Acrylic info

[The Snark]

Just got word from a professional acrylic worker. Two different types of acrylic with the same chemical composition. Extruded and cast. The common acrylics are extruded. They commonly chip and develop cracks as when drilling holes. The cast acrylics are more expensive and much more machineable. HOWEVER, many retail outlets don't even know there are two different kinds and almost always just offer the extruded stuff.

The low down is extruded acrylics are pre-stressed from the process. If you can live with little star cracks and chips around your drill holes, fine. Buy the stuff and save yourself some money. But if you are trying to turn out picture perfect flawless products, go the cast route. Only water jets or laser can cut and drill extruded acrylic flawlessly and reliably all the time.

 

[viper69]

Just got word from a professional acrylic worker. Two different types of acrylic with the same chemical composition. Extruded and cast. The common acrylics are extruded. They commonly chip and develop cracks as when drilling holes. The cast acrylics are more expensive and much more machineable. HOWEVER, many retail outlets don't even know there are two different kinds and almost always just offer the extruded stuff.

The low down is extruded acrylics are pre-stressed from the process. If you can live with little star cracks and chips around your drill holes, fine. Buy the stuff and save yourself some money. But if you are trying to turn out picture perfect flawless products, go the cast route. Only water jets or laser can cut and drill extruded acrylic flawlessly and reliably all the time.

let me guess, cast is $$$$$ ?

 

[The Snark]

let me guess, cast is $$$$$ ?

You folks who work with acrylic need to be the judge. https://www.mcmaster.com/cast-acrylic/

 

[Rhino1]

My father in law owns a monstrous glass company on the gold coast, I picked up a thing or two working with acrylic/Perspex/Lexan.
One is acrylic (cast) and one is polycarbonate (extruded).
Acrylic is harder to scratch but brittle and breaks easier, it is clearer, smoother, shinier and used in display cases etc.
Polycarbonate is easier to scratch but almost unbreakable, this is what we used for planes and race car windows, polycarbonate is used in building bullet proof glass laminates, huge custom fish tanks etc

 

[Ferrachi]

Just got word from a professional acrylic worker. Two different types of acrylic with the same chemical composition. Extruded and cast. The common acrylics are extruded. They commonly chip and develop cracks as when drilling holes. The cast acrylics are more expensive and much more machineable. HOWEVER, many retail outlets don't even know there are two different kinds and almost always just offer the extruded stuff.

The low down is extruded acrylics are pre-stressed from the process. If you can live with little star cracks and chips around your drill holes, fine. Buy the stuff and save yourself some money. But if you are trying to turn out picture perfect flawless products, go the cast route. Only water jets or laser can cut and drill extruded acrylic flawlessly and reliably all the time.

Which one would the AMAC box be made of ?

 

[The Snark]

AMAC box

Extremely clear with little or no optical distortion would be cast. Extrusions always have some variation in thickness and with even less than 1/2 micron variation the optical distortion is visible to the unaided eye if you move it back and forth while looking through the material. Cast depends on the mold. High quality molds are machined then ground surface plate flat. Zero thickness variation.
One easy test is brittleness. Cast will shatter, almost as brittle as glass. Extrusions are flexible. But oddly, cast is much easier to machine with the proper tools. Extrusions also tend to melt while being machined. Extrusion machining requires flood cooling or is even done submerged.