Insulating the hull questions.

[Westgate]

Tony:

There is a good thread on the Plastic Classic site on this topic. Many different techniques/ideas are presented. Perhaps you have already visited but figured it was worth a mention.

Andrew

[ebb]

Have some 1/2" sheet pieces of very light white foam loose in the back of the truck. I knelt on it, put tool boxes on it, stuffed it around things that needed to be imobilized. Tough material. Been there for a year or more - I mean it has some permanent dents - but I won't bet on it. It's amazing stuff. You see it used for packing.
It's called Ethafoam. It was real cheap when I bought it at TAP Plastics. It is bendy and pliable, cuts with knife or scissors. It's CLOSED CELL polyethylene foam. It would be perfect insulation if you could find something to stick to the hull with!
One of its great qualities is that nothing sticks to it!

Another material worth looking into is Tekfoil (and other brands) which is various layers of bubblewrap and foil and sometimes polyethylene. The foil is coated when it's an outer layer. There are seam tapes and double sided tapes to stick it. I'd experiment with carpet tape.
Again no mastics I'm aware of. But I've heard some people are putting it into boats. To keep condensation at bay imco you have to have to glue whatever insulation tight to the hull without holidays. Dunknow?

Years ago I got a deal on some 1/2" Ensolite - it's a tough, light tan colored, closed cell pvc rubber.
Hours of research to find a non-lethal mastic led me to a waterborne gel/paste called APAC 564. It's a 'green' flooring adhesive for all kinds of vinyl flooring products. Have glued some 'panels' onto the hull in one cockpit locker.
The job was a PITA because I did it after I closed it in - like an idiot. But they're stuck and seem ONE with the hull.

There must be some mastic that will glue polyethylene - maybe APAC has it.
You may think that this is the Age of Aquarius BUT it really is the Age Of Glue.
Thing is if you got hot summers or you're going tropics, the fiberglass is going to get really hot. The stickum has to hold through what?... a 150 degree range?

I also found some nice beige 1/4" cut-pile polyethylene auto 'head-liner' material. Not really insulation. Actually the doors & footwell in my truck is covered with similar stuff. (Polypropylene pile is commonly used for auto and boat liners - imco we want material that doesn't hold water. Water FALLS out of my polar-fleece jackets, made from recycled p.ethylene 7-Up bottles. The auto liner is the same stuff.
(Head-liner in the Dodge is a thin fabric not glued very well to friable foam.)
'Carpet liner' has an amalgamated backing allows it to be cemented onto boat surfaces. Intend to glue it onto the Ensolite in storage areas. In other lockers, imagine cutting hull carpets to fit, but hanging them in with velcro hook & loop, so they can be removed and washed. They'll have insulating and cushioning value in difficult access areas.

Consensus has it, we should insulate the hull above the waterline where rapid changes in temp and humidity causes condensation. So I'll be attempting this. Another good reason is that, as with any insulation, we're warmer in the winter and cooler in the summer. Thinking Hawaii!


May have got the cement thing covered with the acrylic pudding APAC564.
But what do I know about the outgassing of super-heated pvc foam. Pvc does NOT have a good rep. MSDS sheets exist to reveal info that's hidden by 'trade secret' clauses. They've got carcinogentic plastisizers and other ingredients that makes PVC NON-recyclable. Plastic bad boy that has contaminated the oceans and toxified landfills everywhere on the planet.
All clear plastic films are also implicated in toxic horror stories.
So lining the interior of the boat with this stuff is something to be real about.

[Tim D.]

Ebb, I have used a waterproof contact cement like "Barge" for years on closed cell ensolite material to outfit kayaks and canoes. It seems to work fine, I am assuming that either this is not what you are looking for or you find its flammability unacceptable.

[CapnK]

Tony et al -

I have found thru experimentation that Gorilla Glue (and likely its similarly-chemical cousins) can be made into a sort of an 'expanding glue'. You just have to mix it with a lot of water (and fast, and apply it fast - pot life is like maybe 10 minutes).

I will be bonding sheet foam (EPS - pink or blue) to the hull using this. Besides a very strong bond, I think the 'foaming' property will cut down on the "holidays" Ebb mentions. Condensation forms from atmospheric water (humidity), so if you can seal off a small area, you shouldn't have that as a problem. I'll be adding a layer of luan/doorskin ply to the outside (the cabin-side) of the foam, and a layer of 10oz glass over that to protect it and make a durable, easily-cleaned surface. Because the EPS foam will be behind wood, I will be able to use cheaper polyester resin instead of epoxy when glassing over it (People may poo-poo polyester it seems, but the stuff has held the boat together fine for the last 40 years, so I have no problems using it where I can!).

