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  #1  
Old 01-17-2009, 01:08 PM
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tbzep tbzep is offline
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Default Estes Apollo Capsule Tower

Does anybody have a capsule from one of the more recent Estes Saturn V offerings or their Saturn 1B, and a set of digital callipers? I think my callipers have gone screwy. I was measuring to order styrene so that I could try to build a new tower structure on my old Centuri capsules, and the numbers are quite large.

For the main vertical rods, I'm showing about 0.055", and for the bracing I'm showing 0.048".

The Semroc 1/70 kit specifies 0.058" and 0.041" rods. After building the Little Joe II, and fitting the dowels in the calibration holes, they look quite a bit thicker than this plastic 1/100 tower, but the numbers are showing an almost imperceptible difference to the eye.

***Edit: 1st tower build attempt is complete. Photos on post 36 of this thread.



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Last edited by tbzep : 02-21-2009 at 09:42 PM.
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Old 01-17-2009, 01:16 PM
foose4string foose4string is offline
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Gimme a sec Tim, I'll see what I get.
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Old 01-17-2009, 01:28 PM
foose4string foose4string is offline
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Keep in mind my digital calipers are cheapy Harbor Freight. I get .050 for the uprights, and about the same as you (.048) for the internal bracing. Hardly any difference between the two and not discernible with the naked eye. This is without paint, fresh out of the package.


Pleeeease scratch build that tower. I want Semroc to release one!
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Old 01-17-2009, 01:37 PM
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Quote:
Originally Posted by foose4string
Keep in mind my digital calipers are cheapy Harbor Freight. I get .050 for the uprights, and about the same as you (.048) for the internal bracing. Hardly any difference between the two and not discernible with the naked eye. This is without paint, fresh out of the package.


Thanks. That's close enough for me to get the idea. This one doesn't have paint either. I know that paint makes the LJII's tower thicker than it was originally. I just didn't think I'd need to order the same size styrene rod for a 1/100 and a 1/70 kit.

My calipers are Mitutoyo, but they were freebies where the very tip of one of the I.D. jaws is chipped off and they were going to be thrown away. A friend got four or five sets this way several years ago and gave me one of them. The broken tip is all but unnoticeable unless you look very closely.

BTW, spell check keeps telling me to use two L's, but everywhere I look, caliper is spelled with one.
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Old 01-17-2009, 02:06 PM
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I covered myself by ordering several sizes, plus I decided to get a bottle of Tenax-7r to try out too.
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Old 01-17-2009, 02:35 PM
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All of the uprights tower struts are 3.5" in diameter as well as the lower cross arm.

The rest of the cross pieces are 2.5".

For 1/100th scale that is 0.035" and 0.025" respectively, simple math.

For 1/70th scale it's 0.050" and 0.0357"
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Old 01-17-2009, 03:30 PM
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Quote:
Originally Posted by sandman
All of the uprights tower struts are 3.5" in diameter as well as the lower cross arm.

The rest of the cross pieces are 2.5".

For 1/100th scale that is 0.035" and 0.025" respectively, simple math.

For 1/70th scale it's 0.050" and 0.0357"


Thanks. I should have known I'd be able to get real diameters from you after your PAT models.

The smallest I ordered was 0.035", so I may go with that and 0.045". It will be about half way between true scale and the Estes kit diameters.
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Old 01-20-2009, 05:23 PM
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I see Sandman posted the original sizes.

FWIW - here is a drawing from the Little Joe-II data which shows the BPC/LES:

http://tinyurl.com/7w6tzs

I am working up a new website that will present all of the Little Joe-II drawings Tom Beach & I worked up, I will announce when it is ready to be open.

Back to the tower, the tower that Estes had done up for the 1989 Saturn-V (merger of features of the old Estes & old Estes Sat-V’s), was not very good. The real tower had round tubing, of course. The Estes 1989 tower parts have a nearly square cross-section, except two corners are rounded and two corners are at 90 degrees. Pretty ironic since the original Centuri and original Estes towers were very accurate, molded round and close to the correct diameter. Now, the original towers were more fragile than the 1989 tower, but still it made no sense to mold them square-ish.

I have built several towers out of styrene plastic tubing and plastic rod. Definitely the way to go is to use a good liquid plastic cement. The liquid cements will melt and bond the plastic together, almost like welding does with steel. CA hoes not work that well. One of the things I did was to use a nearly empty liquid cement bottle and drop some scrap plastic inside, to create liquid cement that had some of its own plastic in it, which helped to fill in some of the joints (I did not add enough to make it into a thick liquid, it was still pretty thin).

I used a printed pattern of the tower to help in cutting and gluing the parts. Actually, for 1/39.5 scale and 1/22 scale models. I used a copy of the pattern to make up an assembly jig. For a 1/100 model, I used the Estes tower for the only thing it was good for, one of the unassembled 2-leg sides of it as a master for casting a female mold, to use that female mold as an assembly jig.

- George Gassaway
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  #9  
Old 01-20-2009, 05:27 PM
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Quote:
Originally Posted by georgegassaway
For a 1/100 model, I used the Estes tower for the only thing it was good for, one of the unassembled 2-leg sides of it as a master for casting a female mold, to use that female mold as an assembly jig.
- George Gassaway


I was thinking about doing something similar with mine. My daughter has some modeling clay. I was thinking about pressing it into the clay to make a stable bed to build up the tower sides. Is that similar to what you're talking about?
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Old 01-20-2009, 05:47 PM
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I wrote:
>>>-->>>
For a 1/100 model, I used the Estes tower for the only thing it was good for, one of the unassembled 2-leg sides of it as a master for casting a female mold, to use that female mold as an assembly jig.
<<<--<<<

tbzep replied:
>>>>>
I was thinking about doing something similar with mine. My daughter has some modeling clay. I was thinking about pressing it into the clay to make a stable bed to build up the tower sides. Is that similar to what you're talking about?
<<<<<

Cast it

I used some double-sided tape to first apply the tape to a sheet of scrap plastic, then stuck the Estes tower 2-leg piece onto it, “flat side down”. Built up 4 walls around it to contain the casting resin. Brushed on a LOT of mold release over the Estes part. Then after the mold release dried, mixed up some Alumilite casting resin and poured that in. The Alumilite gels in about 3 minutes. Then after it hard-cured, I pried the Estes tower part out.

That was the one good thing of that screwy flat sides cross section, because if the tower had been round I could never have doe that, the part would have been locked into cast resin. Though I could have used RTV rubber to mold instead, and used a razor blade to slide up the RTV to allow removing the Estes part and to be able to insert and remove the styrene parts for building the tower.

Since there is an issue with glue getting onto the jig, I drilled holes into the cast jig in all the spots where there were glue joints, so there was air under the glue joints.

Clay might be usable. And I certainly am not suggesting buying casting resin just for this purpose. Something else you could consider would be Plaster. Or, some old epoxy that may be too old to be good for building a rocket with, but still can be trusted to cure.

For a mold release, a homemade release can be made with some alcohol with Vaseline dissolved in it. For something like this, Vaseline smears would not matter, so you might instead try a 50-50 mix of alcohol and Vaseline.

- George Gassaway
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