aluminum interior insulation

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.

I do not have any direct experience with insulating alum boats but I do know you need to be carful here. Alum does not corrode because it has a oxidized surface film. If you block the surface from air but not mosture (for example covering with carpet that may get and stay wet) you will get corrosion. Be careful here I've had to replace or repair many alum fuel tanks for this reason. You can completely coat the surface with a epoxy type coating first and this will seal the metal off from mosture. I think I would do that then look into a spray on type foam. Or you could use a closed cell foam after coating. Good Luck
It's never as easy as you'd hoped

[big cat]

Owens corning makes a basement finishing system that may work. It has an "r-11" rating, is removable, with a fabric facing & has a channel for wiring. try www.owenscorning.com then basement finishing. It should work well in a marine enviroment as it is made for sub grade applications.........


Bob

[PNG]

You can completely coat the surface with a epoxy type coating first and this will seal the metal off from mosture.

Would you have to etch the aluminum before applying the epoxy so it would stick? Would you have problems with the epoxy not flexing the same as the aluminum, or with expansion/contraction from temperature changes and thus creating small voids? And doesn't even epoxy let some moisture thru? I wonder if a thin-coating metal primer wouldn't be better?

[PNG]

I think I would do that then look into a spray on type foam

This was my first thought (I'm not the original person who posted the question here, but I've been thinking about a similar project). But how would you ever get an nice even surface?

[PNG]

Owens corning makes a basement finishing system that may work.

Thanks for the idea and the link big cat!

Not sure the trim looks very good, but the system looks perfect.
http://www.owenscorning.com/around/i...s_benefits.asp

[sailvayu]

Yes you would want to etch the alum first. good catch I missed that step I was the 2nd guest forgot to log in. I've used this system for fuel tanks and as a matter of fact Tiaira Yachts is spending big bucks on a recall to do this to installed tanks on some models. The trick is once etched you have to keep the metal clean and coat ASAP.

[gonzo]

The main problem with coating aluminum, is that if there ever is a nick or scratch all the galvanic corrosion will occur in that spot. I have seen many fuel tank with holes corroded through them in a short time. The safest method is to leave an air gap between the insulation and the hull. If that is not feasible then etching it, priming with zinc chromate and epoxy coating is the next best method. I recomend a tar epoxy like VC Tar because is flexible and very vapor resistant.

look at www.supertherm.ca
under thermal -then supertherm and epoxotherm. these are insulators and long lasting coatings.
write me at technologynw@attbi.com for getting more info and product.

[Specmar.Aus]

Re: coating before installing insulation we have been using Nyalic for several seasons and it has proved easy to apply and has a great coverage rate. This Product is not as messy as the tar based products and if you have a weld repair an area can be cleaned off and repainted in a few minutes. Another great thing is that it’s clear so you can see at a glance if there is any corrosion starting around a penetration or impact damaged area.
HBI are the Manufactures in the USA and this product is marketed by globally at www.nyalic.com
www.nyalic.co.nz www.nyalic.com.au
Specmar.Aus

[AlexMorozov]

Hi, as per my expirience, insulation by spray foam is easy way, but not best, due to possible further repair matter. In any way the good priming is reguired (epoxy better) to prevent direct contact with moisture. Sometimes I glue the closesell foam about 10-20 mm, depends of size the boat or Rockwwol marine bats 25-30 mm. But good vetilation is requires in any way even with spray foam. Better to keep air volume between insulation and lining. I do not recomment to glue the carpet directly to insilation.
Alex

[Dutch Peter]

Hi, my experience in this matter is:
- apply a closed cell foam or glass flackes (by spraygun), don't paint the aluminium the foam will come off with the paint.
- you can close off with wood (as part of interior) or metal sheating (used in engine spaces).

As to the corrosion aspects:
- aluminium tends to protect itself by forming an airtight layer of alu-oxide.
- other forms of corrosion can be harmfull. Example: galvanic corrosion, this depends on different metals used in the construction.
- when looking on alu on the inside, a scratch will protect itself, and galvanic corrosion is not likely to happen as you will need an envirenmont that is damp and salty all the time to make things fail in the time you own the boat.

Good luck


Peter

[Chester]

I insulated the roof of my aluminum cabin with closed cell rigid foam. Which was sprayed with a 3m adhesive so I could add headliner material. The headliner material is the same as you see in production boats Campions etc. It has work for a number of years with no problems and still looks new. The back side of the foam that contacts the hull is bare and if there is any moisture it runs off along the sides. But to keep everything dryer I had an espar diesel heater installed which dries everything out very nicely

[RDB]

We use a spray foam right now but I was about to post a thread asking about Noxudol. This product is really thin, light, and easy to apply. Good insulation and especially sound damping. If anyone has used this product I would really like to hear how it worked out.

[Chester]

I heard that if you are using spray foam this will create a problem if you need to do any further welding or modifications or fixes. If you are welding an area that has foam attached, it will give off a gas which is not good for living things. Also some foam is not closed cell and actually can get water logged and add more weight to the boat.