Neil_W's half-baked design thread

Thinking outside the box
Step1 is to get a board the exact thickness leaving at just the surface of the ball that you want removed sticking out the top. Cut a 40 or 41 mm a hole in the board and stick the ball in it then use a sander to sand off the top of the ball even with the top of the board .may need some vinyl tape to make a tight fit to keep ball from rolling.

Step 2 is a second board the thickness of the ball minus the section that you've already sanded off. Again of 40-41 mm hole. Drop the ball in the hole with the section you've already cut out or sanded out on the bottom so your ball is perfectly vertical relative to the cutout surface on the bottom.. Again you should have just exactly the right amount of ball sticking up above the board. Sand the top off until you're even with the board Just an idea.

An upscale high-power version would be a perfect candidate for next year's BALLS29

BABAR said:

An upscale high-power version would be a perfect candidate for next year's BALLS29

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Ha, yes. If sufficiently upscaled it could use real ping pong paddles, although they're pretty heavy for rocket use. Would be a bummer not to use real ping pong balls though...

Tennis balls and tennis racquets (grid fins).

BABAR said:

Step 2 is a second board the thickness of the ball minus the section that you've already sanded off. Again of 40-41 mm hole. Drop the ball in the hole with the section you've already cut out or sanded out on the bottom so your ball is perfectly vertical relative to the cutout surface on the bottom...

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Sounds like it should work, but I offer two modifications: First, make the plates steel rather than wood. It'll be a lot harder to drill the holes, but the plates won't be sanded down as you process ball after ball, which will ensure much more consistent results.

Second, after the first side is sanded open, secure the ball to your table with double sided scotch tape and then apply the second plate over is. I fear that if the ball is pushed through the hole from above, it could be rolled a bit off vertical and, since it's supposed to be a snug fit, you might not know it until too late.

I still think the drill press is the way to go.

BABAR said:

Thinking outside the box
Step1 is to get a board the exact thickness leaving at just the surface of the ball that you want removed sticking out the top. Cut a 40 or 41 mm a hole in the board and stick the ball in it then use a sander to sand off the top of the ball even with the top of the board...

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There are no words. They should have sent a poet...

kuririn said:

Tennis balls and tennis racquets (grid fins).

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If someone can make a flying frisbee goal.......

https://www.rocketryforum.com/threa...th-and-distruction.149614/page-3#post-1922887

Cool thing about tennis ball rocket, you could make the nose cone ball loose, just a hole in the bottom to fit over the body tube. The nose free falls. I suspect terminal velocity of a tennis ball with a hole in one side wouldn’t be too much of a risk, points for catching it. Of course, that might violate the High Power Rocketry Code....,

jlabrasca said:

They should have sent a poet...

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One source gives the terminal velocity of a tennis ball as about 100 km/h. Two others gave 21 m/s which is 75 km/h. I really wouldn't want to be hit by either of those. Do you really think the hole would make such a big difference? (Of course, it depends on the size of the hole.)

jqavins said:

One source gives the terminal velocity of a tennis ball as about 100 km/h. Two others gave 21 m/s which is 75 km/h.

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Well, given that pro tennis players routinely hit balls at almost 200 km/h, that doesn't sound so bad actually. Might sting a bit but not likely to injure.

Nytrunner said:

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Because I clearly have nothing better to do...


And what IS that smell? Whatever is outgassing cannot be safe to breath.

Gee I wonder if ping pong balls are pressurized with some kind of gas at manufacture? Maybe to keep it rigid?
Time to do some research!

EDIT: Ping pong balls are NOT pressurized. So you must be smelling the thermoplasticizers.
(Yeah, it's a slow day for me).

Apparently (yeah, I just looked this up) celluloid ping pong balls use camphor as a plasticizer. That which outgasses from the plastic on the inside stays trapped inside there until some fool cuts it open.

Also apparently there are new plastic ping pong balls which don't stink like this, but I don't know how common they are at this point.

I better get some sort of new design ready to post lest this become the Half-Baked Ping Pong Ball Thread.

Plastic balls are trash. I'm no good at table tennis, but even a scrub like me can tell the difference in feel.

dhbarr said:

Plastic balls are trash. I'm no good at table tennis, but even a scrub like me can tell the difference in feel.

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Maybe OK for ridiculous rockets though.

dhbarr said:

Plastic balls are trash. I'm no good at table tennis, but even a scrub like me can tell the difference in feel.

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And 6 for a $1 at the 99cent store works better for rockets, too.

neil_w said:

Maybe OK for ridiculous rockets though.

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And 6 for a $1 at the 99cent store works better for rockets, too.

And now we have a Chem Eng PhDs take on flaming ping pong balls

jlabrasca said:

Because I clearly have nothing better to do..

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Starcraft is always a great thing to do!
(I know you're referencing contact, but that phrase will forevor be associated with the protoss Archon in my mind)

jlabrasca said:

Because I clearly have nothing better to do...

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Nytrunner said:

(I know you're referencing contact, but that phrase will forevor be associated with the protoss Archon in my mind)

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I totally did not get that even though I have watched that movie 5 or 6 times.
Scene?

Craft Smart Satin Pink, applied with a dry-brush sort of technique. Looks good.


It did however soak into the label paper and cause it to buckle at least until it dried. Need to play further; could be I’ll need to just go with CWF for the eraser.

neil_w said:

Craft Smart Satin Pink, applied with a dry-brush sort of technique. Looks good.

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That looks spot on. I pulled out my "Pink Pearl" eraser and you've got a great match. What is your dry-brush technique? I would guess that your label paper gives a better eraser texture than the CWF. I like it.

mbeels said:

That looks spot on. I pulled out my "Pink Pearl" eraser and you've got a great match. What is your dry-brush technique? I would guess that your label paper gives a better eraser texture than the CWF. I like it.

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I apply some paint, and then just keep going back and forth over it past the point where the brush is basically dry. I also gave it a quick 400-grit sanding, but I don't know how much that accomplished.

I'd like to use the paper as my surface, but not if it's going to buckle the way it did last time. I'm going to try again under slightly different conditions.

Very nice choice in color and finish for the eraser.

You could try spraying some matte acrylic clear coat onto the label before painting to seal it up but I wouldn’t buy any JUST for this.
I know that my trick of adding white glue (for durability) will cause more buckling so stay away from that.

I bet if you took care in using an almost sadistically dry brush the label wouldn’t crinkle. Using a child’s plastic bristle brush, and blotting the brush onto a paper towel before going to the model. Will take forever to get a full coat tho, might not be necessary.

Some goonie designs make you question whether they're better than the original....

Algoonierre

Dude, you have GOT to build that!

APRO Goonie Lander II

neil_w said:

Some goonie designs make you question whether they're better than the original...

Algoonierre

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No.

neil_w said:

APRO Goonie Lander II

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Maybe.

neil_w said:

Some goonie designs make you question whether they're better than the original....

Algoonierre
View attachment 395255

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Thanks Neil. About to start my Alcubierre upscale and now I have to do 2!!!!!

Lander looks unsurprisingly similar to the real thing lol

neil_w said:

Some goonie designs make you question whether they're better than the original....

Algoonierre
View attachment 395255

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This one might be within my build skills.