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

[Rickster]

The weight of the foam is probably less than the amount of glass/resin you would need to make the boat strong enough to not use foam.

I just re-foamed my square after completely re-building and re-inforcing the back, and the 4# closed cell marine foam added about 13 pounds to the ski.

This foam is USCG approved for fuel tanks and flotation, and based on the container half filed with foam then a measured amount of water on top that has been sitting over night, it does not absorb much water if any...

13 pounds is not a lot of weight in my book, considering it is closed cell foam, and the ski will be used in surf only.

:cool2:

 

[D-Roc]

13lbs is alot if you can use about 3lbs of Dow foam to do it. add another 2-3 lbs of the closed cell to fill voids and it is half the foam weight and almost as strong. just my 2 cents

 

[meatball]

Me, Im using 2 lb. The crush durability is good enough for me and it serves its purpose of occupying space.

 

[freestylegeek]

Me, Im using 2 lb. The crush durability is good enough for me and it serves its purpose of occupying space.

Atta boy! I'll never use US Composites 4 lb foam again. I had a small crack in my throttle side gunwale after Daytona, so I removed some turf, and cut an access hole. I couldn't believe what I saw. the foam was more the n 2" from the back of the gunwale, and there was one 3" diameter void right in the middle of it all. This ski was foamed standing almost straight up and down (leaning against a wall). When I did my old hull with 2 lb Fiberlay foam, I had NO voids, and plenty of contact with the outer surfaces.

 

[meatball]

ouch... Im going to do the first pour with the panels cut out so that I dont create any voids.

 

[cambo au]

i have been watching this thread as i have to re foam my HMAS SUPERJET very soon i like all these sugestions and i think if i where going to use ping pongs i would foam as well that would only be a weight thing but i like the idea of trying to find a clossed cell foam and drain it so if your boat leaks you dont have to fix straight away
when i just refoamed my mates ski i screwed a leek down tester into the tray area and leaked down the ass of the ski before foaming and you would be suprised how many little pin holes where around the bond line when i sprayed detergent around my point is are you sure it is a crack that is doing the leaking?
the thing that sucks about this thread iis that i am racking my brain to think outside the box when i should be ocupying my time with other stuff

 

[meatball]

then just foam it. 2 lb foam in the ski only weighs like what 7 pounds? ping pong balls would decrease it by what? I see the point if you are looking for every pound, but for the average person, 2 lb foam and 5200 fast cure should be fine, and cheaper then a bunch of packs of balls.

 

[Legdragger]

i when i just refoamed my mates ski i screwed a leek down tester into the tray area and leaked down the ass of the ski before foaming and you would be suprised how many little pin holes where around the bond line when i sprayed detergent around my point is are you sure it is a crack that is doing the leaking?

That has me thinking. Maybe I will put a valve stem in my hull someplace so I can give it a 5 or 10 pound charge of air once in a while and see it it is leaking anywhere. At least I can patch the leak up before it lets too much water in even if I just use conventional foam.

the thing that sucks about this thread iis that i am racking my brain to think outside the box when i should be ocupying my time with other stuff

At least you are contributing to the brain storming session. You never know until you try......

 

[cambo au]

i thought preasure testing was comon before foaming i read i think in geeks build that they were going to submerse it in water to check for leaks i just thought that leaking it down was easyer than taking it to the water and it makes it easy to see were the leaks are with detergent and water

 

[waterfreak]

i thought preasure testing was comon before foaming i read i think in geeks build that they were going to submerse it in water to check for leaks i just thought that leaking it down was easyer than taking it to the water and it makes it easy to see were the leaks are with detergent and water

Making sure your hull is perfectly watertight is the key!:biggthumpup: I told Rickster before he ever put that brand new oem in the water, make sure it is 100 sealed from any voids , especially in the bond line area. This way, I'm sure that he won't have to deal with a waterlogged ski for a long time:biggthumpup:

 

[sflsurfrider]

hey steve, post a pic of your hull leak down testing kit....

 

[onesojourner]

then just foam it. 2 lb foam in the ski only weighs like what 7 pounds? ping pong balls would decrease it by what? I see the point if you are looking for every pound, but for the average person, 2 lb foam and 5200 fast cure should be fine, and cheaper then a bunch of packs of balls.

its not so much that 2 or 4 pound foam is to heavy its just to heavy if it ever gets wet. they are trying to think of stuff that does not absorb water.

 

[yamaslut]

lots of good replies guys... thanks.

I think I will go w/ the mix of ping pong balls and foam. I will set the balls in there and pour foam around them. I'm gonna do a test run in a sealed container first to see if the foam crushes the balls... will let ya know.

It's almost like creating your own honeycomb structure...

list of reasons to do

1. It will be almost if not as strong as foam
2. lighter than foam
3. more boyant w/ the mixture
4. less foam to absorb water incase of leak
5. eaiser to refoam if when needed
6. less cost, assuming faom is more expensive than ping pong balls

anyone have any input on this idea???

 

[Big Kahuna]

hey Nick, if there is foam and P.P.B's, it might be hard to de-ball it...... not like you can use a wire wheel attachment like you do with straight foam..........

just a thougth.

 

[yamaslut]

hey Nick, if there is foam and P.P.B's, it might be hard to de-ball it...... not like you can use a wire wheel attachment like you do with straight foam..........

just a thougth.

yeah... I use a high speed grinder... it will chew right through a ping pong ball.... good point though

 

[SuperJETT]

Nick, I'd say don't do it. Ping pong balls are made of celluloid, which breaks down very easily and isn't used for much of anything anymore.

The foam won't crush them, but my gut feeling is the chemicals/vapors that will be inside hull from the foam will cause the balls to break down and lose their strength quickly, then from the repeated stresses of landings they will collapse.

Also, there will be so little room for the foam to expand between them, you'll end up with voids. freestylegeek experienced that using batting insulation.

lots of good replies guys... thanks.

I think I will go w/ the mix of ping pong balls and foam. I will set the balls in there and pour foam around them. I'm gonna do a test run in a sealed container first to see if the foam crushes the balls... will let ya know.

It's almost like creating your own honeycomb structure...

list of reasons to do

1. It will be almost if not as strong as foam
2. lighter than foam
3. more boyant w/ the mixture
4. less foam to absorb water incase of leak
5. eaiser to refoam if when needed
6. less cost, assuming faom is more expensive than ping pong balls

anyone have any input on this idea???

 

[yamaslut]

Nick, I'd say don't do it. Ping pong balls are made of celluloid, which breaks down very easily and isn't used for much of anything anymore.

The foam won't crush them, but my gut feeling is the chemicals/vapors that will be inside hull from the foam will cause the balls to break down and lose their strength quickly, then from the repeated stresses of landings they will collapse.

Also, there will be so little room for the foam to expand between them, you'll end up with voids. freestylegeek experienced that using batting insulation.

yeah... I'm gonna do a test run first to see the effects.
you may be correct on the chemical reaction... There are definately
a lot of factors involved...

 

[Big Kahuna]

why not just fill the sides up with concrete????

ducking and running!!!!!!!!!!

sorry nick, could not resist...........

 

[yamaslut]

why not just fill the sides up with concrete????

ducking and running!!!!!!!!!!

sorry nick, could not resist...........

it's heavier than ping bong balls.. I think

 

[sflsurfrider]

wow. some people think ping pong balls is a bad idea and they may be "correct".

others that think its a bad idea are being "stupid".

:dunno: :dunno: