Jump to content

Welcome to TheMalibuCrew!

As a guest, you are welcome to poke around and view the majority of the content that we have to offer, but in order to post, search, contact members, and get full use out of the website you will need to Register for an Account. It's free and it's easy, so don't hesitate to join the TheMalibuCrew Family today!

Securing sub box


racer808

Recommended Posts

How do you guys secure your sub boxes? I thought I could just screw right into the floor but I thought the bass would just rattle the screws loose & destroy the threads in the floor? Thought about drilling thread inserts into the floor & gluing those then bolt thru the box?

I am struggling: Found a 25" box which is the exact width of the kick panel, but I am not sure I could wedge it back there or not? Found a smaller box but it requires more work moving the heater &, kick panel further back? If I mount the heater to the sub box, it will be a b**** to work with putting in or taking out. Don't want to build a box, already got too much work redoing my amp racks & installing the new sub amp. Anyone? Bueller?

Link to comment

Not sure I have the best answer for you, but from similar work lately (amp rack) I certainly feel your pain about not wanting to take on another project and build your own sub box!

Driving some screws into the floor to secure your sub box definitely may be sufficient. I assume your kick panel is like mine with no sub box on the back and it's held in-place like that. I doubt they changed that on the newer boats that have a sub box on the back of the kick panel but I could be mistaken. Either way, I think your idea to use some threaded inserts is a good idea that should work well.

It sounds like you're looking at off-the-shelf sub boxes. Unless they're already waterproofed, I'm sure most people will suggest you at least pull off the carpet (if it has it) and coat the box with something like Epoxy Resin or truck bed liner to waterproof it. The MDF that sub boxes are usually made of doesn't hold up well to moisture.

And on that note, I've seen many suggestions to get your sub box up off the floor to prevent it from trapping moisture between the box and the carpet (mildew is a concern there as well). After reading some posts I went out looking for some composite decking scraps or something to use as stand-offs between the sub box and floor. Home Depot gave me samples for free (the ones you take home to compare colors) that are about 4"x4"x1" (or maybe 3/4" thick). They seem to work well and you can get by with just 1 or 2 samples and cut them down. Good luck!!!

Link to comment

I'd suggest getting some HDPE at least 1/2" thick or similar from a local plastics or marine store. Cut that in strips that the box will sit on to space it off the floor, secure those and countersink the screws through them. Then fasten through your box to those (carefull not to hit a screw in the HDPE) before you insert your sub in the box. If done right it will be very secure.

Another way I've done it is in an effort to avoid heater hoses and such I built a platform about 2" off the floor with 3/4" birch plywood then secured the box to that, obviously that isn't going anywhere either.

Link to comment

How do you guys secure your sub boxes? I thought I could just screw right into the floor but I thought the bass would just rattle the screws loose & destroy the threads in the floor? Thought about drilling thread inserts into the floor & gluing those then bolt thru the box?

I am struggling: Found a 25" box which is the exact width of the kick panel, but I am not sure I could wedge it back there or not? Found a smaller box but it requires more work moving the heater &, kick panel further back? If I mount the heater to the sub box, it will be a b**** to work with putting in or taking out. Don't want to build a box, already got too much work redoing my amp racks & installing the new sub amp. Anyone? Bueller?

You can definitely screw into the sole of the boat. No more than 0.75" penetration. Not within three inches of the sole to hull joining. Pre-drill first. And run a sacrifical screw in first to pre-tap so the screws thread in easier for the final installation.

You must use a polymer riser so that moisture isn't trapped under the enclosure causing mildew and mold, and so moisture cannot be wicked into the enclosure. You must have drainage and evaporation.

Off-the-shelf enclosures are generally made from cheap China MDF, and a 3-piece folding process. They will not last.

David

Link to comment

You can definitely screw into the sole of the boat. No more than 0.75" penetration. Not within three inches of the sole to hull joining. Pre-drill first. And run a sacrifical screw in first to pre-tap so the screws thread in easier for the final installation.

You must use a polymer riser so that moisture isn't trapped under the enclosure causing mildew and mold, and so moisture cannot be wicked into the enclosure. You must have drainage and evaporation.

Off-the-shelf enclosures are generally made from cheap China MDF, and a 3-piece folding process. They will not last.

David

If I built one, or had one made, wouldn't it just be cheap MDF that is coated?

Link to comment

That's what I'm asking.

