Building a "flying" model base

Go Flight · Post by **Go Flight** » Mon Nov 05, 2007 2:34 pm

Hi all,

A few FSM issues ago there was a nice article on building an X-15. Also included in the article was a few paragraphs on building a base. He used a clear acrylic rod that he must have heated and bent into a sort of "U" shape and inserted one end into the model and the other into the base.

I like that look as the clear acrylic could mimic the exhaust of the plane/craft whatever. But I worry about the heavier nature of the resin kits.
I obviously woudn't want a sag to develop, so I'm thinking the the diameter of the rod would have to be so much larger. And I don't think I would like that look.

The other option would be a metal tube or rod. How would a rod or tube be bent like I mentioned earlier w/o kinking and while it would no longer give the illusion of exhaust it would lift a "landing gearless" craft off the ground.

How do I figure out what diameter rod/tube (either metal or acrylic) could hold how much weight? Thoughts?
What are you guys doing?

TIA

DX-SFX · Post by **DX-SFX** » Mon Nov 05, 2007 5:01 pm

How long is a piece of string?

It depends on what material your rod is made out of and how heavy the model is. Also the length of the rod and the diameter. Without specific figures it's impossible to answer.

Most metal rods will bend. Acrylic can be heated and bent (although in the case of acrylic, there's a knack). Tube of any material tends to crush on the inside of the bend if unsupported so stick to rod.

The simple answer is try it and see.

Mr. Badwrench · Post by **Mr. Badwrench** » Tue Nov 06, 2007 4:32 am

3/8" acrylic rod, which is about the diameter used for a lot of bases, won't sag under the weight of most models. It's pretty sturdy stuff.

TREKKRIFFIC · Post by **TREKKRIFFIC** » Tue Nov 06, 2007 11:12 am

I was thinking maybe about holding an acrylic rod gently against a broomstick handle (or any other cylindrical object) and using a heat gun to heat it up until it droops over the handle say if I wanted a 90% elbow. Wonder if that would work ? Perhaps one could heat it up against a picture frame or angled molding to produce other angles.

I've seen curved tools for bending brass rod at my LHS.

Chacal · Post by **Chacal** » Wed Nov 07, 2007 11:43 am

You need a "pulley-like" object (a "wheel" with a semicircular groove cut into it—this groove has to have the same internal diameter as the external diameter of the rod being bent) to bend the rod around, because a flat, cylindrical former will flatten the inside of the curved rod.

tetsujin · Post by **tetsujin** » Wed Nov 07, 2007 11:46 am

DX-SFX wrote:How long is a piece of string?

249.7mm

Next question, please...

Go Flight · Post by **Go Flight** » Thu Nov 08, 2007 9:00 am

Thanks guys for all the input. Since I really like the look, I'll think I'll try one with the 3/8 acrylic rod and see what happens.

Chacal wrote:You need a "pulley-like" object (a "wheel" with a semicircular groove cut into it—this groove has to have the same internal diameter as the external diameter of the rod being bent) to bend the rod around, because a flat, cylindrical former will flatten the inside of the curved rod.

What I've seen done for other applications (bending copper pipe for a hobby project) is to cut a whatever sized diameter disk out of 3/4 in. plywood. Then cut a second disk a slightly enlarged diameter out of any wood (1/4 in. luan) and screw it on top of the first disk. Then temporarily tack the whole thing to your wooden work bench. In this case they bend put the pipe in and wrapped it around the wooden disk. Should work with plastic too. FWIW, thats what I'm gonna do with my acrylic rods....

Scanam2006 · Post by **Scanam2006** » Wed Nov 21, 2007 11:25 pm

Dear kev,
Acrylic rod is quite strong. I used 1/4" inch rod to support a helicopter in my Apollo recovery diorama.
It is easy to bend the rod once heated in the oven for a few minutes. I bend the rod over a piece of thin plastic sheet I had cut out with the aid of a French curve. the advice in the old FSm article was very accurate

Go Flight · Post by **Go Flight** » Thu Nov 22, 2007 3:41 pm

Scanam2006 wrote:Dear kev,
Acrylic rod is quite strong. I used 1/4" inch rod to support a helicopter in my Apollo recovery diorama.
It is easy to bend the rod once heated in the oven for a few minutes. I bend the rod over a piece of thin plastic sheet I had cut out with the aid of a French curve. the advice in the old FSm article was very accurate

Hi Barry,

Thanks for that. I remember the dio but never paid much mind to the acrylic rod.

Do you happen to remember which issue of FSM that article was in?