How to pour expanding flotation foam in a boat hull - How to Build a Boat Part 10 

Need to use a 2 cartridge hazmat respirator when dealing with any product that produces gas if you're sensitive. I have obstructive Asthma. Not a k95 covid piece of crap.

Emergency floatation, even if the hull is compromised it won't flood with water.

No, we use the foam to provide structural support.

It is advertised as 98% or better. However, experience has proven that over time (years) if the foam remains submerged it will eventually absorb some water. By using individually sealed compartments filled with foam we ensure that not water can contact the foam. If the seal of one compartment is compromised it will not get into other sections.

It is a drain for the front compartment.

Do u leave the PVC pipe in place or take it out?

No. It you mean a patio room that’s drafty, the choices are (1) to lift the flooring and put in a heavy polyethylene sheet vapor barrier or (2) apply tyvek or other brand draft blocking sheet to the underside of the joists in the crawl area. If you mean water is wicking up into a room built on a slab adjacent to a patio, the problem will be that there is wood in contact with concrete that is wetted. Concrete might as well be a sponge. Add flashing behind the siding for the lower of the wall and under the wood in contact with the concrete. To do that, after removing siding and draft wrap, cut and remove 24” of sheathing to un-secure any hurricane tie-down straps or tie bolts and plates, add a 2x10 temporarily where the siding was and lift the building just enough to put the flashing under with bottle jacks. One small inexpensive hydraulic jack every 6 feet is better than using a small number of large jacks. Lift evenly and just enough to slip the flashing under. Let the building down evenly then fold the flashing up the wall. Remove the temporary beam, restore tie-downs, replace sheathing and draft wrap, flash behind siding before replacing siding. If you will pay someone else to do this, it’s around an hour of labor per linear foot of perimeter, plus the present cost of 2x10’s, 1 ton bottle jacks, 10” aluminum roll flashing, 36” aluminum roll flashing, 36” tyvek roll material, 1 lb of #8x1-1/4 stainless screws for reattaching the sheathing, 1 lb 12p common nails to secure temporary beam, 1 lb hot dipped roofing nails to secure the flashing. If existing sheathing was installed using nails, also 1 sheet sheathing plywood per 16 linear feet. For diy include tin snips, drill driver, hammer, wrecking bar, cats paw, level, etc. if known to be without built w/o tie downs and none are required in your area, leave draft wrap and sheathing in place, find and mark stud centers.

Pouring foam into an enclosed space requires more forethought and planning. The enclosed space limits the expansion so you need just the right amount of foam, too much and will push against the panels and warp the shape. Also, air can be trapped in corners creating voids which is not ideal. So while cutting is a bit time consuming we believe it is the best method for beginners.

@@saltboatworks1139 ...Tip: A 2" hole you drill to pour the foam in, will allow any overfill to ooz out, thus fill in all the air voids while eliminating any risk of warping the shape.

You can use resin

@@saltboatworks1139 but wht brand of resin??? What type

Seem like it would make finding leaks impossible

Well lets say you punch a hole into a compartment or two, then you will wish you had the foam.

Foam is for support not floatation I believe in this case

It keeps the boat afloat. Let’s say your going 28mph on a flat and you hit an old little piece of rebar sticking out of the sand and cut a 30in long hole in your hull.. well without floatation you’re kinda screwed. It’s floatation nothing more. Sealed compartments stay sealed until they aren’t.

You can pour the foam in larger batches but 1) you will have more waste and 2) bigger batches can get "out of hand" with first time users so we demonstrated using smaller batches. Yes it is more time consuming but can be less intimidating for beginners. Also, every compartment we foam fill is already a watertight compartment, meaning water cannot reach the foam. We never recommend foam in an area that is not sealed.

If hull is punctured or boat is swamped that air will definitely prevent the boat from sinking.

Fill it with sealed plastic soda/water bottles instead of this foam. Chop up pink foam into small bits for placement into the areas around the bottles. Those two materials will never absorb any water at all.

Older foam is a different thing. It’s polyethylene, not polyurethane. The older foam is an open celled foam and acts like a sponge. New polyurethane is a closed cell system and would have to be submerged for 30 years to have a barely noticeable 20% moisture. If you regularly take it out of the water, you don’t have to worry.

