I think that it will be imposible to make a strong sleeve like that,

How ever if you make a plug with this method and then molds then you can control the strength of the sleev.

This great method came from Phill to make a snuffer ring, but a mast sleeve is not the same as snuffer ring.

****. A 3position switch that allows you to pump up the bladder, adjust volme, monitor volume, and release when complete. I dont have a pic, but the company that makes them is Med Choice, and they are called "Infu Stat" Disposable Pressure Infusers.

Look in the plumbing section at Menards or Home Depot. They have bladders that are used for pushing clogs out of piping. They have a garden hose barb on one end, but you could get/make a converter to hook your compressor up to it. They expand quite a bit and are made to take water pressure from a faucet. Not sure what exactly how much pressure they would hold, but I would expect at least 40 or 50 psi.

I've worked out a method that is showing promise.

Anybody got broken carbon masts they want fixed?

Bill

do tell!

First attempt was using a bike tire folded in half, wrapped with carbon, peel ply and plastic. This worked ok, but the middle of the part has a noticable dimple on one side and a butt cheek like seam on the other. The tire tube wanted to expand into a round and didnt conform well to the shape of the mast. Plus I was using a Acat mast, and that mast wall is pretty thin, so I couldnt use a whole lot of pressure because it would deflect the mast out of its original shape.

I decided that I needed a way to approximate the shape and keep the wrap pretty close to its final shape before applying pressure. So, I used some aluminum flashing, which will bends easily in a nice fair curve. I found a larger bladder - A 6x40 Hoty dighy bladder that worked better.

Stick the bladder in the flashing, wrap with carbon, peel ply and plastic onto the flashing, and slide carefully into the mast, being careful not to wrinkle the carbon or plastic. Pump up the bladder and let cure.

Next day deflate bladder and yank the whole assembly out using plyers. The plastic is pretty slippery and the whole assembly slides out easily.

Im going to rough up the insides of both sections of the mast, and insert the splint half way into each end and glue. Once thats cured, I'm going to sand back the original mast and fair in more uni carbon.

I'll keep track of the mast bend by comparing it to my other A cat mast to make sure its similiar. Too stiff and I'll sand it a bit. Too bendy - add more carbon.

With the HT mast I've got a pretty thick section to work with so I should be able to get close to the original mast bend.


The Acat mast if more of a challenge to get close to the original mast bend, but I'm planning on using this mast with a spin, so I'll need to stiffen it up a bit.

Bill

pic 1

Dang Bill! That looks incredible!

Very low tech, but if you ever break a Wave Mast, we have broken two, here is the solution. Cut a 2 by 4 down to slip inside the mast, a section about 4ft long will do. Put in several screws, both top and bottom side of the repair. Then glass over the outside, making sure you retain the track for the plastic section. Lasted all year, so will repair others the same way in the future.

Caleb

dood. that looks great.

Just for information. The primary concept of composite structures especially carbon is not to add more to get the structure stiffer or less for a more bendy structure. It is determined by the lay-up schedule and the materials used. An example would be if you used only uni-directional cloth and laid it up in one direction (0,0)the lay-up would be stiff in the 0 degree direction and flexiable in the 90 degree direction relative to each other. If you wish to do a proper repair and you do not know the lay-up schedule of the structure, then you should scarf the area of damage and identify the amount of plies in the lay-up and the direction the layers are laid ( i.e. 0, 90, 45, -45 degrees) . The strength and resistance to bend is achieved by the continues fibers and the direction they run. To return back to the original properties you need to reconnect the fibers that were severed when broken. To do this you remove the damaged area by scarfing (tapering) the damage then replace the layers, smallest first then larger, and in the proper direction of each layer. In designing a repair of a structure the designer would add one to two extra plies depending on the structure and repair because you can not physically reconnect the broken strands. Following this procedure will get you as close as possible to the original structures properties. This is a basic overview of how we would repair a stealth fighter, a 757 airliner, or any other basic composite structure.



Hope this helps, it is always great to see other ideas of doing blind repairs. The repair I did in this photo was a two stage repair. Since it was a hole through the structure it could not be bagged initially. So the hole had to be sealed from the back side unable to see (blind repair) before the surface could be repaired using a vacuum bag method. Good luck with your mast.

Carl
Saylor Specialties
www.saylorspecialties.com

I used a section of the same mast. Remove the exterior track and then cut the flat section out or off. Narrow the flat section until it it will just fit against the inside of the flat section of the mast. Remove material until the main section and the flat section have a real tight fit on the inside of the mast and the two parts have a tight fit against each other. Now you have your splice.

The main part is springy, it pushes against the inside of the mast. If you fit it right the main part presses the flat part against the inside of the mast.I figured I had it right when it took light taps from a rubber mallet to get the spice inside the mast.

The splice should be 3 mast major diameters inside each side. The splice should be 6 mast major diameters long plus any damaged section you want to replace

I did my carbon fiber mast repairs (6) pretty much the way CarlBohannon did: a mast section the same or close to the broken one. Be sure the cut section matches well when inserted inside the broken ends (some have flats or ridges to be shaved off). Difference- I inserted the U-shaped section in a polyethylene sleeve into one end of the broken mast then inserted 2 layers laid up over the open mast track side. Insertion of a cut and sealed motorcycle innertube attached to a stick allowes its inflation at 5 psi that makes a lovely oval shaped section to be pulled out when hard.

This completed oval section is sanded, checked for proper fit and length (accounting for about 6 inches of shattered bits). Externally sanded mast ends then are fitted for a 6 foot U-shaped wooden external trough to ensure straightness. Assemble everything first to be sure it all fits. Then epoxy plus some cab-o-sil thickener is buttered on each side of all contacting parts and the section is tapped into place in one end, pinning with a nail at the proper depth. The second half is then inserted until the correct length is obtained. Insert a section of angle aluminum into the exposed sail track, all then is wrapped with polyethylene and bungeed into the trough. ((No inflation tube up to the middle of the mast is necessary)).

Resulting repair: comes out absolutely straight but now needs reconstruction of the track- which does not need to be dramatically strong, just the correct width and smooth inside. ALso wrapping the depressed area with CF cloth to fill- probably mostly cosmetic but makes it look pretty good. None of these 6 have broken again at that repair over 2-5 years hard use, and appear to work well. Original mast bend restoration? Perhaps wishful thinking. But this made a strong, very light-weight repair.

this was mine on a wednesday nite

then thursday morning

thursday afternoon

friday morning

friday afternoon

friday evening

saturday morning