# Cox Saturn V.

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#### Steven

I had always been curious why the company didn't get the roll pattern correct on this. Even as a kid it stuck out as a sore thumb back in the day and it's certainly hasn't changed since. What gives?

#### Initiator001

##### Well-Known Member
I had always been curious why the company didn't get the roll pattern correct on this. Even as a kid it stuck out as a sore thumb back in the day and it's certainly hasn't changed since. What gives?
When Cox re-issued their RTF plastic rocket models in the late 1980s-early -90s I asked about the original roll pattern on the Saturn V interstage.
I was told it was done that way as it was easier to make the (painting) mask.

I mentioned the inaccuracy to the Cox R & D Director when the Saturn V was going to be re-issued but he told me it was too late, the company stayed with the original (Incorrect) pattern.

Only 1,000 of the re-issued Saturn V models were made by Cox.

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I see someone is selling a Cox replica of the Saturn 1B on ebay for about $60. The advertisement says that it is 3D printed. It looks like it is unpainted. I wonder if this is any good? Does it have the internal motor mount parts like the original Cox kit? #### Steven ##### Lifetime Supporter TRF Lifetime Supporter I see someone is selling a Cox replica of the Saturn 1B on ebay for about$60. The advertisement says that it is 3D printed. It looks like it is unpainted. I wonder if this is any good? Does it have the internal motor mount parts like the original Cox kit?
I've seen these on Ebay before and believe that the surface will probably have a grainy appearance to it as the 3D parts for my Sheri's CM and LES tower did from Shapeways. I think this one on Ebay states they ARE capable of flying so it's a safe guess to believe they have similar if not identical internals. Right now, I'm trying to find a Cox parachute for my Nike Zeus which has yet to fly.

#### Steven

When Cox re-issued their RTF plastic rocket models in the late 1980s-early -90s I asked about the original roll pattern on the Saturn V interstage.
I was told it was done that way as it was easier to make the (painting) mask.

I mentioned the inaccuracy to the Cox R & D Director when the Saturn V was going to be re-issued but he told me it was too late, the company stayed with the original (Incorrect) pattern.

Only 1,000 of the re-issued Saturn V models were made by Cox.

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That's some interesting historical notes on that. I was hoping someone might have some insight as to the decision making process and you certainly came through with something.

Boyce Aerospace Hobbies is selling many Cox replicas using 3D printing. I'm concerned with Steven's comment that these plastic parts may be grainy. On the Boyce website they state that the model can use wet sanding and primer to achieve a glossy finish. I was going to order the Saturn 1B, because I had the original Cox RTF model 45 years ago and it flew fine with really no work at all, but I am concerned about sanding all the contoured surfaces on the latest Saturn 1B. I've ordered the Nike Zeus instead. There was a thread on TRF about Boyce back in about October 2016, I think in the new vendor section. It looks like Boyce has quite a few new plastic models. It will be interesting to see what they like.

#### rharshberger

##### Well-Known Member
Boyce Aerospace Hobbies is selling many Cox replicas using 3D printing. I'm concerned with Steven's comment that these plastic parts may be grainy. On the Boyce website they state that the model can use wet sanding and primer to achieve a glossy finish. I was going to order the Saturn 1B, because I had the original Cox RTF model 45 years ago and it flew fine with really no work at all, but I am concerned about sanding all the contoured surfaces on the latest Saturn 1B. I've ordered the Nike Zeus instead. There was a thread on TRF about Boyce back in about October 2016, I think in the new vendor section. It looks like Boyce has quite a few new plastic models. It will be interesting to see what they like.
When I get home I will post photos of my Boyce Aerospace Mercury capsules here so people can get their own view of them. Personally I believe they have excellent quality. One is their vanilla 4" ( square porthole) the other is a custom Mercury Atlas (round porthole).

#### Steven

I've never been certain as to why 3D printing leaves things grainy. It's taken a fair amount of work to bring Shapeway's CM module and LES tower to a smooth finish.

#### Steven

I've never been certain as to why 3D printing leaves things grainy. It's taken a fair amount of work to bring Shapeway's CM module and LES tower to a smooth finish.
Along with the SLA Adapter and IU as well.

