sealing MDF

[bletort]

I'm building a MDF speakerbox to put in my console for a 10" sub as well as an amp/battery charger rack since my console is very small and I have nowhere to mount them. The box is done and I'm wondering if I should fiberglass or bondo the box or if there is another epoxy like compound which could be used, sanded & painted to seal the box? Any other suggestions?

[LI32]

Nothing absorbs water as good as mdf. You will need to fiberglass it with both cloth and resin to keep it from falling apart.

[bletort]

That's what I was afraid. It should not ever get wet being mounted in the back of the console, however I do want to overbuild it. Standard polyester resin?

[yottyboy]

As the previous note says, best start over with at least exterior grade plywood. If you coat the ply with a layer of resin and glass cloth before you cut the panels, it makes life much easier as all you have to do is tape the joints with glass and resin. This way, the speaker box will live forever.

[reckless]

coat it with expoxy resin
if it ever sees water it will last
as long as you dont scratch the surface

[bletort]

reckless - 5/27/2008 6:43 AM

coat it with expoxy resin
if it ever sees water it will last
as long as you dont scratch the surface

Does epoxy require a filler? Or is it just similar to a gel-coat?

[Montauk Local]

Why not make it out of starboard, versatex, sintra or komacell and be done with it?

[bletort]

Thought about starboard, but no sealer bonds well to it. MDF would provide the best acoustics I believe. I enjoy projects like this anyhow.

[Montauk Local]

versatex or Azek is available at most lumberyards and pvc cement will bond it together. its paintable with solvent based paints too.

[LI32]

If I were building it, I would probably go with 1/4" lightweight MDF (for accoustic reasons) and coat the entire exterior with two coats of glass mat and polysester resin; then gelcoat or paint it using two part polyurathene.

[capt crunch]

Use West System or another epoxy, and thin it 10-20% with acetone before painting it on. The MDF should absorb it like a sponge. I don't think I'd bother with FG cloth.

[lifeisfun]

Get Extera ( weather resistant MDF)

[DogTired]

Never use MDF in wet locations. If you want a chipboard product used Advantec!! Awesome stuff!

[lifeisfun]

Once again Extera is MDF designed for exterior use you can soak it in water (not painted) and it will NOT expand or deteriorate.

[jenkinsph]

bletort, MDF is great for speaker cabinets and is a good cheap material. Extera may be a good alternative
but there are surely lots of other materials that will work very well, lots of the composite materials that offer
good resistance to flexing with controlled density can work well for this purpose. Kind of pricey but Lexan does
a good job and can be made waterproof. What you want to avoid is materials that do not glue well as these
have a tendency to vibrate and buzz. If you want to go cheap try the Extera and simply paint it, should be a
decent yet thrifty solution.


Steve