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dan5505
01-01-2008, 10:37 PM
has anyone ever used it. a buddy of mine has access to a bunch of 1/2'' stuff. any ideas how it will perform compared to mdf.

mrbomb
01-01-2008, 10:40 PM
sounds like a pretty cool idea, i say give it a try if you say you have access to a bunch and let us know

mapolley07
01-01-2008, 10:45 PM
i have no idea....polypropylene tends to build up quite a bit of static though (think plastic grocery bags and the slides at Chuck-E-Cheese). I don't know whether that would make a big electrical impact on the sub or not

mrbomb
01-01-2008, 10:47 PM
true on the static but if its screwed to the car it would be grounded so it should cancel the charge

GSRswapandslow
01-01-2008, 10:48 PM
it'll flex i'd assume.....i mean...try it, obvioulsy, and if it doesn't work....simple as that.

helotaxi
01-01-2008, 10:50 PM
It will flex like hell.

dan5505
01-01-2008, 10:52 PM
i have no idea....polypropylene tends to build up quite a bit of static though (think plastic grocery bags and the slides at Chuck-E-Cheese). I don't know whether that would make a big electrical impact on the sub or not

actually, grocery bags are made of low density polyethylene i believe. the only problem i can see happening with a polymer like polypropylene is that it has different elastic modulus than woods. the problem with polymers is that, depending on slight variations in chemistry, the mechanical properties like elastic modulus change. for a sub box, my guess is a high elastic modulus would be best, so, i guess it all depends how stiff this polypropylene is. i haven't seen it yet.

mapolley07
01-01-2008, 10:53 PM
crazy flex+static buildup=bad box material imo

i would maybe try it in combination with MDF, or use it for spacers in doors or something. i don't thing that polypropylene would make a good box on its own

dan5505
01-01-2008, 10:54 PM
the whole idea of using polypropylene was to make an weather prof box and put it in a jeep.

Kil4Thril
01-01-2008, 10:54 PM
Large, straight panels flex like a mother****er. I tried it with 7/8" HDPE (think really thick cutting boards). If you could mold it so there aren't any straight panels, it works fine. Kinda like the Thunderforms and such. The plastic does work fantastic for mounting rings in doors since it can't soak water.

dan5505
01-01-2008, 10:55 PM
maybe if it was braced to hell, the flexing would be minimized.

dan5505
01-01-2008, 11:02 PM
or, i suppose, there are better ways to weatherproof a box made of mdf

miker
01-01-2008, 11:16 PM
What is polypropylene??

97gmcsierra
01-01-2008, 11:32 PM
My subs have polypropylene cones:fyi:..... They dont flex...:p:

I wouldn't think big sheets of it would be good without bracing.



What is polypropylene??

http://en.wikipedia.org/wiki/Polypropylene

miker
01-01-2008, 11:35 PM
What about outdoor paint?

97gmcsierra
01-01-2008, 11:40 PM
How about that rubberized undercoating nice and thick on MDF? Wouldn't you think it to be waterproof since it is used to spray under vehicles and stuff? Or some kind of bed liner?

Immacomputer
01-01-2008, 11:47 PM
or, i suppose, there are better ways to weatherproof a box made of mdf

Add a couple coats of polyurethane with the end grain of wood sealed and you will be fine.

helotaxi
01-02-2008, 12:47 AM
My subs have polypropylene cones:fyi:..... They dont flex...:p:

The cone shape is what gives them rigidity. Lots of subs have paper cones, doesn't make it suitable for sub enclosures.

For a waterproof box, make it out of MDF and cover it in fiberglass resin. Downfire the sub to keep it dry.

97gmcsierra
01-03-2008, 01:23 AM
The cone shape is what gives them rigidity. Lots of subs have paper cones, doesn't make it suitable for sub enclosures.

I know. just messin. :D

He could get a marine sub that is somewhat "weatherproof".

ramos
01-03-2008, 08:58 AM
The cone shape is what gives them rigidity. Lots of subs have paper cones, doesn't make it suitable for sub enclosures.

