Box Seats DIY Fiberglass Mold
 

Been playing with the idea of making box seats for my 23' Tsunami. Actually they're more than box seats - the are more like an "L", with a seat facing aft for passengers.

After my resto, I installed (2) pedestals thinking that was good enough for me. Flash forward a few years; wife, (2) kids !

My fishing boat has become more of a family boat - even thinking of getting a tow rope and inflatable to pull behind !!! Just a metaphor for my scene !

Anyway, I saw a really nice looking, mid 70's 26' Bertram recently with great looking, aftermarket I assume, fiberglass "L" boxes; each box had a swing seat mounted on top of the box for the helm and a nice aft facing cushion/seat for facing aft.

Questions :

- How hard is it to make a mold for this and can the mold be used twice or do I have to destroy the molds to remove the fiberglassed work ?

- After you spray mold release, do you spray gelcoat in the mold, then mat ?

- Where do you glass in plywood for support - the whole structure ?

- What layup would you recommend using polyester resin ?

This will be my first mold attempt and if it goes well, I will have to plan out a hardtop next... Or, the hardtop and then the box seats ...

Thx

Exactly what I was thinking. I'm watching this one

If I had the coin I would get two of these for my Sceptre

http://www.nauticaldesigninc.com/ima...aning-Post.htm

RIP,

Thats the one !!! Who makes it and how much ? I think I have to make it myself due to $$$ - unless its not too much $...

Captain Cabo on bloody decks has built a number of similar things by glassing wood and they come out super nice.

Don't want to glass wood per se.

Want to make a mold with wood/melamine - then gelcoat, glass in and add wood to areas that need the wood structurally.

Do all sides need wood glassed to them for structure ?

I would core the whole thing but use core cell instead. Nautical designs has come a long way over the years. Looks like a quality product but at nearly 2k apiece thats some serious coin.

strick

Thx Strick - would I need to make two molds or do you think I could get away with one ?

You have a preferred layup schedule or is it somewhere on the site already ?

Here are a few ideas:
first on the Moesly 21, then on a Formula 233 and finally on the Seafari. Only the Moesly unit is glass. The support is only 3/8" ply and only under seat - I'll get a closer look for you tomorrow if you like. The wood is not glassed in but still solid 47 years later...

http://i1011.photobucket.com/albums/...-01-24_506.jpg

http://i261.photobucket.com/albums/i.../frontdeck.jpg

http://i261.photobucket.com/albums/i...s/5f4789e2.jpg

If you want to get fancy make a mdf mold split it down the middle add a flange to both halves so you can un bolt it to help get the part out. Considering you want two of them.

Lay up 2 layers of 1.5 oz matt 1 layer 1708 3/8 core cell 1 layer 1708 all corners re inforced with the same type cloth during each layer.

strick

Strick,

A few questions:

The spilt mold would leave me with a seam that would have to be faired etc, right ?

If I decided not to use gelcoat, what would you put down first as a base ?

Just two layers of 1.5 oz mat would do it ? Not familiar with core cell, but would I put down the two layers of 1.5 oz, then core cell and then more mat on top of that ?

Would I have to weigh down the core cell on each side till cure ? So, one side of mold at a time ?

Lastly, what do you use to create the radius' inside the mold ? Clay, cabosil, other ?

Thanks - Alan

Strick,

A few questions:

The spilt mold would leave me with a seam that would have to be faired etc, right ?

If I decided not to use gelcoat, what would you put down first as a base ?

Just two layers of 1.5 oz mat would do it ? Not familiar with core cell, but would I put down the two layers of 1.5 oz, then core cell and then more mat on top of that ?

Would I have to weigh down the core cell on each side till cure ? So, one side of mold at a time ?

Lastly, what do you use to create the radius' inside the mold ? Clay, cabosil, other ?

Thanks - Alan

You may be able to hide the seam with clay and get away without having to fair it if you decide to go with Gel. I like to use duratec sanding primer which is a two part primer that is easy to sand to a nice finish. You can Awlgrip over it easily.