I'd like to sneak in a radiant barrier right up against the hull if I can. A layer of mylar 'space blanket' material would work great, or maybe aluminum foil. Have to play with that a bit yet, make up some test pieces, see if the GG can bond to either of those materials, or if I'll need to perforate it...

I'll be putting insulation (AKA 'flotation' ) against every bit of hull I can, above and below waterline. Condensation forms all over, everywhere - I have seen it often in the past 4 years of living aboard. It is a bit more prevalent below the waterline, when conditions are right - but that is not always. I also want to treat the overhead in the v-berth, somehow...

I like the GG because I think once it is cured, it will not 'outgas' much, if at all, and seems to be a really stable substance. The other material I considered was something like 4200/5200, but the GG can do the same job for much less money and mess. I want whatever it is to be pretty much permanent - it would suck to have your hull insulation/liner delaminate after a few years, and my experiments with other glues like contact cement, Goops, acrylics, and such showed me that you need to make sure it is a really good bond, when going up against the hull. Most of these failed to some degree. GG becomes an inert solid after it has set up, whereas the rubbery adhesives are always slowly degrading (outgassing) to some degree - losing some of the very stuff that makes them what they are. How long until that has an adverse effect on the job they are doing? Your guess is as good as mine. So I am opting for a glue which does not have that propensity.

I like the idea of solidly encapsulating a solid foam (as opposed to gluing in a pliable foam) because it seems that would hold the materials in stasis better, for longer. If balsa can stay as dry as it does in the deck for 40 years (assuming no water penetration), so that it looks like it was installed yesterday when brought into the light, it just seems to me that encapsulation is the way to go.

[ebb]

Kurt, we have talked about your pink foam idea befor, so excuse me please if I repeat stuff. Pink and blue foams are relatively stiff sheet POLYSTYRENE FOAM insulation usually found at the big box depots.
Small panels could be heated and softened and pushed into the compound curves of an A/C hull. The compound curves are essentially minor in small sections. Gorilla polyurethane glue though is fairly expensive. But probably a good choice considering hull heat and cold cycling.
I think the pink foam is gluable with anumber of mastics - I wonder if tube 'threshold cement' could be used? Or perhaps tube glazing caulks/sealants (not silicone) that are formulated more toward heat extremes than construction goops.
[later EDIT: one structural polyether tube goop, I can recommend, is Chemlink M-1, considered green, non-toxic, bonds almost everything.
But haven't used it for the purpose here myself. There may be a problem getting it to set if no air moisture can get to the glue under closed cell stuff. It may not matter becauwse it begins setting immediately. So after tooling it on both surfaces with a toothed plaastic spreader, the open time may have been enough of a catalyst to promote it becoming rubber. More elastic formula Chemlink Novolac might be better for this app.]

I agree that polystyrene should be encapsulated.
As you say to protect the boat's interior from the foam's outgassing when the hull is heated by the sun or the ship's stove.
The encapsulation might also be augmented with paints. A good one imco would be a waterborne rubber urethane. As in deck paint without the antiskid.
Or an acrylic latex exterior house paint.
The encapsulation is suspect too, even plywood has formaldhyde in the glue.
SO encapsulate with glass or ceramic!!

Polyethylene foams don't have the same outgassing problems that the Bisphenol A toxin group has.
Note that when this foam burns it doesn't produce lethal smoke - which can't be said for other foams.
Who knows for sure? To be safe ALL foam insulation in the enclosed interior of a boat should be encapsulated.
Ensolite is used for a host of consumer products, everything from kneepads to yoga mats, and Airex is the same stuff in expensive closed cell mattress form. Bad chemicals. Goodlord maybe warmed up gelcoat and epoxy paint will compromise my tired immune system.

Tim,
I'm old enough to believe that that most of my body's complaints is due to decades of direct exposure to chemicals/solvents I've used. I think most of my toxic episodes are cumulative. Once thought the liver and kidneys where born-again and repairable.
NOW I go nuts trying to find less lethal materials to use on the boat,
especially inside.
Can't work with a canister mask on - besides having a beard which screws up a mask's breathing seal.
That non-toxic floor adhesive is not bad stuff - altho finding it was a problem.
Waterborne glue takes longer to set up than solvent glues - especially when you're gluing on closed cell material! Might ask if it ever sets up in some places? You have to be able to hold it in place by putting props or pressure on the panels.

