Laser cutting.

[Banshee Ambulance]

I have just been reading up on some Farr 3.7 build blogs. The thought that I was having was... can you laser cut pre laminated foam/carbon sheets? Anyone got any ideas?

[mike_cooke]

Think water jet cutting might be more useful for this!

[ross_burkin]

Laser cutting generates a lot of heat and i think you'll end up with a proper messy/burned/melted edge. You could easily use CNC router or as cookie suggested, water jet cutting.

[JimC]

An issue with doing foam panels might be that you usually want the edge to be angled, not at 90 degrees to the material. I wouldn't be surprised if the technology is there to cope with that, but it sure ups the complexity of the required data file. Most foam boats in our sort of size don't have anything like the number of pieces you have in these very sophisticated wood construction boats, so its less of an issue for boats. Building jigs on the other hand... But then you'd probably make those from ply or fibreboard anyway wouldn't you. Must admit those cutting plans for the Farr do look awesome, but I have a used Farr boat to do the next time I feel like getting embedded in wood shavings and there are no cutting lists for that one...

[Andrew Whapshott]

I've cut 10mm MDF with the cutter at my college, and it got through it pretty easily, just made lots and lots of smoke.     

[ross_burkin]

An issue with doing foam panels might be that you usually want the edge to be angled, not at 90 degrees to the material. I wouldn't be surprised if the technology is there to cope with that, but it sure ups the complexity of the required data file. Most foam boats in our sort of size don't have anything like the number of pieces you have in these very sophisticated wood construction boats, so its less of an issue for boats. Building jigs on the other hand... But then you'd probably make those from ply or fibreboard anyway wouldn't you. Must admit those cutting plans for the Farr do look awesome, but I have a used Farr boat to do the next time I feel like getting embedded in wood shavings and there are no cutting lists for that one...

Use angled router bits around the edge

[phil_kirk]

I agree that the laser cut parts looked great.  If we were going to build lots of cherubs and wanted to create a kit of parts an automated cutting process might create an advantage however for 2 or 3 boats you are likely to spend less money and time by creating some accurate ply or mdf templates from the first set and cut more from that. Then sanding the chamfered edges by hand afterwards does not take to long.    With practice this would become a quick and accurate method. 

I found that the cardboard E5 templates gave a good start to the shape but it took a while to turn this into an accurate shape by sanding, fitting and then sandiing some more ...

[Torchy]

Is this thread about what I think it is?

We could get together and pre-laminate lots of foam/carbon sheets, cut these sheets to a template then stitch and glue (or pin and glue) an E5?...lots of E5s

E6 curves are very lovely but in the end don't chines go just as fast in the end usually?

...especially if the E6 becomes the Olympic boat and generates interest in the class - this would be a low cost option for people starting out.

...back to the original Cherub vision but in carbon.

[Torchy]

Sorry, this is a bit of a (hobbit having a) 'This stuff comes in pints!' moment...

Are pre-laminated carbon/foam sheets available commercially?

[JimC]

Are pre-laminated carbon/foam sheets available commercially?

I don't think you'd want to do a shell like that, but if you were putting an interior in a shell built by one of the pro guys (or a new interior in an old shell) then I reckon its worth considering.  There should be a substantial saving because you are taking all the time consuming fiddly bits out of the build. I've had Bloodaxe make carbon panels for me in the past. I thought the price was reasonable. I didn't do anything sophisticated when I used them though, just made cardboard templates and cut the sheet when I was satisfied with the shape. Here's one I prepared earlier...

[Phil Alderson]

One of the good things about foam carbon panels is that they are quite stiff, so not so good as ply for stitch and glue.

A prelaminated sheet is V useful for bulkhead.

[Torchy]

So...let the expertes do the fiddly bits then a double floor, a semi-sunken foredeck, the transome (such as it is) and use carbon tubing for the mast support, racks, rudder gantry...

hmmm...

[JimC]

So...let the expertes do the fiddly bits

yep, although I'd say its the other way round - let the experts do the bit that's a nightmare if it all goes horribly wrong, and do all the fiddly time consuming and thus expensive bits yourself where in general its not a disaster if you stuff up and have to slice it out and do it again. For the same reason I'd probably buy pre-made tubes and glue them together rather than make them myself, although there's a lot of experience in tube manufacture available to the beginner through sticky weekends.

[Clive Everest]

I can thoroughly recommend this build technique. I used a FiberFusion in Falmouth to make a kit for a big foiler.
They have a 400 ton press for making carbon foam panels and a water jet cutter. The quality and precision of the parts is fantastic.
You send them a cad file and get a flat pack boat back in the post.
It then took a weekend to assemble the hull with no tooling except a very simple MDF jig that they also water jet cut.
There is no need to bevel the panel edges. The volume of bog required to fill it is trivial.
Next time I would try and make a roller to slightly crush the foam - Trap hook style - so that there is a small recess for the tape.
I would also add castelations to the panel edges so that they lock together rather than just fitting together.
The boat flew but was never fast. Compared with a Moth it felt like I was trying to fly the Queen Mary.
It also became clear that my initial presumption that you had to be <10 stone to sail a Moth was wrong.
I am trying to find the time to come up with a cad file for a simple canoe to build like this.

Clive

 

[TSC]

All the carbon ribs for Invictus were made by Fibrefusion down at Falmouth, and I would concur with Clive that they are incredibly accurate and well made. The water jet cutting provides incredibly crisp parts and from memory they are not expensive.