cold molding vs strip building for dinghy

[peterchech]

Which is lighter, cheaper, quicker etc.? Ive never built either and so i need to chose, and lightness is my number one importance but price a close second.

I think i really understand the strip building process, but not too clear on cold molding. I was thinking to use two layers of 1/8 in ply stapled to the frames with metal brads, but how do u get the brads out later? Pull them or just leave them and sand them smooth? Is there any hidden cost besides the sheets of ply and a few gallons of epoxy if im building a small open boat? (Ie is vacuum bagging necessary for a home builder) and would 1/4 in thick cold molding be any lighter than 1/4 in stitch and glue hull?

Any thoughts on this welcome

[CatBuilder]

Asking a follow on question:

What is the lightest, "yacht tender looking" dinghy you can build or buy that will carry 6 pax and luggage?

Originally Posted by peterchech

Which is lighter, cheaper, quicker etc.? Ive never built either and so i need to chose, and lightness is my number one importance but price a close second.

I think i really understand the strip building process, but not too clear on cold molding. I was thinking to use two layers of 1/8 in ply stapled to the frames with metal brads, but how do u get the brads out later? Pull them or just leave them and sand them smooth? Is there any hidden cost besides the sheets of ply and a few gallons of epoxy if im building a small open boat? (Ie is vacuum bagging necessary for a home builder) and would 1/4 in thick cold molding be any lighter than 1/4 in stitch and glue hull?

Any thoughts on this welcome

Lightest is cold moulded, cheapest Strip planked, quickest (not always) S&G.

Do not use ply for cold moulding, but veneer instead, you otherwise waste a lot of material because it is laying in the wrong direction and has to be compensated for, by additional thickness.
Use "Raptor" plastic staples on cold moulded hull veneer, you can easily sand them down. Pulling metal staples (a must) is a pain in the....

As a absolut novice you will be best underway with a strip planked boat.

Regards
Richard

[Homefront]

Another vote for strip planking and glass/epoxy. No vacuum bagging needed.

Have you chosen a design? Do you have the plans? Station moulds can be made directly from the table of offsets and most plans give a stem and transom profile.

Cold moulding could be full of pitfalls, without proper guidance.

You don't mention what experience you have, but if you've never built a boat before you would do well to avail yourself of the many well written books available on lofting and picking up lines, planking, glassing, etc.

Here's a great place to start: http://www.woodenboatstore.com/Books/departments/1/

[peterchech]

Well i have built two small wooden boats before and im kind of itching to try something new. I guess strip building is the way to go but tere is just something about. Old moldinghat makes me give it a shot before i do strip building, maybe its just the idea that i wont have to deal with fiberglass and sanding fiberglass. My other boats were s&g and sof, but i also built a wooden surfboard using a process very similar to strip building so i guess i wanna try something else... i know veneers are ideal but i only have access to ply will that be as heavy as s&g if i have to build it up to 1/4 in?

And one question, when pulling metal brass how do u do it, between layers or all at one shot once entire hull is done? I am guessing that the first layer wont hold its shape when dry if u pull out the brass but i really don't know... thanks for the help

[peterchech]

Btw i was thinking to build an ilya outfitted canoe, keeping it light enough to cartop, i have the offsets for the molds

Originally Posted by peterchech

..

It will probably be heavier. (no idea what you mean with building up to 1/4)

Again no idea. What is metal brass? The staples?

How would you pull them when the hull is done? Of course one pulls them after each layer is cured (completely).
The Gougeons describe a valid method in their Bible. (heavy packaging band)

Regards
Richard

[peterchech]

Haha sorry smartphone doesn't recognize the word" brads" and changes it to brass... very smart phone huh? Sorry i don't have the gougen bros book and too impatient to wait for the mail order to arrive... so packaging bands hold down the first layer while the second is applied? What are packaging bands exactly, like big rubber bands or bungees?

The "brads" are a unknown quantity for me, sorry.

Is it possible to speak clear English here please?

[peterchech]

At home depot and onseveral boating websites that were called brads. They are essentially small nails that are shot out of a staple gun. A previous poster refered to them on this tread. Google them if that isn't clear enough

We have no home depot in Europe (thanks god) and as a boatbuilder I don´t use "brads".

It is better to use staples, not nails. You cannot pull nails and they don´t distribute the load you need. Cold moulding is definetively done with staples only. (and I google nothing to reply to a enquiry)

The packaging band as I name it is the plastic (in earlier years it was metal) band that is wrapped around heavy crates and then cramped with a small handtool, to hold the box together.

You shoot the staples through a strip of this band laid over the veneer. When the resin has kicked sufficiently you can pull the band with the attached staples.

[peterchech]

Thanks that's a great idea!

[Boston]

that is kinda an interesting trick
question though
if your sanding a bit between layers to get a good fit on the next whats the banding helping out any
why not skip the banding until the final layer where you will want to nix the staples and just leave the plastic staples in the rest
seems like if you set the air on the stapler right you should get a nice snug fit and then just sand off the heads that might be standing proud of the wood, doesn't seem like it would mater if there is something left of the crown other than in the final layer where you have removed the staple altogether. Your slathering it with epoxy anyway.

cheers
B

speaking of which I asked on another thread but might as well fire away here as well
is there really a financial penalty for going cold molded when there is such a glaring difference in the cost of fasteners
plastic staples used in cold molding and epoxy cant possibly be as expensive as bronze screws

time considerations aside whats the financial difference
if its the same then cold molding would win out by providing a better stronger lighter hull for the same cost but takes more time

Yes Boston,

when time is no issue (and the skills are there), CM is the better way. Costwise it comes out nearly equal, because veneer is expensive and the staples are not for free too.

I was referring to plastic staples already, they are the best way to go because you just sand them down if need be. But the thread opener obviously does not like that way.
And for metal staples (which MUST be pulled), the Nylon strap is the way to go

Regards
Richard

[Boston]

thanks
B