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Sweet Addiction
12-02-2004, 07:26 PM
I am going to take my back seat and build the whole thing into a sub enclosure. So what is the best material to use for this? Some one once told me partical board from any local hardware store, but that stuff does not look like quality material. There must be something else out there. Would appreciate any input.
Thanks Jared.

ROZ
12-03-2004, 12:59 AM
Your application requires 3/4" marine plywood...

1stepcloser
12-03-2004, 07:55 AM
Yeah, what he said.

Sweet Addiction
12-03-2004, 08:39 AM
Thanks for the input. The only really hard problem about Marine Plywood is I cannot find it here at all. So my other thought was build it out of the speaker material and lay resin all over it to seal it. Not sure if this is a good idea. Tying to get some different opinions.
Thanks Jared.

1stepcloser
12-03-2004, 09:40 AM
The standard material for enclosures is Medium Density Fiberboard reffered to as MDF. It's similar to particle board except the particles are much smaller and much more tightly compressed.
The problem with using it in a rear seat enclosure is strength. MDF has no real "grain" in the wood, and as you run the various fasteners into it (screws, staples, etc.) they have a tendency to crack and pull out.
Marine plywood, having a grain, is far superior in strength than a particle board type of wood.
Whichever you choose it needs to be coated in resin, and its a good idea to use some fiberglass cloth as well.
One more thing to consider, use stainless steel screws for everything.
As far as availability, I would think that a major lumber yard could special order the marine ply for you.

ROZ
12-03-2004, 11:26 AM
In your appliation MDF will be directly exposed to h2o. If you use it and glass it, you'd better make sure it's completely glassed. Even a pinhole exposed will suck up water like a sponge if given the chance..Don't use MDF. If marine ply isn't available, get std 3/4" ply and float a good coat of resin on it...

Havasu Hangin'
12-04-2004, 06:06 AM
The standard material for enclosures is Medium Density Fiberboard reffered to as MDF. It's similar to particle board except the particles are much smaller and much more tightly compressed.
The problem with using it in a rear seat enclosure is strength. MDF has no real "grain" in the wood, and as you run the various fasteners into it (screws, staples, etc.) they have a tendency to crack and pull out.
Marine plywood, having a grain, is far superior in strength than a particle board type of wood.
Whichever you choose it needs to be coated in resin, and its a good idea to use some fiberglass cloth as well.
One more thing to consider, use stainless steel screws for everything.
As far as availability, I would think that a major lumber yard could special order the marine ply for you.
Yeah...what they said.
Marine ply is gapless, so the accoustical properties are similar to MDF. Box builders like MDF because it's dense, and easy to cut. However, MDF has little structural strength compared to plywood.
You probably could use regular ply (if marine is not available), and probably won't notice any accoustical difference. I'd still pick regular ply over MDF for a seat base.
My buddy had a shop use MDF in his seat base. They looked good, but he eventually put his foot through the top. :jawdrop:
Ya gotta think long term.

Sweet Addiction
12-04-2004, 09:57 PM
Excellent info. Looks like I will try finding some marine Plywood. Hopefully I can get it ordered through the local hardware store. If all else fails I will build the seat out of regular plywood, and also the boxes and see what happens.
You probably could use regular ply (if marine is not available), and probably won't notice any accoustical difference. I'd still pick regular ply over MDF for a seat base.
So using this info I will build it and see what happens. If there is something wrong or not right, then I will build boxes out of MDF and then build the seat structure around the sub boxes with some a better quality plywood.
Thanks everyone, Jared.

Shallow Minded
12-06-2004, 04:02 PM
I was looking at replacing the sub boxes in my boat and looked at marine plywood (3/4) after reading this thread.... is it really over $100/sheet?

ROZ
12-06-2004, 04:43 PM
I was looking at replacing the sub boxes in my boat and looked at marine plywood (3/4) after reading this thread.... is it really over $100/sheet?
propably close to 85-100 for 3/4"... Spend the money to do it once. If you use an inferior product, you will be redoing it. Labor and frustration doing it a second time will easily make up the difference of dollars spent up front...
* You can still use std 3/4" ply, Just make sure to float a couple coats of resin...

Shallow Minded
12-07-2004, 06:26 AM
"Labor and frustration doing it a second time will easily make up the difference of dollars spent up front..."
Good point, I'd just as soon not have to tear my bench seat apart again... Can you fill me in on the resin part, though? Available at a local hardware store? Brush on a couple of coats and you're good-to-go? Thanks in advance...

Havasu Hangin'
12-07-2004, 07:18 AM
"Labor and frustration doing it a second time will easily make up the difference of dollars spent up front..."
Good point, I'd just as soon not have to tear my bench seat apart again... Can you fill me in on the resin part, though? Available at a local hardware store? Brush on a couple of coats and you're good-to-go? Thanks in advance...
The reason marine ply is so expensive is that not only is it pressure treated, but it uses higher quality wood, so there are no gaps in the plys, which makes it consistant. MDF accomplishes the same thing, but in a different way.
If you use regular ply, I think Roz is telling you to get some resin from West Marine, and coat all the surfaces to keep water from penetrating the wood. Good interior shops will do the same thing to seats- it makes them last longer (prevents dry rot from moisture).
If you want them to last longer than the rest of your boat, use some fiberglass!

ROZ
12-07-2004, 09:45 AM
The reason marine ply is so expensive is that not only is it pressure treated, but it uses higher quality wood, so there are no gaps in the plys, which makes it consistant. MDF accomplishes the same thing, but in a different way.
If you use regular ply, I think Roz is telling you to get some resin from West Marine, and coat all the surfaces to keep water from penetrating the wood. Good interior shops will do the same thing to seats- it makes them last longer (prevents dry rot from moisture).
If you want them to last longer than the rest of your boat, use some fiberglass!
What he said...
You can get polyurethane resin at Home Depot, Lowes, or like HH said, West Marine...
If you want to take it a step further, glass the box then add 2 layers of fiberglass mat :D

Shallow Minded
12-07-2004, 10:08 AM
was just out on West Marine's web site, any recommendations for a resin and hardener combo?

ROZ
12-07-2004, 10:27 AM
fastener-express.com (http://www.fastener-express.com/index.asp?PageAction=VIEWCATS&Category=218)
K-Grip upholstery adhesive (http://www.glfi.com/supplycatalogg.htm)
fiberglass and resin @ uscomposites.com (http://www.uscomposites.com/)
Now all you need it wood :D
EDIT: I meant polyester resin not polyurethane. You can use epoxy resin, though...

Sweet Addiction
12-07-2004, 01:04 PM
I was at the local Boating store and I can pick up a gallon of Polyester Resin for 24.99 a Gal. I thought it was a pretty good deal. I have come to the conclusion that I am going to seal all my seats and pieces in Resin to keep them from wrotting again. When I start my project in a few weeks I am going to take pictures and post in a new thread. Good luck to all.

ROZ
12-07-2004, 01:51 PM
Fantastic! Keep us posted! Remember to put it in the "howto" section as well :)

Eliminator 4 Life
12-07-2004, 04:32 PM
I had my speaker boxes line x seems to be doing okay..........

Sweet Addiction
12-09-2004, 07:44 AM
Fantastic! Keep us posted! Remember to put it in the "howto" section as well :)
I will take pics of my re-build including the floor and the rear seat and post in the how to section so everyone can get a look at it. Maybe it will help some out. I have talked to guys in the Central section that have boats like mine and they are also in the midst of projects.