@@It-b-Blair Actually you are incorrect. Two part foams have not changed and all will absorb water. They need to be completely encapsulated from water. Polyethylene (think pool noodles) will not sponge up water like two part foams. It is chemically resistant and is an excellent choice for flotation. It too is coast guard approved. Do a search on two part foams on RU-vid you will seee tons of failures. It does not have to be submerged, just contact over time. Go to Totalboats and read the data sheet on their two part foam, same with US composites. They both say it will absorb water. I just took 3 or 400 lbs of soaked foam out of my boat. I would NEVER put it back in.

@@bryanturner683 I'm with you based on real world experience using the same product as in this video. This pourable 2 part urethane foam is fairly water resistant, but it WILL ABSORB water over time. I poured some into an approx 5 sq in x 8' long subfloor channel last fall. Thinking it closed cell, I left the end at the bow unsealed, and the after end had a 1" diameter drain hole from manufacture. Last week, I noticed water weeping from the drain hole. I figured some standing water had wicked up into the area around the foam, perhaps as much as a few cups, not even considering the bow end which I thought sealed by the foam itself. When the weeping continued for 4 days with temps in the high 90's and the boat itself tilted up perhaps 25 degrees bow-high to facilitate draining, I began looking further, uncapping the places I had used as pour spots last fall. Turns out that there was water along the entire length of the subfloor channel, perhaps a gallon or more based on the weight of the foam which I have subsequently removed. Doing this job for the second time now, because this foam was not completely encapsulated IMMEDIATELY after being poured. I think I am going to embed some sealed plastic soda/water bottles, saving both pour time and material$, and best - which will never leak.

This is straight from uscomposites website. As long as you aren’t submerging it for an extended period of time, the foam will not absorb water. 14. Is this foam water resistant? Yes, but with the following caveat. The foams that we sell are considered closed-cell, which means that each cell that makes up the foam structure is completely closed off from surrounding cells which prevents it from acting like a sponge. It is completely safe for this foam to be in contact with water for hours/days/weeks and even months with no adverse effects. However, it should never be submerged in contact with water permanently. Over a period of years the water contact can begin to soften the foam and cause it to lose its closed-cell status. This foam is designed primarily to be used as an insurance policy in case of damage/holes that could cause a vessel to lose buoyancy. Pinhole sized openings would essentially have no effect on the foam since the amount of exposure is so minimal but you should always make repairs as soon as possible to keep the foam effectiveness as good as possible. This will be the case with all after market closed-cell polyurethane foams and even manufacturer installed foams.

It's not like the old foam that turned to dust or got water logged, plus if it's done right you won't have water ingress. The density is there to get the weight below the deck, it's deliberate in an effort to reduce the centre of gravity. The only thing missing in the video is the safety side and correct respiration gear, ventilation.

@@andrewiannello6548 Reduce the centre of gravity ? That’s pure nonsense.

@@andrewiannello6548 What way of ventilation do you know? However, I would like to avoid the accumulated condensation when building a boat ... Thank you!

"Styrofoam is not fully waterproof. A Material is called waterproof if it’s wholly impervious or impenetrable to water. This means water cannot pass through that material and also not absorb any water in the process. So, for example, styrofoam insulation can be water-resistant but not fully waterproof. This is because styrofoam does not absorb moisture from the air but can absorb water if it directly interacts with water. "

It is a USCG requirement to have flotation foam in boats under 20'. So until they change this federal regulation, we will continue to use foam in the most responsible ways possible, bu sealing each cavity 100% to make it water right.

@@saltboatworks1139 Pool noodles in the compartments. Light, buoyant, and won't absorb water. Foam in boats is the scourge of boats in Alaska.

@@saltboatworks1139 the old school guys don't realise the modern closed cell foam is waterproof. It's been tested to death. Don't blame them, the old stuff used to turn to chalk.

@@akdoug6437 excellent idea. Now you've got my imagination running wild on how to keep 55 gallon plastic barrels from taking on too much water and possibly sinking. Thanks.

100lb braided fishing line like piano wire, works well if you have a base to pull across

Been there done that . In the 70's they used that stupid surfboard open cell sponge foam

What’s the alternative?

That's why they have closed celled foam 😊

Closed cell foam does not absorb water

Good eye, not shown here (because we forgot to film it) we used 5200 to seal in the front compartments and transom.

Plus a number 4 for lunch.

@ yes, you can get styrofoam for free. And its weight can be 50% less

@@maxmackinlay618 Styrofoam melts down with almost all the resins. But you can use with epoxy.

USCG requirement for foam flotation in boats under 20'. We also take advantage of the compressive strength of the foam and use it to assist in supporting the floor and hull bottom.

If you get a hole, the boat won’t float anymore unless you have foam