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A DIY Carbon Fiber Mast

Posted: Sun Oct 16, 2022 7:53 am
by Alext
I am building a Quattro 16, of Woods Design. I made cross beams, fore beam and boom out of Carbon fiber/ epoxy with PVC core.

The mast will be 8.6 meters long. The PVC is 4 meter lengths and joined with reinforcement insert pieces I made with my CNC.

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The profile fits snuggly inside the oval PVC tube.

I used epoxy with some wood flour to glue the pieces together.

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Re: A DIY Carbon Fiber Mast

Posted: Sun Oct 16, 2022 10:18 am
by fallguy1000
Almost every professional will tell you it cannot be done properly.

How did you get a laminate schedule and how will you do the lamination?

Or did you buy a premade carbon profile?

Re: A DIY Carbon Fiber Mast

Posted: Sun Oct 16, 2022 3:39 pm
by Alext
Yes. You are very correct.This will be difficult. It is in an experimental stage. There will be loads of testing and I may fail. Richard Woods recommended buying a mast.

I am following some articles I detailed in my previous post. One from this website and another by Ted Hugger of “Profession Boatbuilder”.Also with what the local market can bear.

I live in Beijing. China is not a DIY culture. Anyone here will tell me that building a boat is the wrong game here, Still I persist.

I’m gleaning information from any and every source that I can. I don’t have a set formula or theory. It would be great to have this experience and back ground.

I first compared aluminum spars, wall thicknesses and profiles. I need my carbon fiber to be as strong or perhaps stronger. I am using 3k 220gm carbon fiber twill fabric. It is 0.28mm thick. So I estimate 4 layers to be 1mm. I’m not calculating epoxy or thickness added to the fabric.

Wall thicknesses of aluminum T6 or T7 extrusion are 1.5 to 2.5mm thick. So to get that strength I calculate that I need 6 to 10 layers of carbon fiber, perhaps more.

Re: A DIY Carbon Fiber Mast

Posted: Tue Oct 18, 2022 4:10 am
by Alext
Image

Here I laid up 1 meter wide, 3 layers of glass fiber. I think I should have put only one layer. This is to provide something more solid for the carbon fiber to adhere to. Also I wanted to see if I could wrap the whole length without having to cut the fabric into 2 50cm strips. It went well.

Re: A DIY Carbon Fiber Mast

Posted: Tue Oct 18, 2022 7:34 am
by fallguy1000
Why didn't you just build a foam core that stays behind?

Most masts are supposed the be a certain weight to balance ship movements. Have you considered?

A lightening strike would shatter the carbon mast. Will you run a lightening rod?

Re: A DIY Carbon Fiber Mast

Posted: Tue Oct 18, 2022 8:00 am
by Jaysen
Most masts use internal line/cable routing. Can’t have a solid core. Also you want the upper side of the boat as light as possible. The weight isn’t the critical issue, the material properties related to flex, fracture and torsion are the big deals.

Re: A DIY Carbon Fiber Mast

Posted: Tue Oct 18, 2022 8:55 am
by OrangeQuest
Looks good from the picture and hope it works out good for you.

Re: A DIY Carbon Fiber Mast

Posted: Tue Oct 18, 2022 9:54 am
by Alext
Thanks for the input. All things considered, and I have considered most things, weight, strength, flex etc.
I have considered foam core, and wood core (if I could only get veneer). I would like an anodized
aluminum mast and boom, that would afford me an easier way out, lol.

No replies from spar companies abroad and no one builds them in China. Again I’m in the wrong game,
or so they say. But no complaints either, I’m a stubborn old man.

So we’ll see how it goes. I’ve done preliminary testing with the cross beams and fore beam.
It’s all looking pretty good but there really is no way to be sure, until it all comes together.

Re: A DIY Carbon Fiber Mast

Posted: Tue Oct 18, 2022 11:25 am
by narfi
Alext wrote: Tue Oct 18, 2022 9:54 am Thanks for the input. All things considered, and I have But no complaints either, I’m a stubborn old man.
This approach has worked well for me in my projects so far :)
Research + pure stubbornness usually wins in the end.
Good luck!!

Re: A DIY Carbon Fiber Mast

Posted: Thu Oct 20, 2022 2:36 pm
by OneWayTraffic
I’m no mast expert but if you could find some aluminium profiles long enough it could serve as reinforcement and a path for lightning both?

Re: A DIY Carbon Fiber Mast

Posted: Thu Oct 20, 2022 6:14 pm
by Alext
Thanks for the input. All things considered. This is the concept I based these ideas on.

