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Selfmade fiberglass fins

Thread Status: Hello , There was no answer in this thread for more than 60 days.
It can take a long time to get an up-to-date response or contact with relevant users.
can you post some photos ?

Yes, there are few pictures. I will send you a PM with my conservation with a Sales representative of Charles-Austen.
 

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wouldnt it be easier to make a mold and press the fins to get rid of bubbles?
vacuum seems like it wouldnt create enough force necessary to make a really tight laminate.
 
It was somewhere in earlier posts that it would be impossible to re-create the same pressure mechanically. It was here or somewhere esle, and there were some calculations. THe point was that VP is a much better option.
 
so basically all i have to do is get a few fiberglass sheets and some resin, and stick them together painting over them with resin?
 
[ame=http://youtu.be/G0xtwn97nwI]Installing fiberfins blades on a freediving footpocket - YouTube[/ame]
 
Valen35, are you sure you have read through the posts of this thread? Zmagoj explained very precisely what material he used, including the exact specifications, so I do not quite understand what more information you are looking for. Already when you look at the first 2-3 posts of this thread, you should have a pretty good idea what material you need to find.
 
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Hello after a looong time.
For this season we have made a new version of the fin. This time the performance is really great and I think this will make an end to my project. We succeeded to dive down to -65 m.
From previous versions we have improved bending curve, which has a progressive shape in air and near circular in the water. Here we made a compromise, since we wanted long (90 cm) and soft fin. Therefore in the tip, the fin is very thin, but at the footpocket is a bit thinner than it should have been according to the calculation, but with ticker blade we would also get stiffer blade. However, the blade performs very well in water and has a near circular bending shape.

Molding:
1. Same mold as before
2. PVA release agent Partall Coverall Film (R&G),
3. Unidirectional fiberglass AERO UD 220g/m^2 (R&G),
4. Peel ply, flow mesh and PVC cover,
5. Vacuum infusion as described before - Low viscosity epoxy: Epoxy resin L + EPH294 hardener (R&G),
5. Infusion at 40°C for 24 h, annealing for 16 h at 70°C
7. cut out from the finished laminate

The novelty is a new laminatplan which is described in the table below. The fiberglass is unidirectional and oriented so the fibers are along the blade. Because the tip of the blade is very thin and US fiberglass weary weak in perpendicular direction, we added a small layer on the tip, which has its fibers oriented perpendicularly to the rest of layers.
For better look we also added black color paste "Universal color paste RAL 9005 (R&G)" and the fins look as made from carbon.
For material cost you can search R&G page – catalog.
 

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Hello to all of you,

my name is Henning and first of all, i would like to say that this is a great thread so far...
I do have a few questions to you, especially to zmagoj. After i bought some C4 wahoo fins and recognized, that they were much to soft for me, i started thinking what to do.
I decided to build my own fins to, as i have a few friends wich are very familiar with lamination and stuff... I would like to build the fins in carbon as there is different type of cloth available for me from my friends. I read the entire thread and also i found the link to the HST blades. So i am searching for the right lamination and layers for my fins. I have to say that i am quite big and weighing around 115kg. Also i would like to get a real hard blade.
To be honest, i dont understand your lamination-scheme zmagoj.
My questions are:
Why does every layer have a L1 and a L2-lenght? What does it mean?
so, layer 1 is 740mm or 860mm? The Layer 1 and 15 are the longest this i understand. But where does for example layer 9 start and where does it end?
Do you not using any biax? There is written only UD.

It seems that i can get the following carbon cloth:

Biax 200gr.
Biax 400gr. and
UD 500 or 600 gr.

Basing on this, i started with another drawing. Maybe somebody with a little experience can give a few comments? The foot-end of the blade will be around 2,4mm at the moment. Is this ok ? What do you think?

THX a lot,

Henning
 

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hello Hennigap

I you are thinking on crbon fiber , your fins will became to stiff

Also atentions to the method that you aregoing to use. wet layup, wet infusion etc

also 20 cm distances from fin lip are to big, and will crate a very big stress point

don´t you get a uniderectional tissue around 150 gr ?
 
Hi pvilela,

thanks for your quick reply... I would like to use Carbon and a wet layup, as this is in my opinion the easiest and fastest way with an acceptable finish...

I asked again and i think i can also get 300gr. UD. I did a new lamination scheme with this and i also shortened the distances a little bit. This length distribution could be more precise, basing on the load case zmagoj showed before, i will try to calculate!
But what do you say now, should this lead to a usable solution?
THX a lot again,

Henning
 

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Hello

i am using wet layup on my fins

Currently i am using :
plain tissues 200 gr
Twill tissues 200gr
unidirectional 200 gr
ans some unidirectional 600 gr , near the foot pocket ( the craks in these area are very easy to get )
on my next fins i am going to introduce 45º angles fibers ,
i am facing some peeling on some bending areas . and i thing is becouse fins movements aren´t always the same

Try to make your calculations to getaroun 10 cm gap near the lip
and 30 cm gap near the foot
don´t forgot the foot pocket influenc on trhe bending movement.
i hope it helps
 
Hi pvilela,

does this look better? Your fins do not getting thicker the last 300mm? How thick are your fins at the bend and at this 300mm ? And what do you think about the thickness of mine?
regards,

Henning
 

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Hey,

L1 and L2 are overall length (used for cutting the cloth) and length from the tip to the inclined edge at the footpocket used to accurately position it on the mold.

I used only UD because the blade is rather narrow. However, there is a UD layer oriented perpendicular at the tip of the blade.

Your laminate plan seems OK with 300 UD and biax as outer cloth. However, I have no experience with carbon, therefore I cannot comment about absolute stiffness. My fins are on the softer and used by 60 - 70kg divers.

I would do the blade as thin as possible at the tip - maybe additional triangular shaped cut out in UD at the tip would work to soften it a bit.
It is the opposite at (and near) the footpocket side. If you want a strong blade, I suggest extending the layers 2 and 3 close to 4 to get stiffness where you need it the most. I did this with one of my blades and it worked well. My layer lengths were calculated with the assumption that the fin has constant width, and therefore such an extension corrects the error.

If you can find someone who can run a numerical simulation would greatly excel the design.


hope it helps
 
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Hi Zmagoj,


After i painted down your scheme it became clear, what you where writing about. But i am a little bit afraid, because there are 5 layers all ending nearly at the same point. Does there not occur something like a buckle?
Anyway, i lenghtened the two layers, but softened this a bit and i think i will give this one a try...
One more question, where do you buy the rubber rails?
regards,
Henning
 

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Henni,
attention this is carbon , not glass fiber
i thin you are pushing to much layers.

200 gr tissue will give you a 0,2 mm thickness
so by adding 9 or more layers you will have over a 1mm thickness.
near the footpoket is ok , it will prevent cracks.
if you have it on the middle of the blade , you will no be able to bend it .
attention to the fin length
as i see your fins are going to be around 85 cm to 90 cm
also , if your fins are to be big, don´t make then to large .

Yesterday i have test a 80 cm x 21 cm , and it give me a hard time to deal with them , special because of the footpocket i used that were very big.

Sorry, just some thoughts to think before starting :eek::eek:
 
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