us composites expanding foam ...

[bigbad4cyl]

hello all , i need to order some expanding foam , any tips on what to order it will help support a floor in a 18 1/2 foot bowrider i think 20 sq feet will work , and im thinking the 4 lb foam would be best ..... the 8 lb sounds to hard .....is 4 lb overkill ,,,, and is there any other little gagets to order from there that will make it go eaisier ...

 

[crab bait]

Re: us composites expanding foam ...

only help i can offer is when mixed,, it better be mixed exactly equal.. if not,, you just made a sponge..

 

[snapperbait]

Re: us composites expanding foam ...

2lbs density is fine, IMHO... <br /><br />4lbs, ahhhh, I would'nt say overkill, but 8lb, now that's overkill....<br /><br />Little gadgets?.... disposable mixing sticks and disposable containers for mixing.... Don't forget the latex/rubber gloves.... The stuff is nasty-stickey, and it will stick to you for days...<br /><br />One big pour makes a mess..... Do multiple smaller pours...

 

[KilroyJC]

Re: us composites expanding foam ...

Hello - <br /><br />I used the 4# in my 18' runabout last year, & thought it worked great. <br /><br />I used the disposable paint can liners for mixing, and cut 2" strips of the leftover plywood from my deck for mixing sticks. I found that worked better than the paint mixing sticks.<br /><br />RUBBER GLOVES AND OLD CLOTHES!!!!<br /><br />TIP: When the foam is expanding, if it comes out through any holes, seams, etc, pull it off (wearing gloves) before it sets & tamp down the exposed edge to seal it. Much easier than waiting until it sets and then cutting it off.<br /><br />TIP: The foam will not stick to Saran Wrap or equivalent, so anything you don't want foam on or in, well, you know what to do...<br /><br />For my boat, I used 14 gallons total (7 Part A; 7 Part B), and touched up a couple voids with the 2# "whipped cream" from Home Cheapo.<br /><br />I fit weren't for the expense, I would have gone for the 8#, because I'm an overkill kinda guy.<br /><br />Let me add again that I am glad I didn't know about this stuff in high school - I'd STILL be working off detentions!!!

 

[epresutti]

Re: us composites expanding foam ...

Bigbad,<br /><br />During my rebuild I was more interested in floatation that structural support. Additionally I wanted the sound deadening. I chose foam that provided 60lbs of floatation per cubic foot of foam, it is none structural, I depended on the stringers and the cross members to support the deck.<br /><br />I have an 18' Mitchcraft hull and I figured I used about 32 cu ft. when all was said and done. Should give me about 1800 lbs of floatation, overkill maybe <br /><br />I used 8 oz dixie cups the expansion was 30 times the liquid volume.<br /><br />Just to echo KilroyJC, you should stand back and watch if you put 16 fl oz in a 32 oz bottle seal it, shake it and throw it on the front lawn, an amazing lawn ornament appears <br /><br />Hope this helps.<br /><br />Ed.

 

[epresutti]

Re: us composites expanding foam ...

Sorry for the double post, any minors listening, DO NOT PUT EXPANDABLE FOAM IN A SEALED CONTAINER IT WILL BURST THE CONTAINER! I STRONGLY ADVISE AGAINST IT!<br /><br />Sorry for the shouting. Just didn't want anyone repeating my mistake.<br /><br />Ed.

 

[bigbad 4cyl x2]

Re: us composites expanding foam ...

how big of holes and how many should i drill in my already glassed in floor . anyone know.

 

[Realgun]

Re: us composites expanding foam ...

3 inch holes work well. 2Lb foam is all thats needed for floatation ahd 4 lb is minimum if used to install a gas tank per USCG regs.<br /><br />The 8Lb and 16Lb are for things other than boats.

 

[Tail_Gunner]

Re: us composites expanding foam ...

Just finished a 8lb foaming job,let me tell you its incredibly hard and stiff, so much so i am a bit worried about it increasing the hull rigidity to much.<br /><br />It is very easy to work with,but the expansion rates are a bit dismal @ 85f. I drilled holes every 18 inches screwed the center down to the stringers leaving the out side loose in the event of over expansion ( ) it worked out extremely well.<br /><br />I am quite sure there will never and i mean never be a soft floor on this boat, right now its as hard as concrete and i havnt even glassed it yet<br /> <br />4lb would be enough after this experience,however im am quite sure this boat will not have any or if any torsonial twist ever.

 

[Realgun]

Re: us composites expanding foam ...

2lb foam expands a lot 4 lb not so much and 8 lb hardly at all. <br /><br />There was a ratio of 16 oz of 2lb foam is 1 cubic ft<br />16oz of 4 lb is .5 cubic ft.<br />and 16oz of 8 lb is .25 cubic ft fully expanded.<br /><br />I amy be off on the amounts but the same amout of foam expands less the higher the number or Lbs.

 

[bigbad 4cyl x2]

Re: us composites expanding foam ...

so im thinking of getting some 16 oz dixie cups and a wide mouth orange juice plastic container with a lid . poring the dixies into the oj container then shaking it up then poring it down a funnel through the hole in the floor ..........is this correct

 

[Tail_Gunner]

Re: us composites expanding foam ...

No i wouldnt shake the product up, its a two part product and they need to be thourghly stirred to combine as one new product. You will have about 30 seconds to accomplish this which is no problem<br /><br /> In my particular case i used 1 quart containers and poured them both into a milk jug and dispenesed it into 2 inch holes cut 18 inches apart. I also screwed down the center of the floor leaving the edges open allowing the faom to push up the edges to a line that i had chalked, when the edge (floor) hit the line i just stood on the deck forcing the foam to go where it was needed.<br /><br />In the end it all worked fine, i am very satisfied with the results and now i am convinced that foaming play's a very important role in adding structure. <br /><br />I guess it would be advisable to do a small quantity pour and see what type of expansion rate you will get, from there it's simple it it doubles in size or quadruple's just make sure you have that much avaible space for expansion, and definatley do the pour @ least 80 degrees temp and the hull @ that temp would probably very benefical.

 

[ondarvr]

Re: us composites expanding foam ...

After you use the funnel in the first hole it will be toast, just pour it from the paper tub directly into the hole. If it's warm out you won't have much more time than it takes to mix and pour, plus the warmer it is the more it will expand.

 

[ondarvr]

Re: us composites expanding foam ...

 

[Realgun]

Re: us composites expanding foam ...

I went to the paint store and bought 20 of the 1 quart and 10 of the 1/2 gallon mixing cups. they gave me the stir sticks for free so i grabed a lot! Pour part A and B in the small cups then pour into the big cup. Stir for 30 seconds. In about 15 more seconds you have to start pouring it or it will just start epanding like crazy. If you can mix in the boat near your pour points/holes the better. More foam will end up in the areas you need and not left in the cup.