Well, silence here for some time, as have been busy tackling the challenge of the front and rear seating units on the Safari! As you can see from the photo above though, we’re finally there!!
A large part of the “challenge” was due to us deciding that we really wanted to have curved seating units, as lots of sharp corners just didn’t seem to sit (sic) right with the beautiful curves elsewhere on this 50s Airstream. And as we need to tow the trailer, keeping weight down was paramount, so no hope of buying some pre-formed MDF off the shelf and cutting it down to size.
We therefore got to learn quite a lot about plywood, and the fact that it’s a bit more complicated than just needing any old piece of “ply”. After a bit of Googling, it seemed as though what we needed was ‘Vohringer’ ply, as it’s about 20% lighter than standard Birch ply (and about 40% lighter than MDF). Getting hold of Vohringer in the UK though is somewhat of a challenge (that word again!), as no-one seems to stock it! Luckily though, we happened across the helpful folks at Morland who informed us that Vohringer is actually a German brand of Poplar ply, so if we could get hold of some Poplar, that would do the trick. In the end, we weren’t able to purchase it from Morland, as they were just too far away, but managed to find it at the equally helpful AvonPly down in Bristol.
A few calculations and a bit more Googling to find the right thicknesses we needed, and we were proud owners of what seemed like a vast amount of 3mm poplar ply for the curves, 9mm for the straight sections and some pine battens to form the framework. The fun was about to begin!
The approach for the curves was that we would laminate together 3 or 4 layers of the 3mm in the required curved shape, then hope it didn’t all unravel when the glue dried! To form the shape though would require a mould – or in fact 2 moulds, one for the inner surface, and one to go on top to clamp it all together while the glue could go off.
Making the moulds themselves was going to be a fairly complicated task, but luckily we came across some wonderful stuff called Curvomatic which was designed with just this in mind. It’s essentially a series of aluminium extrusions which slot together to form a flexible sort of mat which you lay on top of formers in the desired shape, lay the glued layers of ply on top of that, then another layer of Curvomatic on top, clamp it all down with the straps provided, then leave it to set.
In the end, for cost reasons, we decided to make the inner mould with flexi-MDF screwed onto the formers, with the Curvomatic just being used for the outer mould – this did probably make things a bit more difficult as it was essential to get the MDF completely square, which would have happened automatically with the Curvomatic, but a 50% cost saving seemed worth the effort!
Since it was the first time we’d ever done anything like this, we did a test piece to start with, which all went well, so our hallway became a carpenters’ workshop for a while, and we got going on those curves. While in theory it is possible to form both the ply and a laminate at the same time, we decided to do the laminate separately, just in case anything went wrong with the forming.
Happily though it didn’t, so in fairly short time, we had our 6 curved sections for both the front and the rear seating units – and after a bit of trimming of the edges with a router, we were ready to fit the jigsaw together.
The first stage was to join the separate units together to form the front face of the seating units, using a combination of Sikaflex caravan adhesive and the pine battens:-
With the front faces secured, there followed some considerable amount of work scribing and cutting the 9mm ply and 9mm ply battens for the seats themselves, but the results we think are worth it:-