Violating a Princess!

SquirrellCook

Full Member
So this weekend we managed to do a bit more (demolition :( ) to Betty. I mentioned some time ago much of the water ingress into the habitation area was due to the fact the bonding between the windows and body was failing. A few weeks back my window man came to visit and said he was more than happy to remove a pain to two, give us a couple of days to do any repairs and then rebond the glass or replacement panels depending on if we are keeping glazing at that location.
So back to the water problem, I say water because it's beyond moisture. There must be a severe leak in the roof? So the painful job of stripping the internal roof panelling began. Such a shame because when we bought it, it was very good. In the short time we have had it, it's got grotty very fast.
With the roof panelling removed along with the polystyrene insulation it was clear that the roof was leak free and in very good condition. The only minor horror was the fitment of the upper corner marker lamps. Anita made some glass fibre boxes and these will be bonded over the back of the lights to stop any water getting in.
The cold nights and warm days showed exactly what was happening. The amount of water on the inside of the roof was beyond belief. I expect many motorhomers who think they have leaking roofs have the same problem. For the insulation to work there must be no movement of air behind the insulation. Pushed in insulation is not good enough. When it is redone, any seems that can be sealed will be before PU insulation is used to fill the gaps. This then will be taped in place to further seal it. They did use polycoated ply for the roof panels, but as they didn't seal the edges it still delaminated.
Again I'm reminded that if we had purchased a newer coach, all these problems would still exist. I guess when being used commercially they get to dry out better than being parked up, so the damp is not as much of an issue.
Shouldn't be too long now before we can do a trial mock-up of the bed frame.
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SquirrellCook

Full Member
So finally some construction, the fitting of a Maxxair, Maxxfan.
The first job was to remove a layer or two of paint from the glass fibre roof. I was worried about the quality of the bonding of the paint. I didn't want any leaks under the paint. The sanded area was then painted with polyester flow coat. In hindsight, just getting it flat would have been enough before painting again. The glass fibre resin didn't appear to react with the paint. So a days waiting before it can be touched again.
From the inside I measured and marked the required aperture. The corners were drills with a hole saw to keep them strong. I then used an air saw to cut along the lines. The Fan attachment flange was predrilled with 3mm holes. When I was happy with the position I drilled four more 3mm holes into the roof. Four screws were partially fitted to maintain the alignment and then the rest were drilled.
I was hoping I had some 18mm Buffalo Board, but I had to settle for 15mm. From this a reinforcement panel was cut to stiffen the inside of the roof.
This was clamped in place and all the holes were predrilled 3mm.
The roof was cleaned and lightly sanded as top coat is slippery. Butyl mastic tape was applied to the inside of the mounting flange. Outside of this a bead of panel bonding PU mastic was applied. The mounting face of the stiffening flange was also treated to an ample bead of mastic close to the inner edge.
Before I glued the mounting panel I drilled the 3mm holes to 4mm to help it pull down. A bit of a fight was had trying to fit all 3 parts together. Lots of clamps would have helped but I was worried about over squeezing the mastic and tape.
On completion I had a sensible amount of mastic ooze around the edges and even inside I had mastic ooze up to the mounting flange.
So three independent seals, so shouldn't leak. Once the external mastic has set I'll trim it with a scalpel and put a finish bead of white mastic around the edges and over the screws. Hoping it doesn't look like it was attacked by seagulls.

Rear door seal flange replacement I think will be the next horror to attack.
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wildebus

Full Member
Nice install. I had just one tiny leak from my Maxxfan install - through one of the screws via capillary action. Nipped up the nut and jobs a good 'un.

I know you like to keep an eye on your electrics ... I did a check on the power consumption of the fan at the different power settings. These are the results I got for mine. I'd expect yours to be very similar.

Maxxair Power Consumption
by David, on Flickr
 

SquirrellCook

Full Member
Nice install. I had just one tiny leak from my Maxxfan install - through one of the screws via capillary action. Nipped up the nut and jobs a good 'un.

I know you like to keep an eye on your electrics ... I did a check on the power consumption of the fan at the different power settings. These are the results I got for mine. I'd expect yours to be very similar.

Maxxair Power Consumption
by David, on Flickr
Not to bad Dave, I intend to leave mine on all the time to keep damp at bay. No electrics as yet, but as it’s going to be all 24volts dc dc converters will be required upping the consumption a bit. Forgetting the cost I expect multiple dc dc converters will make sense depending on how much each 12 volt item is used. Rather than one big converter left on all the time. Lots to think about on a new build rather than an evolution of a vehicle in use.
‘Another good thing about a slower build is the chance of seeing how joints weather before being sealed away.
 
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