Where to buy MDF board?

George, I built one with mdf as Mrtennis and also built a similar unit but used Pennsylvania slate. Shouldn't be wobbly if you tighten the nuts.

I would guess that if you can buy threaded nuts that flange out to a large diameter, you would not have problems with stability. Using large fender washers might also provide some advantage, but not as much advantage as flanged nuts.

Not that I think Achetype racks are all that stable either (nor, ulitmately, is the Synergy Twin which I own, compared with a truly stable non-adjustable rack like a Billy Bags or similar), but George's home-brew experience was undoubtedly further compromised because Salamander prefers to make the Achetype design not with MDF shelves, but solid hardwood. Personally, I've been thinking of making some replacement shelves for my Synergy, either out of hardwood (the top and bottom are already maple), or high-density particle board, or perhaps 1/2" HDPB laminated to 1/2" MDF and covered in matte black, Formica-type high-pressure laminate to create somewhat of a constrained-layer sandwich with dissimilar resonant properties (or at least a greater resistance to chipping!).

MDF has Formaldehyde in it as well, in fact it is just another form of particle board, the particles are much finer and uniform that the cheap stuff that Ikea uses for most of their furniture. This fine grade of wood waste particle allows MDF to have a "uniform tear" thus you get a great edge when you saw it. I recommend using a carbide saw blade if you do cut it because the resins that hold it together will dull most other saw blades. Zaikesman has the right idea, laminating a "Formica" type product to MDF will give it strength beyond all get out, however you can't put a nice paint finish on it after you laminate it.

Hi guys
I arrive at the thread rather late,I strongly believe that the Archetype design is unstable no matter what.Having said that my copy of the Archetype is more unstable and I know why.I used rubber washers between the metal 5/8 washers and oak plywood .True it can use a little mor torque on the bolts however the archetype is NOT a stable design.For the record I used the end caps that Salamander uses instead of bolts that other hobbyists use as a compromise.I bought them from Audio Advisor as replacement parts.
A good rack in my opinion is the Billy Bags.I got their reference amp stand and it is massive.
My home made aluminum rack is really beyond compromise.
George