# spray foam to reduce box volume



## slim j (Nov 30, 2005)

I built a box that is a hair over .5 cf too big. Can I use spray foam to reduce the internal volume or do I just have to build a new box?


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## JoeHemi57 (Mar 28, 2006)

use some 2x4 pieces of wood, i wouldn't use spray foam.


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## GlasSman (Nov 14, 2006)

He could use blocks of floral foam. You could seal them by painting them.


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## invecs (Jul 30, 2005)

Spray foam will make it sound as if it is in a larger box...and painting them just to seal the pores is just too troublesome. I suggest using some styrofoam instead.


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## T3mpest (Dec 25, 2005)

slim j said:


> I built a box that is a hair over .5 cf too big. Can I use spray foam to reduce the internal volume or do I just have to build a new box?


put anything in the box that is .5cf. I get a piece of wood and measure it out.


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## -db (Mar 14, 2007)

Or cut 3 pieces of mdf and box off a corner.

When he says spray foam, I am thinking Great Stuff. How would that make the speaker act as if it's in a larger box? The foam gets hard and forms a crust that would seal it.


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## thormx (Sep 16, 2007)

if by spray foam you mean expanding foam (like great stuff), then i think it would be fine. just seal it off with some resin, maybe even a layer of glass...


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## ErinH (Feb 14, 2007)

airsoft pellets will work just as well. We use these in pressure tanks at work. 

Might sound funny in the box, though.


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## Infinity (Jun 28, 2005)

bikinpunk said:


> airsoft pellets will work just as well. We use these in pressure tanks at work.
> 
> Might sound funny in the box, though.


Might be neat in the pole vent, too


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## khail19 (Oct 27, 2006)

Infinity said:


> Might be neat in the pole vent, too


Yeah, I don't think pellets are a good idea. 

Expanding foam would work fine if you had a way of accurately measuring 0.5 cu ft of foam. I think a couple of blocks of wood would be easier to measure.


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## GlasSman (Nov 14, 2006)

invecs said:


> Spray foam will make it sound as if it is in a larger box...and painting them just to seal the pores is just too troublesome. I suggest using some styrofoam instead.



When I mentioned the floral foam thats along the same lines. It's just green instead of white.

Just make a box out of wood thats .5 cu ft....... or 2 are are .25 cu ft and use the spray foam to fill the box or boxes. 

Take the box apart and you have your now lightweight space grubbing block or blocks.


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## T3mpest (Dec 25, 2005)

GlasSman said:


> When I mentioned the floral foam thats along the same lines. It's just green instead of white.
> 
> Just make a box out of wood thats .5 cu ft....... or 2 are are .25 cu ft and use the spray foam to fill the box or boxes.
> 
> Take the box apart and you have your now lightweight space grubbing block or blocks.


if you go the trouble of building a .5 cu ft box, just put it into the bigger box, basically the same thing, lol


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## invecs (Jul 30, 2005)

GlasSman said:


> When I mentioned the floral foam thats along the same lines. It's just green instead of white.
> 
> Just make a box out of wood thats .5 cu ft....... or 2 are are .25 cu ft and use the spray foam to fill the box or boxes.
> 
> Take the box apart and you have your now lightweight space grubbing block or blocks.


Styro is easier to work with...all you need is a cutter and some glue...that's it. It's a lightweight option vs using wood.


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## kskywr (Oct 2, 2006)

What woofer are you using and do you have an EQ? If the oversized box is giving you a bloated low end, you could just EQ it out.


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## Oliver (Jun 25, 2007)

slim_j,
Is this a sealed or ported box? what is the displacement of your sub?


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## drake78 (May 27, 2007)

I tape up a phone book and threw some wood blocks. Pretty much anthing solid would work. Just get the volume calculations right for each item.


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## slim j (Nov 30, 2005)

It is a sealed box for the FI Q D1.

Right now it is 2 cf. and the largest reccomended is 1.5.

If I knew the appropriate port length, could I port it? When I try to do it, the best I can do is 1.8cf with 18.5" of port length using a 4" aero.


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