aluminum interior insulation

[Dutch Peter]

Chester,

You're right about that, some foams will form a noxious gas. But why the worries about repairs. On a steel or aluminium "pleasure craft" I wouldn't be to worried about making weld repairs. And if God does punish you, remove the foam locally and welding is no problem!
If glasswool or rockwool is fitted you will have to remove the insulation also, otherwise you can't make a proper repair!

[MikeJohns]

Have a look at this thread too

Structural Foam for Aluminum Hulls

I am looking into building a 26 foot aluminum cuddy cabin fishing boat and weekend plus cruiser. I boat in alaska most of the time but hope to take trips further afield some day. Does anybody have any recomendations for covering the iside of the cabin. My wife wants something that is easy to clean. I want something durable and warm. We have talked ablut indoor out door carpet but worry that this would hold moisture and have a damp feel. I am not sure it would be practical to line the boat with even thin plywood. I guess I am looking for some type of unicellullar foam and something to cover it with or perhaps a ready made product. Does any body have any experience with this. Thank you for your help.

Check out EagleCraft boats in Campbell river. They use both foam and another insulation/sound deadning material that looks metalic.

[D'ARTOIS]

There used to be a product with the brandname "SOMVYL" a foam type of heavy
wall liner of a kind of foam-vinyl material. That material was used to line many sailingyachts in the 70's and 80's and was glued with a special tuype of glue alsoused in shoerepair shops. That material is water resistant, you can clean it very easy and it glues well. The manufacturer is called SOMMER from France or
Belgium. Maybe you will find it in the US.

[hang5]

I have an extensive amount of experience coating aluminum in a wet environment and find many grains of truth in the above thread but also many of the ideas suggested above are quite unsuitable. First off, as regards the issue of corrosion on the interior, the surface must have a very very wet condition for electrolytic corrosion to take place. This could happen for instance in a bilge area but would not be a concern thoughout the rest of the boat.

By far the best (and the ugliest) coating is a 2 part tar based epoxy coating. It is thick, ugly, and difficult to apply (generally swabbed or troweled...yes, it is that thick). It is also difficult to remove but it will provide "forever" protection in areas that are regularly submerged. It provides only moderate insulating properties but will reduce condensation.

The second best coating is a roller, spray or brush applied PVC plastisol based aquatic paint (www.poolequip.com is one reliable source) applied after passivating and priming the aluminum. Again, some insulation value is achieved however this is an evaporative solvent based product (as opposed to a catalitic reaction as in a two-part product) and this will result in some micro pinholes. A second coat will generally cover 99.9% of the micro pinholes. PVC of course is the insulation of choice for almost all modern electrical wiring. You may want to employ additional insulation for comfort but the condensation will be controlled in most environments and your electrolytic issue is solved. This is fairly easy to scrape and grind away if repairs are required. It is easy to retouch up with a brush.

PVC is then easy to attach various foams to via spot adhesive or even solvent welding if the closed cell foam is PVC based.

I hope this is helpful.

[AlexMorozov]

Hi, as per my expirience with aloy, if you use the spray foam, then the priming is not required as foam close practically all corners while "inflate".
But when you glue the sheet foam or other material, the proper priming is essensial as some air/wet channels between sheet and metal available for corrosion. Practically every company has own scheme for priming alloys (say International or Hempel), please go with recomendation and you will get good result.
For insulation besides spray foam, sheet foam, also awailable 3M Thinsulate, expensive, but easy to cut, light and easy glue.
good luck

[Pavel]

Reading about insulation/corrosion of alu-boats: is it very crazy idea to leave a gap between the insulation and the hull, say, to lay some foam or glass mat on stringers - that is about 5cm away from the aluminium hull plating?
Some of the glass mats are sold with a one-way moisture foil, that could be facing the plaiting and from inside the boat the whole structure would be covered with another breathable foil and then lining. Has anyone experimented with this idea? Issue is potential condensation, but if this is done well, it should not really allow much moist-air going under, if it does it will be only distilled water collected in bilges. Of course, it might not work best in the roof area, but it might be okay on the hull. Any suggestions/experience?

[FAST FRED]

Early methods of cat construction used foam sprayed in place . The hassle was that the foam interior needed to be faired before the cielings and overheads could be fitted.

They use a Sureform plane attached to an automotive "Jitterbug" with a jig of ply with simple nails sticking out to get constant insulation thickness.
Messy as heck but fast.
BEWARE most spray foams are higghly flamable , and VERY VERY hard to extinguish once ignited.

Cover every surface and don't sink wiring in the foam.

FAST FRED

[Pavel]

Found this web page from pro-alu builder which does suggest insulation method in contrary to what was said here so far. I.e. need for painting under the glued-on sheets of foam. Check it out here. They dont seem to be short of money to do the first class job:

http://www.setsail.com/dashew/hull_insulation.html

Any comments you might have to this method of insulations would be GREATLY appreciated as I am about to be convinced to use this method on our boat. No need of painting inside the alu hull is also suggested by Gerr in one of his books. He was also involved in rather super-yacht projects. Thanks!

Pavel

[cyclops]

The fire issue is my biggest concern. Have most of you seen what a uncontrollable fire, fiberglass boats are. Toxic, it will at least brain dead you. The foam should be perfect to start the fiberglass burning sooner and faster. How about the good Zinc Chromate primer and epoxy job. Then a couple of layers of the small bubble - bubble wrap. Smaller flames??-------------------------------------------------------------------------Why not just build a false wall away from the hull by 1/4" to 1/2" and mount any type of insulating material on THAT?? Could be fire proof. New construction lets us do these things differently.

[raymond]

Can anyone tell me what is closed cell foam?

[FAST FRED]

Closed cell foam will not absorb water .

If you took a foam hunk , stuck it under a rock underwater ,it would weigh the same after a year as the day you submerged it.

FAST FRED

[chantelormerod@]

Originally Posted by raymond

Can anyone tell me what is closed cell foam?

Closed cell foam is a two component foam, which when mixed forms a closed cell structure as it expands.

Look at www.spray-insulation.co.uk

[capefearboat]

we are also using supertherm on top of rust grip (made by the same company). Before we paint we glue pins to the walls and ceiling and after painting add additional 2" of Navy board. This is a dense fiberglass board with a nylon cover. The pins have one way washers to hold it tight to the wall.