Thye use of Carbon Fiber in Timber Framing?

[KBforester]

I haven't read anything on the subject, nor have I ever worked with Carbon fiber.

But I've used plywood fiberglass/epoxy composites with boat building....

But does anyone think a T strap could be created with carbon fiber, or possibly a plywood carbon fiber composite, in place of 1/4 steel? I'm thinking about where two beams meet over a post... nothing too crazy. It would have one on the front and back of the joint with through bolts or lag screws.

Any thoughts? I like to get crazy ideas out of my head as fast as possible if they are indeed crazy.

[D Hagens]

Short answer is yup I've made them before, colored the resin to match the wood that we used to build a log cabin.
Carbon fiber is mainly epoxy, easy to use and not much to make a mold for just about anything

[bill m]

Why carbon fiber? Real carbon fiber is expensive and needs special design engineering and processes to make structural components. Google DragonPlate.

[jueston]

i'm no expert on the topic, but from my understanding there is a huge differance between the kind of carbon fiber people make in there garage or put on there honda and the real carbon fiber used on $30 million fighters.... so i think for this use, steal is the best option. when looking at materials you have to find the right balance of cost of production and strength.  real carbon fiber might be stronger then steal, but if it costs you $500 each plate, then is it really worth it?

but thats just my 2 cents

[Ianab]

Could you?  Sure...

Is it really practical? Like cheaper, stronger or easier to manufacture than a piece of steel? I doubt it.

Carbon fibre is used where strength and light weight is needed. In a building, so what if you replace a 10lb piece of steel with a 1/2 pound carbon fibre piece. The house wont fly any faster or use any less fuel.

As for making it in your garage. This was basically designed and built in a guys shed.
http://en.wikipedia.org/wiki/Britten_V1000
Engine is of course cast / machined, but all the other frame components are carbon fibre, of the jet fighter kind. But this machine is designed to be FAST and ounces counted in the design.

Ian

[KBforester]

Thanks for the replys. I think there might be some confusion here. I'm not sure I understand what people are talking about when they say "Real Carbon Fiber". I'm not talking about using carbon fiber plate. I'm talking about using carbon fiber cloth and epoxy resin to make any shape I want. Or, use plywood as the base material and put multiple layers of carbon fiber on either side (with epoxy). Carbon fiber cloth is "REAL" carbon fiber... that's what the plates, tubes, motorcycles all start out with.  Here is some links to some U-tube videos:

http://www.youtube.com/watch?v=IAdVO8Rkv6c&feature=related

Only difference from that video would my "part" would be simple, and essentially a two dimensional T-strap.  How thick is something I would need to figure out.

http://www.youtube.com/watch?v=-sOU3zEigt0

OR, I would use a plywood T-strap, and cover each side with multiple layers (alternating weave orientation) of fiber.

The cloth is definitely not cheap, but I think in the application in question it would be comparable to steel. The cloth (50" wide) goes for about $38 a yard. I could probably make oh... 5 of so components with one yard, more if I use the plywood method.

I have nothing against steel. But the thing is, I don't have any of the tools required to cut, drill, or weld 1/4 steel plates. I'm afraid the costs I would have to go through to pay someone to manufacture them would far exceed the cost of the material.... maybe I should have asked that question first. How much time/money do you think it would cost someone to manufacture the plates for me? Or does anyone know of some cheap, not fancy, per-manufactured brackets?

I've manufactured my own fiberglass components before, and thought it would be an easy transition to carbon fiber. Or Kevlar.   

[bill m]

For a well equipped welding/fabricating shop to make T shaped brackets it would cost less than you could buy the materials to make carbon fiber ones.

[KBforester]

You think so? I'll see if I can find someone.

[shelbycharger400]

what is the dimensions of the t-strap?
I have a few machinist buddys, one stampin buddy
sheet steel is cheap,  fairly easy to work with, and if something isnt quite right, most of the time it can be welded. Dissimmilar materials can be fused or bolted together ect.
carbon fibre...is one shot, breaks or not right..goes into the can

[D Hagens]

 Thanks for the replys. I think there might be some confusion here. I'm not sure I understand what people are talking about when they say "Real Carbon Fiber". I'm not talking about using carbon fiber plate. I'm talking about using carbon fiber cloth and epoxy resin to make any shape I want.

No confusion at all here, I understand exactly what you're talking about
You're on the right track about how to do your lay-up. It's fairly simple, the big thing to remember is the strength factor. Like the application that you're going to use the product for.
I wish I had some pics here to show you but I will try to explain. My uncle builds experimental planes, for the wings on one of his planes that I helped build everything was done in molds which is a pain unless you plan to use them over and over again.
For smaller parts making a template and wrapping layers of cloth and epoxy over it made some pretty strong parts. These parts have to be shipped out and tested before they can be used.
If done correctly these products can be stronger then steal, thing is, is it worth all the trouble to go through? Like what is the main objective of the application that you're thinking this way?
 

[KBforester]

is it worth all the trouble to go through? Like what is the main objective of the application that you're thinking this way?
 

