maxx flight

Back to the edge filling, You can use diluted whte glue, I found elmers yellow carpenters glue sets up faster. diulted about 25%. I used plain old gift wrapping tissue also... NOT THE BEST Choice but can work as long as you don't try to move it around much after application Jap tissue is MUCH easier to work with.

Dan:
I've never tired coating epoxy with tissue, I've used Clear Pacta aeorgloss dope with tissue but never epoxy. Does the coating epoxy form a better bond to foam and/or balsa?