Foam question

[AlabamaNewbie]

I am planning ahead for the day I actually get far enough to think about foam. Haha

So at one of my jobs, we use the same 2 part foam for creating packing for irregular shaped parts ( take a box and line it with thin plastic sheeting, inject the foam, fold the plastic over and wait for it to start rising, place the part in, cover with plastic, inject foam in the tol and seal the box). Its a pretty snazzy system. There are 2 55 gallon drums and hoses and a nozzle and the pump pulls it all up and mixes then comes out of the nozzle. This is going to save me a ton of time - hopefully. I could have my i jection holes in the deck, take the boat to work and inject the voids. The problem is that with this system, you really need to be able to see because since you aren’t mixing it, you don’t really know how much your putting in. The other idea is to take the boat before the deck is on and fill the voids. This might mean that foam goes higher than the stringers. I don’t know how trimming the top off the foam might affect its buoyancy or water repellancy.

The third option would be to have my deck pieces cut out but not glassed or atta hed. I could fill the voids, cover with our thin plastic sheet, and set the plywood down, and the weight of the plywood should prevent the foam from rising to high. Then back home i could take the deck back up and do the other stuff.

Thoughts?

 

[GA_Boater]

The expanding foam I've had to hack through to get to a fragile item isn't closed cell. Is the stuff at work closed or open cell? Open cell is almost a sponge.

 

[tpenfield]

I would also question if the packing foam is the proper type of foam. The ability to pour through holes in a finished deck is important for structural strength.

if you were to use automatic dispensing equipment, you time the pours based on the volume needed. You would want to do some experimentation to determine the rate at which the foam comes out.

Would your place of work even allow this?

 

[Scott Danforth]

Packing foam is open cell foam at about 1/2 pound density.

It is NOT flotation foam

Flotation foam is 2 pound density or higher closed cell

 

[AlabamaNewbie]

Packing foam is open cell foam at about 1/2 pound density.

It is NOT flotation foam

Flotation foam is 2 pound density or higher closed cell

We do not use open cell shipping foamI knew that we used 2# close cell foam- I buy it. Our parts we ship are irregular shaped and fairly heavy. We use the stiffer close cell foam not to protect our modules, but to prevent them from shifting in the box and busting through and collapsing a stack of stuff on the truck. Open cell foam collapses under the weight and the 60-70 lb modules shift and destroy the packing and boxes before reaching its destination.

 

[Scott Danforth]

iff your foam is closed cell, polyurethane based, then by all means use it if you want to. I wouldnt, as packing foam still isnt flotation foam.....however that is me. in all my years of shipping things foamed, the foam is open cell..... including 400# heat exchanger assemblies

 

[MTboatguy]

You should be able to get the specifications on the expanded volume of the foam from the manufacture of it. Also, I know in the closed cell foam applications I used to for shipping, we had a chart that stated how long to inject to fill a certain void. You might also be able to get a specification on floatation factor from them. Companies that produce shipping foams often times manufacture all different kinds of foam for different applications.

 

[tpenfield]

2 lb foam is a 30:1 expansion foam:liquid if used at about 85 degrees F.. heat matters with foam activation.

 

[Woodonglass]

I wouldn't spray it, I'd jus get a couple of gallons of both parts and then mix it and pour in the finished deck access holes like everyone else does.

 

[tpenfield]

Don’t mix it all at once. You have about 45 seconds until the liquid starts to foam. Small batches and quick pours unless you have an automatic mixing nozzle as initially described

 

[sheboyganjohn]

I'm with WOG on this one, get some of each part and do the mixing and pouring at home. my two biggest worries about injecting it would be giving it a bit too much and popping something, or having an accidental discharge while moving the hose around in the boat giving you a big sticky mess to clean up.