Making a Mold Board

[James Mills]

In about a month, I'm going to start construction on a 24' x 8' mold board. It will sit on top of a boat trailer and be able to roll in and out of the shop.

Is formica the material of choice for the top surface??

Thanks,

James Mills

[ondarvr]

What do you plan on making the rest of it from, what exactly do you plan on making on it and how often do you plan on using it? The surface and what you make the rest of it from are dictated by the last two.

[James Mills]

The general plan is to make a substructure of probably steel -- like a strong back that will set on the trailer. (welder and experience at hand). Then build a panel of 2'' aluminum cross beams (like those used to build patio cages in florida - I have a lot of them) with 2" iso foam board (often used on roofs) between the aluminum supports. Layer the aluminum and foam with probably 2 alternating layers of 3/8" exterior ply - screwed and glued. Formica or something else on top. Probably put one layer of 3/8 ply on the bottom of the panel to somewhat get the sandwich stiffening effect. Try to make it as weather resistant as possible. At times I may drag it off the trailer onto saw horses and cover it with a tarp.

First project is to build a new floor for the motorboat. Probably use polypro honeycomb. I've used it before and like it. My existing 4 x 8 mold board may be larger enough for that project.

The real project is a 20' sharpie out of composite panels. Probably make the exterior glass panels first. Have them post cured in a friend's oven. Shape the very flimsy and fragile hull with copius support. Glass and vacuum bag in the core and inner skins.

The hull must be fair and no print thru.

That's the dream -- that's hopefully coming to fruition.
Lot's of work.

Possibly extend the mold board in the future for larger hulls.

[ondarvr]

Large flat molds are very difficult to make and keep flat. With steel, aluminum, a couple of layers of plywood and foam everything will be moving and changing shape at different rates with temperature and humidity. If you're making flat panels without core it won't be as bad, but with a core you'll be locking in whatever shape the mold is in that day with no way to straighten the part. Get a good tarp and keep it as dry as possible and with limited use the Formica will hold up OK, but only if it's well protected when outside.

[thudpucker]

I looked up Mold board and Mouldboard on Wickipedia and both ways they talk about a Plow. For Farmers.
So what is this thread about? What's a Mold Board?

[ondarvr]

It can go by many names, but is typically called a flat stock table, just a large flat mold that can be used for many different things.

[thudpucker]

A table? You mean like a Work table or a Kitchen table?

[James Mills]

Basically a flat smooth surface to make fiberglass parts. Of course they will pop off the board flat. Ideal for making panels for bulkheads, hardtops, etc. I made a hardtop for my motorboat by laminating one skin and core and then bending to shape -- in one plane only-- and then glassing the inside skin.

Some builders and designers have taking the mold board to a whole new level. Creating entire large boats from the panels. Not sure that is route is for me when/if I make my big boat, but is interesting.

Check these sites:

http://www.kelsall.com/

http://www.cata-ballotta.com/