#### Saluki

##### Well-Known Member
TRF Supporter
Here is a few pictures of Boyce Aerospace Saturn 1b. You be the judge.

#### rharshberger

##### Well-Known Member
Here's some other Boyce Aerospace products. The red nozzles for the LES are grainy, and will probably be recieving an acetone vapor/wipe treatment to smooth. The rest of the capsules and stuff are pretty good according to my brother who has access to a really nice Makerspace and several of his own 3D printers. These parts are all fairly large, that may have something to do with the graininess, thinner parts more grainy, larger parts less so, the Larger capsule is for a 4" Mercury Redstone, and the smaller is for a 5.38" airframe based Mercury Atlas (diameter of capsule is a bit larger than a BT-80 which fits inside the missle adapter on the bottom of the capsule). The smaller capsule was a custom order, and the Boyce's were both very involved and communicative for the entire process.

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#### rharshberger

##### Well-Known Member
All in all, it looks like my stuff from Shapeways with the grainy look. Is it good? Is it bad? :confused2:
Steven the last photo I added during the edit is a cropped but not quality reduced, as for the grainy part some smoothing is usually necessary is my understanding, but I too am far from a expert on 3D printing.

#### Steven

Steven the last photo I added during the edit is a cropped but not quality reduced, as for the grainy part some smoothing is usually necessary is my understanding, but I too am far from a expert on 3D printing.
Yeah. Pretty much the nature of the beast.

#### Incongruent

##### Well-Known Member
I've never been certain as to why 3D printing leaves things grainy. It's taken a fair amount of work to bring Shapeway's CM module and LES tower to a smooth finish.
I'm assuming that grainy refers to the ridges; if not, that's probably why the rest of the post is weird.

3D printing (or the method typically used-more on that later) involves using an extruder to lay plastic (usually PLA or ABS) onto itself. The plastic bonds to the underlying layer (though not as well as it does within each layer, which is why 3D printed parts are weaker in the vertical axis unless further treated, such as with solvent or additional material.) The ridges come out of the process the same way there are gaps between the layers of the mountain you (or it could just be me...) make self serve ice cream machine. (ignoring the texture from the extruder)

Other methods of printing include using UV light to solidify material in a liquid vat (this method reportedly yields smooth surfaces because the layers are much thinner, however, I have not seen it in person to confirm) and using a laser to melt powder in layers (the powder is in a hole that has a lowering bottom, the laser zaps a pattern, tray lowers a bit, powder is spread into the extra space, repeat). Of course, many materials can be used with each process, and each process has pros and cons.

For finishing, people use primer (as mentioned earlier), epoxy, filling putty, sandpaper, acetone (the process here is to knock down the high parts of the ridges and use acetone to solidify the dust that's in the crevices to the rest of the part), and probably a bunch more methods if you check out the 3D printing threads. Oh, and if you don't know yet, (how does one suggest without making it seem like they think others are stupid?) a search method if you're searching for 3 letter or less words or are tired of Forum games: Word Association & such threads popping up for search results (since TRF does results by presence of key words ranked by time since most recent post) is (key words) site:rocketryforum.com in Google.

tl;dr (found out what it meant about a week ago - I'm not a normal "kid these days" )

Printing is bumpy because the plastic is put down in relatively thick layers.

I got the Boyce Nike Zeus today. It does have that layered look. The instructions do give finishing directions as mentioned earlier in this thread, starting with 400 grit wet/dry sandpaper, followed by automotive primer and sanding, and then grey primer before painting.

#### Steven

I've chosen a different route, I apply upwards of two coats of laminating epoxy from Zap mixed with denatured alcohol. The alcohol allows spreadability of the epoxy while shortening curing time. There is still sanding in-between coats, just less of it. Then I follow with primer and Bondo for small areas.

#### OverTheTop

##### Well-Known Member
TRF Supporter
Other methods of printing include using UV light to solidify material in a liquid vat (this method reportedly yields smooth surfaces because the layers are much thinner, however, I have not seen it in person to confirm)
Confirmed. SLA printing makes for seriously smooth prints. We got one of these printers for work about six months ago. Have used it for a few parts.

As for smoothing 3D prints done in ABS, I coat them with Loctite 401 then sand, and repeat. Seems to get to a good finish quite quickly.

#### OverTheTop

##### Well-Known Member
TRF Supporter
Other methods of printing include using UV light to solidify material in a liquid vat (this method reportedly yields smooth surfaces because the layers are much thinner, however, I have not seen it in person to confirm)
Confirmed. SLA printing makes for seriously smooth prints. We got one of these printers for work about six months ago. Have used it for a few parts.

As for smoothing 3D prints done in ABS, I coat them with Loctite 401 then sand, and repeat. Seems to get to a good finish quite quickly.