Isolation of aluboat

[Jasper_ghost]

I intend to isolate a new aluminium boat bco heated cabin, so looking for some advice/comments.

First. OK to just isolate the bare aluminium or should the hull be painted with PU/epoxy paint before.

2nd. Material. OK to use EPS glued to hull and standard construction PU foam in corners, or should I buy the expensive self adh. foam. Im aware of engine area and hot areas should have mineral isol. to avoid fire. Do you recommand special material with low water absorbsion.

[lazeyjack]

I intend to isolate a new aluminium boat bco heated cabin, so looking for some advice/comments.

First. OK to just isolate the bare aluminium or should the hull be painted with PU/epoxy paint before.

2nd. Material. OK to use EPS glued to hull and standard construction PU foam in corners, or should I buy the expensive self adh. foam. Im aware of engine area and hot areas should have mineral isol. to avoid fire. Do you recommand special material with low water absorbsion.

you mean INSULATE?
NO NEED TO PAINT
use there are all sorts stuff, I used same as they use on lifejackets, does not absorb water,
google up foreman insulation in NZ

[DanishBagger]

you mean INSULATE?

Yes, that would be the most likely. But if he's from Denmark (and propably Sweden and Norway too) then " to insulate sth." would be "at isolere ngt.". And "to isolate sth." would also be "at isolere ngt." – that's propably the reason for the confusion.
I wonder how well you'd fare at french or italian :p

You have to remember, that not all of us are native english speakers.

[lazeyjack]

Yes, that would be the most likely. But if he's from Denmark (and propably Sweden and Norway too) then " to insulate sth." would be "at isolere ngt.". And "to isolate sth." would also be "at isolere ngt." – that's propably the reason for the confusion.
I wonder how well you'd fare at french or italian :p

You have to remember, that not all of us are native english speakers.

sorry Bags I feel so dumb only being afluent is 1.5 languages, us ENGLISH. , MY rUSSIAN IS COMING ON, AND MY fRENCH IS PASSABLE
Mon Francaise , ?? c'est tres mauvais

[DanishBagger]

Ah, good. But I bet "passable" includes a lot of weird pronunciation and that there's a few mistranslations when you have to explain something in those languages?

Come to think of it, it actually does make sense (even though it's wrong) to say "I isolated my house". The reason being: A well insulated house, has no cold-bridges to let the cold come in/the heat go out of. The inner climate should in fact be isolated from the outer climate as much as possible.

Anyways, it doesn't matter – you also gave him good advise :-)

[Jasper_ghost]

Sorry for the confusion, should be insulation. Danish bagger is correct, im from Denmark, means this is my 2nd lang.
Anyway any good advice thanks!

[DanishBagger]

I can't help but think, than when aluboats take care of themselves when unpainted on the outside, I don't think there would be any problems having it unpainted on the inside – even if you insulate it.

If I were to paint a boat on the inside – I would only do so, if I were trying to keep the infamous cobber penny isolated from the aluminium. So the aluminium wouldn't corrode if the electrician drops a few threads of copper wire.
(I don't own an aluminium boat, though).

Also, you'd want closed-cell foam – but you're propably aware of that.

[lazeyjack]

Sorry for the confusion, should be insulation. Danish bagger is correct, im from Denmark, means this is my 2nd lang.
Anyway any good advice thanks!

i always paint under the sole area,(floor) the reason being it makes it easy to keep clean Also dont let dirty water and oil and filth lie in pockets in alloy cos it can lead to corrosion if the air can not get around it, , if you want advise on painting, PM me, its been covered so much here, but I will give you what worked for me,

[kmorin]

All,

If the insulation is spray foam based on urethane/formaldehyde reactions there are some considerations for surface prep.

That foam will break down into a formic acid solution that can, if not drained, create corrosive cells in aluminum- especially if the original mill scale is not removed.

Closed cell styrene based material that is glued to the metal is inert. The glues usually evaporate their volatiles and become inert too. So if you're gluing in panels or sheets of closed cell materials from this group of plastics- there's much less potential for corrosion.

Any aluminum sheet that is in a boat should be etched to remove the mill scale before the exterior is left to weather OR the interior is finished. The majority of damage to un-etched aluminum is from the reaction resulting from the electrical differential of the mill scale to the underlying metal. Once atmospheric humidity condensates on the bare metal that moisture is enough to causing pitting in a new boat.

So good practice is to etch the inside AND outside as a minimal preparation step to use or finish. If the interior will be finished by insulation and ceiling joinery, the removal of the mill scale allows the natural oxide of aluminum, which mill scale IS NOT, to defend against moisture-driven poultice corrosion cells.

If spray insulation is used its best practice to use a chromate primer to give a more resilient oxide to the surface that might see an acid solution in its future. Its not common to insulate, sprayed or otherwise, in the bilge and urethane foams should NEVER be used in where they could be wet by salt water.

If the same foam is kept dry and the surface on which its sprayed is not humid when its applied it will adhere well, and not cause corrosion. But the bond is much better on bare aluminum or on a chromate primer than on mill scale.

cheers,
kmorin