Making a 'Bubble Window'

[Jeremy]

I've mentioned before that I bought my bus because of it's large flush-fitted windows, and I'm keeping several of them as part of the conversion rather than replacing them with inferior RV units. The existing windows are tinted, and where one of them is being taken out I am replacing it with an identically-sized fibreglass panel that will be painted gloss black, so from a short distance the bus should still give the appearance of having an unbroken span of glass for the whole length of the sides.

The 'bathroom' window will be replaced by one of these fibreglass panels, but I decided to add an extra complication by adding a 'bubble' to the panel to give a few more inches of space inside the bathroom - I've bought one of those pretentious semi-spherical glass wash basins, which look great but have quite a large diameter, and being able to mount this 3-4 inches nearer the wall will help quite a lot.

Anyway, I thought it might be useful if I described how I made this one-off fibreglass panel with a 1970's custom van-style bubble.

Unfortunately the first set of photos I took were lost, so I'll have to describe the first step:- the windows of my bus are curved in the vertical plane, so I started by making a simple plywood former that recreated the curve, and used that to make the initial panel, which was made up of three layers of 200g CSM (ie. basic fibreglass mat), followed by a 1/2" layer of foam and another three laminations of glass. The resulting thickness of the fibreglass panel is identical to the thickness of the original double-glazed window units, so should be a direct replacement.

The next step was to cut a large oval shape out of this panel where the bubble would be. The bit I cut out wasn't wasted as I used this bit to make a smaller 'non bubble' panel for another window - this smaller panel is shown painted in primer here:



As you can see the curvature of the panel is only slight, but it is essential that the curve is 'moulded in' as the panel is extremely stiff and there is no way you could bend it even that small amount. (Actually, to be fair the curve is greater than it seems in the photo, and remember this is the small panel - on the larger ones the curve is obviously more pronounced).

Going back to the larger panel, the bubble was formed by inserting more 1/2" foam sheet into the oval hole, as shown below:



The 1/2" foam is very flexible at this stage, but doesn't weigh anything and so holds it's shape quite well as more fibreglass is applied to both sides, at which point it becomes totally rigid. Then it's just a case of sanding and filling the rough surface of the fibreglass until it's ready for painting, as shown below:



The final pic shows the panel loosely placed into the window opening, just to give an idea of what it will look like:



Once it's on the vehicle like this the 'bubble' suddenly looks quite small, and I could probably have got away with making it quite a bit deeper if I had wanted to, but it does what was intended so I'm happy with the way it is. Once it's painted black I suspect the bubble will be even less noticeable. The window furthest from the camera in the photo is in fact not a window at all, but the small fibreglass panel shown earlier, now painted black.

Hope that's of some interest to those contemplating one-off fibreglass work

Jeremy

[JohnEd]

Jeramy,

You broke new ground here.  I know for a fact that the laminating process you used creates phenomanally strong structures.  Never heard of anyone making a curved panel.

Thank you very much for sharing that.  I know I will have use for your process.

Brit huh!  Whood a thunk et?

Thank you,

John

[buswarrior]

Excellent report from the old sod!

thanks for sharing!

happy coaching!
buswarrior

[gumpy]

This is cool!


I have an increased respect for the Brit.   


Now, if it he had incorporated an actually bubble window in the process.....   

[Airbag]

Put some lintless felt over it and put your acrylic in the oven in a frame and you can drape a window off that. You will need to loose the sharp corners first. Or you could vacumm form it. If you were here I'd put it on my table. These are some acrylic lenses we made. I have considered a bubble skylight (with a chair )in the roof for mine.



My home made vacumm table with overhead heater.