Retooling molds?

Im wondering about the retooling of an older mold vs constucting a new mold. Im going to be visiting the yard that has the mold soon. The yard tells me the mold is fine and usable. However I am not so sure. Mold is about 20 years old and hasnt been used in at least 10 years. This is for a fiberglass boat in the 40 ft range. Im counting on the fact it is not usable.. but I dont know enough about molds to know. Also, I am not sure if retooling is successful, or possible. Anyone know about retooling??

Thanks
James

[Corpus Skipper]

Nomad??? NOMAD!!!???? This one's for you!

Hi James,

A twenty year old mold could be in better condition than a new one...
There are a few things you might look at:

First, was it built well, was care taken? - if it looks poor on the outside, whats it like on the inside?

Then,

Is the mold "Right"? ie- is it twisted, bent around a centre line, symmetrical?
Was the original plug built true? How has it been stored/supported for the last ten years? Do the molded parts fit together well - especially hull/deck join? will moving the mold open up a can of worms?

Are the mold laminates and framing in serviceable condition?
How has it been stored -up side down in the corner of a shed, or right way up outside in the weather?
Is it fair? and I mean Really fair. Look at the reflection (in the mold) of something straight like the edge of a shed or the roof line- is it wiggly, or fair? Problem areas might be near framing or corners.
Looking at a built boat will tell you a fair bit (pardon the pun..) about the molds.
Does the gelcoat colouring look like a patchwork quilt - indicating lots of repairs? How many boats were built off the mold?
Are there stress cracks in it?

Does the tooling gelcoat still have a gloss? (It would help if the mold was clean) If the mold was well stored -protected- but the gelcoat was "chalky" then it might be indicative of further evils in the mold, or construction methods.

Will the mold handle your build methods - ie post cure/cooking, RTM etc.?
Does it come with full design deliverables or a set of construction drawings?

If all was right in the world and the mold/s were in perfect condition then all you should do is remove and replace the release agent.

If the mold was fair and in good condition but the gelcoat was toast, you may be able to cut/polish/re-finish it, or even sand back and re-spray/re-finish.

Much more than that and I think it could be easier to bulid another mold. To do that you could take a part out of an old mold, fair it, and use it as a plug for a new mold.

Good luck,
Rob

Hmmm.. Lots of good info on here. Thanks. The yard told me first time they didnt know the condition as it was covered and had not been viewed in many years. Second call someone had removed the coverings and given it the OK. Next call I was told it was stored inside and in good shape.

Forgive my lack of knowledge, but I am an just getting started in all of this and dont know what the mold laminates or framing is?

Also what is the difference between full design deliverables or a set of construction drawings?? I am fairly sure it has no laminate schedule, but Im hoping the yard that built it can give me that info. Other than this I dont know.

Any book or other type of resource someone can point me to, for learning more about molds and boat building in general I would welcome it..

Thanks
James

Originally Posted by RThompson

Hi James,

A twenty year old mold could be in better condition than a new one...
There are a few things you might look at:

First, was it built well, was care taken? - if it looks poor on the outside, whats it like on the inside?

Then,

Is the mold "Right"? ie- is it twisted, bent around a centre line, symmetrical?
Was the original plug built true? How has it been stored/supported for the last ten years? Do the molded parts fit together well - especially hull/deck join? will moving the mold open up a can of worms?

Are the mold laminates and framing in serviceable condition?
How has it been stored -up side down in the corner of a shed, or right way up outside in the weather?
Is it fair? and I mean Really fair. Look at the reflection (in the mold) of something straight like the edge of a shed or the roof line- is it wiggly, or fair? Problem areas might be near framing or corners.
Looking at a built boat will tell you a fair bit (pardon the pun..) about the molds.
Does the gelcoat colouring look like a patchwork quilt - indicating lots of repairs? How many boats were built off the mold?
Are there stress cracks in it?

Does the tooling gelcoat still have a gloss? (It would help if the mold was clean) If the mold was well stored -protected- but the gelcoat was "chalky" then it might be indicative of further evils in the mold, or construction methods.

Will the mold handle your build methods - ie post cure/cooking, RTM etc.?
Does it come with full design deliverables or a set of construction drawings?

If all was right in the world and the mold/s were in perfect condition then all you should do is remove and replace the release agent.

If the mold was fair and in good condition but the gelcoat was toast, you may be able to cut/polish/re-finish it, or even sand back and re-spray/re-finish.

Much more than that and I think it could be easier to bulid another mold. To do that you could take a part out of an old mold, fair it, and use it as a plug for a new mold.

Good luck,
Rob

[
Mold Laminates: The actual FRP that constitutes the mold shape
Framing: The structual support network for the Mold Laminates, also stabilises the mold on the floor, might be made of tubular steel, plywood, or composites of both or even something completely different.

By full design deliverable I mean anything to do with what a design office might supply with a design- all the graphical material, numbers and specifications that may not be included in "construction drawings".
Someone referring to "construction drawings" could mean just about anything Drawings for a 40' production boat could be three or four sheets or 20 to 30 sheets..
I would imagine, from what you say, that they will supply a minimum of information on the boat, and how to build it.

, for learning more about molds and boat building in general I would welcome it..

Gourgeon Brother's on Boat Construction (West System) is an excellent boat building text. (I don't have it in front of me right now, so the name might be a little wrong) If you were to buy it, and read it from cover to cover you will save yourself a lot of fumbling around. It dosen't directly address production FRP, but it is very relevant to any FRP composite building.
Learning whats involved in building the boat before you part with your money will probably save you a great deal of grief down the track. Really.

Rob