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Best way to joint fabricated carbon strut structure.
Best way to joint fabricated carbon strut structure.
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Best way to joint fabricated carbon strut structure.
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Tobias
Tobias
posted 12 Years Ago
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Hi there,
I am pretty new to working with carbon, but have a good background in other materials.
I am working on designing a strutted framework, fabricated out of 5mm pultruded carbon tube, and I thought it best to seek some advice about how best to make the joints. My plan is to build a jig which holds everything flat, and use a braided sleeve to form a reinforced skin. However since I also plan on painting the structure, I don't necessarily need the braid for aesthetics, however I also don't want 'spider knees' at each join.
To simplify things, lets assume i am building a small chair, with some structural triangulation, which needs to hold about 10kg ( so in real world terms I guess it has to be over-engineered to not fail under 50kg, or something of the kind ).
In my crude drawing I have 3 potential jointing processes, but I wonder if there is another I have not considered, or if I would be better off making a mould and a core, and using a cast component joined by tubes, rather than attempting to join struts together.
Thanks,
T
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Warren (Staff)
Warren (Staff)
posted 12 Years Ago
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They should be bonded in using a structural adhesive like our
ET515Semi Flexible 15min Epoxy Adhesive
The braiding you want to add will just add further strength but isnt essential if you use inserts.
Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant
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Tobias
Tobias
posted 12 Years Ago
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It would appear that the ET515 has no structural value at all, as it seems to neither bond to degreased aluminium nor to roughed carbon, as in I can scrape it off either with my fingernail after three days of curing. I only discovered this when I had a catastrophic failure of a rather beefy join.
I kind of feel that the ET515 is no stronger than Araldite, no more nor less rigid, and in a similar manner is no more respective of its apparent 15 minute working time.
Warren (Staff) (11/07/2013)
They should be bonded in using a structural adhesive like our
ET515Semi Flexible 15min Epoxy Adhesive
The braiding you want to add will just add further strength but isnt essential if you use inserts.
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carbonfibreworks
carbonfibreworks
posted 12 Years Ago
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Hello Tobias
I have used the above adhesive on the top fairing mount on my classic racing motorcycle, i used it to join 10mm carbon tube to a piece of pre preg plate . I abraded the parts to be bonded with 180 grit paper and the part is under load and the joint has been 100% reliable.
Regards Chris
carbonfibreworks.co.uk
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Tobias
Tobias
posted 12 Years Ago
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Hmm, this was a 20mm carbon tube, and the join was to a strut coming in below, by means of an aluminium sleeve which wrapped around the tube like a clamp - made from 20x2mm stock.
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carbonfibreworks
carbonfibreworks
posted 12 Years Ago
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I will post an image of the part on Friday.
Regards Chris
carbonfibreworks.co.uk
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Best way to joint fabricated carbon strut structure.
Tobias
-
12 Years Ago
The strongest of the 3 is the tube joiner in aluminium. Such inserts are commonly used to join...
Warren (Staff)
-
12 Years Ago
Hi Warren, So if you were to build such a structure, you would work with alloy inserts and a braided...
Tobias
-
12 Years Ago
They should be bonded in using a structural adhesive like our Normal 0...
Warren (Staff)
-
12 Years Ago
It would appear that the ET515 has no structural value at all, as it seems to neither bond to...
Tobias
-
12 Years Ago
Hello Tobias I have used the above adhesive on the top fairing mount on my classic racing...
carbonfibreworks
-
12 Years Ago
Hmm, this was a 20mm carbon tube, and the join was to a strut coming in below, by means of an...
Tobias
-
12 Years Ago
I will post an image of the part on Friday. Regards Chris carbonfibreworks.co.uk
carbonfibreworks
-
12 Years Ago
When bonding any metal I still use the wet sanding technique using 240 wet and dry sometimes 120 and...
Shaneer22
-
12 Years Ago
how big is the gap?? I have used ET515 personally for bonding inserts and its been a good bond. You...
Warren (Staff)
-
12 Years Ago
As above, I've used that to bond halves of wings together and not had a failure yet
ajb100
-
12 Years Ago
I generally consider an adhesive to be something which adheres with a chemical bond, in this kind of...
Tobias
-
12 Years Ago
If you are adhereing it to smooth (albeit degreased) aluminium then I would have expected the...
Warren (Staff)
-
12 Years Ago
For future reference, I've just had confirmation from customer service at Permabond that the correct...
Tobias
-
11 Years Ago
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