Can you melt clear styrene and then form it?

[Wurger]

It is impossible rather to recycle clear sprue into clear sheet. It is because the polystyrene used for sprues is moulded in pressure-thermal way. This causes that all moulded parts and the sprue frames keep thier shapes Of course to a certain extent. Going beyond the point it is damaged or catches a fire. You may do an experiment with a piece of frame sprue. Warm up the piece and stretch it a little bit. Then let it get harden. And then try to warm it gently again. Look what can happen to the stretched sprue.
And this is the reason for using a clear sheet for moulding clear parts of cockpi canopies for instance.

BTW The easiest way for getting clear parts for a model is to use pieces of clear foil/box obtained from wrapped items. A such plastic is vacuformed and has many shapes. It is almost always possible to find an area of a such formed foil with a required shape that can fit your model.

 

[Robert Porter]

It is impossible rather to recycle clear sprue into clear sheet. It is because the polystyrene used for sprues is moulded in pressure-thermal way. This causes that all moulded parts and the sprue frames keep thier shapes Of course to a certain extent. Going beyond the point it is damaged or catches a fire. You may do an experiment with a piece of frame sprue. Warm up the piece and stretch it a little bit. Then let it get harden. And then try to warm it gently again. Look what can happen to the stretched sprue.
And this is the reason for using a clear sheet for moulding clear parts of cockpi canopies for instance.

Yep, that has become my understanding as well. But I am always the stubborn one and like to try for myself, which I did, and of course learned exactly what you and others predicted. Ah well, it was as they say worth a try.

One great source of "free" or low cost clear styrene sheet I found is my local sign shop. They make lots of things other than signs from clear styrene and I asked if they had a scrap bin. They did, and they were happy to let me have it! They are all odd sized pieces but all of them are big enough for canopies etc. They also had piles of white, grey, black and even brown styrene in the bin as well. I got quite a bit enough to start practicing my scratch building!

They did not have "L" shaped pieces or tube either hollow or solid. But I imagine with my melted styrene and a die I could make my own. Have to give that a try!

 

[Wurger]

Just edited the post above. You might not see the entire text written.

 

[Robert Porter]

Just edited the post above. You might see not the entire text written.

Had not thought of that source! Excellent idea!

 

[Wurger]

Glad you like the idea. I have used a couple of such cut out pieces and it works. Also you may use pieces of other already shaped plastic wrappers and items.

 

[Wurger]

Here is and example.. these light glasses are cut off pieces of wrapping pills. All I had to do was to find these bulges of a correct shape and diameters . And the bulbs inside are made of stretched clear sprue pieces with "swelled "endings.

 

[fubar57]

If you want ready made "L"s, channels and other plastic shapes...Shapes
Depending on the size of tube you want, I just did a quick experiment with a Bic pen ink tube heated over a candle...

​

....a bit of trial and error will give you the size you need.

 

[fubar57]

Dayum!!!! I just realized the clear section of the 109 fuel line that runs in the cockpit could have been done this way instead of being paint silver. Next time.........

 

[mikewint]

That is IMPRESSIVE fine detail work to say the least.
I should have been clearer about the acetone, I use the nail polish remover which I have from the "Fill without sanding" method. The "blob" remains mold-able for hours and hardens from the outside inward. Initially I used this on "Glow-in-the-Dark" plastic. Ordinary putty-type fill would have not matched the parts being filled.
I'm surprised at your boiling water results. I would have thought the gentle 212 (100C) heat would have worked

 

[Robert Porter]

That is IMPRESSIVE fine detail work to say the least.
I should have been clearer about the acetone, I use the nail polish remover which I have from the "Fill without sanding" method. The "blob" remains mold-able for hours and hardens from the outside inward. Initially I used this on "Glow-in-the-Dark" plastic. Ordinary putty-type fill would have not matched the parts being filled.
I'm surprised at your boiling water results. I would have thought the gentle 212 (100C) heat would have worked

I avoided bringing the water to a boil, it did, but then I would back off on the heat. I was trying to slowly warm it rather than shock it in hopes it would retain its clarity. Hmm have to try full out boiling and see what happens.

 

[mikewint]

You cannot heat water (pure) to a temperature hotter than 212 (100C). N.B. That's at 1 atmosphere of pressure if you're in Denver that becomes 203F(95C). Rapidly boiling water or gently boiling are at the same exact temperature 212F. Steam can be much hotter and thus contain more energy (thus STEAM engines not HOT water engines)

 

[parsifal]

You would need some high tech shite to take your steam temps above 100C. Its called superheated steam and is used mostly in turbine applications. superheated steam cannot co-exist with liquid water except under some very specific, and very technical circumstances, and then only for brief periods. we are getting into the high end of town here I can assure you.

