Originally Posted by Erich H
Believe it or not, there really is no weight difference between mdf and Baltic birch.
Today I picked up some Baltic 15.25" subwoofer flat packs and compared them with the mdf 15" flat packs I already have. The Baltic was .25" bigger, but the hole cutout was for a 12" and the mdf cutout was for a 10" woofer. So pretty close the same material. I was surprised to see that they were both exactly the same at 27.2 lbs. I weighed them both twice because the mdf box ticked up to 27.4lbs, then back to 27.2lbs. I think the scale goes to the nearest whole number, so the mdf box must be right around 27.3lbs.
I was actually hoping that it would be less for shipping and didn't expect them to be nearly identical in weight. I knew they were close, but not that close. There's a nice domestic birch plywood that is suppose to be lighter and very good quality. I'll try that stuff next.
They are not the same (weight) but I'm not going to drag this out anymore...I cannot speak precisely for the plywood you're using though because I haven't seen it.
Every 4x8 3/4" sheet of TRUE BB I've ever handled/used hasn't weighed more than 85lbs (most are around 82)...it varies a bit on the type and amount of adhesive used, but certainly no more than a few pounds, tops. Yes I have a scale in my shop and can easily weigh them.
That said, virtually every sheet of 3/4" MDF on earth weighs at LEAST 94lbs with many nearing 100lbs depending upon species/adhesives utilized- with more and more poplar thrown into the mix, that has added a few more pounds per sheet.
Check here: http://www.wolstenholme.com/pdf/Baltic%20Birch%20Plywood%20Specifications.pdf
Check the MSDS' on either product.
Pick up a 4x8 sheet of either.
They do not possess the same mass.
But thanks again for all of the work you're doing.