The only reason I'm looking at carbon fiber for an option is I don't have the equipment or the know how to deal with steel. And, I am suspicious that it would cost quite a bit to have someone else fabricate them for me. I feel like I can tackle carbon fiber myself. I imagine it would take a long time to do... so I'm all for using metal if its comparable or cheaper in price. But it might be a long winter  :

[beenthere]

I don't see the composite having the crushing strength that might be needed around the bolt holes, whereas steel would have.
That is if

I'm thinking about where two beams meet over a post...

will have tension forces trying to pull the beams off the post.
If I understand it right... :

A tension rod along the top of the beams might be as good or better than the T strap. It might be out of sight and do the job.

[Dave Shepard]

Let's take this discussion back a few steps. Is this new construction, or a repair to an existing building? This issue should have been dealt with at the design stage. It would be better to have the two beams meet in the side of the post. A better understanding of the frame should help.

[KBforester]

This is new construction. I call it a ridge beam method...





Real simple no notches... hope that doesn't anger anyone

Beams and posts are both 6X8 Larch

I'm willing to take opinions for the dimensions of the T strap if anyone is willing to give their opinion.

[beenthere]

Do you want the look of a T strap?
Are you using the T strap in place of the angle braces?

Look at what Dave Shepard said, and as well back into the archives of previous threads. Joints over posts are not giving you the full strength of the beam between posts.

[jueston]

I'm not sure I understand what people are talking about when they say "Real Carbon Fiber". I'm not talking about using carbon fiber plate. I'm talking about using carbon fiber cloth and epoxy resin to make any shape I want. Or, use plywood as the base material and put multiple layers of carbon fiber on either side (with epoxy). Carbon fiber cloth is "REAL" carbon fiber... that's what the plates, tubes, motorcycles all start out with.  Here is some links to some U-tube videos:

I shouldn't have been so vague in my use of the words real carbon fiber, what I mean, is there is a difference between aerospace grade applications, and epoxy covered sheets of carbon fiber. Even the tiniest air bubble on the epoxy greatly reduce the load bearing capacity of the finished product, when nasa or Boeing make carbon fiber parts they vacuum bag it and then auto-clave it. are you planning on doing that? I think it might be possible, but I don't know how to do it.
So I didn't mean to sound condescending when I said real carbon fiber, because anything which employs those sheets of carbon fiber clothe, really are carbon fiber, but that doesn't mean its going to be stronger then steal. Only if it is engineered, assembled and handled with the right expertise and equipment.

[SPIKER]

I've worked with both, and under the "Real Carbon Fiber" area there are way too many variables for do it yourself carbon fiber for a structural member.   And you wont get much out of a yard of fiber. for making a structural "T" brace.

also like someone mentioned the crush resistance is only good when the items in between the crush does not move or continue to compress/crush.   the carbon fiber while strong and excellent mechanical abilities cranking down on a bolt with even hard dry wood between will crush and splinter the carbon fiber.


There are a lot of places who build many "T" braces.   pick up a Log Home Magazine and look in back at the adds for custom home parts.   or just go to your local steel welding shop.   a T big enough to fit a 8x8 would cost maybe 8~10 bucks in materials.   drilling can be done by you at home nothing special drill bits & time.   or having shop punch them at a price...

mark

[Dave Shepard]

Thanks for putting up that drawing. So you are trying to tie the plates together over the posts? If you must use short pieces for your plates, then I can see that a T plate is a good way to go. A decent sized fab shop with an iron worker could make those plates pretty cheaply. I'd bet much cheaper than you could try to experiment with carbon fiber. If you could find a way to make those horizontal beams continuous, then I would buy a bucket of FastenMaster Headloks, or GRK RSS screws and screw every connection. You will still have to find a way to add diagonal bracing to your frame. It is not uncommon for braces to be nailed in, even on older frames. One ~1800 frame I have looked at recently was scribe ruled with nailed bracing.

It doesn't bother me that you are not doing a full mortise and tenon frame, it actually helps to know that.

[KBforester]

Thanks! Those are some good answers. I'll defiantly be looking harder into finding a machine/welding shop. The equipment is definitely around- mostly loggers and fishermen. I might have to travel to the big city (Bangor) to find someone willing to do this kind of thing. Thanks again!

[bigshow]

I realize its not a full mortice and tenon frame.  But, hardwood splines i would think would solve this issue, and take less time than fabricating your own solution.  Of course, going to a welding shop and getting some plates made would be cheap, and far less time consuming.

[D Hagens]

K pics really do help Now that I see what you're doing have you ever thought about adjustable straps? Not sure if you can get them in your area or not, out my way we can. In short an adjustable strap is like taking a T strap or gang hails and bending them but these have pivot points in them and adjust to just about any angle without any kinks in them.
I don't use them much but when there's an odd angle they come in handy. I'm pretty sure I have a few in the shop and if I see them I will post a pic for you

[KBforester]

Thanks for everyone's suggestions! I went and had them fabricated at a large size metal distributor/ fabricator. A lot less expensive than I anticipated. Glad I listened to reason!