We recently returned from a trip away with my brother who has an Autotrail motor home. We camped alongside with our caravan. After the inevitable discussion about the merits of each other's mode of travelling home I noticed that his vehicle had a GRP body shell. I swear I could have punched it and it would not have caused any damage. However, if I look at my super white aluminium sides in a less than friendly way, a dent appears. Is it weight, cost or some other reason that prevents caravan manufacturers going down the GRP route?
GRP v Aluminium
- Thread starter HomerS1
- Start date
That's a good question and there seems to be split in GRP and aluminium from manufacturers. We've just broght a new van which is GRP, even the underside of the floor! My guess is that GRP is stronger and more damage resistant and doesn't need painting. Like yours, our old van was aluminium and, as much care as we took of it, dents seemed to just appear. We'll see how the new one goes!!
I think there could a number of reasons why caravans tended to use aluminium and motorhome have more GRP.
The first is the time it takes to produce a large moulding in GRP. Caravans are produced in greater numbers and so the time and space needed to produce enough GRP mouldings would be considerably more for a caravan manufacture compared to a motorhome manufacture.
The second is weight, Area for area a strong enough self supporting GRP structure is probably heavier than Aluminium fabrication for the same job. We have seen many reports of GRP and other moulded front and rear panel suffering from stress cracks, looking at the problem simplistically that means the GRP or moulding was insufficiently strong in those critical areas, One solution would be to layer it up more thickly, but that means more weight....
Another approach which I have not seen used in caravans, would be an ABS sandwich filled with a self bonding structural foam. I know a guitar case manufacturer who uses this process and the results are incredibly strong, and highly thermally efficient and much lighter than older more traditional guitar case designs, so much so, he produces cases for many of the best top end guitar manufacturers.
The first is the time it takes to produce a large moulding in GRP. Caravans are produced in greater numbers and so the time and space needed to produce enough GRP mouldings would be considerably more for a caravan manufacture compared to a motorhome manufacture.
The second is weight, Area for area a strong enough self supporting GRP structure is probably heavier than Aluminium fabrication for the same job. We have seen many reports of GRP and other moulded front and rear panel suffering from stress cracks, looking at the problem simplistically that means the GRP or moulding was insufficiently strong in those critical areas, One solution would be to layer it up more thickly, but that means more weight....
Another approach which I have not seen used in caravans, would be an ABS sandwich filled with a self bonding structural foam. I know a guitar case manufacturer who uses this process and the results are incredibly strong, and highly thermally efficient and much lighter than older more traditional guitar case designs, so much so, he produces cases for many of the best top end guitar manufacturers.
We changed 3 years ago to GRP and yes there is more resistance to knocks and bangs, not that anyone who knocked the 'van would be alive to tell the tale.
Ours is GRP inside as well which has been really good for hanging pictures using the 3M sticky things. We've rather enjoyed finding canvases of a holiday nature to hang around the place.
Ours is GRP inside as well which has been really good for hanging pictures using the 3M sticky things. We've rather enjoyed finding canvases of a holiday nature to hang around the place.
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