[Edit: Updated to add PLA and ABS to the list of compatible materials]
Polycaprolactone or PCL is a white plastic that is very hard and slick at room temperature, but melts to a putty-like consistency when heated under very hot water. Make Magazine has an excellent article summarizing some of PCL’s many uses, and in fact that article is where I first learned of it.
PCL is very useful as a clay-like molding material, and as I discuss in a previous post, as a material for Reversible, semi-permanent PVC glue joints and custom fittings.
Compatibility with other plastics
Depending on your application, PCL’s tendency to stick to other plastics may or may not be desirable. I compiled this table of compatibility based on my own experiments:
|Material Type||Common Uses||Result||Notes|
|PLA (Polylactic Acid)||3d printing||sticks very well||Be careful not to overheat and distort PLA||ABS (acrylonitrile butadiene styrene)||3d printing, Lego||sticks very well||Custom Lego!!!|
|PVC (Polyvinyl Chloride)||white plastic pipe||sticks very well||preheat pieces for best bond|
|CPVC (Cross-linked Poly Vinyl Chloride)||yellowish plastic pipe||sticks very well||preheat pieces for best bond|
|Polycarbonate (aka Lexan)||very strong glass substitute||sticks very well||preheat pieces for best bond|
|PEX||flexible water pipe||does not stick|
|PET / PETG||soda bottles||does not stick|
|Metals||copper, steel, aluminum||does not stick|
Polycaprolactone is sold under a number of brand names including InstaMorph, Shapelock, Friendly Plastic, Missing Link plastic, etc.
As far as I can tell they are nearly identical products, with the exception of Missing Link — they sell a “flow formula” that is a bit less viscous when melted, which may be useful for some applications.
- Make Magazine’s Maker Shed sells Shapelock brand
- Amazon sells various brands and sizes for prices mostly in the $10-20 range. I found that the best way to find all your options on Amazon is to
- rather than any particular brand.
Buying through my Amazon links has the added benefit of modestly subsidizing my experimentation, for which I thank you.