California has led the way in safer products. You can legislate the great corporate planet polluters into making more friendly products.
But never turn your back on those jerks. Remember WCField's first law of consumerism:
"Never give a sucker an even break - or smarten up a chump."

[CapnK]

Right-o, Mr Ebb - sorry for the shorthand, should've explained: "EPS" stands for "Extruded PolyStyrene". Can be used with epoxy resin, but not polyester, generally; polyester resin has as a component styrene, which will dissolve EPS foam (you can use polyester resin with EPS foam and get minimal melting damage to the foam, if you kick the resin hard and fast, but... it's dicey. Better not to.).

I am simply going to kerf the foam sheets to get them to conform to the hull curves. Most of the sections are short, so there is not a lot of conforming to be done. Can always fill in any big kerf holes with epoxy and microballoons also.

I tried a buncha glues out. Lots of them will dissolve the foam. Styrene? Dunno, but something in there doesn't like it. On the advice of a 'long time flooring professional' guy who was working at one of the BigBox hardware stores, I tried some really tough floor glue prior to GG. Turns out that on these materials it only bonds here and there... Strong, remains adhesive, but just won't be consistent with grabbing the foam or the ply. Have two 4'x8' sheets of that made up already... Going to try to stick GG in there and see if it will hold well enough that I don't have to waste the material. If so, will use that for less structural stuff.

A guy on another sailing board I read swears by Glidden Porch and Floor for a cheap hard boat paint. Seems like it is a 1-part epoxy. At $25/gal, it's darned affordable, so I am going to get a small bit and check it out. Might be great for a finish on the interior. I have read of others who use garage floor paint also. Likely, any 1-part epoxy paint will do well for this application.

[ebb]

Hey Kurt,
I'm just assuming that ANY waterborne (aka NON-SOLVENT) mastic/glue will not eat up polystyrene. Adhesives formulated with solvents are there to make the adhesive set up faster. Commercial outfits want fast materials - to hell with the worker's health. Waterborne flooring adhesive paste which you put on with a toothed trowel would give abundant coverage. I've already successfully stuck Ensolite with it. Putting foam everywhere is a lot of square footage!

Beware of one part epoxy coatings. Very often the only epoxy in them is 'epoxy solids' - whatever that is.
Somewhere else on this Board I was just saying that I am about to use a TWO-PART WATERBORNE EPOXY ENAMEL. These words until recently have never been used in the same phrase together - but coating chemistry is radically changing these days, probably because of new stringent LowVoc and HazMat regulations.

The coating I'm trying out for the first time has many attributes of solvent and 100% solids epoxy. High adhesion, chemical and acid resistance, resists strong cleaners, interior/exterior aps. It also has low odor, will cover just about anything (has more flex than usual epoxy coatings), water clean-up, glossy, and won't lift conventional coatings (no voc solvents).
Has a 6 to 8 hour pot life, sets dry to touch in 30 mins.
Bummer, the stuff has to have a surface temp of 60degrees to apply.
I see it as a finish coat, or if I wish it can scuffed and topcoated with nearly anything else.
Comes in colors. I choose white for the interior of lockers.
It's an institutional coating. I had to pay near $100 for a gallon kit. Better be GOOD! Haven't had 60degrees this year yet.


KURT,
You got me thinking about encapsulating these foams.
You are absolutely correct that if the boat is to be 100% habitable NO foam should be exposed in the interior.

I think that a flexible waterborn polyurethane rubber coating may make a great BARRIER.
I have a gallon of white UTRA-TUFF I'll try. It is a one part coating - the kind you'd paint onto your boat deck with rubber granules mixed in it.
Mine's special order plain. It ought to stick perfectly on the Ensolite and be flexible enough to never crack.
It's a quranteed to never leak and to always have 100% elongation. So my assumption is that it would make the perfect foam barrier, eh what?

This is a highly touted abrasive resistant DECK coating. Should also protect the foam against abrasion, easy to clean, easy to repaint if necessary. It's an all-weather coating and it ain't no fru-fru 60degree stuff - it goes on as low as 40degrees!
http://www.ultratuff.net/utmindex.htm