I've got two conflicting pieces of advice for illusion construction; the Osborne plans in The Big Black Book say the base for a Bride of the Blades illusion should be made from 1/2" plywood. The Seven Basic Secrets of Illusion Design by Eric Van Duzer recommends 3/4 ply for bases.

The person in the box weighs around 160 lbs. (72.5 kg) and I'm using additional 2x4's (with handles so the assistant can pull herself up) as support inside the cabinet itself (which will be 3/8th ply); the extra weight is the only reason I'm second guessing the Osborne plans- should I go with 1/2 or 3/4 birch plywood for the base?

Never mind- I recalculated; the 1/2" plywood should easily take the weight, and more, with the internal supports already designed into the base. Osborne does know his stuff.

One thing to keep in mind, the thicker ply will give you additional material to fasten to.
I usually use a thicker material for the bottom than what I use on the sides to allow for a more secure joint.
I also use biscuits to join the sides to the bottom, this will allow you to reduce the amount of internal reinforcements and gain more room for your assistant.

I suggest you to use metal plate, 1.2 mm or 1.5 mm.
This wil make your base thinner. (and stronger).
All my bases or hiding space use metal plate.

Cheers,
CC

Cahyo hit the nail on the head with this one.. Almost all bases of today use metal. It is stronger. has flex and keeps the size down.
Try it. You may like it.
John

Thank you so much John.....
But it could be more difficult to build. Wooden base is easier.

CC.

I have used 1/4" baltic birch plywood for a base used for a 6 foot, 160 lb woman with no problem. using sheet metal reduces the external size but does increase the cost and requires different tools.
bob

Johnnie, I'd love to use metal bases, but Cahyo is right- my welding skills aren't up to the task; I need to take a quick refresher course just to remember how to properly braze steel for a project I'm working on.

JC, concerning the surface area of the join, I use a bevel cut on the pieces, so the sides and bottom would be joined like such- \\____// Not only does this increase surface area as well, it helps distribute downward pressure outwards across the entire base.

I am thinking it might be possible to just use metal on the bottom piece of the base, drilling holes at the edges to bolt it to the wooden sides of the base. This will change how the weight's distributed somewhat, though- has anyone tried this?

Alternatively, since I do have a non-load bearing mock-up of the base I built from scrap (for sizing the illusion to my assistant), I could use it as a mold for a fiberglass shell.

This is exactly what Rand Woodbury does on his deceptive base. I haven't built one myself, but it seems that it would work well. Rand puts screws about every 5" or 6" to attach the sheet metal.

Thanks,
Richard

I used that idea and went with screws on 4" spacing, with little to no sag.
bob

I use 3/4 inch ply for the bottom of my bases. Thanks for the tips with the metal.
Should have thought of this myself since my sword box base is metal. (lol)

Take a look at some of the Owen plans (Candy Cane Dollhouse), plywood covered with canvas to reinforce. Ply is only 1/4" I believe.

Can also be of fibreglass.

Some of mine are made of just plastic sheets.

Blair Marshall,
"ShaZzam!"

Ok heres what I am running into, I have sevearl illusions I have built, and have been great stage pieces. But please tell me, I am desgining several new illusions that require bases, so heres my questions.

A. Does the base always look bigger than it should be to us (being magicans) because we know its purpose?

B. And second, should all props be built on top of bases, despite if its needed to achive the effect, just to have consistincy with props and the audince not start saying, "Hey that last illusion was on a short table, this one is bigger?

Just asking
Used woodburys plans, and some I got from other builders and magician freinds

I have Rand's videos but I do not think I have the books. On the video he doesn't say what kind of sheet metal he uses, but I assume it is not TOO thick as he cuts with with a hand shears.

Any idea? In American measurements?

.

I prefer to use fiberglass for the bottom of the base. They are lighter than metal plates. But I do use sheet metal to make the fiberglass form under the base. When the fiberglass has cured, I then take out the sheet metal form.
Another possibility is to use 1/4 inch plywood and strengthen it with fiberglass and resin.

Also, when using metal what are your plans for insulation? I mean, will you paint it? Cloth backing? If you put a scantily clad woman in the box, that cold sheet metal will not feel nice.

I like Lou's idea of using fiberglass. It's relatively cheap, lightweight and very strong. For more money you could use carbon fiber, which has a similar setup of fiberglass.

I also like Lou's avatar, reminds me of the old Coney Island.

Oh, and Starrpower, sheet metal can be cut by hand up to .075 thickness, maybe even .10 (inches by the way) with good shears. For 1/8" and up I use my Beverly shear mounted in my anvil. You can do it other ways by spending LOTS of money on power equipment, I use my Grizzly bandsaw for cuts under 3 foot. O/A torch cutting is fun, but leaves an ugly edge that's hard to get rid of. An angle grinder with a thin metal cut off disc will work too, but can be difficult to get a nice straight edge. Spend a thousand or so and get a nice plasma cutter (I'd love to get my hands on one), you'll cut just about anything. Then there's laser cutting, high pressure water jet cutting, so on and so on. If you're doing this from your home on a budget, shears and/or angle grinder would be my best recommendation.

In an earlier thread, Thomas Wayne posted this link to a product he likes to use for the bottom. I bought some and am just waiting for time to start building again so I can try it:

http://www.alcancompositesusa.com/produc......aac51170

I just built a base. I used sheet metal. I don't know a thing about working with sheet metal/welding/etc..

Here's exactly what I did...


I had the framework of my base built of wood. Basically it was a square of wood. I called around to a few sheet metal companies in town. I asked them if they could do a specialty project, as I was making something out of the ordinary. And asked if I could come in a actually talk to the worker that was going to be doing the work...

First place I called, said yes. I asked what time I should come in.. I went in the next morning, and I spoke with the owner. I brought the wood frame, and showed him exactly how I wanted the metal to fit.. It included a bend in the metal, and basically was a beveled (wedge) base. He whipped the thing together for me in about 2 hours.


Basically, use people to do what they are good at. I'm no metal worker. But I have a welder who will work for me, same with sheet metal (now) same with choreography, lighting design, etc...


Use people who are good at what they do, and they will make you look good, at doing the thing you do - perform magic!


scott

I agree, outsourcing is not accepting defeat. It is working smart. For example, I have an order for 10 custom swords for swallowing. I already have my steel (.075 inch 316 plate) but don't have the tools for perfect straight cuts. So, I outsource the material to a mill that has a shear brake press. In under 5 minutes I have precision cut blanks for the swords. Had I attempted to do it at home with my humble tools it would have taken me hours of grinding, sweat, cutoff discs and a pretty shabby job of a straight line. Remember, nobody can do it all by themselves.