703/Rockwool vs. other Owens Corning insulation

[jelstro]

I came across a few threads where people had similar issues to this, but didn't really find a definitive enough answer, so hopefully this doesn't seem redundant.

At work we just finished building some new rooms and have quite a bit of left over insulation that we've already payed for:

I believe it's this stuff here.


My question, if you haven't already figured it out, is could we still build useful bass traps by molding as much of our leftover insulation into 2'X4' frames as we can tightly fit?

How much is gained/lost by using this stuff vs. boards of 703?

It'd be much more convenient and cheaper if this stuff would work because when comparing cost it looks like the prices people are quoting for 703 come to about $8 per panel whereas this stuff, even after we run out, would cost about $3.50 per panel and is much easier to get a hold of.

[xaMdaM]

Home Repo sez... "Not Available"... So I'll assume you linked to standard "pink fluffy" insulation or similar... If not, this might not apply...

Regular pink fluffy is about 0.8 lb/sq/ft. 703 is 3.0 lb/sq/ft.

So, to have the equivalent of 703, you'ld need to find a way to compress the pink fluffy stuff by a factor of 4.

4 x $3.50= $14.00 sq/ft in pink fluffy vs $8.00 sq/ft for 703 (which $8 sq/ft for 703 is waaaay too much)

Try SPI for 703 pricing.

[edit]
Just had an afterthought... yeah, I know... scary, huh???

If you make a superchunk style corner trap, you'ld play hell getting the pink fluffy compressed.

But, if you make a 703 cross corner trap, you can back fill the trap with the pink fluffy to add a bit more of a wider "Q" to the trap... thereby extending the absorption upwards in center frequency.

[jelstro]

Originally Posted by xaMdaM

4 x $3.50= $14.00 sq/ft in pink fluffy vs $8.00 sq/ft for 703 (which $8 sq/ft for 703 is waaaay too much)

This was cost per 2X4 panel, not sq/ft, but still, this is a huge help.

I thought the "pink fluffy", which is indeed what we have, was a little bit thicker than that. But I'm still wondering... what would really be lost by packing in a lot of the pink as opposed to single board of 703?

Would it basically be wasted space or would it still be a lot better than going completely untreated?

[xaMdaM]

Originally Posted by jelstro

This was cost per 2X4 panel, not sq/ft, but still, this is a huge help.

I thought the "pink fluffy", which is indeed what we have, was a little bit thicker than that. But I'm still wondering... what would really be lost by packing in a lot of the pink as opposed to single board of 703?

Would it basically be wasted space or would it still be a lot better than going completely untreated?

My bad... I didn't read close enough on the price... but still, the numbers are essentailly the same...

The thickness isn't as important as the mass.

Pink has about 1/4 of the mass of 703. So, until the mass of the pink stuff approches the mass of the 703, you won't have anywhere near the amount of energy absorption that you do from the density of the 703.

I saw the numbers a LOOOONG time ago, so, I'm not sure they're quite right... but IIRC, two layers of R-13, packed as tight as 1", was less than 1/4 as effective at all frequencies of 2" of 703. 3 layers of R13 packed to a density of 1.5" was still only half that of 703. Even when 4 layers of 703 were packed to 2", it was still something like 80% or 85%.

Seems like someone found fault with numbers because it was really two 1" compactions... but regardless... it wasn't nearly as effective as a single sheet of 2"- 703.

But to finally get to your question, IMHO, yes, something is better than nothing.

What many folks have actually done, is to stack their still factory taped rolls of of insulation in the corners, and put frames up to hide them.

Again, the cross corner 703 panel, with the back of the corner filled with pink fluffy was found to be a wider "Q" and therefore, a "better" broadband absorber.

[jelstro]

Originally Posted by xaMdaM

What many folks have actually done, is to stack their still factory taped rolls of of insulation in the corners, and put frames up to hide them.

Again, the cross corner 703 panel, with the back of the corner filled with pink fluffy was found to be a wider "Q" and therefore, a "better" broadband absorber.

Wow! you've been such a great help. I like the idea of using the prepackaged ones because I think we still have 4 pretty hefty rolls still packaged which could at least work for the corners of one of our live rooms. Maybe we'll give that a try first and then start pricing out the rest of the from the ground up with 703 type material.

Thanks again!