Who said resin infusion was easy?

[ahender]

I fret about infusing my 12' male canoe mold.

Now I feel better!

alan

[Landlubber]

China!

[robherc]

LOL, I think I'll PASS on THAT nonsense! rofl

[daiquiri]

Geeeze, is that what they call PROGRESS?
That's why I prefer wood and metal.

[ahender]

Words you do not want to hear.

"Boss ... I think we have a leak."

alan

[JeroenW]

I hope those are bleeder lines and not feeder. Imagine how many resin would go just in filling those up...

[robherc]

LOL, imagine how many buckets they'll have to run in series to catch all the excess resin! ...maybe they got wise & started using 55gal drums for the purpose! rofl

[Splint]

Wow, they must really be paranoid about ending up with a dry spot in the job.

So, if you are going to make a snug fortune abroad, do´nt build boats in China! Become the hose supplier next door.

[Knut Sand]

Thats impressive...

And then feeding stops...
We have a leak....
Who to tell the boss....?
Better solution;
We go on the pub....
During the evening a conclusion emerges from the haze;

"Let's blame it on the resin guy..?"

[JeroenW]

Guys, why are the rolls of peelply still unpacked....

[Herman]

They sold them to Belgium...

[sliderule]

Has anyone built a carbon fiber roller furler (torque tube) to replace an aluminum tube? This is a different problem than building a mast or boom out of carbon fiber, because it needs significant torsional strength and stiffness. The forestay will continue to carry the majority of the bending load and the tube should actually bend with the forestay. I would like to reduce both the windage and weight, but create an strong, durable torsion tube that can be partially furled under jib sheet tension, with a strong luff groove that won't pull out or split apart. Easy! right? There must be a reason why the commercial products currently cost over 25k.

I would like the tube to be about an inch in diameter, and 57 feet long (I'm not kidding), with a single luff groove (double luff grooves on roller furlers are silly because you can only use one halyard at a time). I am going to install it one time and leave it on the 68 foot mast so it doesn't need to be segmented, but it still needs roller bearing inside on the solid rod forestay.

My ideas so far:
1. Use pvc tube or stiff polyethylene tubing as a mold. Problem - getting the tube out after the lamination. Use 1/4 diameter polyethylene tube to mold the luff groove.
2. Suspend the tubing on tensioned wire or low stretch rope (two trees 60 feet apart), unfortunately my barn is only 34 feet long.
3. Use biaxial carbon sleeve at near max diameter to align the fibers to increase torsional strength and allow some bending in the tube when installed.
4. What layup to use? A sleeve over the 1 inch tube, then another sleeve over the 1 inch tube plus the 1/4 tube to create the luff groove. Other configurations?
5. Use infusion technique? I am really unsure about this. Can you pull resin 57 feet with a vacuum pump? Do you need an intermediary material to allow the resin to flow the length of the layup?
6. I am thinking that I would pre-install the (journal) roller bearings on the rod rigging forestay (machined torlon or delrin) held in place with tie wraps or nico-press sleeves. This is because I would like one continuous section, not segments like commercially available products.

I did a 3 foot test section by wrapping and half overlapping unidirectional glass at a 45% angle with regular epoxy and a vinyl tape wrapping. It was a fairly poor job but revealed that the sleeving is probably the right way to go. the torsional strength of a wrap is not equal in both directions. With the wrap, it is very strong (tightening the winds), the unwrapping direction was not as strong tending to delaminate the windings. This suggests to me that sleeves at near maximum diameter will give consistent torsional strength and allow bending.

Has anyone tried putting carbon powder in resin (versus gel-coat) as the bottom coat of a layup to facilitate mold release? I think that this would be really helpful in the luff groove to make it slick in the finished product.

Looking for good advice and experience.

[Herman]

You are planning to tackle a very interesting job, and below I will give you some comments:

Originally Posted by sliderule

Has anyone built a carbon fiber roller furler (torque tube) to replace an aluminum tube? This is a different problem than building a mast or boom out of carbon fiber, because it needs significant torsional strength and stiffness. The forestay will continue to carry the majority of the bending load and the tube should actually bend with the forestay. I would like to reduce both the windage and weight, but create an strong, durable torsion tube that can be partially furled under jib sheet tension, with a strong luff groove that won't pull out or split apart. Easy! right? There must be a reason why the commercial products currently cost over 25k.

