Where to seal

[MickinOz]

I'm changing the plan as I go - so much so that I'd forgive anyone who alleges some initial lack of planning.
A biggy is the change from single skin roof to internally lined.
I was just going to connect the two side walls with 30mm by 19mm spars and fit a single skin, leaving them exposed inside. The walls buckled a bit so I decided to make the top flat section a double skinned box. The strength from such a light structure is amazing, it holds the walls nice and straight.
Then I fitted the front lower panel.
Then I decided it really needs an inner 'headboard" panel so I am not pushing against the outer skin with the pillows if I sit up in bed.
At that point I realised I only needed one more 5 x 3 sheet of ply to have a complete double skin. So I am shooting for that, using a piece of feather light appearance grade 3mm interior ply.
That's all great, but do I need to seal the inside of the outer skin? I didn't do it before I put it on as I wanted to glue to raw wood.
It'll be a messy job, and it''ll be hidden by the inner skin, but if I'll be risking the camper down the track by not doing it, i'll persevere.
Opinions?

[John61CT]

Depends how long you want it to last, how often used, how damp the climate.

I'd fully encapsulate all wood myself.

[tony.latham]

...but do I need to seal the inside of the outer skin?

Nope. As you know, you need to seal the exterior and the interior, but nothing inside the ceiling or walls.



Keep the rain out and any condensation from yourself limited to the sealed interior surfaces and you'll be just fine.



Tony

[MickinOz]

Dang - 1 vote for each. I'll never make up my mind.
(You oughta see me in any sort of Asian restaurant where they have a couple dozen main courses. Got so the missus just gets me a #16 whether I want it or not )

Actually, I have sorta made up my mind.
I started on the roof and realised I was painting over little spots of mould on one spar!!!
When it got wet the other day I should have dried it out more before getting diligent with the covers.
So I ceased and desisted on the varnishing/sealing.
Instead, I went over all the bare wood looking for mould - armed with a spray bottle of hypochlorite mould killer.
The other thing that does a number on mould is sunlight, they say.
So, I will work on the drop tomorrow, take it around to my mother's place tomorrow night and park it under the carport.
I will take the missus to Adelaide for more treatment for her eye on Friday. It is forecast for rain on Friday, Saturday and Sunday, so the beast can stay under cover.
I'll probably get the boat out of the shed and see if it still floats.

[John61CT]

Yes, vapour barriers in even very well insulated spaces are rarely 100%

[edgeau]

My vote is take the time and seal everything you can get to now. Water has a nasty habit of getting where it is not welcome!

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[MickinOz]

Yep. I get what Tony says, if you have no leaks and keep the condensation out you don't have to, but an hour or two of work now will see the interior surfaces of the inner and outer skins sealed.
I will never see them again, but I will also not sit there wondering how they are holding up.
It is a little bit tricky - when sealing the panels before installation, I'm trying not to seal the surfaces for the glue.
I'm still doing everything with the Sika Bond Techgrip. The data sheet says best bond if both surfaces unsealed, and lightly dampened with water.
So I give everything a light sand, blow the sanding dust off with the air line and wipe with a wet rag before glueing.
I believe you used Techgrip. Holding up OK?

[edgeau]

I believe you used Techgrip. Holding up OK?

Magic Stuff. I tried 3 other glues to fix the bubble in my wall exposed by the porthole. None lasted more than 24hrs but that stuff is still holding strong after nearly 3 years

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[John61CT]

Sika makes great stuff.

Anyone knows how that compares to their sealant+adhesive #292 or #295? latter comes in a UV formulation too.

[MickinOz]

I've got a couple of tubes of the 292. I will use it as gap filling sealer in a couple of spots, but no way do I think it is as strong as the techgrip.