"Foam" is a 4 letter word.... :(

Big Kahuna

Big Kahuna

Administrator
Location
Tuscaloosa, AL
yamasaki said:
only problem with the partial fills/pours is that you would need to find a way to provide resistance so it just doesnt keep going UPwards.. instead if fills OUTwards tightly into the crevices, know what i mean? like, how do you provide a "ceiling" for the foam's height expansion so it will be forced to expand in other directions (path of least resistance)

i dunno.. just thinking outloud.
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mix really small amounts, that is how I did my tray area, did not have to defoam it just did several 3" bores to the bottom to check for water, then started mixing small amounts and pouring in until I had it totally filled.
 
Y

yamaslut

Guest
yeah... like that, ed...:biggthumpup:

thanks for the observation..
 
Big Kahuna

Big Kahuna

Administrator
Location
Tuscaloosa, AL
I poured it in as soon as it started clouding up, that way it was still in a runny form.......... It is gonna expand to its on density, if it in a closed cavety, it will travel in the path of least resistance......... so, no more pressure at any given space.... except for maybe where the entry hole was, but it would try to come out there, so releiving pressure in that area also.......
 
Matt_E

Matt_E

steals hub caps from cars
Site Supporter
Location
at peace
yamasaki said:
wellllllll..... i can't say i really agree with that. if you don't provide resistance for the foam while its expanding, wouldn't it just be really thin/sparse.. maybe that's what you want though so its not so dense/heavy?

i guess the question is, does it matter how dense it is after its expanded? if the answer is no, then you guys are right, no resistance needed while expanding.. i have no clue if it matters or not.. probably not now that i think about it.
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I played around with this a little. Properly mixed warm foam will expand to its advertised density and no further. No less, either. :frown:
 
meatball

meatball

User Title Unavailable
Location
Maryland
I think that's were personal preference will come in. I have some blocks of both in the basement, and the DOW stuff (the pink sheets right?) is definitely more durable, while polystyrene is a lot lighter, more crushable (probably why they pack stuff in it). That said, the DOW stuff is pretty amazing, my brother has an airplane built out of the stuff... R?C but even then it has a 7 foot wingspan, using a yardstick as a spar.
 
D-Roc

D-Roc

I forgot!
Location
Dirty River Rider
the pink is for above ground and blue is for below grade and is better at resisting moisture. we got a 4 inch slab of the blue in the shack and some 1 1/2 for the tighter areas.
 
Y

yamaslut

Guest
D-Roc, legdragger pete called last night w/ some of that stuff...

he's gonna do a saturation test on it. (put a brick on top of it in bucket to see if it takes on water..):smile:
 
yamanube

yamanube

This Is The Way
Staff member
Location
Mandalor
Okay I know its been asked a million times and I have read it somewhere just not sure where. I am going to order all my crap to do my one-way and holds and need to know which foam to get....I have read 2lb in some threads and 3lb in otheres...anybody got a quick answer?
 
wishihad

wishihad

X
Location
va
My 2 cents

My 2cents:
I spent 12+ years building high performance lightweight composite aircraft and various prototype parts for individuals and various NASA projects. The primary concern was always to achieve the required strength with the least amount of weight. We also had concerns such as building integral fuel or water tight compartments within the wings that could with stand the vibration, flexing and tremendous loads applied to the wings without leaking. So after reading this long thread I thought I’d throw a possible solution into the mix based on my knowledge and experience.

My solution would be to add multiple bulkheads, possibly 3 or 4, in each side rail creating enclosed compartments. Then seal each compartment with a waterproof sealant and add an individual drain plug as well as an individual pressure valve to each compartment. In this configuration each compartment could be drained after each ride and in the event of a hull breach only a small section of the hull would take on water, keeping the ski from completely sinking. Then a repair could be performed on the hull without having to refoam. Additionally the bulkheads would add strength and rigidity to the side rails, while the pressure valve would keep from blowing out a bond line if the outer hull were to flex in due to a hard or irregular landing. I think with a little effort and creativity other bulkheads or compartments could be created in the nose and possibly hood for added flotation if needed.
 
Y

yamaslut

Guest
wishihad said:
My 2cents:
I spent 12+ years building high performance lightweight composite aircraft and various prototype parts for individuals and various NASA projects. The primary concern was always to achieve the required strength with the least amount of weight. We also had concerns such as building integral fuel or water tight compartments within the wings that could with stand the vibration, flexing and tremendous loads applied to the wings without leaking. So after reading this long thread I thought I’d throw a possible solution into the mix based on my knowledge and experience.

My solution would be to add multiple bulkheads, possibly 3 or 4, in each side rail creating enclosed compartments. Then seal each compartment with a waterproof sealant and add an individual drain plug as well as an individual pressure valve to each compartment. In this configuration each compartment could be drained after each ride and in the event of a hull breach only a small section of the hull would take on water, keeping the ski from completely sinking. Then a repair could be performed on the hull without having to refoam. Additionally the bulkheads would add strength and rigidity to the side rails, while the pressure valve would keep from blowing out a bond line if the outer hull were to flex in due to a hard or irregular landing. I think with a little effort and creativity other bulkheads or compartments could be created in the nose and possibly hood for added flotation if needed.
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we have experimented w/ the nose section by putting bulkeads in... it worked well. thanks for the input
:biggthumpup:
 
D-Roc

D-Roc

I forgot!
Location
Dirty River Rider
yamaslut said:
D-Roc, legdragger pete called last night w/ some of that stuff...

he's gonna do a saturation test on it. (put a brick on top of it in bucket to see if it takes on water..):smile:
Click to expand...

FYI: Smitty did the same thing a couple years ago, i am most positive if i were to walk in his garage today it would still be under water in his bucket.:biggthumpup: If it was good enough for him and his abuse on a ski i am down with it.
 
Legdragger

Legdragger

Bringing it back
Location
New Hampshire
That blue Dow foam is exactly what we have laying around here at work. I came by a piece that was in a snow bank most of the winter and it was dry as a bone. I still want to see how the piece in the bucket looks after a week though. It is super tough stuff.

Yamaslut advided me on the foam fiberglass bulckhead I put in the nose of my old superjet. It took a licking and kept on floating. Even eith the nose missing. Ask Ross. He rode it around with the nose broke off it totally but it was still sealed up. Thta thing was totally over built. It wasn't super heavy though. Most people thought it was reasonably light when they helped me with it.
 
Marshj

Marshj

DarkHorse
Location
Ann Arbor
D-Roc said:
FYI: Smitty did the same thing a couple years ago, i am most positive if i were to walk in his garage today it would still be under water in his bucket.:biggthumpup: If it was good enough for him and his abuse on a ski i am down with it.
Click to expand...

i miss smitty:frown:

Jonny Smith where are you?!
 
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