The answer is nothing is wrong with MDF that is coated in Epoxy Resin or a Bed Liner Material. It need to be elevated off the floor of the boat so that water can not get trapped under the box and absorbed into the MDF.

Also would recommended 3/4" MDF

Link to comment

And as far as securing the box I would do to Home Depot or Lowes and get some 2" x 2" aluminum angle bracket and or bigger if you can find it. Cut some pieces that are two inches long and file down corners. Make three holes in each piece and screw on side to the box (screws dont want to poke thru the inside of the box and screw the other side to the floor.

Link to comment

How long will a box hold up if I don't coat it?

Depends how wet it gets. If you can keep it dry you could potentially get a few seasons out of it. That would also depend how your winter storage goes, etc..

Link to comment

Racer,

I have had an off the shelf non coated box in my old Bu for 5+ years with no issues at all. With that said it has never gotten wet and is garage stored everyday of the year.

We are in Colorado where it is pretty dry with little to zero humidity most of the year. If you are buying or building a new box just rip the carpet off and coat it if you store your boat outside or think that it might get wet at some point.

Link to comment

How long will a box hold up if I don't coat it?

Not for long. MDF is like pressed paper and will absorb the humidity without getting wet directly. With wet carpet or a little water in the bilge, a covered boat in the sun is the most humid environment possible. MDF is also micro-porous which means air will travel through it (especially end to end), although with resistance and slowly.

Polyester resin works. Epoxy resin is a bit better. Polyurethane bed liner when professionally applied, very thick, works well. Even a cheap polyester resin will shed water as long as the water can drain and evaporate. The coating offers little protection if the box is resting directly on carpet. The biggest part is the box building execution. You cannot protect a poorly built box no matter what the coating.

There are also forms of MDF and plywoods that are constructed with solvent-based adhesives rather than water-based. They hold up much better but still should be coated.

Many people are running carpet (trunk liner) clad off-the-shelf automotive boxes in boats. The box seams often fail in the first year but the carpet covering conceals the fact for years.

David

Link to comment
  • 2 months later...

Living in WA, moisture is always a factor. I would never put an MDF box without proper resin / coating as it simply would not last more than a couple years. Fiberglass is the way to go IMO, and isn't really that hard to work with. Here is a couple pics of my recent sub upgrade to my VLX.

Added and rewired amp rack to accommodate additional amp

IMG_1433_zpsc9b958ec.jpg

kick panel prior to install

IMG_1448_zpsb5f60b9a.jpg

Sub box made out of MDF, then covered inside and out with fiberglas matt / resin

IMG_1453_zpsc18bd394.jpg

Sanded smooth before paint

IMG_1455_zps1cf66f2c.jpg

After Paint

IMG_1461_zps6eec6102.jpg

I masked the existing panel, and made a template of the sub box for speaker cutout

IMG_1463_zps58f28dcb.jpg

Then, epoxy the face of the sub box and clamp to the kick panel

IMG_1467_zps9ddbe8f4.jpg

IMG_1469_zpsd87f3232.jpg

Having the sub 'hang' from the kick panel wouldn't work long term, and it needed support from underneath. So, I pieced some of the scraps from the hole cut into the existing supports, and then fiberglassed them over to bond them together. Also added fiberglass between all seams of the box and kick panel.

IMG_1475_zps54d523ea.jpg

IMG_1478_zpscdec39b2.jpg

IMG_1480_zps685c183e.jpg

IMG_1481_zpsbf673a33.jpg

repainted, and ready for install

IMG_1485_zps93bd65ec.jpg

IMG_1494_zpsc7be9369.jpg

Finished Product

IMG_1497_zps65f5a32a.jpg

It may take a little bit more work to make a custom sub box, but the results are undeniable. I only went with a 10", as I typically only listen to Raegae and it hits hard because built with a solid box. My 2 C's.

  • Like 2
Link to comment

Very nice. I ended up making a square box resin coated and carpeted. Looks good sounds good. Redid my amp rack coated but I just painted it black and since the carpet in the observers cabin was so dried it out it just fell off so I painted the wall to the right black made stand offs and mounted my rack there. I will take some pics when I get it perfect. A speaker wire, one power to the amp wire was just a tad short so its not as perfect as I want. My clips for the wires over the top of the observers cabin came off so I need to fashion more and clean it up, then I will post some pics when I get it right

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...