Honeycomb fiberglass hull...

[Externet]

Good day to all.
I know nothing about, that is why am here, to listen and learn.

Not about engineered commercial composite panels, but a third-world approach to make a hull of this type. Please let me know your comments for an unusual approach.
There is no calculations on thickness nor on strength. Just looking for qualitative opinions on this description:

An existing hull, to be used as a mold; upside down covered with plastic film. Let's say 60 feet long, 15 feet wide.
A ~half inch layer of fiberglass cloth, o mat, or chop or a combination of them properly applied with resin on top of the film.
As this final resin is wetting the outer layer, placing bamboo slices one next to the other as to form a honeycomb layer, lightly pressed-in.
They are 4-to-5 inch diameter bamboo slices, say 1 inch tall, half inch wall, all in contact with their 'neighbor' slices.
After set, a second ~half inch layer of properly laid fiberglass and resin.
With the proper reinforcing attention and considerations to any edges or areas that deserve it.
After removed from the 'mold' and righted up, to add internal strengthening members.
I do not know how to obtain figures for bamboo strength calculations when used that way. By 'smell', I would say brutally strong. The sawed edges of the slices are very resin wicking-adherent.

Thanks. :rolleyes:
Miguel

[Ad Hoc]

have to be very careful with bamboo...it seems to contain loads of weird bacteria once cut (not present when growing), which slowly eats away the bamboo. has been a problem with bamboo furniture and all sorts for many years..despite lots of research to stop it.

[alan white]

Try PVC pipe instead. You will have to pre-fill pipe with foam before cutting, then it might support the glass/resin applied over it. I wouldn't want to be the poor fool running the cross-cut saw.

[Externet]

PVC... would the resin aggresively stick to it ? Seen ~1/16" thin wall fiberglass pipe, could be used for the slices too... or treating the bamboo as it is practically a $0 material.

Would such contraption hull work ?

Miguel

[alan white]

I'd experiment. Make up a few test panels. PVC seems to marry to polyester resin in my experience, but someone else here may actually know how well they bond.
As far as saving money on the hull, bamboo may be cheap, but I'd do a solid layup for the same money and stiffen with stringers. I personally don't like overly stiff structures because they are like eggshells. The do not yield a lot.
Stringers aren't stiff (like a modern fiberglass-framed camping tent. Bash one with a baseball bat. Does it break?)
Racing is another matter. Racing boats count on stiffness to carry huge loads without a lot of weight. But they don't suffer damage well, like punctures from underwater objects. In other words, I am wondering if you are attempting to get a very stiff hull, and if so, if it is intended for a specific purpose.

[Jimbo1490]

RE: PVC and poly resin: They don't bond well, not permanently anyway. But your idea is interesting, and there is a plethora of tube-shaped goods out there to choose from, many of which will be compatible with all the materials at hand.

But you need to consider is how the combination of drape and vacuum (you are pretty much committed to vacuum bagging to join the second skin to the core) is going to affect the practicality of this concept. Think of the cell size used with typical honeycomb. It's usually no bigger than 10 mm, maybe 13 mm max. Wet cloth will not sink very far into the open span of such a small cell, though it sinks in some. If you use a really big cell size as you are proposing, the wet cloth is going to sink WAY deep into the cells once put under vacuum, which will not be acceptable for a number of reasons. Going to a more conventional cell size will mean many hours fiddling with tiny tube cut-offs, gluing them in place one by one. Sounds like a job for the new guy :D

Anyway, it's a dilemma you need to face.

Jimbo