Mold support

Why not the whole MDF?
The mold is 5.4 meters long.

 

Different material = Different CTE. Note the support has a gap and not touching the mold.

With metal boxframe, support is even less.

Did you get the book?

 

@rxcomposite the book needs 7-10 days to arrive to my location so I still don't have it.

Let me know please if I unterstood well.
In the picture below are you saying that the wood that is running from one side to the other on the deck shouldn't be touching the mold or just a small area and then put it in place with cloth or maybe cabosil?

 

If I had to frame anything like that kayak mould,the frames would be bedded on an area where there had been a local addition of coremat that covered the entire bonding area and a thin mat over the coremat.I would also run the longitudinal stiffeners along each side to avoid the risk of hinge points where they end as they would reach the transverse frames.That way you would still have the cockpit area clear for access when bonding the two halves together.You also have the choice of running the longitudinals first and then adding the transverrse sections as they primarily prevent the mould tumbling over while laminating.

It is also possible to remove a sliver from the frames and replace it with foam.The transverse sections can be very useful if the mould hangs up on the plug as it gives you a place to bolt a sturdy beam-to which a jack can be applied.

 

Yup. It is just a support. Assuming your mold design is reasonably thick. Your mold has a very high aspect ratio. I suggest a metal frame. There are many approaches. Wet Feet approach makes sense and is workable.

 

Thanks for all suggestions; the mold released fine from the plug both the deck and the hull with minimal effort. The thickness is 8mm.

@wet feet, I'm not joining the deck with the hull inside the mold, I do a different method outside of it which works quiet well.

 

Thanks a lot for the replies. One more question please.
How long ideally I should wait for complete curing until I start waxing the new mold and use it?

 

It is cured when you can no longer smell the volatiles like a week or so. To accelerate, place it in a hot sun for two days. Once heated, you can smell the strong odor of styrene. It is cured when you can no longer smell it. Lacking the sun, you might try heat lamps indoors. The mold should become hot and the smell of styrene strong. Be sure to vent out the volatiles. If not cured properly, the 1st part will stick to the mold. MEKP in the laminate tends to seek out the uncured mold and tends to penetrate however thick the wax you apply.

We had one mold destroyed because the part stuck to the mold. The guys omitted the curing part and relied on heavy waxing.

In our case, we place it in an oven to "break in" the mold. For insurance, we use spray liquid Partall for the first part. Partall seems to block MEKP migration.