From one of the pioneers of foam sandwich construction for sailboat hulls, Derek Kelsall
gives his view on the new line of plastic honeycomb products. He also does not hide his dislike for balsa core
products as a build material for a boat.
Hi Boat Builders,
Our friend Rob Denny raised the topic a couple of weeks back. I have had a few inquiries talking about the pros and cons of the much cheaper honeycomb and pvc foam.
To quote my answer to one where impact damage was of concern, and the belief that honeycomb would be best in that case -Thin skins are more prone to damage to the outside skin, which takes the form of a tear as in clothing
I have never seen damage that has gone right through both skins of foam sandwich. That is due to the toughness of foam. Linear Airex is the toughest and a layer of kevlar could be added between glass skins if that was of major concern.
can be kept out of individual cells, what would happen if damage coincided with a join in the sheets
of honeycomb?Honeycomb has other handling disadvantages apart from infusion (which isstill a huge advantage in being so much cleaner etc.)- cutting, sanding
,routing, bevelling, joining sheets
and joining into blocks of foam forshaping are all part of the job.
What about that finishing task?One more. Take a plastic honeycomb sandwich and hold it to the sun. To be comfortable you will need extra insulation
If honeycomb showed overall benefit I would use it. I have no connections with any foam producers (they all sell balsa, which I condemn, so do not always make friends with them either).What I would advise is to test samples before making that finaldecision. Take a sledge hammer to both foam and honeycomb sandwich, break it, cut it, sand it, soak it, boil it - and let us know what you find.No doubt there are ways to avoid some of the potential problems I mention here. I do not have lots of honeycomb experience. I do know that PVC foam has stood the test of time, which has included a few situations where foam has proven itself to be exceptional against impact damage in particular. Much better than solid glass.
It took me five minutes to get water
through a typical skin to Nidacorecells using a hair dryer and water from the tap. Nidacore is a finecore for interiors.Enjoy your boat building - more with KSS resin infusion.Ballotta boat builders were mentioned also. Ballotta is KSS, resin infusion and pvc foam oriented. Their success is down to efficient method, access to our range of designs and our custom design service
but above all to good management and high standards. They can quote for a very wide range of sizes and types, without further investment in tooling.Do not expect any compromises from Ballotta or Kelsall
, to save a dollar on materials.We enjoyed the Denny/KSS proa project
we did in Australia
last year and would be happy to do more similar - for KSS foam build.Derek.-- Derek Kelsall, FRINA.,Kelsall Catamarans ltd.Tel 00 64 7863 3332.More information about