Which Acrylic Manufacture?

Sorry if this posting has been done before.

I am hoping someone can direct me to the best place to get some dark tinted (smoked) Acrylic for window replacement in my Gemini sailboat.

It seams that there are some significant variations in the quality and appearance of acrylic manufactured by different producers. What have you found to be the best? I only want to do this once and figured I would go off of other's trial and error instead of my own this time!


Thanks

 

Your best bet is to contact firms that cut to order and buy a small sample in the color you want and thickness. You might get it for free.......... there are several firms that do this then you are sure your getting what you really want. It has been years since I bought Lexan so that is what I would do.

 

You need to decide what you want, then get the appropriate product, which can be easily cut in your garage.

Polycarbonate is 30% more expensive than acrylic. Acrylic is about 20 times the impact resistance of glass. Polycarbonate has 250 times the impact resistance of glass. Acrylic also has better clarity than glass. Acrylic is very rigid whereas polycarbonate can be bought in flexible grades. Acrylic cracks more easily than polycarbonate under stress. Acrylic can be polished to restore its clarity, but not polycarbonate.

Acrylic can be used in temperatures from -30 degrees (F) to 190 degrees. It may expand and contract with changes in temperature although it won’t permanently shrink over time. Polycarbonate can handle temperatures up to 240 degrees and is also highly resistant to chemicals such as gasoline and acids.

Both can be cut with conventional tools (saws, routers, etc), though acrylic cuts easier than polycarbonate. Acrylic will crack if it is drilled near an edge or with a drill bit not designed for plastic. Polycarbonate typically does not crack when being drilled, even if drilled close to the edge with a standard drill bit. The edges of acrylic can be polished smooth if necessary, polycarbonate can't be polished.

Heat bending works better with acrylic than polycarbonate, but polycarbonate can be cold formed or bent without heating. Both can be glued, but acrylic gives a cleaner glue line than polycarbonate.

Acrylic has a low chemical resistance and needs more specific cleaners. When cleaning acrylic, it is best to use only mild soap and water or a plastic cleaner. Polycarbonate has a higher chemical resistance than acrylic; it can be cleaned by harsher cleaners containing chemicals such as ammonia. Neither plastic should be cleaned with solvents. Both acrylic and polycarbonate can scratch, so wool rags and paper towels should be avoided. Acrylic is more likely to chip than polycarbonate because it is less impact resistant. It does not scratch easily, however it's less likely to yellow over time.

Lots to think about, but generally polycarbonate (Lexan) is preferred for it's strength.

 

Definitely go with the Lexan. Much easier to work with and does not tend to crack like acrylic can and will.

 

One area touched upon by PAR where Polycarbonate (Lexan) is not good is resistance to petrol (gasoline) and I have not double checked to see if it likes your high ethanol content stuff!. Just try coating a scrap piece an watch it craze to pieces in a few minutes. A lot of things like motorcycle helmet visors and car headlights are polycarbonate, but are treated or coated to improve this resistance. You will also find the automotive guys using wet and dry down to 3k grit to help polish scratched headlight lens(es) to get a clean cutoff line! At least here in the UK this is a requirement at the annual inspection for road worthiness. Mercs are a common culprit btw.

Any decent polymer stockholder should carry or be able to get a wide range of colours and tints of either material. You will also find that 'drilling' using a plunge router in plunge mode is very effective and clean in both materials. An aluminium file is fairly useful for dressing these polymers but the acrylic can be a little brittle and fractionally chip if your not careful. I would expect the stockholder to stock material from reputable manufacturers such as Basf, DuPont, Hoechst, Repsol etc etc. You may find some people have used cheap PVC as a replacement 'clear' material - this is a very different beast - good for transom flaps though...

These materials cut fine on a table saw blade with no set (non ferrous and polymers), be very careful if you use a standard cross cut wood blade. You can even just about use a very sharp wood plane, to sweeten the edge faces, but again watch for very light chipping, depends how careful or skillful you are to get this to work....
Leave the protective plastic covering on as long as possible to avoid scratching prior to installation.

 

Polycarbonate scratches more easily than acrylic. There are coated types of polycarbonate that are more scratch resistant than others. There are even, at a price, laminated polycarbonate with acrylic surfaces as used on F-16 canopies.

 

I recall the first one piece F16 cockpit mouldings once they were sufficiently optically perfect at approx 50m thickness (2") were around 16k USD (circa years 1999/2000). However the service life was around six months or a bad bird strike.... It actually saved the US taxpayer a lot of money as it replaced a 2 piece design which cost a shed load more.

I believe they were fully polycarbonate and treated, however later developments may have been caried out.

 

The world leader for methyl metacrylate is Lucite with 'Perspex' as their brand name. Earlier products suffered from cracks due to UV radiation, the current production is much more stable.

Cutting acrylic requires some skill because the friction quickly heats up the saw. It must be done at very low speed or faster if a helper adds plenty of water during cutting.
For straight lines I prefer using a modified box cutter like a glass cutter and break the material on the edge of a table.