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Rock solid custom Seats
By:Paul Jacobson
Date: 9/19/1998, 8:07 pm
In Response To: Re: Custom Seats (Rick C.)

> Hi howdy Mark,

> FORGET IT! What a pain in the a--!I tried it with a garbage bag. At least
> it was contained. And the foam needs air to cure, mine sat for about six
> hours, and was still like pudding.
> . . .
>
> I think it
> was P.J. that did his with the expandable stuff. How did that turn out
> Paul?

Paul Stomski did the molded expandable foam when he modified his design into a sit-on-top. He did not report any problems. Perhaps he used a differen type of foam. The foam should not need air to set. Perhaps it was sitting on the shelf too long before you got it, or did not mix right. Either way, I suggested the bag, and as you have seen, it is a lot less messy if things go haywire.

I can't remember if Stomski glassed over the expanded foam, sealing it in place, or if he removed it and sliced it so he could duplicate the pieces in minicell foam. Maybe someone should e-mail him, as I suspect he is spending his free time paddling in his lovely boat, and not just talking about it on this board. (and in Hawaii, too, the lucky guy!)

There has been some consideration of using plaster of Paris for molding another seat form. The ideal seat form is probably your own.

My experience with plaster of Paris and molding body parts consists of a life-mask I made of my son for a Halloween costume several years ago. Using the mask I made a replica of his head, with an incredibly detailed face that scared many people. He laid on his back and I put about a 1/2 inch thick layer of stiff plaster of Paris over his face. A couple of soda straws in his mouth let him breathe while the stuff set -- a matter of only 10 to 12 minutes. The mold was still damp and delicate when I removed it, but it stayed in one piece. I bought 5 pounds of plaster of Paris and used about half the container. It gets warm as it sets up. but the temperature does not get hot enough to do any damage. About the time it gets hot enough to make you sweat it has hardened enough to remove. I have heard that there are several other areas on the internet which will go into detailed descriptions of how you should wrap your naked body in saran wrap and have an assistant cover you with plaster (check them out if you dare -- I won't). Certainly it does not sound like a one-person job.

A person of average proportions would probably need to use 10 to 20 pounds of plaster of Paris if it was put on thin and they were careful. More might be better. That gets into the $10 to $15 range for material.

Art supply stores sell the material used for making casts, a plaster impregnated cheesecloth. A rol of the material is dipped in water to activate it, and then either wrapped around the injured limb, or draped over a form for an art project. A few rolls of this might serve your purposes instead of a plaster puddle. Again, it gets warm as it sets, but not so much that it causes problems.

For the cheapest mold you might consider the infamous Chicago Swimsuit technique. Get one sack ( 60 to 80 pounds ) of sandmix concrete and an 8 foot 2x4. Cut the 2x4 into 4 equal length pieces, each about 2 feet long, and assemble these pieces to form a bottomless box, approximately 2 feet square and 3 1/2 inches deep. You can get rapid set concrete for under $6 a bag, or regular concrete for half that. A 2x4 shouldn't cost you over $3. That makes the estimate of this mold about $4.50

In use the box is placed over a flat surface (a deck, patio, sidewalk or a piece of plywood set on the lawn), which is protected by being covered with several layers of newspaper, before you set the box on it. (Using the Chicago Tribune would be a nice touch, but this is an area where substitutions can be made) The concrete is mixed into a stiff mix and poured into the box. It is smoothed, and the person to be fitted is impressed into this. There are two variations to this technique. The traditional Chicago style is to leave the person in the concrete. The second variation, sometimes called the Grauman's Chinese method, is to remove the person immediately after making the impression. The Grauman's method relies on the concrete being stiff enough to hold the impression until the concrete has set. The Chicago method leaves nothing to chance. I strongly recommend NOT using the Chicago method.

Now, this is a process you can do yourself. Before getting started though, I suggest you think up 2 good stories to tell the neighbors.

The first is to explain why you are wearing a plastic bag over your pants and immersing yourself in a bed of concrete.

The second is to explain the shallow, 80 pound planter you now have on your patio.

Disposing of this mold may involve some work with a sledge hammer. If you do this at night and work fast, you may never need to tell the neighbors either of these two stories. Best of luck to you. Paul Jacobson

Messages In This Thread

Custom Seats
Mark Bodnar -- 9/17/1998, 9:49 pm
Re: Custom Seats
Rick C. -- 9/17/1998, 10:42 pm
Rock solid custom Seats
Paul Jacobson -- 9/19/1998, 8:07 pm
Re: Custom Seats
Mark Bodnar -- 9/18/1998, 9:02 pm
Re: Custom Seats
John Waddington -- 9/19/1998, 7:31 am
Re: Custom Seats
Mark Bodnar -- 9/20/1998, 7:59 pm
Re: Custom Seats
Mike Spence -- 9/18/1998, 3:07 am
Re: Custom Seats: Paul Stomski did it....
Tor-Henrik Furmyr -- 9/19/1998, 5:53 pm
Re: Mold from a comfortable seat?
Ross Leidy -- 9/18/1998, 8:53 am
Seat Mold
Jay Babina -- 9/18/1998, 9:35 am
Sand mold
Jay Babina -- 9/21/1998, 9:55 am
Re: Form Fit Seat
Mark Kanzler -- 9/20/1998, 11:24 am
Re: Seat Mold
Mark Kanzler -- 9/20/1998, 11:18 am
Re: Seat Mold
Paul Jacobson -- 9/19/1998, 4:50 pm
Re: Seat Mold
Mark Bodnar -- 9/18/1998, 9:13 pm
Re: Seat Mold
Ross Leidy -- 9/18/1998, 1:06 pm
Re: Seat Mold
Bob Harding -- 9/18/1998, 2:39 pm