Plug Construction and post cure.

If I am buying a CNC machined plug, with putty and foam over OSB, I'm expecting very high tolerance. But this combination of materials is going to stretch and twist all over the place as it goes through changes in heat and humidity. It's been suggested that we will be able to get higher tolerance if we post cure the substrate prior to applying and machining the putty.

I'm asking for your experience with these issues. Who has used a post cured plug to build a mold. Did you obtain higher tolerance from that than with an uncured plug? Is it all a moot point since the plug is going to be loaded onto a truck with a forklift and shipped cross country?

What do you guys think?

 

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compassboats.com
956-237-8075

 

If what you are referring to as OSB is what I believe it to be;namely large wood particles formed into boards,you may be faced with the conflicting behaviour of the mixed materials.The wooden parts of the structure will move in response to changing moisture content and not necessarily in a uniform manner,the plastic elements will move according to temperature.You make no mention of the physical characteristics of the foam that will be used.Have you consulted the suppliers of the materials?What kind of dimensional tolerance are you seeking from the component to be made?This is not necessarily the same as the accuracy to which the plug is machined as both the mould and the subsequent moulding can be subject to distortion as the resin cures.

 

Clark,

You should at least coat the OSB sheets with something, varnish, polyester, epoxy or whatever to limit expansion and contraction from changes in humidity.

Probably wouldn't hurt to shrink-wrap it for shipping either.

Yoke.