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FLOATATION FOAM
http://www.hobie.com/au/en/forums/viewtopic.php?f=14&t=42610		 Page 1 of 1
Author:  faceplant2012 [ Thu May 10, 2012 6:56 am ]
Post subject:  FLOATATION FOAM
Hello H16 world,
I drilled all the softspots on the deck with a grid of 1\4 in holes. I punched through the bottom side of the sandwich on many of the holes, so can I just fill the entire hull with floatation foam and then hit the holes with resin as planned?
Author:  jsloan999 [ Thu May 10, 2012 7:17 am ]
Post subject:  Re: FLOATATION FOAM
This would make the hull too heavy.

Where you drilled clear through you will need to plug the hole at the bottom of the sandwitch so the filler (GitRot is what I use) will stay between the layers.

Now how do you plug the the lower hole? Maybe silicone the original top/bottom holes and redrill the top part when it has hardened. It would need some cleanup whith a bent nail to make the GitRot flows beetween the layers.
Author:  faceplant2012 [ Thu May 10, 2012 7:38 am ]
Post subject:  Re: FLOATATION FOAM
thanks,

I guess i'll stay away from the floatation foam.

i was going to use an allen wrench mounted in my drill to clear a radius inside the sandwich to create a space to accept the resin.

so i need to stuff the push through holes with silicon. can you recommend anything else. how bout some micro balloon thickened resin.
Author:  56kz2slow [ Thu May 10, 2012 7:43 am ]
Post subject:  Re: FLOATATION FOAM
You could use thickened resin to plug the holes, and drill new holes nearby through only the top layer to put the gitrot.

When you drill, put your drill speed really really slow.
Author:  faceplant2012 [ Thu May 10, 2012 7:45 am ]
Post subject:  Re: FLOATATION FOAM
http://www.fibreglast.com/product/2_Lb_ ... 7QodXAKoGA

the foam is only 2# per cubic foot. this doesnt seem like much of a sacrifice because the hulls already have a v-shape solid styrofoam insert. the styro is probably 2 cubic feet.
Author:  jmecky [ Thu May 10, 2012 8:38 am ]
Post subject:  Re: FLOATATION FOAM
I recommend a dremel for making the holes. You can hold the dremel like a pencil so you get a lot more control, and it has variable speed control. It is also light so the weight of it wont push like a regular drill.

Once I did the same thing, i drilled to strait through all layers, but did not notice. I then injected 4 oz or resin strait through the deck. It landed on the foam block. I kept thinking wow the soft spot is taking a lot of resin, then I realized what was happening.

Also I've read about a few guys who had there hulls completely filled with expanding foam. They said it leaves the hulls super stiff and only added 20lbs per hull. So it is doable and practical if you have a very old boat, that needs some stiffening. Viagra works wells too.
Author:  MBounds [ Thu May 10, 2012 9:07 am ]
Post subject:  Re: FLOATATION FOAM
jmecky wrote:
Also I've read about a few guys who had there hulls completely filled with expanding foam. They said it leaves the hulls super stiff and only added 20lbs per hull. So it is doable and practical if you have a very old boat, that needs some stiffening.

Filling the hulls with foam is a really bad idea.
1) Adds weight. 20 lbs is significant.
2) You can't fill every void without exploding the hulls.
3) If you can't fill every void, every void will eventually hold water - which adds more weight.

There are other problems, too. This has all been discussed before, and there's even a real world example - the Sizzler.
Image
The Sizzler was made from hydroformed aluminum sheets and filled with urethane foam. They worked great until they invariably leaked. They took water in and never let it out. They got heavier and heavier and heavier.

Sure, "filling" the hulls with foam will work for a while. But it's bad for the boat in the long term - and for resale value.
Author:  faceplant2012 [ Thu May 10, 2012 9:47 am ]
Post subject:  Re: FLOATATION FOAM
ok, so to do it right you would need to pull the whole deck and install the expanding foam. no thanks.
I will go back with a dremel tool and some thick resin.
Any advice on filling the push throughs??
Author:  MBounds [ Thu May 10, 2012 2:56 pm ]
Post subject:  Re: FLOATATION FOAM
faceplant2012 wrote:
Any advice on filling the push throughs??

Just fill them with thickened (very thick - peanut butter thick) epoxy. Use microbaloons or colloidal silica (Cab-o-Sil).
Author:  waldorf [ Sat May 12, 2012 7:06 am ]
Post subject:  Re: FLOATATION FOAM
If you take your drill bit and wrap masking tape around it (about 15 times) only leaving an 1/8" or less sticking out... it works quite well....

i also used an dish soap bottle to fill with my epoxy ... the nipple on the end fit right in the holes, and i could squeeze the epoxy into the voids...

another tip... mask off everything you don't want covered in the stuff.. to do a good job you make quite a mess....
Author:  jmecky [ Sat May 12, 2012 7:26 am ]
Post subject:  Re: FLOATATION FOAM
MBounds wrote:
Filling the hulls with foam is a really bad idea.
1) Adds weight. 20 lbs is significant.
2) You can't fill every void without exploding the hulls.
3) If you can't fill every void, every void will eventually hold water - which adds more weight.


20 lbs is not significant if you do not race, and if its a very old boat, who cares.

Not every void will hold water, the mistake with the sizzler was the foam was not water proof. That allowed water into voids, which could not be removed.

If you did use waterproof foam the voids or the foam would not take water.

Expanding foam is only a last option for a very very old boat, in a location where you can't get hulls.
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