Building 1 time use mold. input?

[Dave Hirshberg]

Thanks Strick,
I was hoping you'd chime in.
I agree with you on that middle part flexing . After I posted last night I thought about Laying up the flat skin on the hardboard in three sessions. First the gel coat on the entire part. Then a skin coat of 1/2 oz glass and 1/4 inch coreboard in three peices( sort of like a tri fold wallet. I believe that this would stifen the three sides and still leave a thin layer of glass to bend around the radius on each side. Then finally a layer of 1 oz in each of the radius before tacking it to the plywood mold.

[jw]

Dave,
You might check out some baltec core material, it is scored for making radius'sssss. I believe you can get it in foam or balsa, and in different thickness'sssss. It may be a bit more work, but the coring material my help insulate the live well, and you can still gelcoat it or paint it.
A buddy of mine enclosed the windows on his 31 Bertram, he used this stuff, if you know a 31 bertram you know the weird curves on the front outboard windows.

Hope this helps,
JW

[Dave Hirshberg]

John an JW,
You must have been posting the same time as I was.

I hear what your saying and i'm planning on using a coring material in three places on the outer skin of the mold. Leaving two 3 inch gaps between the sections that will form the corners. The coring will be running vertical to the top and bottom of tank. I'm hoping this will stiffen the three sides and prevent buckling while allowing me to bend the still green fiberglass around the D shaped base and D Shaped top (3/4 Ply) and form the two radius curves in the front before it completely kicks. I then plan to add core board to the radius to keep it from trying to lay flat after the base board is removed. This is just going to be a flimsy single use mold to lay up the actual fiberglass part . As I lay up the part itself I may use some coring material as well to stiffen and insulate. We pretty much bottom fish here with Shrimp, Pinfish, and grunts. All pretty hardy baits. I find that good water flow is the most crucial, they don't tend to bunch into corners. however, I plan on forming a clay radius on all corners of the mold before laying up the actual part.
Keep the input coming, I appreciate it.

[John R]

Cool - if you can, can you document with pics how you do it?

Thanks,

John

[EBEACH]

Dave,
An easy way to do it would be to use a plastic container from someone such as Rubbermaid. Home Depot, office supply, and toy stores might be a good place to look for your mold. Wax the container then use a non-waxed gel coat and coat the inside. Then just glass it. You can add core material as well for insulation.

Great thing about the rotational molded plastics, they have a taper built into the part, and your piece should pull right out. If not, just cut it off. Further more, the plastic totes and garbage cans come in all shapes and sizes, even stating the volume in gallons . They have relief’s in the sides that will add to its strength.

You’ll have a great looking fish box in no time at all. [img]images/icons/wink.gif[/img]

Jim

[Dave Hirshberg]

Good Idea Jim,
But I'm very confined to the size and type of well I need . It has to cover or blend to a nonskid outline already on the dck of the boat. I bought the Melamine board yesterday and I'll photo the process for better or worse to show how it comes out. I'm considering doing one the sixe of a shoebox to see if and at what point the laminents will bend. I'll keep you posted.

[strick]

Dave- Sounds like you got it figured pretty good and it's probably going to work just fine. Looking forward to the pics. The only thing I would do different is make the flexable part of the mold out of hard board rather then using a laminate espically if you are going to throw it away when you are finished. I think it would be quick and the 1/8 inch hard board would bend very easily around the plywood has a smooth shiney surface and is easy to cut.

John- I made the leaning post out of a piece of plastic bent at a 90 degree angle. then I laminated two pieces of plywood at a 90 degree angle slightly narrower then the plastic base. The Vinyl cushion is attached to the plywood backing and then it is bolted to the plastic base. There are some handles on either side of the leaning post that are hard to see in the pic. It's a quickie job and I've always thought that I would add a tackle center to the underside rear of the post but never did. Not sure exactly what I'm going to do on the new boat as of yet.... still thinking about the stern [img]images/icons/smile.gif[/img]

Strick

Strick