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[johnm]

Put my name on it!  I'll try to swing it this year, if not next, I promise! 

Written in ink!

I am away from the board for a few hours and look at what I miss!!!  Wow is right.  Now I need to figure out how to get down there before I go to San Antonio.

Mike, Monday is a holiday but at least Bryan and I will be in the lab.  Technically, you and John B. already meet the criteria so...

[jim in paris]

oh la la !!  ....John !

that's a great project : i like the way you recycle the tiniest bits to add up to the "sauce" ! i'm sure your mom has taught you some cooking 
and the molds are beautiful metal objects!

thanx for sharing your experiences and good luck for future ideas

how about a chocolate tops contest for the future local meeting ?

bye

jim

[kevinm]

wow! you guys do everything there, build the molds, recycle the plastic...
it is so impressive what skilled people can build.
now, thanks to jim, all i can think about is chocolate tops though.

[the Earl of Whirl]

Well, now I have a few minutes.  We just finished the annual Memorial day parade here in Miamisburg.  It was fun to get our people on bikes and ride in the parade.  I always ride my high wheeler.  What a treat to do what is normally illegal....going back and forth across the road and even pedaling on the wrong side.

I won't be able to go to Cincy today but I am dreaming about a trip tomorrow morning.  Wonder if any of the amazing C-City Spinner crew are around on Tuesday?

[johnm]

Well, now I have a few minutes.  We just finished the annual Memorial day parade here in Miamisburg.  It was fun to get our people on bikes and ride in the parade.  I always ride my high wheeler.  What a treat to do what is normally illegal....going back and forth across the road and even pedaling on the wrong side.

I won't be able to go to Cincy today but I am dreaming about a trip tomorrow morning.  Wonder if any of the amazing C-City Spinner crew are around on Tuesday?

Sounds like you had great fun this morning!  Why not make it two days in a row?  Tuesday would have been a normal work day for us but with the possibility of Mike stopping in it could be a great day.  I believe everyone should be around for some spinning action.

[poptop]

hey John, What are you using for tips? 

[johnm]

hey John, What are you using for tips?

Before they made it to a dumpster, I grabbed some rusty old laboratory ring stand posts from which I machine the tips.  They are just regular mild steel so without care they will rust again.

[Trevor]

ultimate hardcore modder-creator! salute to u! love those tops u've created, they're beautiful!

[SpinQueen]

Found this info on melting/molding plastic just incase some of you wanted to try it out:

http://www.instructables.com/answers/Expertise-needed-on-melting-and-remolding-plastic-/

Important info:


http://www.instructables.com/id/HomemadePlastic/

She melted HDPE plastic bags in a pan on the stove, and successfully molded them into a wheel for a robot.

HDPE melts at 265 F (often a bit lower), while PP doesn't melt until 320 F. But the plastic chips you were using might not have been polypropylene. If they were one of the "thermosetting" polymers, they wouldn't ever melt at all, just like you can never melt a hard-boiled egg.

Any of the plastics with recycling triangle numbers from 1 through 6 are "thermoplastic" polymers; and can (at least in theory) be melted, molded, cooled, remelted, etc. indefinitely, like a ice cube rather than a hard-boiled egg.

HDPE (#2) and LDPE (#4) have the lowest melting points and emit little or nothing in the way of fumes. And since they are both the same polymer (polyethylene), they can be melted together.

PP (#5) melts at 320 F, but may sometime have additives that emit harmful fumes.

PET or PETE (#1) has little or nothing in the way of fumes, but doesn't melt until 500 F.

PS (#6) melts at 465 F, but may often have additives that produce fumes that are much better avoided.

PVC or V (#3) melts around 220-265 F, but always produces very nasty, harmful, dangerous fumes. Don't try this at home, kids. DANGER, WILL ROBINSON! AVOID AVOID AVOID.


I'm considering giving the turned melted plastic block a try.  I don't actually purchase milk from jugs but I noticed that a number of my garden plants came in big #2 black plastic tubs and I found a cool silver tub as well ...too bad I'm not a Raiders fan

[ta0]

Very good info SQ. Thanks!
I look forward to seeing your results.

[poptop]

She's a hot momma you know 

[Neff]

Thanks for the research SQ, the idea of melting and turning some HDPE really turns me on.  In a makin' stuff kind-of-way.

I don't actually purchase milk from jugs...

I have to ask, how do you get yer milk?

[the Earl of Whirl]

I can see my top in the very first picture on this thread.  I am now the proud owner of the scarlet and gray Ohio State top on the far left of the colored tops.  Can you see my cute little baby?  He is such a beautiful little top and I am the proud papa!!!

[johnm]

HDPE melts at 265 F (often a bit lower),

Nice list of melting temps and dangers.  However, the melting temperatures are just that--the temperature of the phase transition between a solid and a liquid.  For HDPE (its the only one I've worked with) the melting temp of 265F is rather low for a 'working' temperature of the material.  The plastic gets sticky at 265 but doesn't flow together to form a single piece of plastic (at least in a tolerable amount of time)--it basically becomes a collection of lots of pieces just stuck together as you can see from that 'instructable' project.


A block of skeletal material like that is not something I'd want to spin quickly in my lathe or try to cut, much less try to throw as a top.  I've found that a temperature around 360 F allows the material to flow together nicely under just the force of gravity to form a single piece of stuff.  HDPE at 360 degrees is still ridiculously viscous and there is no hope of pouring it as someone might cast iron or bronze or chocolate.  Cooling from this temperature, the block will shrink a lot in an uncontrolled way so the resulting block will be smaller than the container and will have an unusual shape to round out as you start turning (be careful of catches).  For me there always seems to be voids in these large blocks.  Sometimes there has been a single large void, and other times there have been multiple small cylindrical voids.  I'm not sure why these form, maybe due to trapped air during the melt or perhaps just a shrinking event.  Regardless of the source, hidden voids can be a real surprise while hollowing out a top.

Good luck to those who try this.

[SpinQueen]

I don't actually purchase milk from jugs...

I have to ask, how do you get yer milk?
[/quote]

Well Neff, I know you're just dying to hear me say that I have my own Jugs, and as mentioned by Poptop, I am a "hot momma", but alas.....I'm of the non lactating/childless variety......and, since I only consume milk in limited quantities...on my cereal.... I buy my milk in cartons.

Short answer:  From COWS! (Proceed to spin your top)   Oh btw, "Happy Cows Come From California"


John,   thanks for the additional info.  I wasn't imagining my melted blob/mass would look much like this "skeletal" donut before I attempted to turn it.  Perhaps Neff would like to throw this donut I was hoping for something much more evenly congealed and uniform, but perhaps that's just wishful thinking.

I would love to see a photo of one of your final melted blocks if you should turn another.  Do you think it would be possible,  or helpful even,  to pound the melted plastic mass as one might do to cake mix to prevent air bubbles/voids or is the plastic not liquid enough?