Insulating while refitting rear cabin

[Blueknarr]

I have never seen this much pinholes in paints before either, and btw I only brush and roll the paint, so no contaminations possible from a paint gun.

The paint was a small pack of 750ml total with a mixing ratio of 2:1, but as it came in a pack I just dumped the catalyst into the base and mixed it up.
At first I tried it without any reducer and that went on a little better but a too heavy coat, so I added some reducer and that made to problem worse.

I have put down 3 coats of rolled Hempel Hempadur 15570 epoxy primer with a coarse roller and without thinning the primer, so the paint thickness should be fine.

I only want to cover the floor with polyurethane for a nicer finish and to make is easier to spot dirt and corrosion in the future.

Now that I think about it, the reducer I used was for an earlier version of the paint where the mixing ratio was 4:1, where’s as it is now 2:1, so that could contribute to the problem as well if they changed the reducer too.

Anyway all the poly paint is washed off again, and I’ll let the primer cure some more and try again in a bit warmer weather.

The steel was 3-4 degrees and air was 8-1o with a humidity around 60-65%, so too close to the dew point I think.
I could also dissolve the primer a little bit with the solvent used for washing off the paint, so it was clearly not 100% cured either.

I’ll put it down to being too impatient

You have fish eyes in your paint. These are caused by contamination of the paint by the wrong thinner.
Cool temperature also contributed.
The older thinner was probably contaminated with water from condensation.

Polyurethane is particularly sensitive to water. Any water condensation on the surface prior to painting will result in fisheyes.

Many brands of tack clothes also cause fisheyes in urethane. Consult with your local auto body shop as to which brand of tack cloth to use.

 

[DocSjulle]

A lot of progress have been made in the boat

I decided to stop thinking about how to mount the strips of wood to the ceiling and just go with the original mounting method, we’ll sort of anyway.

Small pieces of plywood was glued to the T iron bars, and the strips of wood was fastened to them using screws.
I put insulating in between all the plywood pieces to cover as much of the steel as possible.

Then the entire roof and walls were insulated using 19mm Kaiflex foam.

The floor was painted with another 2 coats of white epoxy primer to give it that nice bright look.

 

[DocSjulle]

I need your some advice on how to mount two Gebo 560 x 560mm hatches in the rear wall of the hull.

The hull is slightly curved both ways, which results in about 5-10mm gap at each corner of the hatch frame.

Would it be ok to mount the hatch using small spacers at the screws, and then just fill the gap with sealant or maybe epoxy filler ?

Or do I need to make a steel frame and weld it to the hull to create a perfectly flat mounting ?

 

[Rumars]

In theory epoxy filled with CSM can do it, but it's a mess to do right.

My preferences in order:
1. Use stainless frame hatches and weld them to the hull with spacers where necessary.
2. Weld a steel frame to create a flat then bolt with sealant.
3. Make a contoured spacer from plywood or G10 to create the flat, bolt with sealant on both faces.
4. Use epoxy with CSM to create the spacer, it has to be cast in place. Then bolt wit sealant on both faces.

 

[DocSjulle]

Thanks, I have decided to make some frames and weld them to the hull.
It will be a bit more work, but it surely is the correct way of doing it.

 

[Steelboat]

Your work is looking good.
Did you glue the Kaiflex foam in place, or just close fit for removal and inspection later on? I am interested how it is working to prevent condensation.

 

[DocSjulle]

The Kaiflex I have used is the self adhesive type and it is a very strong glue.
If you try to pull it off again it tears apart.

It is working very good for condensation, because before I got the ceiling insulated it would drip with condensation in the morning on the cold days.
After insulating with 19mm Kaiflex only between the stringers, there would be drops of condensation on the them.
But now after putting 3mm Kaiflex insulating strips over the stringers no condensation can be seen.

it is a little hard to cut but there was a ceramic knife in the kit I bought, and that is much better then using a normal knife which go dull quite fast.

 

[Steelboat]

That sounds really good, and much cheaper than hiring a spray contractor. From what I read it sounds like a good product.

Did you wrap it around everything- frames stringers and all? Any pic to share?
Have you experimented removing it? I would think maybe something like isopropyl alcohol might remove the adhesive.
Did you use any other sealant for under the frames and tight corners?

I am going to look for a source for testing!

 

[DocSjulle]

It's the same kind of product as Armaflex just slightly cheaper. And I wrapped it around everything and put it between the plywood blocks which hold the wooden strips to cover as much metal as possible.

The only placed I used sealant is in the corners which has a small crack because it was only welded from the outside.
All other places just had a lot of paint on it, and judging by the condition of the ceiling after 36 years, will surely hold up for many many years to come

I imagine it should be easy to remove the glue with some type of solvent after scraping of the foam if ever needed.

 

[Steelboat]

Nice neat work! Sure looks a lot better than spray foam does. Spray jobs mean a lot of masking and cutting excess away.

I just ordered a test roll of Xcel foam from Amazon. If all the gaps and corners are carefully filled I don't see why the performance would not be the same. 1/4 the price quoted by the spray crew.

Quite easy to go back and squirt some Sikaflex into any gaps that are missed.

 

[DocSjulle]

More progress.

1. Made some new floorboards.

2. Cut two holes in the rear and welded in frames for the hatches.

3. On the inside most of today was spent building the frame for the walls.

 

[DocSjulle]

Painting the hatch frames and building the base for the bed.

 

[DocSjulle]

I have been working all day every day in the boat and have actually reached my own deadline of getting the walls cut and fitted yesterday.

I have a bit of question if I should varnish the backside of the plywood walls before installing them, to prolong their life, or if they should be left untreated ?

 

[bajansailor]

I have a bit of question if I should varnish the backside of the plywood walls before installing them, to prolong their life, or if they should be left untreated ?

It would be better if you could seal the backside of the plywood, and especially the edges - but I would use epoxy resin to do this, rather than varnish.