A succesful nose cone experiment.

[sandman]

I had cleaned up my shop earlier this week...don't ask!

Well, I got all my projects completed and shipped and even made a special tool or two.

Then I saw this 1/2 sheet of 2" thick pink foam called "Foamular" by Owen Corning that i had purchased for a big project.

I cut some scraps on my band saw, it cuts really easy. Used my rip fence and made some square stock about 1" x 1" and about 4" long.

I glued a 1/4" wood dowel into the end with Gorrila glue.

When the glue cured i put it on my lathe and used a tiny rasp to rough shape it and finally used an emery board to finish it off.

Here is the results.

It weighs oh...I'm guessing 5 or 6 grams for a BT-50 size.

I call it an FMC-50X, the "F" stands for foam.

 

[sandman]

Finish may be difficult. may be an acrylic or water based paint. Or a Sharpie pen!

I also tried sanding it with the backside of the sandpaper, just friction, to "burn" a skin on the outside. It sorta worked.

That will require more research but it has possibilities.

Suprisingly easy to do.

This may be something for a "high performance" or contest model.

 

[jflis]

now, *that's* cool

If you go to a good craft shop, they have spray paints that are foam safe. Their chrome is really nice

 

[flying_silverad]

Will you coat it with something to stiffen it?

 

[radiO]

Originally posted by flying_silverad
Will you coat it with something to stiffen it?

that is the question i had too. bet you could even rub wood filler over it and then sand it smooth?

 

[jflis]

Heck, for small cones (FNC-50 and smaller), you could just dip or paint them with epoxy...

 

[sandman]

Well, for truly high performance we need a tail cone.

This was very very delicate work. I can't believe I didn't wreck it.

The foam cut super easy...too easy...you have to use a very light touch.

I finished smoothing with 400 grit. Anything else cuts too fast!

Cutting the center motor tube hole was particularly nerve wracking, I think I may have bitten through my tongue.

 

[sandman]

The nose cone has a 1/2" length of wood dowel glued into the base and sanded smooth so it weighs 4 grams.

The tail cone...weighs a little over 1 gram.

Can I make a foam tube?

Here is a set for an Astron Sprint.

 

[rstaff3]

I have had good luck with this foam. I fill lightly with F-n-F and then coat with thin epoxy.

All foam, eh? (this is not that type foam, or coated)

 

[sandman]

The pink insulation foam I used is pretty smooth and tight. No visable gaps or bubbles like regular foam. 320 or 400 grit paper leaves a very smooth finish.

I made a 4" cone for Gus for his "Barbie" rocket and we just left the "pink" color as our final finish.

It's called "Foamular" by Dow Corning.

It's very light. A 4' X 8' X 2" thick sheet is about 2 pounds total weight.

Not cheap at about $10 a sheet but...THAT is a LOT of foam!

I usually just wack off a hunk with a hand saw then clean up the cut on the bandsaw.

Turning it on the lathe is kinda neat. You would think that the tiny pieces of foam would go everywhere but no...static electricity seams to make it "orbit' around the piece being turned.

When the "cloud" builds up too much I leave the lathe running and just vacuum the particles as they spin around the part...really neat!

I have to try something bigger now...maybe something "free-form" that I can cover with fiberglass and epoxy then remove the foam.

Neat stuff!

The only problem I've found is glueing the foam. Wood glues don't work very well and anything with a solvent in it attacks the foam RIGHT NOW!!!

Gorrilla Glue seems to work really well but it is expensive and a lot denser than the foam. Great for bonding the foam to wood.

Great Stuff foam insulation in the can seems to work well also for laminating large slabs to make bigger blocks and the density of the spray foam is "close" to the pink stuff.

The bad part about the "Great Stuff" spray foam is cleaning the nozzle when you are finished...it's worse than cleaning an airbrush!

 

[DynaSoar]

Originally posted by sandman
Finish may be difficult. may be an acrylic or water based paint. Or a Sharpie pen!

