baffle board material

[CraigB]

Hi, I am looking for your collective opinions and advice on what material you would recommend for a Deluxe Reverb size cab.  Just like in a DR, the speaker will not be centered on the baffle, but off to one side to clear the PT, OT, taller chassis items.

I started with 5/8 finish plywood, the straightest sheet I could find, which was only slightly bent.  As soon as I cut it and routed the hole in it, it took some unexpected shape, which I had hoped would be counteracted by the rigidity of a speaker mounted to it and bolting down to the cleats.  That seemed to look OK, but then when I stretched the grill cloth over it, that seemed to accentuate the warped-ness even more.  No likey. 

I am thinking about 3/4 MDF as an alternative.  I'm assuming I could just spray it with flat black paint to seal it, or should I use bullseye sand & seal, then spray paint?

Appreciate any input you all have to offer!  Thanks - Craig

[Willabe]

I don't think I'd try to use MDF for a guitar amp speaker baffle, but I could be wrong about that.

How many plys does the ply wood have? 5/8" multi ply should not have a problem with twisting or wraping.

Depending on the weight of the speaker and the power output of the amp, 3/8" to 7/16" plywood should be plenty.


                          Brad   

[Boots Deville]

Yeah, 5/8" cabinet grade plywood should be fine.

I usually use 1/2" Baltic birch for baffles, but here's a pine speaker cab the same dimensions as a Deluxe Reverb that I recently built that I used 3/8" Baltic birch for the baffle:
http://i40.tinypic.com/t9dxro.jpg

That's a 1/2" front panel resting in front of it.  Here's a poor quality shot of the finished cab at a bar this past Friday with me standing in front of it. It's the blue/gray cab in the middle:
http://i41.tinypic.com/selx1v.jpg

I've never had an issue with warping.  Are you sure something about the way it's mounted in the cab, or the way the speaker is mounted to the baffle isn't causing stress on the baffle that's causing to the deform?

[Willabe]

Hey Boots, those cabs look great.


                   Brad     

[Boots Deville]

Thank-you Brad!

-John

[CraigB]

Hey, that cabinet looks really nice Boots!  Great work... 

I've not had this issue before, either...

Yeah, the baffle piece is definitely warped.  The cabinet pieces and cleats are dead flat/straight.

I got the wood from home depot.  We have a lumber place nearby that sells hardwood and stuff like that.  I think I'll go see what they've got as far as plywood. 

How many plys should it be?  This stuff I used has a super thin veneer on both sides and 5 plys.

Thanks - Craig

[Boots Deville]

I can't get the cabinet grade stuff at the big home centers around me.  I get it in 5'x5' sheets at a specialty place, probably similar to the one you mentioned.

I think the 3/4" stuff I use has 12 or 13 plys and the 1/2" around 8 or 9.  I don't have it in front of me to say for sure, but it's definitely more than 5, and it's void free.

What I was getting at with the my comment about the way it's mounted is something like an non-square baffle that is binding against the side of the cab, or a gob of glue in way, or misaligned screw holes between the speaker and the baffle...something like that, but I bet your problem is the wood itself.

[Willabe]

How many plys should it be?  This stuff I used has a super thin veneer on both sides and 5 plys.

The 2 veneers are not giving/adding much strength. If your counting those as plys than that sheet is realy 3 ply and I think that's the problem, 5/8", 5 ply. I'd say that's the bare minimum # of plys for stability. The more the # of plys the more stable it will/should be.

I've bought _ finish _ ply (AA "face") from home depot before and it's not always very stable.

When they make ply wood they peal/unroll the log like a roll of paper towels in to one long sheet. If there's knots in the log a number of them will fall out and when they glue up the thin sheets together (@90 degrees to each other) there will be voids and that weakens the sheet. Cheaper ply wood will have more voids, even thou you can't see them, there are there. When you cut up the sheet and cut out the hole/s for the speaker/s there's less "meat" to keep the sheet flat. Some times you can get away with it and sometimes you can't.

I bought some 3/4", 7ply, AA, pine, ext. glue from menards, that was very good as far as stability. I made a work bench out of it and it's flat, strait, stable, solid as a rock. I think I paid around $30 a sheet. I'd buy it again. IIRC they also have it in 7 ply, 1/2". I would trust it to make a speaker baffle, altho I still think that's a little too thick for a single 12" speaker, but who knows? Might sound/work great?

Baltic birch is no void, multi ply and is VERY stable, but very pricey too. It is the favored ply wood for amp cabs and speaker baffles. I think 1/2" has 13 plies? But you wont find it at a big box store, I've never seen it there.

You can find it on line and you don't need much depending on how many baffles you need to make.

This might help you;

http://www.madehow.com/Volume-4/Plywood.html

                        

                              Brad       

 

[stingray_65]

I started with 5/8 finish plywood, the straightest sheet I could find, which was only slightly bent.  As soon as I cut it and routed the hole in it, it took some unexpected shape, which I had hoped would be counteracted by the rigidity of a speaker mounted to it and bolting down to the cleats.

WOW!

I would be very afraid of distorting the stamped  steel cage and possibly ruining the speaker.

If Baltic birch is unavailable to you (1/2" is fine BTW), I would use particle board. It has gotten a bad rep in the past, but mostly from improper applications. (IMHO) The binders used today are MUCH better than in the past, it's extremely flat and very rigid. MDF is another good choice, again just my opinion.

The stress on a baffle board is minimal in an open back cab, closed back I wouldn't use anything but BB

Ray

OH! and Zinser sanding sealer is a must on just about everything I build. Great stuff, cheap, easy to use, accepts all other finishes, or its a great finish all by itself.

