This is lengthy, go get a cup of something first...
As I was planning to refurbish the windows in my Halmatic 30, 'Liberte Boo' I thought this would be a good opportunity to document how I approached this and perhaps some lessons learned. Of course my Gebo windows (1990 vintage) are neither badly crazed or leaking, but then I'm not really paying either...
Setting the (wet) scene...
'Liberte Boo', or LB for reference, is one of the last H30 built, being moulded in 1988 and commissioned in 1990 by the first owner Richard Boobier. Richard was a hands on engineer who clearly spent way too many hours sourcing and fitting the best equipment. Not liking the standard H30 fixed windows with mitred corners he went to Gebo (NL) to have some custom units made with radius corners. Great choice. So this is what I am taking out.
First thing to note ; this always takes longer than intended, so I only managed one window (and a small Gebo hatch) in a day. Of course the fact that it was spitting with rain and blowing strong didn't help.
The Gebo units clamp in, fixed with inner rings and self tapping screws (into the back of the outer frame). The frames themselves are twin channel so extend beyond the lining on the inside. My units are also pre-bent to follow the curve of the coach roof.
The Plan
My plan was to remove the windows and cover the holes with 9mm MDF purchased from that well known nautical supplier B&Q that morning. Of course the first problem was that a 120 x 60cm sheet was always going to be too short for a window measuring over 150cm, but I figured I could butt some lengths to cover. I had also cut some scrap plastic (in this case polycarbonate from old RNLI windows) into pieces ~300 x 40mm (10mm thick) to use as stays/braces. I also had a roll of 100mm Gorilla tape (which proved useless in the wet conditions) and a roll of single sided 10 x 10mm EPDM sponge gasket. Lastly a range of M8 machine screws of various lengths, plus nuts (in the form of threaded sleeves - these were to hand) and a bottle of Acetone, plus some tools...
Removing the inner rings
There's always one! There were many screws, but one sheared! This came out on the bench. My approach was to loosen each by hand (with a correctly sized screwdriver) and then let an electric screwdriver do the legwork once I knew they were willing to undo. I then teased away each end from the lining using an engineers wedge. Once free it was straight forward to release the rest. My inner rings are in two halves. Some may be in one piece.
Freeing the outer frame
Though there were signs of bedding compound between the frame and the cutout I figured that most of the bonding was on the outside. The first task was to try and loosen the bedding sufficiently so it would be possible to get a wedge in outside to lift the flange away from the GRP. As my twin channel frame was strong and accessible on the inside I elected to use a Mk1 rubber hammer to gently shock the bedding into partial submission, particularly at the ends. Hammering is normally a last resort, but as my frame was stiff and strong (and more importantly the hammer had a rubber head) I figured a few moderate whacks would not cause any damage. If you don't have a rubber/plastic hammer make sure you use a piece of wood or plastic as a drift so there's no metal to metal contact and to spread the load. Anyway this appeared to work as moving to the (wet) outside I could see the ends had lifted ever so slightly.
The lifting was not sufficient to get a Stanley blade in (I had conveniently forgotten to add 'scalpel' to my phone check list), so I employed some engineering wedges. These worked a treat on the upper part of the frame and by working along, cutting with the Stanley as I did the top of the frame was quickly free. Not quite so easy with the lower frame section as obviously the deck was in the way, but moving in smaller increments with the wedge/blade combo got the job done and soon enough the frame was out.
Preparing the cutout
This was done in two stages; the first was to remove any of the remaining bedding compound from the outer face (GRP) and for this I used some acrylic scrapers (strips of scrap acrylic cut at an angle on our bandsaw to create a tapered end). The great thing about acrylic scrapers is that they won't scratch GRP, the disappointing thing is that they blunt quickly so have several to hand - we will happily give you scrap acrylic to make these). The second stage was fitting the EPDM gasket around the cutout hole, but we'll come back to that later.
Marking up and cutting the temporary cover
I'll be honest, this all got quite wet thanks to the inclement weather. The first task was to mark a suitable depth guide for the cover by placing strips of masking tape on the MDF. Then, I used some mole grips to clamp the forward end (remember the MDF was not long enough) at the correct depth (~25mm overlap). Then went outside to position the aft end.
This was not quite so easy as I'd not considered how I might do this beforehand. Hindsight is great and for you I would suggest a couple of lengths of wood and a good clamp so that you can extend the lengths to make a batten which you can have one end tucked under the gunwale and the other against the lower edge of the MDF. This would have been great, if I'd realised beforehand, but I made do with resting the MDF on the tape roll placed on the rubber hammer to act as a wedge. Not perfect but good enough to get things rolling.
With the MDF in position I returned to the relatively dry cabin and scribed around the cutout onto the MDF with a marker pen. I then removed the MDF returned to the wet cockpit and set to with the jigsaw, cutting ~30mm outside the marked cutout line, whilst trying not to electrocute myself.
Returning to the inside I then drilled a 8mm hole for the aft most stay and then then refitted the now window shaped cover.
