Metal vs Plastic

[knightflight]

I've searched awhile and haven't found any answer to explain this....why are most if not all roof vents/ refrigerator bases and covers made from plastic, I know its easy and cheap but is there another reason why I shouldn't replace my sewer stack vent with a metal one or even replace my fridge base and vent with the metal version that is sold at close to the same price I might add, or doing the math I replace once instead of multiple times, I'm in the Texas heat and sun damage is the worst enemy it seems more manufacturers would be making a metal version but then again I might have just answered my own question, they can't sell something if you don't need to replace it. Anyway what's everyone else thinking on this. I think I'm replacing mine with metal this go around unless there is a compelling reason not to use metal ones I'm unaware of.
thanks CJayco

[barmcd]

I'd use a metal vent over plastic if it was available. My fifth wheel wasn't stored covered and I replaced all the vents on top every 3-4 years because the sun just dried them out.

[bobmac]

I for one, wouldn't want metal roof vent covers. These are attached to the coach roof - which is fiberglass in my case - and if it were hit by a low branch would likely take part of the roof with it. While the roof is fiberglass, it does not really have any structural strength unlike fiberglass used on boats.
While I generally agree that metal in appliances is preferable to plastic, I would think that it would add extra weight and cost. Appliances are really commodities today and I think most consumers would not attribute incremental value to metal if other brands used plastic and would likely buy the cheaper product. Newer appliances are largely disposable and not like older ones that could be economically repaired. My 2 cents worth!

[knightflight]

Thanks for the input guys I found metal for both vents I needed and I'm living on the edge of the curb here and going with metal, after all using the famous last words I haven't hit the roof yet not tall enough trees in Texas.

[Mr_D]

I'd think the metal would be noisier in the rain, which we get a lot of where we live.

[TQ60]

Metal is lots more expensive than cast plastic.

Plastic can have a better fit as it can be stiffer than sheet metal.

Lighter weight and does not rust.

Aluminum would be metal of choice if metal is preferred.