Recent content by PAUL GRAHAM

Using plywood on three sides would make a strong support and significantly simplify the design. Most commercially available aquarium stands not made of welded steel use this type of construction. If they are budget-minded they use particleboard. I would use 23/32" CDX or PIytanium Structural 1...

Herman: The aquarium does carry the load - empty. Put 640 lbs of water in it, if the support is not distributed evenly, the glass panes will be severely loaded, tensioning the silicone seals. The pressure will persist until the seal fails. berkeman: Yes, I have always done my electrical...

There's a reason why my drawings look like that.

The above drawings should have sufficient info to convey what this thing is and how it's gonna get made. berkeman thought a sketch would help. This is the sketch. Whatever happens, it's on me. I'll gratefully accept any comment. My original post was an attempt to find out if I could use doubled...

Well you're right about that berkeman. After today's input I am starting working drawings. I'll have something as you suggest in a couple of days.

Certainly not a substitute for glue. Joints are simple lap overlay. Contact surface area where upper platform frame attaches to leg is 18.375 sq in on one side and 26.25 sq in on the perpendicular side, and, similarly, 12.25 and 17.5 where base frame attaches to leg. A minimum of three...

The base of this space-frame surrounds the perfectly vertical legs, 3" x 5" in section, with 2 x 4, having a perimeter congruent with the top, now 2 x 6, platform. Attachment of all 2-by members to the legs is by Timberlok lags, two lags at each end and staggered with those used on the members...

Actually, a 5/8" MDF panel goes on top of the space-frame and a 0.2" high-impact neoprene mat goes on this. The aquarium bottom is elevated by the thickness of its plastic rim. That rim is transferring the weight of a full aquarium to the space-frame and the mat eliminates point stresses. The...

Baluncore; As stated this is not assigned study, but a hobby project. I am a 78 year old retiree whose education is in historical geology and environmental engineering. I am not a PE and am not in training to become one. I know just enough about some things to frame an intelligent question on...

Not homework as in "assigned" study. I am designing a post-and-beam table, 48" x 18", to safely carry an 800 lb static load (an aquarium), with legs in each of the four corners. Except for the tops of the horizontal elements (beams), there is no top surface. The weight bears uniformly around...

I am scientifically curious, an autodidactic polymath. Occasionally I come upon a question that pertains to a physics topic which I can clearly express but do not have the information or training to solve. For example, the question that brought me tonight concerns a simple structural engineering...

Two 2 x 4s are laminated by means of glue and screws to form a horizontal beam 3.5" deep x 3" wide supported at the ends and uniformly loaded by static compression. Compare the bending resistance of this beam to that of a single 2 x 6 which is 5.25" deep x 1.5" wide under the same load.