Superheated steam generates a lot of pressure and for that reason can be used to generate a lot of special circumstances when speccy processes are wanted. This is getting right to the edge of what I know, but superheated steam has a drying effect and can be used to suppress oxidation.

how you might use this in a hobby situation I don't know, but at least knowing something of the theory can be interesting if nothing else

 

[Robert Porter]

I would not even attempt to make use of steam. Having been around live steam in an industrial setting (I worked on the control software) I have no interest in attempting to create or use it in my home.

I think I might have been misunderstood, I was not claiming to heat water past boiling I was slowly bringing water to the edge of boiling and backing the heat off to stop the boiling in an effort to slowly warm the plastic. I could of course heat water/steam at home in a pressure cooker however I doubt seriously it is something that would accomplish my goal. I have accepted that I will use methods like Geo mentioned about Bic Pen tubes etc, or using packaging materials I encounter in my day to day efforts. Or lastly buying what I need from online or local sources.

"In a sealed pressure cooker, the boiling point of water increases as the pressure rises, resulting in superheated water. At a pressure of 1 bar or ~15 psi (pounds per square inch) above the existing atmospheric pressure, water in a pressure cooker can reach a temperature of up to 121 °C (250 °F), depending on altitude."

 

[fubar57]

You can't go wrong with the Evergreen plastic

 

[mikewint]

Pure water can be at 212F(100C) and 1 atm of pressure and NOT be boiling. It requires extra energy/heat to convert liquid water to gaseous water (water vapor) i.e. 540cal/g @ 100C (2260J/g) That's why the vapor bubbles form at the BOTTOM of he pan where it is the hottest. The bubbles are filled with gaseous water which rise to the surface and burst. The gaseous water enters the colder air above the pan and condenses back to liquid water which is visible to the eye, These rising small droplets are what most people refer to as "steam". Water vapor is a gas just like Oxygen or Nitrogen and just as invisible to the naked eye (you can't SEE humidity).
So the fact that your water was not actively boiling does not correspond to a temp below 100C. Polystyrene melts somewhere between 210 - 249C BUT being a non-crystalline solid they begin to FLOW at their glass transition point which for polystyrene is about 100C.

 

[Robert Porter]

You can't go wrong with the Evergreen plastic

True! And they have just about every shape you can imagine. There used to be a competitor I heard of that was a little less expensive but I can't remember the name now.

 

[Robert Porter]

Pure water can be at 212F(100C) and 1 atm of pressure and NOT be boiling. It requires extra energy/heat to convert liquid water to gaseous water (water vapor) i.e. 540cal/g @ 100C (2260J/g) That's why the vapor bubbles form at the BOTTOM of he pan where it is the hottest. The bubbles are filled with gaseous water which rise to the surface and burst. The gaseous water enters the colder air above the pan and condenses back to liquid water which is visible to the eye, These rising small droplets are what most people refer to as "steam". Water vapor is a gas just like Oxygen or Nitrogen and just as invisible to the naked eye (you can't SEE humidity).
So the fact that your water was not actively boiling does not correspond to a temp below 100C. Polystyrene melts somewhere between 210 - 249C BUT being a non-crystalline solid they begin to FLOW at their glass transition point which for polystyrene is about 100C.

Exactly, I was not trying to melt it just get to flow so I could hopefully mold it. Which did indeed work, just did not retain its clarity.

 

[Airframes]

Are you thinking of 'Plastruct', Robert.
They provide a huge range of shapes, mainly for architectural modelling. From memory, the are a bit more expensive, and their products are made from a different type of plastic (not styrene, but can't remember the type) which require a CA or epoxy adhesive.

 

[Robert Porter]

Are you thinking of 'Plastruct', Robert.
They provide a huge range of shapes, mainly for architectural modelling. From memory, the are a bit more expensive, and their products are made from a different type of plastic (not styrene, but can't remember the type) which require a CA or epoxy adhesive.

That sounds right, but I remember them being less expensive. Ah well, time marches on!

 

[Robert Porter]

Are you thinking of 'Plastruct', Robert.
They provide a huge range of shapes, mainly for architectural modelling. From memory, the are a bit more expensive, and their products are made from a different type of plastic (not styrene, but can't remember the type) which require a CA or epoxy adhesive.

Just checked their site out, they offer most things in one of three types. ABS, Styrene, and Acrylic. It is indeed the supplier I was trying to remember! Thanks again!