Dinghy mould - To Buy or Not to Buy?? Auction ends soon

NZjohnson90

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OK spur of the moment, just saw an Auction for a 8ft dinghy mould on trademe
http://www.trademe.co.nz/Browse/Listing.aspx?id=272730431.

I know it's old and pretty well used but just fancy having a go at building one, just for fun. It's super cheap so I got nothing really to lose on the mould (next cheapest I can find in NZ is $1200).

How much, roughly would I be looking at for material costs/amounts, and build time.

Is it achievable for me, I move house maybe 3 or 4 times a year, have limited tools and may or may not have a garage to work in, but I am fairly practical minded and and can figure most things out.
 

Bondo

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Re: Dinghy mould - To Buy or Not to Buy?? Auction ends soon

Is it achievable for me, I move house maybe 3 or 4 times a year, have limited tools and may or may not have a garage to work in,

Ayuh,... Unless you plan to set up a production Shop,... Forgetabout it....
 

erikgreen

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Re: Dinghy mould - To Buy or Not to Buy?? Auction ends soon

Looks too damaged to be usable... you'd end up resurfacing the whole thing.

If you really want to try making one, either get a set of the free/low cost plans for composite (plywood and glass) dinghies online and build it with stitch and glue, or if you must, build a foam and plywood plug, surface it, use it to pull a female mold, and then use that to pop out a few boats.

Depends on whether you want to learn by doing or end up with a usable boat, or both.

This is another one of those projects I might take on if I had free resin and glass, plus some materials to resurface that mold, plus a lot of free time, plus a use for a solid glass dinghy that small :)

Erik
 

SBTOM

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Re: Dinghy mould - To Buy or Not to Buy?? Auction ends soon

I have to agree. that mold looks pretty beat up and you would probably spend more time and money on trying to restore it than it would be worth. Its is much easier to sand a plug than it is to repair a mold because you would have to get in and grind out, repair, fill, sand, and fair all of those corners that look like they are either de-laminating or have been filled with putty. It would be almost impossible to get that inside surface perfectly smooth.

Also, it doesn't look like that mold was made properly. The inside should be nicely polished tooling gelcoat... I think that most of tooling gel coats are either black or reddish orange? someone else might know that, but one of the possible reasons why it looks like it has been repaired so many times is that if you don't a low shrink resin and tooling gel coat, the mold won't hold up as well. Good luck with the search! - Tom
 

NZjohnson90

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Re: Dinghy mould - To Buy or Not to Buy?? Auction ends soon

ok, so maybe I should forget about it......

Whats the dissadvantage of the well used mould (is it just the cosmetic finish in the end?)

And do you have any idea for materials needed. I do have access to real cheap resin and possibly glass. Have boxes of glass sat in the garage right now, but not sure it's usable for this as its odd shape offcuts, but I'm sure I can get more.
 

SBTOM

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Re: Dinghy mould - To Buy or Not to Buy?? Auction ends soon

the biggest disadvantage would be the end finish, but also remember that with this type of mold you are building the boat from the outside in. So your first coat would be the gelcoat that would eventually be the outside finish of the dinghy....

Simply put, a beat up looking mold will produce a beat looking dinghy unless you want to be in a TON of work... That being said, I think that most iboaters will admit to having taken on a project that was less than practical!
 

NZjohnson90

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Re: Dinghy mould - To Buy or Not to Buy?? Auction ends soon

OK, outside finish I'm not too bothered about. As I said it's just fun and I couldn't afford a mould that would give a perfect finish anyway.

BUT.... That's only if material costs are reasonable too though. Anyone know how much resin/mat/ply I would need? Roughly
 

erikgreen

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Re: Dinghy mould - To Buy or Not to Buy?? Auction ends soon

Paging ondarvr.. ondarvr to the thread, please :)
 

NZjohnson90

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Re: Dinghy mould - To Buy or Not to Buy?? Auction ends soon

OK, been trying to google/look on here to find answers but not getting far quickly.

$120NZ ($6/meter) 20m of CSM (3 layers, 6m each) + couple spare
$100NZ 10 Litres Poly (using 450gram csm, that is 1/2 litre per meter roughly?)
$100NZ 10 litres Gelcoat

$320NZ + consumables and some bits of ply for seats.

Does this sound vaguely right to anyone. I really am guessing based on the little info I could find.
 

ondarvr

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Re: Dinghy mould - To Buy or Not to Buy?? Auction ends soon

In your position, no shop, no garage, moving frequently, no tools, it would be cheaper to just buy a small boat.

Glass parts weigh about 1lb per sq foot per 1/8th inch.

This boat would be slightly over 1/8 thick, maybe 3/16. plus a few odds and ends. More if you want it stronger.

it's going to cost you a little over 3.00 a lb to build it here, not sure of the prices there. But you will need to add some for waste, plus fixing up the mold.


You just need to figure out the Sq feet.
 

NZjohnson90

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Re: Dinghy mould - To Buy or Not to Buy?? Auction ends soon

OK, might not have been a good idea???? but I bought it anyway. The auction was ending and I figured at $30 not much to loose if I decide against.

I know I could have bought a boat much cheaper than this will cost to make, but the point is that I will have made it!! And I don't even really have too much interest in the finished boat - I have my ski boat for fun. I just wanna have a go for the fun of it.

OK just called around some shops and suppliers. I recon with a bit of time and effort the materials can all be gained cheap enough - just for comparison this is what I have found in the last hour alone.

Gelcoat
Marine shop - 500ml $30
Supplier - 1000ml $16.25
Boat builder - 1000ml 10 if I bring my own container

Poly Resin
Marine shop - 1000ml $52
Supplier - 1000ml $16.25
Swimming pool manufacturer - 1000ml $4 If i bring a container.

CSM 450gm
Marine shop - $9 sqm
Supplier - $6 sqm
Boat builder will sell me a roll 30KG for $150 (thats less than $2.50sqm) but thats far more than I need.
Have not found a cheap source for small amounts yet, but I will!!! Leftover rolls come up on trademe often enough from other peoples project

So based on 6sqm and 3 layers of 450g csm, thats 18sqm.

so totals
CSM - $108
Gelcoat - $40 (based on 0.7g per sqm)
Poly Resin - $180 (based on 2:1 ratio with the mat weight)
+ release agent $????
+ Ply (will get that free or cheap from somewhere)
Various consumables $?????

Tools I have limited as I said before, but as I just finished some glass work on my ski boat I think I have all I need for this. Just need to wait till I got a house with a shed to work in. Probably after the snow season.

So Probably looking in the region of $400 for the finished Boat??
 
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