I also tried sanding it with the backside of the sandpaper, just friction, to "burn" a skin on the outside. It sorta worked.

That will require more research but it has possibilities.

Suprisingly easy to do.

This may be something for a "high performance" or contest model.

It may be a source for reproducing North Coast kits' foam noses.

Chemical finishing? Find a solvent for the foam and use a cotton ball or piece of flannel with some of that on it while turning it on the lathe?

 

[Bill]

Originally posted by sandman

Turning it on the lathe is kinda neat. You would think that the tiny pieces of foam would go everywhere but no...static electricity seams to make it "orbit' around the piece being turned.

When the "cloud" builds up too much I leave the lathe running and just vacuum the particles as they spin around the part...really neat!

Got pictures?

Happy Birthday, BTW...


Bill

 

[rstaff3]

Originally posted by sandman
The pink insulation foam I used is pretty smooth and tight. No visable gaps or bubbles like regular foam. 320 or 400 grit paper leaves a very smooth finish.

That's the stuff I use. The grain is a lot finer than, say, white foam. BUT if you use a drill vs. a lathe and whatever sandpapers you have around the finished product is not all that smooth. But its easily fixed. Plus the epoxy coating is light, provided a glass-like finish, and makes the cone tougher.

 

[rstaff3]

Originally posted by rstaff3
That's the stuff I use. The grain is a lot finer than, say, white foam. BUT if you use a drill vs. a lathe and whatever sandpapers you have around the finished product is not all that smooth. But its easily fixed. Plus the epoxy coating is light, provided a glass-like finish, and makes the cone tougher.

Plus you can make large cones fairly easily.

Heh, responded to my post instead of editing it...cha-ching, up goes the post count.

 

[Stones]

I had a friend "whittle" a cone for a static display of an Amraam I did awhile back. There's a 1"x1" piece of pressure treated in the center.
It's 17" long and is 4" in diameter.

 

[Stones]

Here it is with the tip shaped. No lathe on my end so, it was a manual labor thang.

 

[Stones]

With West Sytems epoxy, 2 coats and a little bondo to fill in the imperfections.

 

[Stones]

Sitting on the Amraam.

 

[sandman]

Good one Stones!

The foam is so cheap you can afford to mess up a few but it is suprisingly easy to work.

I did another experiment last night...a conical...sanding a sharp tip is hard but doable. The tip tends to "flex" away from the sanding tool.

The tip is acceptable and very flexable...not fragile like balsa.

This is also sized for a BT-50.

 

[rstaff3]

Very nice work guys! I suspect that my tools and techniques need refining. I never could get a nice point. But since all my cones have been free-form, I worked around this short fall. My last cone was the exact opposite of your point sand!

 

[sandman]

Every time I look at that particular nose cone...I think of Janet Jackson!

Hey...it's my birthday...I can think like that if I want to!

 

[rstaff3]

If we meet at a coming TRF launch I'll break my 'look but don't touch rule' (for the rocket that is!)

BTW, I liked your comment so much that I formally nicknamed the rocket Janet Jackson

 

[sandman]

Oh I have made large nose cones with foam and fiberglass. This onbe was for CTulanko and was covered with fiberglass/epoxy.

https://166.82.74.22/attachment.php?s=&postid=8062

My current experiment is for making LPR nose cone is the BT-50 to BT-70 range.

I'm just seeing if it's aviable and practical media for small nose cones. Trying to make them super light and avoit epoxy if I can.

So far it seems to be working.

 

[SwingWing]

Originally posted by sandman

The only problem I've found is glueing the foam. Wood glues don't work very well and anything with a solvent in it attacks the foam RIGHT NOW!!!

Look in the construction adhesive section of Home Depot or any home cemnter. There are a couple of adhesives made just for foam. One in a spray can, similar to 3M #77 spray adhesive, only for foam, and another in a caulk gun tube.