Hard Bimini Construction? Foam & Resin Construction?
 

Good advise Lew, thanks. Have you worked with this foam before? Trying to
figure out how it is to work with and the general methodology of working
with it (& maybe some of the pitfalls).

Glenn.

"Lew Hodgett" wrote in message
...
Subject

Building a male mold for a bimini is very straight forward.

A basic 4x8 sheet of 3ply, 1/2" plywood is about 42 lbs.

Divinycell foam is about 6 lbs/ft3.

Trying to fabricate a bimini using plywood will end up being a top
heavy slug and totally change the sailing characterstics.

You simply don't want to go there.

Lew

Hard Bimini Construction? Foam & Resin Construction?
 

Sounds like interesting stuff. Do you know where I might find information
on this Deckolite stuff? I did a google search and found others reference
it but not a supplier. Thanks.

Glenn.

"Garland Gray II" wrote in message
...
I made a hard bimini out of Deckolite (maybe Dekolite ?) that worked well.
It is end grain balsa between skins of "glass. Stuff's rather expensive
though.

"Glenn (s/v Seawing)" wrote in message
news:jADKi.764$x%6.264@pd7urf2no...
We cruise on our Gulfstar Auxillary 41 centre cockpit. Our bimini is now
old and will need replacing this season. I have been thinking of
replacing
with a hard bimini that will last longer than a sunbrella one, allow the
mounting of solar panels, water collection & other cockpit ammenities.

I am considering building one myself. Some folks at the boat-yard
suggested
building one out of some kind of foam, that can be cut & fit & when the
desired shape is reached, painted with resin to harden and so on.

Anyone built a hard bimini? Advise? Used this foam stuff?
Advise?...what's the stuff called & where can it be aquired? Advise on
bimini for a cruising boat?

Thanks all!

Glenn.
s/v Seawing

Hard Bimini Construction? Foam & Resin Construction?
 

Joel, I'm going to show my ignorance here...what is Origami boat design?

Glenn.

wrote in message
oups.com...
On Sep 26, 8:02 pm, "Garland Gray II" wrote:
I made a hard bimini out of Deckolite (maybe Dekolite ?) that worked
well.
It is end grain balsa between skins of "glass. Stuff's rather expensive
though.

"Glenn (s/v Seawing)" wrote in
messagenews:jADKi.764$x%6.264@pd7urf2no...

We cruise on our Gulfstar Auxillary 41 centre cockpit. Our bimini is
now
old and will need replacing this season. I have been thinking of
replacing
with a hard bimini that will last longer than a sunbrella one, allow
the
mounting of solar panels, water collection & other cockpit ammenities.

I am considering building one myself. Some folks at the boat-yard
suggested
building one out of some kind of foam, that can be cut & fit & when the
desired shape is reached, painted with resin to harden and so on.

Anyone built a hard bimini? Advise? Used this foam stuff?
Advise?...what's the stuff called & where can it be aquired? Advise on
bimini for a cruising boat?

Thanks all!

Glenn.
s/v Seawing

I built a hard top dodger. I used Ply and fiberglass and expoy. I
think that now I have looked around I have become interested in
Origami boat design. I think that using the origami method you could
shape a flat aluminum sheet into a curve to proper shape for a
bimini. With my next boat I am going to use the origami technology
build both my hard dodger and maybe a bimini.

Joel
Fat Tuesday

Hard Bimini Construction? Foam & Resin Construction?
 

Now I never thought of that. Starboard is pretty interesting stuff. My
father's threatening to replace some of the hard-to-sand teak hand-holds on
his Grand Banks with ones make of Starboard...never thought of a bimini
though.

Glenn.

wrote in message
oups.com...
A few years back, a fellow built a hard dodger using starboard
material. He ordered a 4 x 8 sheet of 1/2" and formed it over his
existing bimini frame. He used a heat gun to warm the material to
pull it down on the sides. Turned out really nice.

Hard Bimini Construction? Foam & Resin Construction?
 

