Two part mold registration

and having proper plans/diagrams for the top and bottom can help with the measurement, how would you do it without actually making a diagram incase the plug deviates from what the diagrams are, im thinking for of a "freehand" design to fit the top deck after the fact
Here is another pictures, traditionally the plugs are made ups side down and the parting flange is already on this, I also assume the BULKHEADS EXTEND ABOVE the plug parting line, how will the top deck be fitted?

 

If it is the same boat in the last two posts,somebody made those guys a lot more work than was necessary.I would have eliminated every other frame from about No 5 to the stern and saved a bunch of time that way.The hull mould in the most recent post appears to be devoid of framing and I do hope the fellow who made the decisions about frame spacing on the plug can be kept away from the job.I also hope the guys on the shop floor have enough sense to mark the waterline in at least six locations before releasing the mould.I absolutely guarantee that somebody or other will insist that a laser level is the only way to do the job.It can be.It can also be wrong if it has been dropped and not verified to be accurate.So my habit is to use a water level to mark at least three targets,on the workshop walls,on benches or even the intended boat with a pencil line and to verify that the laser agrees with the line from the water level.In the unlikely event that nobody has been persuaded that a laser level is essential,a water level alone is quite sufficient as long as the people on both ends understand which part of the meniscus to reference and the perils of parallax.

To deal with the boat shown isn't difficult if the building has overhead cranes as the framed mould can simply(!) be lifted free and wheeled away for trimming and then waxing.Inverting the plug isn't necessarily difficult or dangerous if care is used.A novice has several pitfalls to avoid and the possibility of damage or injury is a very real possibility,which absolutely has to be guarded against.The whole process is made a bit more complicated if one has to wheel the whole thing outside and use a hired in crane.It isn't impossible and it can be really useful to have a couple of dozen old tyres of various sizes to cushion the plug as it is rolled over.Two good crane drivers can turn them with very little risk of damage if the funding for two cranes can be extracted from somewhere or other.

With the hull plug in the same attitude that the boat is expected to assume,it can be checked for level and squareness before starting on the deck plug.Depending of the way the construction was planned,and if it wasn't planned things won't be made easier,work can progress.Bulkheads are irrelevant to the plug and will be bonded into the hull when the real hull is laminated.The framing for the plug can be attached to the existing plug framing with butt straps and if the plug had insufficient thought put into it's construction,some of the framing will have to be cut away to get down to deck height in places.For such situations it will be necessary to produce accurate patterns,which once again is easier with a good CAD model of the boat.In the case of the boat shown,the people working on the deck plug will be cursing the number of frames they have to perform gymnastics around as they will have very little working space.In other situations you will have to dig out straight edges,framing squares and dividers.The plug frames will obviously stop at the inboard surface of the plug and a strip of ply or MDF equivalent to the distance to the outer surface of the vertical flange is simply added all round the outside of the plug and then a horizontal flange is attached below it.

 

Thank you for your attention to this thread - So how would you fit the top deck to the vertical strip applied to the outside circumference of the hull? Are you saying flip the plug over and build the deck over it? Having to possibly cut frame bulkheads for the proper access?

 

Its the easiest way to get the job done.You are creating the surface that the component has to have and there is no simpler way.It is important that the hull plug has not distorted,and it will need to be checked.

 

OK same question except building the two parts with an OUTWARD FLANGE rub rail
Seems like I would have to integrate the parting flange into the mold plug somehow because it may be tough to register the two parts if sprayed separately
I will be making by hand without computers so I feel the only way would be to spray the bottom mold first and then build the top deck directly from the bottom, WITH a stronger more accurate flange...
How would you build the flange for this type of plug?
Seems to me the plug would need to be one piece for this type of mold flange as the "shoe box" style would have more allowance for fitment
This is how I build my latest mold
Hope I am making sense

 

You are making some sense, but are we discussing the plug construction or the series production of full size boats? The usual solution for full size boats is to assemble the deck on the hull with both out of their respective moulds. Which implies that there is little to guarantee accurate registration of the parts. Something the size of a kayak is commonly assembled and bonded by bolting the moulds together while the components are still in place and then bonding them. Which does give good alignment,but leads to more cosmetic work on the joint line.

 

Well thats a good question - I guess I am trying to learn how a meter long model boat would compare to a full size 5+ meter long boat (how both types of plugs needs to be designed). Issue is I don't really want to make the model boat with a shoe box joint line, I want to use the outward flange, so on my next build how should I incorporate the parting board? I feel I need to build the parting flange in into the plug directly without using a flimsy plastic and fill the holes with clay. Because the plug itself will be all one piece, not two sperate pieces. I feel how the plug is made will determine how eventually the hull is made during production off the mold anyway. For the shoe box design, I guess that would need two separate plugs??? Am I over thinking this

 

Make an accurate template of the plan view of the sheer.Then use it on both sides of the parting board.Do keep in mind that you will have no alignment of the components unless you drill precisely square holes through both moulds that are outside the flange width you propose to use.You would have to do the same with two separate plugs.You would get a neater joint if you added an inward facing flange,but it would be a challenge to get a void free edge.