Why not MDF?

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#221
I'd always been interested in producing a pair of cabinets from recycled HDPE.

At college, some 15 years ago, a girl was using this stuff to make furniture and then I'd wanted to have a go at some speaker cabinets but never had the time.

It is an eclectic colour mix for sure, but can be machined easily heat or epoxy bonded and available in sheets of varying thickness. it's also very environmentally friendly !!!

Would make an interesting project for sure.

HDPE supliers UK
 

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#223
Yes it would require a fair bit of R & D.

I think they would look cute as a pair of bookshelves with some Seas or Jordan full rangers in them 🙂 or maybe a slim pair of floor standers.

Maybe when my daughter grows up enough to appreciate hi fi I could make a pair, nice and bright and cheery !!
 
#228
That depends how much time and effort you put into laminating the panels 🙂 It certainly wouldn't be difficult to laminate a bunch of panels at once and place heavy objects on top of them while they dry. Then when you're ready to use them you can square up the sides and work with it like you would a normal panel.

I did mention working on a curved enclosure. That's one case where you can use thin sheets of material and build up curved layers for a nice solid lamination.

planet10 said:
http://www.hsi-luidsprekers.nl/Kastmaterialenonderzoek.htm
Click to expand...

Anyone know what materials this guy was using in his tests (besides MDF of course)?

Edit:

spaanderplaat is particle board

multiplex is probably plywood
 
#229
spaanderplaat is particle board

multiplex is probably plywood

Yes, Meranti is of course Mer... and berken is birch.
Beton is concrete or something similar like housefix.

Do not hang me since my Dutch suxs, but "versteviging" means bracing.
I don't understand Dutch when spoken, it's "easier" to read!

Cheers,
Peter
 
#230
Why make like difficult if you want a laminated material? 5 years ago, Terry Cain noted this:

"There exists a product that is the best of both worlds. It's called "Classic Core" and is made for the upscale cabinet and office furniture market. Like seafood and restaraunts the best goes to established commercial customers. 3/4" material is available in all domestic veneers and some imports. 3/4" has two 1/8" mdf substrate layers mainly for blemish free face veneers and also perfect thickness control. You guys never mention my main PEEEEEVE with most plywood and that is it's undersized ie. 3/4" is really 11/16ths and so on GGRRRRRRRRRRR! Classic core is probably available wherever BB is too. I prefer 3/4" popple (poplar) core hardwood plywood with 1/2" or 1/4" masonite or industrial particle board liner pre glued/sized prior to machining. TC"

If you can't get it, then I reckon birch ply is still the best bet. It's far lighter & stiffer than MDF etc., which would need to be rather more than 1in thick to match the rigidity of 3/4in of birch ply. Along with all its other issues. BB ply wasn't / isn't the material of choice for pro-audio bass-horns for no good reason.
 
#235
Anything that smells like MDF when it is being routed or sawn cannot be good for your health.

However, when I worked as an accountant for a plywood manufacturer twenty years ago all ply veneer was treated with both a fungicide (tri-butanyl tin, I think) and an insecticide. Additionally, I would not put any of the glues on my morning toast. They smelled worse than MDF.

Finally, does anyone know if 25mm, or even 32mm, MDF is accoustically inferior to 15 or 18mm plywood? It is usually significantly cheaper.

Graeme
 
#236
1- zero measurement
2- Room measurement
3- 10mm chipboard
4- 18mm chipboard
5- 18mm MDF
6- 18mm meranti plywood
7- 18mm birch plywood
8- 18mm MDF with bracing supported over 40 cm
9- 18mm birch plywood with bracing supported over 40 cm
10- sandwich of 18mm chipboard & 18mm birch plywood
11- sandwich of 18mm chipboard & 18 MDF
12- sandwich of 18mm chipboard & 18mm birch plywood & foam
13- 18 mm MDF strengtenth with 20mm concrete without bracing
14- 18 mm MDF strengtenth with 20mm concrete with bracing
 
#237
Scottmoose said:
Along with all its other issues. BB ply wasn't / isn't the material of choice for pro-audio bass-horns for no good reason.
Click to expand...

Sorry to disagree, but ply is used because it is lighter and more robust than MDF in road use. Pro designers would earnestly agree to your face, then laugh out loud about hifi superstitions in the pub that night if you suggested they did it for sound quality. 🙂
 
#239
planet10 said:
If you want to do flat-sheet multiply properly it is handy to have a 10-ton press available.
Click to expand...

MJL21193 said:
What if you only have 8 Tons?
Click to expand...
Hi,
with air pressure to hand, an 8foot by 4foot sheet will have over 30tons of force if vacuum bagged.
If you only need 10tons then one third of a bar vacuum gives that force.
Doesn't take much of a vacuum pump to suck a bag down to 10psi absolute.
 
#240
AndrewT said:


Hi,
with air pressure to hand, an 8foot by 4foot sheet will have over 30tons of force if vacuum bagged.
If you only need 10tons then one third of a bar vacuum gives that force.
Doesn't take much of a vacuum pump to suck a bag down to 10psi absolute.
Click to expand...

Hi Andrew,
You changed my quote, it said TOMS, not tons (a poke at Dave's mistake that he later fixed).
No matter.

I was on the brink of building a simple bypass pump/reservoir for vacuum bag use, but changed my mind. I would not use it enough to justify its existence.
I use clamps and various ingenious jigs to laminate material, and unless you're looking for absolute uniformity of thickness, that's fine.
I've also used weights as clamps as Brian suggests. See the attached pic. the paint cans hanging from the ends of the board is my favourite.
 

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