Image

When we are done sailing we take the mast down and fold the sail.

Re: A DIY Carbon Fiber Mast

Posted: Mon Nov 07, 2022 4:09 am
by Alext
I did the layup of the first roll of carbon fiber today. 8.6 meters long and 1 meter wide.
That makes 3 wraps, 0.83 mm thick. Richard Woods recommended 1.5 mm wall thickness
of aluminum. I want to put 6 layers, that will give 1.68mm and should (I hope) be strong enough,

Image

I’ll add the next roll of carbon fiber tomorrow. Then let it cure.

Re: A DIY Carbon Fiber Mast

Posted: Tue Nov 08, 2022 6:55 am
by Alext
Image

Re: A DIY Carbon Fiber Mast

Posted: Tue Nov 08, 2022 7:22 am
by Jeff
Nice work!!! Jeff

Re: A DIY Carbon Fiber Mast

Posted: Tue Nov 08, 2022 7:48 am
by Jaysen
I’m not sure if your “thickness equivalency” is correct. I checked a round mast here on a freedom 40 and it was much thicker than an aluminum equivalent.

If you have validated your layup that’s great. Stick with what was approved. If not you might want to have a material engineer weigh in to be safe.

That said, it looks great. Makes me dream of doing that for my little boats.

Re: A DIY Carbon Fiber Mast

Posted: Tue Nov 08, 2022 8:25 am
by fallguy1000
To support Jaysen's comments a bit. Richard is a minimalist. In a carbon diy mast; this can be bad. One way you can verify that a hand laid carbon mast is sufficient is weight. It should NOT be less than 20% lighter than aluminum. Carbon masts are best painted to avoid repeated maintenance of clearcoats every 2-3 years.

I am watching the post with interest because also building a 12' carbon beam.

Can you explain the process of how you did the lamination? How did you keep the carbon from sliding at the start?

Re: A DIY Carbon Fiber Mast

Posted: Tue Nov 08, 2022 8:26 am
by fallguy1000
Also, post your mast and boat specs on boatdesign.net to verify the layup.

Re: A DIY Carbon Fiber Mast

Posted: Tue Nov 08, 2022 9:20 am
by Alext
Again thanks for the input, it is very much appreciated.

I should post this cat, it is designed by Richard Woods.
I finally got the last 2 coats of polyurethane, set for 24 hours
and moved it outside.

Image

I moved the Zest into the part of the shop that I put a 4.5 meter door on.

It’s a long story about this item on my bucket list since I was 10. Trying to buy a mast, a sail, etc.

The carbon fiber mast is a test, an experiment if you will. I’m taking every piece of information I
can get and applying it. Richard did not endorse this mast, in fact he strongly encouraged me to
buy a mast.

I’m estimating strength/weight/wall thickness. When it is built and on the step, I will have to
decide if it seems to be strong enough to transport to the lake for further testing.
My friends sailing club. If it appears not strong enough at any point of testing, I will sand
and add more layer of CF.

Thanks again for the input. Alex.

Re: A DIY Carbon Fiber Mast

Posted: Tue Nov 08, 2022 10:04 am
by Alext
As for the lamination, I wish I had taken pictures. I will add that to this post in a day or two.

Re: A DIY Carbon Fiber Mast

Posted: Tue Nov 08, 2022 9:04 pm
by Alext
I’m using PVC as a core. Paint the PVC with common PVC adhesive and let it dry.
This will give a good surface for the epoxy to stick to.

At first I did my beams, at 2.45 meters (8 feet) max, they were much easier. I propped
up the PVC tube at each end. It could be rolled it but not easily, I want it to stay in place.
For the mast, much longer, I put 4 round supports, positioned to keep the work straight.
The mast will have to be lifted off of the supports and turned. In each case the supports
were covered with plastic packing tape.

Paint the PVC dried surface with a nap roller. I used a 100 mm (4 inch) wide roller. Let the
epoxy get tacky. ( I didn’t actually let it get tacky, my epoxy takes several hours to get tacky,
I don’t have patience for this.)

At one edge of the fabric stretch it end to end on the PVC core. Let it hang down in front of
the core. I used my hands to stretch the fabric to remove the wrinkles. Moving from one end
to the other. You will need to lift the fabric to get the wrinkles out.

After the wrinkles have been removed from a section, say 100-120 mm (4-5 inches). Use the
roller to apply epoxy, sparingly to that section. Turn the form to do the next section. When you
have gone all the way around the PVC tube you are working back onto where you started. Try to
tuck the first layer under the second layer and remove any wrinkles. As much as possible. Continue
rolling, laying the fabric and applying epoxy as req’d. I work the fabric from one end to the other,
then back.