Fitting the gasket (stage two from above)
In theory you should be able to tape the cover to the coach roof using the Gorilla tape , but given it was spitting rain and surfaces were constantly wet this not an option. Thankfully I had bought some gasket.
The key stage here (after cleaning away the remnants of old bedding compound) was to dry the GRP and wipe over with Acetone, then fitting the gasket as I went along. The Acetone is key as it helps hugely to allow the single sided gasket to stick.
I did a complete ring of gasket in one hit in spite of the fact that the initial cover was only partial. In dry conditions I might even have tried to superglue the ends together, but instead just ensured the gasket was cut overlength so that the ends would push together.
Creating & fitting the inner stays
As mentioned, I'd had the foresight to cut some polycarbonate strips. These I shortened so that they would fit flush against the inside, inward of the curtain rails (the long one in the photo below is only temporary and was later shortened).
For the aft most hole I cut the strip and drilled a hole in approximately the correct position. I then fitted a longer than required machine screw (M8) from the outside and with the stay in position added the sleeve and hand tightened. At this point both ends were secure.
Having estimated where extra stays would be needed I cut and drilled these and then holding these by hand in position drilled through the stay to the MDF for the upper hole. I then popped outside and added the machine screw before returning to add and tighten the sleeve. At this point I could drill the lower hole and repeat. In this way I added all the stays. Note that with some I had to start with longer machine screws to pull the cover in and then replace these with the final shorter fasteners later.
Adding the short extension and developing Plan B
I realised that my one piece of MDF was not going to be sufficient for both sides. This wasn't the end of the world for me as a) I realised I was probably running out of time/light and b) that as I could twist Tim's arm to refurb the first window tout suite I could reuse my first covers on the other side. This decision (Plan B) left sufficient MDF for the smaller extension needed to complete one side. The approach was the same as for the larger piece, except that I missed out the shaping of the exterior (ie no radius on the front). I was also planning to put some tape over the join but this wasn't possible as by this time the outer face of the MDF was well wet.
Learnings
This actually went quite well, particularly considering the wet conditions, but to ensure you do an even better job here are some learnings...
If you're older (60+) like me, write a list of everything you will need beforehand. I do this on my mobile. Every time I think of something else I pop it on the list before I inevitably forget it. I'll add my list at the end.
Consider how you will hold the cover against the cutout before you mark/cut the required shape. One or more humans pressing from outside can offer the ideal solutions (my wife wasn't available or interested). Alternatively think about how you can brace the cover in position from the outside. Clearly if using material which will cover the whole length then both ends need to be secured externally. If like me you opt for two sections then you can clamp one end through the cutout - though not for the second element).
Get some engineers wedges - we are going to have the plastic versions available for purchase. Have a suitable drift (I used a short length of 10mm polycarbonate ~30mm wide and 120mm long) to but up against the wedge so that you can use your hammer away from the GRP.
Have a plastic/rubber hammer to hand. Metal hammers are dangerous and will damage GRP. Have some drifts too to ensure the hammer head is kept well away.
My list
Blue masking tape (tends to be more sticky than white)
Permanent marker pens (better to see on the blue tape) - Amazon basics
Stay bolts in various lengths c/w nuts (mine were M8 50/70/100mm long using the shorter as final. M8 is complete overkill but we stock these for the Lids4Lend covers so were to hand).
Stays - I used 10mm polycarbonate as we have plenty of this, but wood battens would work fine. Have more than you plan and remember to account for their thickness in choosing your stay bolts.
Portable drill (fully charged!) and drill bit for the stay fasteners (M8 in my case)
Screw bits & electric screwdriver
Screw drivers
EPDM gasket (I used single sided (ie adhesive on one side) 10 x 10mm sponge - source on eBay etc.
Superglue (for EPDM - as stated above I didn't use, but might have in the dry - be careful not to glue the gasket to the GRP though)
Gasket shears (because we have them, but some good scissors will be fine here)
Jigsaw
Gorilla tape (fat lot of use this was in the wet, but in the dry....)
Acrylic scrapers (to remove excess bedding compound - you could use a blade but be careful)
Acetone (IPA would be an alternative)
Wood drift (to use with hammer to push out the ends of the frame away from the GRP)
Multitool and Bosch flexible blade - this combo can be VERY useful if your flange/bedding is wide or if some idiot has used a PU adhesive like Sikaflex to bed your frames on. The advantage of these blades is that they don't have a serrated edge so are less inclined to scratch the frame or GRP. Click on the link for details. As my flange was narrow and the bedding had some give I didn't need to resort to this. Good to have in your tool chest anyway IMHO.
Heat gun - again, not needed in my situation but could be crucial if your frames are fastened from the outside. Basically heating the (alloy) frame around the (stainless) fasteners results in the frame expanding more than the fasteners thus aiding their release.
A tool kit - I keep a multi-piece toolset from Sealey on the boat. This includes screw drivers, sockets, pliars etc etc
Mole grips - for securing the stay nuts while you're outside screwing them up
Comentarios