"Glenn (s/v Seawing)" wrote in
message news:UW_Ki.8439$x%6.7141@pd7urf2no...
Good advise Lew, thanks. Have you worked with this foam before?

Built a 55 ft Bruce Roberts double head sail ketch using 1" Airex foam
for the hull and 3/4" Divinycell for the deck.

It is a very mature construction technique.

Lew

Hard Bimini Construction? Foam & Resin Construction?
 

On Sep 26, 3:21 pm, "Glenn \(s/v Seawing\)"
wrote:
... Anyone built a hard bimini? Advise? Used this foam stuff?
Advise?...what's the stuff called & where can it be aquired? Advise on
bimini for a cruising boat? ...

Many places have a fiberglass shop that can supply all that you will
need including advise. It is worth looking in the phone book or
asking around at the boat yard. There are online places too.
Jamestown Distributors has some basics. Try http://tinyurl.com/yv2p8u
for their selection of cores. There are lots of ways of going about
the process and not knowing what you are using for arches or if you
need a dodger as well as a bimini makes it hard to speculate on the
best method for you. Like everyone else, I think you will be happiest
with a cored glass construction. Some foam cores will tolerate heat
forming and many cores can be bought scored with light glass mesh. Be
aware that some cores are scored so that they will lay into molds and
some are scored to help with resin infusion. You want the former.
Core-cell is the gold standard but balsa is least expensive and plenty
good enough for what you want...

Good luck!

-- Tom.

Hard Bimini Construction? Foam & Resin Construction?
 

Glenn (s/v Seawing) wrote:

Good advise Lew, thanks. Have you worked with this foam before? Trying to
figure out how it is to work with and the general methodology of working
with it (& maybe some of the pitfalls).

Glenn.


I have.
It's a bit more challenging than plywood for one off coring.
But it would be the way I'd go if I were going to do this.
It's a weight issue.

For all the ins and outs may I refer you to the amateur built aircraft
industry - composite moldless construction as developed by Burt Rutan.

There is quite a bit of prior work to study there - and besides, you are
not worried about the wings folding so it's nowhere near as critical.


I recently made a pair of bunk shelves for my boat.
It's a Catalina Capri 18 - pretty small inside - although is seems big
enough outside.

The shelves are urethane foam cored with woven fabric skins. And West
resin - since that was what I had handy.

I used 5 ounce BID (BI Directional) glass (cuz that's what I had handy)
with 4 or 5 layers to get a good solid surface. Besides, the cores were
only about 3/16" thick, hence the heavy skins.

Wish I had taken pictures as I went along - but as usual I was too busy
wetting and squeeging.

They came out ok though. Haven't managed to paint them yet because I
took them out to the boat for installation fit - and they have been
there ever since...


For what you want to do I think I'd recommend something between 1/2 and
1 inch thick foam for the cores. I'd also make a plywood form to set
the desired curvature - and probably vacuum bag the skins.

Figure the bottom side could have lighter skins because (usually) nobody
will be walking on the bottom surface.

Look at what they call "units" in boat building rather than using woven
glass for something like this. (Cloth would be way expensive compared
to the boat unit approach). Units (as I understand it) are two (or
more?) layers of dissimilar materials - chopped strand matt and woven
roving or woven matt and woven cloth fabric.

I'd really like to buy Roger Long a cold beer and get all this straight
from the sea horse's mouth. All my experience is aircraft work - which
is quite a bit lighter stuff.


You may not absolutely need the vacuum bagging on a panel this size, but
if you've done it before you would know why you'd want to go to the
trouble and expense. (Better bonding to the core material - and a lot
easier surface finishing)

But it could be done as a straight forward hand lay up quite
successfully.

For a first time project this is really a bit big.

Building an airplane, one usually starts with a rudder and fin.
Small pieces to learn the techniques.

Then advance to the bigger and more critical structures.

I'd kind of like to do a project like you are discussing as the next
step before laying up an entire hull and deck.
'Specially if someone else is footing the bill :)


For what its worth, Glenn.


