Yet another plywood dilemma (THT)

[vann]

That is chipboard, also called particle board, not OSB, or Oriented Strand Board. I don't recommend using either for anything, because the dust from both, when cutting, is quite toxic.

So practically, it's more of a health concern than structural?
I could live with some dust from few cuts for some braces (I would cut them outside)... But more I think about it, the more I lean toward buying that extra 8'x4' board so I don't have to assemble panels 5 and 6 from 2-3 pieces. I think I sow few ppl wrote about it being major PITA (and it seems like it will increase my mistake margin).

My tools are very limited and I plan on having all parts completely precut (aside for braces). Yes I know plans are calling for cutting panels one at a time while determining size by dead reckoning... but I can't afford buying expensive tools atm. I'll rather precut all and borrow friends tool (and hand) if I require some interventions.


The worse case scenario for me (money-wise) is having to buy 3rd 4'x8' board of 3/4" ply, plus another 4'x8' board of 1/2" veneered ply just for braces (that one is almost double the price of the 3/4" ply).
Will the increased thickness from braces made from 3/4" ply be too much in the sound waves path? Maybe I could bevel/round a bit the sides facing the horn throat?

[wounded horse]

I think DJs advice is sound. If you're cutting sheet material on a table saw or handheld you either do it outside - preferably with a mask or with dust collection in place. I find it all an irritant, particularly ply with bondo and/or PL in the dust when I'm sanding. I don't use MDF for anything because of this. Breezy days are good for cutting to get the dust away. PL needs doing outside or well ventilated with a mask. Read the small print hazard notices on that stuff.

[Gregory East]

With a continuous bead of adhesive which has shear strength greater than the strength of the wood itself, the stiffness of each individual 12mm panel is increased to the stiffness of the set of braced panels and said braces.

As a young student I stood on a 4m long bridge made from 20mm x 10mm sticks and cardboard. It didn't even wobble. Do not underestimate the utility of pressed fibre products.

[Rick Lee]

Vann, 3/4" ply for bracing won't affect the sound quality. It is overkill but if it's cheaper for you than the thin veneer stuff go for it! That way you just have to buy one more sheet- you won't have to splice any panels together and there will be plenty left over for braces.

As far as toxicity is concerned it's all bad- if you work around any wood long enough with cutting and sanding at the least it will decrease your breathing capacity.

And, these cabinets can be built out of plywood, MDF, OSB, fiberglass composites, etc. etc., but the ideal material with the least compromises is Baltic Birch plywood. Thankfully I can get BB in my area for a good price so it's what I use. The Arauco from my local Lowes store has always been good (no warping) so I use it occasionally.

On this forum we always advocate to use BB or Arauco because it's the best and the price difference is minimal. So many times we'll say, "Don't use _____ !!!!!" even though technically it is possible to use those other materials without the cab falling apart. Since you live in an area that you say doesn't have BB or Arauco is the reason I said you could get away with chipboard or whatever. But definitely sounds like you just need an extra sheet of the 3/4" stuff.