3/4 inch plywood ok for second baffle?

[Havasufreak 3]

i just finished my 5 CuFt box for my fi bl 15 and i used just about every square inch of my MDF wood i had for the box.

my question is if its ok to use 3/4 inch plywood for my second baffle? i have a bunch lying around and would be nice instead of buying a huge sheet of MDF i would barely use.

lemme know what u guys think!

Thanks!!

Edited April 3, 2011 by Havasufreak

[bassahaulic 155]

Should be just fine man.

[RXdriver11 2]

Yo dude saw your txt. Looking good. Forget that ply and go get a half sheet of mdf..

[RXdriver11 2]

Also you gonna be running the same amp?

[RAM_Designs 25]

More rigid than MDF, I'd say go for it.

[bassahaulic 155]

More rigid than MDF, I'd say go for it.

There ya go!

[Havasufreak 3]

perfect!!

thanks guys!! and yes im using the same amp

[shizzzon 461]

when attaching hardwood or plywood to MDF, make sure you clamp or put a LARGE and long lasting pressured load on both baffle pieces for at least 12hrs for glue to bond properly.

It's been known that gluing oak to mdf has actually cracked the OAK in just a simple HT box...

Plywood may not be as porous as mdf which needs extra care during the cure time.

[Havasufreak 3]

when attaching hardwood or plywood to MDF, make sure you clamp or put a LARGE and long lasting pressured load on both baffle pieces for at least 12hrs for glue to bond properly.

It's been known that gluing oak to mdf has actually cracked the OAK in just a simple HT box...

Plywood may not be as porous as mdf which needs extra care during the cure time.

ill definitely take that into consideration! thanks!

you say the oak cracks? hmm... that doesnt sound to good. lol

[RXdriver11 2]

That may be all good info but keep in mind when you put screws in and out of ply it will tear to shit. And it wont hold t-nuts as good either. We both know you will be pulling that thing out a few times.

[shizzzon 461]

yea, i had read about it sometime ago on guys using more rigid material above MDF like Birch Veneer, Baltic Birch, Oak, Maple, etc...

There argument was while more rigidity is better at reducing flex, ANY material can have great rigidness if BRACED.

this is 100% true though..

But in an HT box, most bracing is done internally where spl designs in car audio are done externally...

So i have to go thru different scenarios and see which ones may apply to the car audio field.

High rigid enclosure material will resonate higher which can have an adverse effect on SQ..

So.. the debate was to use a high rigid material on the OUTSIDE and MDF on the inside.

The way they put it is MDF appears to absorb the sound since MDF is so dense and makes it sound better.

Well, when the user glued oak to MDF, within a few days or weeks, cant remember, the oak actually cracked on the outside of the box.

I do not know exactly why but it was being focused on the possible fact that the oak never completely attached to the MDF properly.

Assumption.. but cant remember.

[shizzzon 461]

That may be all good info but keep in mind when you put screws in and out of ply it will tear to shit. And it wont hold t-nuts as good either. We both know you will be pulling that thing out a few times.

What?

MDF would be the material that would tear to shit...

Plywood is actual wood rather than dust particles and glue...

[RXdriver11 2]

True mdf does tear and the correct t-nuts can prevent that. But if you want to use ply i would reinforce the crap out of it. Havasu i kno from being on here that shizzon is very knowledgeable but i could bring you an old box that was done like that and show you what i have seen happen..

If you do use ply i would also make sure it is hardwood ply (ie birch) because it has the characteristics for strength. Chances are the stuff you have laying around aint birch..

[Havasufreak 3]

the wood i would use is VERY durable and heavy. send me a picture of the box your mentioning RX.

and thanks shizzon for what u posted!!

i think it wouldnt be to bad to use plywood. im kinda second guessing it tho...

[Tirefryr 1,742]

That may be all good info but keep in mind when you put screws in and out of ply it will tear to shit. And it wont hold t-nuts as good either. We both know you will be pulling that thing out a few times.

This statement is the exact opposite of what it should be.

I have laminated MDF with several types of plywood and OSB for use on baffles and never had any issues and in my part of the country it is easy to see 30-40 degree temperature changes in a matter of hours. If anything would cause cracking, that would, and none of the enclosures have had any type of failure.

[Havasufreak 3]

hahah! im just gonna go for it.

thank you all for your input

[RXdriver11 2]

That may be all good info but keep in mind when you put screws in and out of ply it will tear to shit. And it wont hold t-nuts as good either. We both know you will be pulling that thing out a few times.

This statement is the exact opposite of what it should be.

I have laminated MDF with several types of plywood and OSB for use on baffles and never had any issues and in my part of the country it is easy to see 30-40 degree temperature changes in a matter of hours. If anything would cause cracking, that would, and none of the enclosures have had any type of failure.

I never said anything about cracking im talking about mounting and having your mounting holes split. With the screws being installed and removed over again a few times. True i have seen this happen with mdf.. but t-nuts will prevent that (when properly installed). I have not found a good fix for that in plywood. Although i dont have a lot of experience with plywood in speaker boxes just that 1 experience. I do however use ply in various remodels and yes if put a screw in it and leave it alone it will hold great. But when constantly removing and readding screws it starts to splinter. And for all i know that may have been a soft ply, this box was built 10 yrs ago and i dont remember all the specs of the wood. But ill look for some photos when i head back to my folks place..

[Tirefryr 1,742]

MY cracking comment was not directed towards your post, hence the separate paragraph. However, plywood will hold a thread and a tooth better than MDF. It's just a fact, no matter your experience. THe only reason the hole will splinter or strip is if you tighten it too much. That's where you are having the issue, and if you are using T-nuts or any other kid of insert, you are relieved of that problem.