Once the whole piece of fabric has been laid up onto the PVC, it’s time to get my hands in. I keep
a bottle of acetone and a good supply of rags handy. I rinse my hands with acetone and wipe it off,
with a rag. Keep clean when using.

You could leave it here if you like. There is excess epoxy and the fabric will not be tight. It will drip
and probably sag.

So I use my hands to work the fabric, stretching and squeezing out any extra epoxy. I want the fabric
to be wet but not drippy. I work it until there are no wrinkles, no loose fabric and the epoxy is getting
tacky, so it won’t drip.

If you allow the epoxy to dry, remember to sand it before adding more.

Re: A DIY Carbon Fiber Mast

Posted: Tue Nov 08, 2022 10:23 pm
by Alext
https://dragonplate.com/carbon-fiber-vs-aluminum

http://www.dexcraft.com/articles/carbon ... materials/

I’m not sure how much I would bet on this. I would still want to test it in the specific context but.
Studies show that 2 directional carbon fiber with common modulus, has 30% more stiffness and
60% more ultimate strength, when compared to aluminum with the same wall thickness.

There are many grades of carbon fiber with different modulus.
The stiffness increases as the modulus, however ultimate strength decreases.

From what I can see the disadvantage of CF is that although it will flex and bend, it always
Wants to return to its original shape. When it reaches its limit it breaks..

Re: A DIY Carbon Fiber Mast

Posted: Wed Nov 09, 2022 6:31 pm
by fallguy1000
Curious why not try infusion?

Re: A DIY Carbon Fiber Mast

Posted: Wed Nov 09, 2022 6:48 pm
by Alext
I hadn’t thought of that. I’ll be looking into it.

Re: A DIY Carbon Fiber Mast

Posted: Wed Nov 09, 2022 8:25 pm
by fallguy1000
Alext wrote: Wed Nov 09, 2022 6:48 pm I hadn’t thought of that. I’ll be looking into it.
I think you wrap it with 3M spray glue and then pull the resin.

Re: A DIY Carbon Fiber Mast

Posted: Thu Nov 10, 2022 5:21 am
by Alext
So here I am, a little over 36 hours later. The temp is lower. It’s solid with still
a little flex in it. I hoped it would be perfectly straight, but not.

Image

I will add some more layers with the sail way. Today I glued the PVC that will
become the sail way. I think I will add 3 more layers to this.

Image

Re: A DIY Carbon Fiber Mast

Posted: Thu Nov 10, 2022 10:12 am
by narfi
I used pex tubing for my sail track, and while it works, I was not as happy with it as I had hoped. I did not put enough time and thought into the jig for cutting the slot and it was not uniform, so there are tight and loose areas. I sanded the tight areas to make them work, but loose areas can be an issue. I ended up not being able to slide the bolt rope of the sail through it and used plastic slugs which worked much better.
I did the same on the boom, but I cut the slot too loose for it and when using on my ice boat (which puts more force on the sail than the trimaran) it pulls out. So I ended up needing to lash the sail down to the boom to keep it from slipping out.

Just some thoughts :) your pvc might be harder than the pex I used and you are probably smarter in cutting your groove after...

I love seeing projects like this that are inventing on your own "outside of the box"

Re: A DIY Carbon Fiber Mast

Posted: Thu Nov 10, 2022 10:43 am
by Alext
Thanks for the comment. The Idea is to have the PVC provide the form. Layers of FC fabric will wrap around the mast and now include the sail way track. The strength will come from the FC and epoxy. When the FC cures I will draw a line with chalk and grind the slot with my angle grinder. Very carefully of course. BTW all of the ideas I will be using for the accessories are from, or inspired by, the tutorials on this site.

Re: A DIY Carbon Fiber Mast

Posted: Thu Nov 10, 2022 12:14 pm
by fallguy1000
Alext wrote: Thu Nov 10, 2022 5:21 am So here I am, a little over 36 hours later. The temp is lower. It’s solid with still
a little flex in it. I hoped it would be perfectly straight, but not.

Image

I will add some more layers with the sail way. Today I glued the PVC that will
become the sail way. I think I will add 3 more layers to this.

Image
Consider getting it straighter and leaving it cure longer that way. Takes epoxy a good week for full cure and if you postcure; it can change shape still.