For a waterproof box, make it out of MDF and cover it in fiberglass resin. Downfire the sub to keep it dry.

winner winner chicken dinner , easiest way I know to do it. I also do this with every baffle I put in a car door. :)

luvinthebass
01-03-2008, 09:22 AM
The polypropylene box would have to be hella thick then.

iamamp3pimp
01-03-2008, 01:05 PM
the whole idea of using polypropylene was to make an weather prof box and put it in a jeep.

fiberglass resin will do that for you.

iamamp3pimp
01-03-2008, 01:06 PM
The cone shape is what gives them rigidity. Lots of subs have paper cones, doesn't make it suitable for sub enclosures.

For a waterproof box, make it out of MDF and cover it in fiberglass resin. Downfire the sub to keep it dry.

or 6th order...

Chevyaudio
01-03-2008, 01:10 PM
Spray-on bedliner also works very well if applied correctly (and im not talking about the rattle can you buy from walmart)

Immacomputer
01-03-2008, 01:40 PM
winner winner chicken dinner , easiest way I know to do it. I also do this with every baffle I put in a car door. :)

Polyurethane is cheaper and easier to apply!

bumpin buick
01-03-2008, 01:55 PM
Im currently at work, at a company called Alcan Packaging, we work primarily with polymers. I am cheimical engineer intern here. I asked one of the engineers thats been here for a long time, They said a polypropylene composite should work great. I think he's referring to like the stuff they use on decks now, its expensive but very sturdy and easy to work with.

Immacomputer
01-03-2008, 02:04 PM
My uncle builds fire truck tanks out of polypropylene and I've seen some enclosures that some of the employees have made from scratch and they're not very sturdy at all. They can easily flex by pushing on them. I also have a few storage containers around here and they're not sturdy either. Anybody who says they would work great probably doesn't understand enclosure construction or design very well.

dcole18
01-03-2008, 02:27 PM
My uncle builds fire truck tanks out of polypropylene and I've seen some enclosures that some of the employees have made from scratch and they're not very sturdy at all. They can easily flex by pushing on them. I also have a few storage containers around here and they're not sturdy either. Anybody who says they would work great probably doesn't understand enclosure construction or design very well.

he's talking about the composites, that look like wood... they make decks out of the stuff..

if you could get a sheet of the stuff i dont see why that wouldnt work

azbass
01-03-2008, 02:32 PM
the whole idea of using polypropylene was to make an weather prof box and put it in a jeep.

a normal mdf box covered in bed liner. done.

bumpin buick
01-03-2008, 02:36 PM
he's talking about the composites, that look like wood... they make decks out of the stuff..

if you could get a sheet of the stuff i dont see why that wouldnt work

The only problem is Ive never seen them sold in sheets, they always sell them in planks like 1"x4" or something. I have no reason to doubt a composite would work well and there much more forgiving when you over tighten they dont crack instantly.

dcole18
01-03-2008, 02:41 PM
The only problem is Ive never seen them sold in sheets, they always sell them in planks like 1"x4" or something. I have no reason to doubt a composite would work well and there much more forgiving when you over tighten they dont crack instantly.

thats what i was thinking... idk where you could find it in a sheet

bumpin buick
01-03-2008, 02:43 PM
I can get thin polypropylene sheets here, i can make them but I think I would mess the machine if I made anything over 1/16 of an inch

ramos
01-03-2008, 02:54 PM
Polyurethane is cheaper and easier to apply!


brush one on just like the other . :)

Immacomputer
01-03-2008, 02:55 PM
he's talking about the composites, that look like wood... they make decks out of the stuff..

if you could get a sheet of the stuff i dont see why that wouldnt work

I know exactly what he's talking about and it's the same stuff that make tanks out of. It's strong but it will flex. The stuff I have is 1/2" and the stuff I saw them make the enclosures out of were 1" thick (two 1/2" layers welded together). It's just not a good idea.