There definately is a reason, and I guess you will encounter...

I have not built a similar product, at least not at that length. And what I built was not a furler, but it looked basicly the same.

I would like the tube to be about an inch in diameter, and 57 feet long (I'm not kidding), with a single luff groove (double luff grooves on roller furlers are silly because you can only use one halyard at a time). I am going to install it one time and leave it on the 68 foot mast so it doesn't need to be segmented, but it still needs roller bearing inside on the solid rod forestay.

Installing it is a project in itself, but I guess you know that.

My ideas so far:
1. Use pvc tube or stiff polyethylene tubing as a mold. Problem - getting the tube out after the lamination. Use 1/4 diameter polyethylene tube to mold the luff groove.

Getting a suitable tube in that length is already a problem. Getting it out can be done by heating up the assembly during cure, and after cure and cool, one could probably pull it out with a car.

But I give you another option as well: Buy thin walled carbon tube (preferably with lots of +/- 45 in it) in 2 sizes. Glue them together, fill the "sides" and wind more carbon over it. Then cut open the small tube.

2. Suspend the tubing on tensioned wire or low stretch rope (two trees 60 feet apart), unfortunately my barn is only 34 feet long.
3. Use biaxial carbon sleeve at near max diameter to align the fibers to increase torsional strength and allow some bending in the tube when installed.

getting the sleeve over the tube? Interesting job... Although winding requires more hardware, it is easier to do.

4. What layup to use? A sleeve over the 1 inch tube, then another sleeve over the 1 inch tube plus the 1/4 tube to create the luff groove. Other configurations?

getting the laminate right indeed is a challenge...

5. Use infusion technique? I am really unsure about this. Can you pull resin 57 feet with a vacuum pump? Do you need an intermediary material to allow the resin to flow the length of the layup?

No, you will not pull resin 57 feet. This product however can be done by infusing from small tube to large tube, but not from bow to top of mast. (you get the picture).
Actually, when winding, I would hand laminate. After laminating one could apply shrink tape or shrinkable peelply, or even regular tape or peelply, applied with a bit of tension.

6. I am thinking that I would pre-install the (journal) roller bearings on the rod rigging forestay (machined torlon or delrin) held in place with tie wraps or nico-press sleeves. This is because I would like one continuous section, not segments like commercially available products.

I am not too familiar with the technical construction, so I will leave that to other people to make decent comments.

I did a 3 foot test section by wrapping and half overlapping unidirectional glass at a 45% angle with regular epoxy and a vinyl tape wrapping. It was a fairly poor job but revealed that the sleeving is probably the right way to go. the torsional strength of a wrap is not equal in both directions. With the wrap, it is very strong (tightening the winds), the unwrapping direction was not as strong tending to delaminate the windings. This suggests to me that sleeves at near maximum diameter will give consistent torsional strength and allow bending.

You should wind a couple of times, in both directions. Otherwise you will indeed lose strength. Getting control of the winding is a bit tricky. Automation is the key, but cost dollars. Hence the 25K....

Has anyone tried putting carbon powder in resin (versus gel-coat) as the bottom coat of a layup to facilitate mold release? I think that this would be really helpful in the luff groove to make it slick in the finished product.

Yes, this can be done, and has been done, but keep in mind the black debris. I would opt for a glass tube, and a can of McLube.

Looking for good advice and experience.

Hope this helped...

[Landlubber]

I have no idea, but it may be possible to use centrifugal force by using carbon fibre sleeve inside a tube (say PVC) and spinning the setup, it would not have to be all that fast to spread the sleeve to the inside of the tybe.

Alternatively, try CF sleeve again OVER the tube mandral and cover with electrical heat shrink tube, this will fairly evenly squash down onto the mandral...I have done the heat shrink method for rudder shafting parts (not CF though)and it works well.