Re: A DIY Carbon Fiber Mast

Posted: Fri Nov 11, 2022 8:38 pm
by Alext
Jaysen wrote: Tue Nov 08, 2022 7:48 am I’m not sure if your “thickness equivalency” is correct. I checked a round mast here on a freedom 40 and it was much thicker
than an aluminum equivalent.
I think I may have chosen the wrong modulus of CF. This article shows a comparison between CF and aluminum by
weight and by wall thickness.

http://www.dexcraft.com/articles/carbon ... materials/

The common (standard) modulus CF has 160% the ultimate strength of the same thickness of aluminum. As the modulus increases the stiffness increases; ultimate strength decreases.

Re: A DIY Carbon Fiber Mast

Posted: Mon Nov 14, 2022 6:09 am
by Alext
Another test by Dragon Plate

https://dragonplate.com/carbon-fiber-10 ... gh-modulus

Shows strength and stiffness numbers of different grades of carbon fiber. Strengths are nearly equal,
between standard, intermediate and high modulus. I’m more confused now than before.

Re: A DIY Carbon Fiber Mast

Posted: Mon Nov 14, 2022 8:04 am
by fallguy1000
Alext wrote: Mon Nov 14, 2022 6:09 am Another test by Dragon Plate

https://dragonplate.com/carbon-fiber-10 ... gh-modulus

Shows strength and stiffness numbers of different grades of carbon fiber. Strengths are nearly equal,
between standard, intermediate and high modulus. I’m more confused now than before.
All about tradeoffs...

UH is stiffest, easiest to break.

Intermediate is hardest to break.

But stiffness can also be driven by thickness.

So, I'd want intermediate, then make it thick enough to meet desired stiffness.

Re: A DIY Carbon Fiber Mast

Posted: Mon Nov 14, 2022 8:34 am
by Jaysen
I’d warn against thickness as it adds weight. Reduction of weight on the mast is big (low weight increases righting moment).

A secondary factor is stated or unstated mast. I stayed needs more stiffness. Stayed can be a bit more flexible. And remember that some bend is required to maintain sail shape.

Re: A DIY Carbon Fiber Mast

Posted: Mon Nov 14, 2022 9:44 am
by fallguy1000
fallguy1000 wrote: Wed Nov 09, 2022 8:25 pm
Alext wrote: Wed Nov 09, 2022 6:48 pm I hadn’t thought of that. I’ll be looking into it.
I think you wrap it with 3M spray glue and then pull the resin.
Don't try this with the pvc attached. It will not work. I am probably being patronizing here, but don't want you to wreck the work which infusion would do now with the pvc creating voids.

Re: A DIY Carbon Fiber Mast

Posted: Mon Nov 14, 2022 7:44 pm
by Alext
fallguy1000 wrote: Mon Nov 14, 2022 9:44 am Don't try this with the pvc attached. It will not work. I am probably being patronizing here, but don't want you to wreck the work which infusion would do now with the pvc creating voids.
Thanks. Fallguy. I had a brief look at infusion. It seems interesting and way beyond anything
I would be capable of.

Re: A DIY Carbon Fiber Mast

Posted: Mon Nov 14, 2022 9:59 pm
by Alext
As for carbon fiber mast, I think it’s going to be a certain amount of guess work,
trial and error to get it right. I’m researching strength and stiffness data trying to
have a better, more informed idea. I don’t feel any further ahead. Not that I’m a
particularly bright guy, but. Each company that produces carbon fiber or does
significant work with it has their own way of testing and their own, often different
data.

Re: A DIY Carbon Fiber Mast

Posted: Tue Nov 15, 2022 10:43 am
by fallguy1000
Alext wrote: Mon Nov 14, 2022 9:59 pm As for carbon fiber mast, I think it’s going to be a certain amount of guess work,
trial and error to get it right. I’m researching strength and stiffness data trying to
have a better, more informed idea. I don’t feel any further ahead. Not that I’m a
particularly bright guy, but. Each company that produces carbon fiber or does
significant work with it has their own way of testing and their own, often different
data.
My favorite composites experts are on boatdesign.net. They will give you lots of crap, but your best bet for advice is there.

Re: A DIY Carbon Fiber Mast

Posted: Sat Nov 19, 2022 10:56 pm
by Alext
Getting to cold now for epoxy. I don’t have a heated space so I will pause.
I’m pretty confident with my trial and error approach, just have to wait and see.
According to a book published by Glen-L “Rigging Small Sailboats”, the force on
this sail would be 100Kg (225 lbs) in a 20 knot wind. The crossbeams (2.45meter
(8 feet) max) support 100Kg with no noticeable flex. The mast 8.6 meters (28 feet)
will support100Kg with about 10cm (4 inches) flex. I will add layers of carbon fiber
to support the sail way track Then test it.