First Layer On Cold Mold

I am cold molding a 24 foot speed boat with a layer 6mm and a layer of 4mm Could someone tell me what thickness to do the first layer 4mm or 6mm---thankyou

 

I would put the thicker board down first so if you have to make some cuts you can fill them
with resin and cover over with the thinner board. Hide your sins..........and less sanding.

 

Hank you razorinc

 

It doesn't matter, as the first layer on a molded build is a mess anyway. The first layer tends to be all over the place, unless on a well built form, which usually isn't the case, in a typical backyard project. You'll make adjustments and will butter up all sorts of sins and mistakes, as the second layer goes down. It's the nature of the beast, if you're new to this build method. Once you've done a boat this way, the next will have a seriously stout mold and the first layer will be more precisely fitted, saving some cursing and hair pulling, but you'll have to learn these lessons first, unfortunately.

 

WTF is a mm? Inches folks this is the US.

 

Someone has revealed to me (although he prefers to keep his name secret) that in this forum there are members who work with the metric system. But probably that is a rumor without any foundation.
If that were true, I can think of a trick question: are more or less those using this "strange" system? (Strange is the metric system, of course)

 

No great hardship to be familiar with measures in both metric and "imperial" systems, as it is known here.

 

Besides, the wood panels are sold in mm dimensions. Last time I bought plywood it was also in mm dimensions. The world is changing. Go with it or be left behind.

 

Diego,
This is embarrassing! Google has all the answers, if you really need to ask. This is an international forum; don't make Americans look any more ignorant than we are already stereotyped to be. The metric system is all around us. Familiarity with conversion factors is a fact of life.

 

America long ago switched to the metric system on a commercial level, though at the retail level, there's still enough baby boomers around to resist. The military has long ago switched, even when I was in back in the early 70's. If you open an American car's hood (bonnet for you Brits) the nuts and bolts may seem SAE, but they're actually metric. Only a few places on a car are actually SAE. Tires are a good example of this "cross over" effect. My old Suburban has P235-R15 tires on 8" wide rims. The P is for Passenger tire, the 235 is how many millimeters across the tread (about 9.25"), the R is for radial construction, and the rim width is 8" (even though it's actually wider). This cross over stuff is because the old fart baby boomers (I'm one) can understand they need a new set of 15" tires, but just can't get their head around buying a new set of 380's (mm's), which is actually what a 15" rim is. To compound this confusion is the commonality among common SAE and metric sizes. 1/2" is a few fractions of an inch of a 13 mm, 7/16" is 1/10th of a mm of being an 11 mm, etc.

So, in all essential and practical purposes, America is metric, though half the population is too stuck in it's ways, to make the adjustment. Our kids and grand kids have and are taught this way, but the old farts have to die off before it's fully realized.

 

Can't teach old dogs new tricks ? At least Americans did not have to adapt to decimalised currency from pounds-shillings-pence in living memory, back in the day many older people here struggled to make the transition (50 years ago). Some older folk in cash retail just retired !

 

What PAR Said. I was explaining that to my wife earlier today. Darn near everything made in this country is made to metric dimensions, but the marketers still sell it in standard units because they think the public is stupid and won't buy metric. But those good old boys buying ammo for their AR15 are buying 5.56 mm ammo, and PAR pointed out the tire thing. Cars are virtually all metric, and if you buy a boat you better have a set of metric wrenches to work on the engine. I have both, because my boat's engine was built in 1971, but my car engine is a 2005 and the engine was made in Germany by Opel. Read any standard put out by SAE, ABYC, UL etc and the dimensions are both in metric and standard. Even the sport of track and field (I ran the mile in track back in the sixties) is all metric now. 100 meters, 200 meters, 400 meters, 800 meters, 1500 meters. 5K, 1oK, etc

 

Calm down fellas, just a joke. I'm quite familiar with the conversion, but equally irritated, just as much so when dealing with fathoms and feet. When you build things by the inch for 25 years the eye is trained to see 1/8" or .125 not .3175, just sayin. potato, potato.

 

Well I have to admit, I use feet and inches just as much as metric, still. Even though I built two dinghies with metric ply, they are 7' 11" and 11' 11" and 4' beam. So it's a trade off. Fathoms to feet? A fathom is in feet, 6 of them. It's that "by the mark twain" stuff that throws me.

 

I'm sure the ~10% difference between US and "Imperial" gallons caught a few out over the years.