[Boots Deville]

Ray, is this the stuff you're referring to?
http://www.rustoleum.com/CBGProduct.asp?pid=246&sid=00850

[CraigB]

Ray, is this the stuff you're referring to?
http://www.rustoleum.com/CBGProduct.asp?pid=246&sid=00850

Yeah, that's what I use to seal my cabinets, and it works great as a surface for the Super 77 to stick to.  I usually use flat black spray paint to seal baffles.  Hmm, it would be easy enough to seal it with the shellac S&S first, then a quick coat of spray paint on the face.

Thank you for all the info on plywood grades.  I knew you guys would point me in the right direction!

[CraigB]

I started with 5/8 finish plywood, the straightest sheet I could find, which was only slightly bent.  As soon as I cut it and routed the hole in it, it took some unexpected shape, which I had hoped would be counteracted by the rigidity of a speaker mounted to it and bolting down to the cleats.

WOW!

I would be very afraid of distorting the stamped  steel cage and possibly ruining the speaker.

If Baltic birch is unavailable to you (1/2" is fine BTW), I would use particle board. It has gotten a bad rep in the past, but mostly from improper applications. (IMHO) The binders used today are MUCH better than in the past, it's extremely flat and very rigid. MDF is another good choice, again just my opinion.

The stress on a baffle board is minimal in an open back cab, closed back I wouldn't use anything but BB

Ray

OH! and Zinser sanding sealer is a must on just about everything I build. Great stuff, cheap, easy to use, accepts all other finishes, or its a great finish all by itself.

I have 8", 10" and 12" crap speakers that I use for marking up the board prior to cutting and for test fitting.  I left the baffle in the cab with the cheapo speaker in during the week for a few days, hoping that would straighten it out, but as soon as I pulled the speaker off and pulled the board off the mounts, it sprung right back to warped.  Then I had hoped that I could get it to further flatten if I mounted the speaker back on, stapled on the grill cloth, but again, it made it even worse    I should've given up on it and gotten advice here instead of moving on and wasting my time with it.  Where is that Midas touch when I need it most?  It certainly wasn't with me on this one!

[stingray_65]

Ray, is this the stuff you're referring to?
http://www.rustoleum.com/CBGProduct.asp?pid=246&sid=00850

Yeah, that's what I use to seal my cabinets, and it works great as a surface for the Super 77 to stick to.  I usually use flat black spray paint to seal baffles.  Hmm, it would be easy enough to seal it with the shellac S&S first, then a quick coat of spray paint on the face.

Thank you for all the info on plywood grades.  I knew you guys would point me in the right direction!

YUP!

the only shellac in a can worth bothering with. cleans up easy with cheap isopropyl alcohol.

I have nothing but high praise for the stuff.

[CraigB]

[/quote]

YUP!

the only shellac in a can worth bothering with. cleans up easy with cheap isopropyl alcohol.

I have nothing but high praise for the stuff.
[/quote]

Yeah it's good stuff.  The regular bullseye shellac in paint cans and rattle-cans has wax in it, so while it works to seal the wood, it also isn't the best surface for some other material to adhere to.  At least, that's my take FWIW.

Hey, I picked up a 5x5 sheet of 1/2" BB, cut it out and its flat as can be.  It had a bad corner so I got 20% off.  Still set me back $30, but I've got enough to make a bunch more baffle boards with 

Thanks again for the advice.  All I can hope for is it sounds good and looks somewhere near as nice as Boots' cab!

[Boots Deville]

Don't complain about $30 for 1/2" - here in Vermont I pay about $50 for a sheet of 1/2" and $70 for 3/4".  Maybe I should try to find it elsewhere for less.

Thanks for the sealer info - I'll definitely try some on my next cab.

-John

[Willabe]

Hey, I picked up a 5x5 sheet of 1/2" BB, cut it out and its flat as can be.  It had a bad corner so I got 20% off.  Still set me back $30, but I've got enough to make a bunch more baffle boards with 

Very nice. I think that's a great price. Plus you were able to pick it up, not have to wait for it and no shipping charge.

If you can get 3 or 4 baffles out of it even better, $10 or less per baffle.


                     Brad       

[CraigB]

Got it finished up yesterday and really liking how it turned out.  Sounds really nice.



I know, many of you probably don't approve of a Vintage 30 in a DR, but I think it sounds better than the C12R 

 

[Willabe]

I know, many of you probably don't approve of a Vintage 30 in a DR, but I think it sounds better than the C12R  

I think a lot of guys like a Vintage 30 in a DR, besides it's your amp. If it sounds good to you then who cares what any one eles likes.

Your build looks great, inside and out. 


                  Brad          

[CraigB]

I know, many of you probably don't approve of a Vintage 30 in a DR, but I think it sounds better than the C12R  

I think a lot of guys like a Vintage 30 in a DR, besides it's your amp. If it sounds good to you then who cares what any one eles likes.

Your build looks great, inside and out. 


                  Brad          

THanks Brad.  I guess I've never seen anyone use a Vintage 30 in a Fender amp.  I do like how it sounds, but it does make it a bit heavier to carry. 

[Willabe]

How much of that BB ply-wood have you got left?


                     Brad    

[CraigB]

Quite a bit, probably enough for about 3-4 more DR size baffles.

Next up is a Super Reverb size cab, but with 3x10 spkrs 

[bluesbear]

Most any of the high end wood places (Woodcraft, Rocklers, etc) have 1/2" clear baltic birch. I use that. It's a bit expensive but it's always straight and works great. No point in skimping when you're trying to make the perfect amp! It's only a few bucks more per amp. One 4' by 4' sheet makes four of my combos.
Dave