Richard Lamb



A few Marine Links:

http://boatdesign.net/articles/boatbuilding.shtml
http://boatdesign.net/articles/foam-core/index.htm
http://www.marinecomposites.com/ = excellent info!
http://microship.com/resources/micro-trimaran.html


Aircraft links:

http://www.maddyhome.com/canardpages/main (everybody)
http://www.maddyhome.com/canardpages...Dembs/Ch14.htm
http://www.ez.org/resource.htm

Hard Bimini Construction? Foam & Resin Construction?
 

While I didn't build a hard dodger myself, I had one built by a very good
craftsman in Ft. Lauderdale. He took the existing bimini stainless and had
it welded in place so that it had the exact same form as the cloth one. He
used a 1" honeycomb material for the coring and overlaid it with 1/8"
fiberglass sheet on the top and on the bottom. The whole thing was faired
and them Awlgripped.

Everyone who has seen it has asked where I had it made as it's by far
better than anything available commercially, such as a WaveStopper. I will
point out that he said that he would never build another one! :-)

Here's a link to a photo of it:

http://www.geoffschultz.org/Ebay/hard_dodger.jpg


-- Geoff
www.GeoffSchultz.org

Hard Bimini Construction? Foam & Resin Construction?
 

On Sep 27, 11:00 pm, "Glenn \(s/v Seawing\)"
wrote:
Joel, I'm going to show my ignorance here...what is Origami boat design?

Glenn.

wrote in message

oups.com...



On Sep 26, 8:02 pm, "Garland Gray II" wrote:
I made a hard bimini out of Deckolite (maybe Dekolite ?) that worked
well.
It is end grain balsa between skins of "glass. Stuff's rather expensive
though.

"Glenn (s/v Seawing)" wrote in
messagenews:jADKi.764$x%6.264@pd7urf2no...

We cruise on our Gulfstar Auxillary 41 centre cockpit. Our bimini is
now
old and will need replacing this season. I have been thinking of
replacing
with a hard bimini that will last longer than a sunbrella one, allow
the
mounting of solar panels, water collection & other cockpit ammenities.

I am considering building one myself. Some folks at the boat-yard
suggested
building one out of some kind of foam, that can be cut & fit & when the
desired shape is reached, painted with resin to harden and so on.

Anyone built a hard bimini? Advise? Used this foam stuff?
Advise?...what's the stuff called & where can it be aquired? Advise on
bimini for a cruising boat?

Thanks all!

Glenn.
s/v Seawing

I built a hard top dodger. I used Ply and fiberglass and expoy. I
think that now I have looked around I have become interested in
Origami boat design. I think that using the origami method you could
shape a flat aluminum sheet into a curve to proper shape for a
bimini. With my next boat I am going to use the origami technology
build both my hard dodger and maybe a bimini.

Joel
Fat Tuesday- Hide quoted text -

- Show quoted text -

Glenn they are boats designed by folding paper.
Great method...no frames!!

http://www.origamimagic.com

Joe

Hard Bimini Construction? Foam & Resin Construction?
 

"Geoff Schultz" wrote in message
.. .
While I didn't build a hard dodger myself, I had one built by a very good
craftsman in Ft. Lauderdale. He took the existing bimini stainless and
had
it welded in place so that it had the exact same form as the cloth one.
He
used a 1" honeycomb material for the coring and overlaid it with 1/8"
fiberglass sheet on the top and on the bottom. The whole thing was faired
and them Awlgripped.

Everyone who has seen it has asked where I had it made as it's by far
better than anything available commercially, such as a WaveStopper. I
will
point out that he said that he would never build another one! :-)

Here's a link to a photo of it:

http://www.geoffschultz.org/Ebay/hard_dodger.jpg


-- Geoff
www.GeoffSchultz.org

The bimini looks very nice.
What is the canvas top behind it.
I have not seen all of the sailboat.
Where is the dodger?

--Denis