First try for a subwoofer enclosure

**MaXius** · 12-13-2009, 01:15 AM

Seeing as I don't have a spare tyre but I do have a ****ty subwoofer, i'm going to replace it.

So today I carved out some of the foam in my boot to make an area as big as I can.

I'll be putting a Memphis 12" Shallow sub in here, the enclosure should be just about right, 1 sq ft.

The top will be 3/4 inch MDF, and sub will be inset a little bit.

So being a complete n00b with this fiberglassing thing, how much do you think i'll need?

I was thinking maybe

5 square metres of chopped fiberglass matting
4kg polyester resin

I know you make the fibreglass 'bowl' first, with a couple of layers, let it dry and pop it out. Then you reinforce it with a few more layers, until it's all good.

Then cut the MDF to size ready to go on top. I guess i'll need to make sure I have room around the edges of where I want it to fit in the boot, considering i'll be putting extra width on when I glass the MDF in.

Unfortunately in Australia we don't have 'bondo', so I assume normal (or reinforced) body putty would be fine for putting around the inside of the sub to seal up / reinforce the edges of the MDF.

If i'm going off the track already, feel free to steer me in the right direction

**trader007** · 12-13-2009, 09:44 AM

no spare tire, yikes, but i would use something like construction subfloor adhesive inside the box to fill in the gaps. bondo is too stiff, even though it might work. PL400 is wicked stuff, you could actually use it to hold your box together without screws.

**MaXius** · 12-13-2009, 05:28 PM

They give you a can of goo and a compressor instead of a jack and spare tyre. But I have roadside assist anyway (AAA equiv).. i'm not that keen for DIY

**MaXius** · 12-13-2009, 05:47 PM

I don't think there's such as thing as PL400 in Australia either. Almighty Google was hard up for some relevant search results.

**MaXius** · 12-13-2009, 05:57 PM

Ok with the MDF top, should I get 3/4 inch MDF and use a router around the edge of the sub hole so it's inset flush, or should I get 2 thinner panels of MDF and join them together, with one hole slightly smaller than the other (so essentially the same thing)?

I guess i'll have to put some vertical bits of MDF in to brace the top slightly too.

**pulsarsimon** · 12-14-2009, 03:54 AM

if you glass in strategic pieces of MDF to screw the top down, that works well.

don't forget to put dowel or thick rope in the bottom to make the box strong - otherwise it flexes a lot with the sub-bass pressure.

**MaXius** · 12-14-2009, 05:27 AM

Thanks for the tips, I actually read a couple of posts today and saw the rope trick.
Also the base of my boot isnt flat, its got a star in it which will actually help with the strength ironically

**rdholtz** · 12-14-2009, 05:40 AM

Originally Posted by MaXius

Ok with the MDF top, should I get 3/4 inch MDF and use a router around the edge of the sub hole so it's inset flush, or should I get 2 thinner panels of MDF and join them together, with one hole slightly smaller than the other (so essentially the same thing)?

I guess i'll have to put some vertical bits of MDF in to brace the top slightly too.

You're better off to go with a single piece of MDF, but you could use two half-thickness parts if you glue them together over the entire joined area. That's the only way to get close to the strength of 3/4 inch material; screws alone wouldn't do it.

**MaXius** · 12-14-2009, 05:50 AM

Thickest I can find so far is 16mm.. have to ring around a bit more to find a place with thicker.

**jellymonster** · 12-14-2009, 07:46 AM

have you looked into making a aperiodic membrane sub box?
I see yo cutting foam trying to make space bigger, this could solve that. Just my thoughts =)