The seat boxes I did on the 25 seafari have the following:

2 layers of 1.5 oz matt
1 layer 1708
3/8 core cell
1 layer of 1780

They are very strong, solid, and light. When you put down you core you are going to want to putty in between the gaps around the coreing prior to the last lay up.

Unless you vacuum bag you will have to weigh out each side like you eluded to.

There are lots of tricks for the radius. I have used clay, bondo. cabosil/microballoons, pour foam. For larger radius's clay is impractical so you are going to have to get creative.

strick

Ok'ey Dok'ey.

Now I wish I had some of your nice warm california weather to try this now ! NY is FREEZING !

Thanks for your expertise !

Alan

from my archives :)

looks like the core cell was stapled down in the image above. I carved out foam and glued it in place then cabosiled over it and sanded smooth for the big radius's....lots of work but came out nice in the end.

For one off construction I'm not convinced its easier to build a mold and then core the part vs. build the part and then laminate it.

I would be mighty happy to have Capt. Cabo's glassed wood console and post on my skiff...

http://i1015.photobucket.com/albums/...d/IMG_1543.jpg

That consel looks great. I'm sure he has his methods down to a science and can whip out one of those fairly fast and make it look good. Having done it both ways many times over myself I have come to the conclusion that I get a better part with a one off mold. Better meaning a lighter, stronger laminate, and a much smoother finish to work with. If you can keep complications such as alligators down to a minimum then it will be faster.

Keep in mind that with a mold you are glassing in one direction and thus building a TRUE laminate. With the glass over wood method you are using glass to hold together the wood. You have to glass both the inside and out side of the finished part to make it strong....thus you are glassing in two directions. Anything with a wood core is going to be much heavier then using foam core products.

Lastly I feel that glassing over wood to make a part shows a lack intuition on the builders behalf... in other words it's for sissies that are not smart enough to make a mold :)

Just kidding of course Sean. :)

strick

:)

Do you have a link showing some of his work? I had no luck finding him on BD.

strick

I remember that seat you did. It's still is as mind-blowing as when I first saw it. Awhile ago, I mentioned to you I saw your boat in my Long Island waters - to a guy you sold it to. I noticed the beautiful hull, but when I saw the seat - I knew it was your boat !

Questions:

I'm not even going to bother asking about the foam shaping etc. Completely out of my comprehension... When you make a 'normal' radius with cabosil and after it kicks - are you worried about scratching up the mold when you try to smooth out the cabosil radius ?

I understand using the core cell for stiffness, but if I want to mount something to the seat box I want to build, should I use something STRONG, like plywood that can be mounted to ?

Strick-here is a link...

http://www.bdoutdoors.com/forums/che...k-rebuild.html

That was probably the best boat I will ever own. But it was a little too big for getting into some of the tight places that I like to fish in the delta. The 20 is much better suited.

The core cell has a very high compressive strength. If you are worried about strength then throw a couple extra layers of 1708 down in key areas. What you are going to mount to a seat box that will create shear and compressive forces that can crack the laminate?

Cabosil alone is too hard to sand so it does not make a good material for fillets. Mixed with microballoons it is much easier to sand. If you are careful during application then you can keep your sanding down to a minimum and you will not scratch up the mold enough to effect it.

Sean thanks for the the link I'll check it out!

strick

The 3rd option is to pre-fab composite panels, then build your structure from them. Sort of a cross-over method between the plywood structure & molding - like Tuna did on classicmako - (p2, 03/29/2009 post).

http://www.classicmako.com/forum/top...08&whichpage=2

I've been thinking about these methods as well for a LP/LW combo (Strick - you set the benchmark w/ yours) & maybe a console or dog-house. I lean towards the mold I have to say - just not convinced I could get the glassed over seems to fair into the panels (or at least how much time it would take) vs pulling from a mold.

That project is insane ! Talented people out there. Things you think are impossible just... get done !

An interesting concept - a guide coat. How does that work ?