Molding scrap PLA?

[Alex Lau]

Has anyone tried molding scrap PLA?

I've seen a bunch of people using PLA scraps in 'art'..sticking in ovens and such. Not really sure I want to do that to my oven.

Since PLA doesn't create fumes, melting it in a household -should- be fine..I mean I sit next to my makerbot.

There are several casts/molds and melting equipment for bullets and guns available..I was thinking maybe we could co-opt some of them to use for our own purposes.

This precision heater costs as much as a spool of PLA..

http://leeprecision.com/cgi-data/instruct/EM1142.pdf

Metal molds used for ingots

http://www.amazon.com/Lee-90021-Precision-Melter-Grey/dp/B00162UONY/ref=sr_1_3?ie=UTF8&qid=1357814990&sr=8-3&keywords=lee+melting+pot

Now, obviously metal is less viscous than plastic, so it's easier to pour into molds..and then there's the question what are we going to do with a 'plastic ingot'

Currently I'm using scrap PLA to 'weld' together broken prints with a soldering iron..perhaps this idea would dovetail nicely with the PLA hot glue gun..you could use the molds to create "PLA glue sticks", effectively using your scrap PLA..for repairs!

[Jetguy]

"Now, obviously metal is less viscous than plastic, so it's easier to
pour
into molds..and then there's the question what are we going to do with
a
'plastic ingot' "

No, PLA runs like water when melted. That's why it drips out of the
nozzle.
You can heat PLA enough to melt like that with a heat gun. I use this
method to clean nozzles and specifically the threads of the nozzle
when changing them out..
Further, PLA retains heat well and takes a long time to solidify,
especially in mold.

On Jan 10, 5:54 am, Alex Lau <alex....@hublished.com> wrote:
> Has anyone tried molding scrap PLA?
> I've seen a bunch of people using PLA scraps in 'art'..sticking in ovens
> and such. Not really sure I want to do that to my oven.
>
> Since PLA doesn't create fumes, melting it in a household -should- be
> fine..I mean I sit next to my makerbot.
>
> There are several casts/molds and melting equipment for bullets and guns
> available..I was thinking maybe we could co-opt some of them to use for our
> own purposes.
> This precision heater costs as much as a spool of PLA..
>
> http://leeprecision.com/cgi-data/instruct/EM1142.pdf

> Metal molds used for ingotshttp://www.amazon.com/Lee-90021-Precision-Melter-Grey/dp/B00162UONY/r...

[Alex Lau]

Ah, I see. I haven't heated PLA hot enough to get it to flow like that, most of my experiments turn it into fried gunk.

[Alex Lau]

Gave it another shot today...bought small metal pot for a couple dollars and melted all my scraps in it over the stove

Basically the PLA (which was clear) turned black, and cooled hard and brittle. Now, this is likely because I quenched it in water..but I have no idea what I'm doing, and I probably need equipment with better heat regulation.

[Ryan Gerrish]

I've just been crushing my scraps up into small pieces and mixing them in guacamole. Adds a delightful rustic aftertaste, and the mouthfeel is improved dramatically.

[Jetguy]

You need to control the temperature. You are seeing exactly the same
breakdown that happens inside the extruder system when PLA is heated
for long periods of time at high temperature.

"bought small metal pot for a couple dollars
and melted all my scraps in it over the stove"

Not exactly the definition of temperature controlled.

Something like one of these http://www.lightobject.com/Temperature-Controller-C7.aspx
With a matching temp probe into the mixture
http://www.lightobject.com/Premium-Stainless-Steel-Waterproof-PT100-RTD-Temperature-Sensor-Probe-Threaded-P681.aspx
Solid state relay to control the heater
http://www.lightobject.com/25A-Solid-State-Relay-SSR-DC-In-AC-Out-P61.aspx
Matching heatsink http://www.lightobject.com/Heat-sink-for-25A-SSR-P583.aspx
24V supply to run the electronics (smallest they had but more than
workable http://www.lightobject.com/DC-24V-5A-Switching-Power-Supply-Good-for-CNC-stepping-motor-and-water-pump-P579.aspx

I mean basically, you need the same setup for a filament extruder
anyway
http://www.thingiverse.com/thing:24583
Exact same controller.

> >> > using your scrap PLA..for repairs!- Hide quoted text -
>
> - Show quoted text -

[Bluemetal]

Something like this: https://www.flickr.com/photos/blue_metal/7799512282/in/photostream . The solid relay is in the yellow case. This one is to keep hide glue at 64C (it is the glue used to glue together those player pianos from 100 years ago ) using the crock pot. I designed to work on other heating "ventures" as the sensor is a thermocouple encased in metal.