Chemical Laws 1 Madmikes' Law 0

Madmike2

Member
2005-04-24 11:55 pm
Toronto
Just got a call from my carpenter friend. "HI Mike, listen your boxes are big bloated bratwurst right now. I think i am telling you to not do that 'trick' with liquid rubber and epoxy right ? SO why you dont come down tommorow and we see about doing my way this time. And bring money for real wood."

Ill try to borrow a camera and see what bloated bratwurst MDF looks like.
 
Well the replacements are done now with all the stuff left over from the first two that i wrecked. GOing to try the flooring cement and garden rocks thing that one of the other members did.
 

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BassAwdyO said:
Dude, what kind of project is this? Some sort of outdoor subwoofer? I'm not certain what you're talking about.

???


One of the full range DIY'ers lined the inside of his cabinet walls with pebbles and glue for mass. It seems like a worthwhile try. Again i think i just assumed that everyone knew what i was talking about. Its a bad habit i have of forgetting i am not in a room with a group of people all talking about the same thing. Sorry.


EDIT ' and no, its part of my modular speaker system that i am building for my place. Bass ... Mid-Bass..... Mid-High. Build what i need as i need it or afford it.
 

Madmike2

Member
2005-04-24 11:55 pm
Toronto
Normally i wouldnt put ANYTHING on the interior except stuffing and then again not even that. I am from the pro side of things. Baltic birch and carpet with 2 to 4 18's and thats that. Just build it to support the weight of a car.

These enclosures are completely sealed and unpowered so if i ruin them experimenting "oh well" 1/4 inch steal is going to be alot more expensive that a 4 dollar bag of garden pebbles and an 8 dollar tub of flooring glue. Thanks for the idea though.
 
if you do pepples, i gaurentee you that some of them will come loose and you will have rocks rolling around inside your cabinet. bad idea.

there are many ways of making it heavier. i have seen asphalt roofing tiles or whatever, actual asphalt, etc... even super heavy duty bracing would be decent. or, try epoxies or resins. those are pretty dense and heavy.

but i would stick away from gluing rocks to the inside. sounds like a craft project and doesnt seem like it would last.
 
you can try pouring concrete on the inside of the enclosure! simply do one side at a time. Pour to the thickness desired. I'd suggest putting some screws into the wood that the concrete would surround and possibly small steel mesh? To enhance strength. But it kinda makes box calculations fun and it takes a long time! you must be very exact with the concrete

Maybe I will try this on my own sometime....
 
or, if doing concrete, build a box inside a box ;)

leave the top of the outside box open and fill it, steel mesh wouldnt be needed but it would be a good idea. 3/4-1" thickness would add a lot of weight...an enclsore of any size would easily be over 100lbs...also before putting cement on MDF, coat with a few layres of fiberglass resin thined out with acetone 4:1...4 parts resin/hardener (mixed to proper porportions) and 1 part acetone, the acetone simply thins it out to make painting easier, this will keep the MDF from soaking up a **** load of water out of the concrete.
 
I wish I could find the link for the design I'm talking about. An entry on a car audio site competition used a rubber ball with approximate volume of 1ft^3 in an enormous block of concrete. The ball was attached to "pucks" of appropriate size to form a baffle, and the mould was filled until the ball would sit with the pucks flush with the top. The remainder of the mould was then filled and the surface worked so the pucks were completely integrated. Once the concrete was set, some cutting took place to access the ball which was punctured and removed. The resulting enclosure, with perfect spherical chamber, weighed several hundred pounds thus succumbing to gravity while being loaded into a pickup by the builder and ONE friend. This seems to be intentional overkill, but some construction ideas could be gained. If I can track down the original writeup, I will post a link for some entertaining reading and viewing.