Anti-Vibration Leveling Mounts

dtess · Post by **dtess** » Tue Nov 18, 2003 7:57 am

Found this site, thought it might be interesting to some.

http://www.sorbothane.com/PDF/StandardProduct.pdf

Steve, do you think I could use these to float my floor and solve the leveling issue?

Thanks,
Dave

knightfly · Post by **knightfly** » Tue Nov 18, 2003 8:46 am

Sure, if you want to put that plasma screen even further into the future - did you note their pricing? Finding a source of 1/2" neoprene to cut into pucks (and using shims above them as needed) would be a lot cheaper. Also, (although this is true no matter HOW you do it) your floor loading will need to be addressed before you decide on ANY material, if you want the best performance out of your chosen materials.

Did you note this statement in their PDF? "Expect a 20 to
30% deflection when statically loaded. Underloading results in poor isolation." -

This is part of what I was trying to cover in Aaron's "sticky" floor thread... I had read at least 15% deflection somewhere else, but upping that to 20-30 % means even more care when calculating the total weight of the room with gear. It's hard to say just how many DIY floated floors are doing any good at all. For one thing, how do you compare, since the floor wasn't tested WITHOUT floating, only WITH... Steve

dtess · Post by **dtess** » Tue Nov 18, 2003 9:15 am

Yeah, My father-in-law has been looking for a more elegant solution but that usually equals money! I started calculating loads I'll post on the other thread.

Thanks,
Dave

knightfly · Post by **knightfly** » Tue Nov 18, 2003 1:03 pm

Max span for 2x4, 2 & better, on 16" centers for floor joists with 40/20 loading is right at 6'0", just over 5'0" for 24" centers - so 24" centers would cost less for "levelers" - it would take 28 of them at about $16 a pop to do a 12 x 15 floor on 2x4's, so just the levelers would cost about $450 - elegance ain't cheap... You wanna get fancy, just buy some heavy walled angle, cut it in 3" long pieces, drill it for mounting to a joist, drill another hole in the other face (90 degrees) tack weld a 3/8" nut to the UNDER side, screw in a 3/8" x whatever length capscrew (from underneath), slot the non-head end of the capscrew with either a hacksaw or a dremel tool, and voila - DIY levelers (more expensive if you don't already have a dremel/hacksaw and a welder) Check it out...

dtess · Post by **dtess** » Thu Nov 20, 2003 3:30 pm

You da' man

That's a great idea. One question, is there enough surface area on the bolt head not to cause problems? O.K. I lied, more questions 40/20 loading? I started adding all the weight of the sheetrock in the drum room yikes! I'll probably have some questions to make sure my calculations are correct. Any links for material weights 2x4's, plywood, steel studs etc. ?

Thanks,
Dave

knightfly · Post by **knightfly** » Thu Nov 20, 2003 7:15 pm

The bolt head question has more than one possible answer. If you test using a bolt head in order to find the amount of weight per bolt head on your specific neoprene, then you have a constant to use when figuring your suspension, which should (new info here) run between 20% and maybe 60% deflection static, with all gear in the studio. This will allow for people, etc, to be added without exceeding about 80%, which would be getting close to the end of useful spring action with the neoprene.

If your tests show (I've NOT done this yet, so don't know ranges) that a bolt head is too small a surface, you can get thick 5/8" ID washers and tack weld them onto the heads of the bolts to spread out the contact area. This would give over 4 times the surface area and improve stability. Remember than in NO CASE can you CONTAIN the edges of your neoprene pucks, or their hardness goes through the roof...

40/20 loading refers to live/dead load for structures - you might actually want to go up to 60/20 ratings, which for 2x4's on 24" centers, assuming #2 and better fir, would be at 4' 5" maximum. You can get the rest of the methods of figuring this out on the "sticky" floating floor thread - it will entail a bit of "mad science", but at least you'll know where you stand (yeah, that was intentional, what can I say, I'm evil

)

As far as material weights, framing lumber can weigh up to double, maybe more, depending on moisture content. Don't believe me? Go to Home Depot and sort thru their 2x4's, you won't need a scale to know how large a difference there is. Steel studs - negligible compared to all the drywall and other stuff.

For the rest, Here's the gist of a document I keep adding to on my desktop -

Weight of Standard Drywall panels -

Regular Drywall Panels.

Panel Size /Weight /Lbs/SqFt /PCF /kG/M^3

4' x 8' x 3/8" = /45 lbs. /1.406 /42 /675
4' x 10' x 3/8" = /56 lbs. /1.406 /42 /675
4' x 12' x 3/8" = /67 lbs. /1.406 /42 /675
4' x 8' x 1/2" = /54 lbs. /1.6875 /42 /675
4' x 10' x 1/2" = /68 lbs. /1.6875 /42 /675
4' x 12' x 1/2" = /82 lbs. /1.6875 /42 /675
4' x 8' x 5/8" = /74 lbs. /2.3125 /42 /675
4' x 10' x 5/8" = /92 lbs. /2.3125 /42 /675
4' x 12' x 5/8" = /110 lbs. /2.3125 /42 /675

Firecode Core Panels

4' x 8' x 5/8" = /70 lbs. /2.1875 /39.73 /638.5
4' x 10' x 5/8" = /88 lbs. /2.1875 /39.73 /638.5
4' x 12' x 5/8" = /105 lbs. /2.1875 /39.73 /638.5

To convert lb/cu ft into kG/m^3, multiply by 16.04. To convert the other way, divide by 16.04.

Concrete weights approx. 3600 lbs/cu yd when cured, about 3900 pounds wet.
133 lbs/cu ft, or 2133 kG/M^3 -

MDF - approx. 68 pounds per ½” 4x8 sheet

Glass = approx. 3 times weight per unit thickness of sheet rock - roughly 135 lbs for 4x8 sheet of 3/8” glass.

The surface density of ¼” plywood is 0.74 lb/sq ft, or 23.68 pounds per 4’x8’ sheet.

The surface density of ½” plywood is 1.48 lb/sq ft, or 47.36 pounds per 4’x8’ sheet.

The surface density of ¾” plywood is 2.22 lb/sq ft, or 71.04 pounds per 4’x8’ sheet.

I know this comes out crappy in BBS coding, I may post a PDF of it later with some other useful stuff, in another "sticky"... Steve

knightfly · Post by **knightfly** » Thu Nov 20, 2003 7:23 pm

Oh, one other thing - if you DIY my floor levelers, be sure to keep the big bolt hole as close to the inside of the angle as possible and still mount the welded nut under it - closer than shown in the drawing.

Speaking of which, just posted an update of the leveler on the "sticky" floor thread...

Also, I'd mount every other one on OPPOSITE sides of joists, to even out stresses. forgot to mention those two things before... Steve[/b]