US1M Mistral Construction Project

Greetings everyone,
I would like to share with you the construction of my first US 1 Meter boat the Mistral.(Actually my first sail boat period)
I welcome all comments and questions and will be glad to answer them if I can.
Here is the first shots showing the hull planking layup as shown in the US1 Meter construction manual from the AMYA web site.

With the hull all planked ,sanded and primed, I am now applying the mold release wax to begin the mold casting process. Since I do not want to go through the trouble of a fibreglass mold, I am going to try the Ultracal 60 casting material as described in the “Composite Molding Made Easy” by Terry Luckenbach.

Looks nice! Can you explain to me in simple terms how you made the pictures appear in the text?

Vancouver Island


I just found a great way to post the pictures.
Here is a free picture hosting site.
Just upload the picture and copy the messege board link. Then come to this site and insert the link in your messege.
Works great![:-bouncy]


Nice finish on the hull.
Have you got a link to “Composite Molding Made Easy” by Terry Luckenbach.


Thank you for the link. I can now post pictures easy as pie. You may have created a monster.

Vancouver Island

By the way, your shop is way,way to tidy!! I couldn’t build anything in a shop like that, I would be
afraid of getting something dirty!

I lost my test photo too ![:-cry]

Although, it may be the server is down, as even the link to ImageShack doesn’t work this AM !


I thought it was too good to be true.

Vancouver Island

It’ twue,It’s twue!!!

Vancouver Island

Ummm - Don,

Many of us share in your excitement too, but is it possible you’ve seen one too many re-runs of BLAZING SADDLES ? [:D] [:D] [:D]

[:-graduate] <font size=“1”>reference: Mel Brooks’ girlfriend played by Madelyn Kahn seemed to have that same lisp! </font id=“size1”>

Hey guys,
They are there now…[:-cowboy]
The image site may have been down this morning. Everything seems good now.
BTW here is the link to Terry’s DVD on Composites

I now have the plexiglass for the base so I hope to pour the mold this weekend. I will post pic’s.

I am now applying rubber cement to the temporary deck which will keep the hull from sliding around while the mold is curing.

Now with my foam cutter I am cutting out a border the is 1 1/2" higher than the highest point of the hull bottom. This will be glued to the plexiglass with 3M77 adhesive.

I am now going to use some modelling clay to seal the edges of the foam to prevent the Ultracal from leaking of from inside the box.
With the box complete, we will be ready to pour the mold in the morning.[:D]

Well I began to pour the Ultracal 60 this morning. For everyones info, the mixture is 2 cups of Ultracal 60 to 6 oz. of water. I mixed it in a batches of 8 cups to 24 oz. of water.
As you pour it over the plug, you need to go slow as to not create and air bubbles.
With the entire plug covered, we can speed up the pouring process.

I kept pouring and pouring and pouring.[:-bigeyes2] Half way through I decided I needed to reinforce the side with duct tape to prevent the sides from busting apart.
Well, the jury is still out on this molding method for a hull of this side. The Ultracal is made for it no doubt with just a .006 shrink rate and rock hard when cured. I ended up using about 85 lbs. of the Ultracal to fill the mold.[:-bigeyes] This is going to be one heavy mold. I may need a tool and die shop crane to lift it. It may be awhile before this dries and the unvailing occurs. The next post may be in about 2 weeks or so. I would hate to pull off the sides and have it fall apart on me.

So much for waiting for 2 weeks [:-sleep] After 3 hours of curing the “step” [:-boggled] is hard to the touch already and giving off a fare amount of heat. You can bearly touch it and you can see steam rising from it. You can also see from the picture that it is starting to develop whiten dry spots. So, being impatient that I am I gave removing the foam sides a try. No problem [:)] they popped right off.

I filed off the edges and cleaned up the base with a putty knife. Tomorrow I will flip this guy over and try to extract the plug.

I fliped the mold over this morning and this exposed the deck surface. I then began to clear away the edges of the hull removing the overhanging Ultracal from the top of the deck.
With the temporary deck in place it made it to difficult to compress the sides in a little to break the seal to the sides so I had to remove the deck to allow this.

I held my breath and began to pull the plug out…[:-shake][:-shake]

[:-slaphappy][:-slaphappy] Whoo Hoo!!!
It worked. It looks perfectly smooth inside with no chunks coming off the walls. The discoloration you see on the wall must be like some kind of water spot in the Ultracal. I can only see a few pin holes in the surface. I took some compressed air and went over the mold to make sure I exposed any pin holes that might be in the surface. The next step would be to fill the pin holes with a slurry of the Ultracal and sand it smooth.

that look fantastic
congrats on a job well done. you hev done something the first time that took me close to 10 yrs to do. and i still have not got it right totaly. i am pulling a hull right now. i am looking forward to seeing you pull a hull. my fingers are crossed for you
remember you need atleats 4 coast of mold realses wax and 1 coat of pva
good luck
longlive the cup and cris dickson

Cool way of moulding, not used that method before. Niiice job!

Luff 'em & leave 'em.

Cougar and Matt,
Thanks for the compliments.
I really was amazed at how easy this stuff is to use. Although I probably would not use it to make anything bigger than this. It is darn heavy. I suppose I could use it as a parking block for the car when I am through with it.[:-bigmouth] I have put 6 coats of mold wax on and the PVA is ready to go on. I will need to stop and pickup the carbon in the next day or two. I think we will go for the clear gel coat over the carbon.[:)]
I have already started thinking about the deck construction and I think we will be trying something a little different.[;)]

Tom -

just a suggestion… [:-bulb] can you please resize your photos to about 4" x 6" or so before you post them? Yer’ killin’ us guys with dial up modems ! Too big of image sizes takes too long to load. [:-headache]


Sorry about the picture sizes and quantity. I guess I got a little carried away with this new found way of posting. I have weeded out a few of the needless pictures and will cut down the size of future ones.
BTW…I picked up all the exopy products and will pickup the carbon tommorrow.