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how do you repair moses silente mast?

Posted: Thu Dec 06, 2018 9:18 pm
by grandeand
my name is Andrea, I write from Italy.
I wanted to ask you for information on how to fix the base of attack of a mast of the silent moses.
I send you a photo, so you can see what happened.
I have two options: -
1) I glue the plate in place and then create an external reinforcement in carbon and glass fiber;
2) I could cut under the plate and create a tuttle attack.
the first solution seems to me faster, but I do not know the final strength also because the carbon work it without vacuum and oven.
on the other hand, the second solution has the problem of the thick tuttle case.
the mast is thicker than 16 mm, which is the thickness of a tuttle.
so I should create a bigger tuttle attack on the mast and also make a suitable draft on the board.
what do you think?

Re: how do you repair moses silente mast?

Posted: Thu Dec 06, 2018 10:26 pm
by grigorib
I don't think gluing it back in is reliable option. Drilling through top of plate into the mast and gluing in long rods/bolts might help keeping it together but I'd call that plate a goner.

Maybe you can find a large aluminum mast plate which would fit the mast the closest, machine mast down to fit and then glue the mast into it. But then again, vertical rods glued in might help securing pieces together.
Or alternatively make your own plate adapter, after reshaping the top of the mast.

What happened to it?

Re: how do you repair moses silente mast?

Posted: Thu Dec 06, 2018 10:37 pm
by BWD
I would try to get someone who is an experienced carbon artist to rescue that mast, unless you are pretty confident yourself, and not worried about losing your foil if it breaks again.
Converting to tuttle or rebuilding the top of the mast/plate are both options... would not put any metal plate in there, looks like it already suffered from rust and weak glass

Re: how do you repair moses silente mast?

Posted: Thu Dec 06, 2018 11:00 pm
by grandeand
this is one of the first silent moses on the market. I do not know how many owners he has had before me, but he has done the last two years ... I have never clashed with sand and other obstacles in two years. he is torn from the table immediately after a jibe. otherwise, I had thought of an aluminum plate as it is in the picture. cut under the plate, insert the mast inside and fill with epoxy resin, microspheres and glass fiber.

Re: how do you repair moses silente mast?

Posted: Fri Dec 07, 2018 3:21 am
by BWD
Looking at the pictures there is a rust stain that goes down from the plate into the top of the mast, and the plate itself looks like a mix of fiberglass and carbon.
The best way to fix it would be without adding metal, especially aluminum, which has worse corrosion problems worse and faster than steel, when mixed with carbon.

If you are willing to do all the work, you could repair the mast by gluing it back together with extra reinforcement, both internal and external.
It would be like repairing a broken femur for an orthopaedist, though. A serious job.

This is what I would try:
Drill/dig and carve out the cavity in the top of the mast to a good depth below the plate -hopefully 10-15cm, as far as practical and possible.
Use a high modulus or toughened epoxy that cures at room temperature.
Reinforce the inside of the top of the mast with carbon fiber cloth. 2-3 layers of +/-45 biaxial 200gsm.
Fit the broken pieces together and make sure they align correctly. Do what you must to make them fit correctly.
Drill holes in the top of the plate, maybe 10-12mm diameter. 4 or 5 of them, 1-2cm apart.
Buy premade solid carbon fiber rods to fit in the holes.
glue the old parts together with your epoxy.
make sure they are aligned correctly.
pour or inject epoxy filled with milled glass, carbon or microfibers through the holes to fill the cavity, minus the volume of the rods..
insert the carbon rods through the holes into the epoxy filled cavity.
let the epoxy cure minimum 24 h.
trim excess length of the rods above the plate.
sand the exterior of the repair from plate to 15cm below the break.
reinforce the exterior with minimum of 800 gsm EACH of unidirectional carbon, preferably 640MSI or greater modulus, AND 800 gsm +/-45 biaxial carbon cloth, preferably 640MSI+.

All surfaces must be clean and sanded to 60-100 grit.
Epoxy should be a room temp cure, "high modulus" and preferably "toughened" type.
Layers of cloth should all be applied ideally at once, or "wet on wet" or within 24 h of the preceding layer.
Ideally, the repair should be post cured at a higher temperature (typically 65-70 C) according to the resin supplier's specifications.
Do not try to use the mast for 7 to 10 days after cure, ESPECIALLY if not post cured.

If you want an easier job and don't mind a shorter mast, cut off the mast below the lowest point of the break.
Buy an ALL CARBON tuttle or KF to plate adapter.
Ketos and Horue can supply them, maybe F-one also.
Fit the mast into the cavity of the adapter.
Glue with epoxy filled with carbon or high strength fibers, as above.
Create a large fillet of filled epoxy around the mast, tapering down the mast 12-15 cm or so. This more or less recreates the original shape of the mast top.
Cover the plate and fillet, and an additional 15cm+ of mast below it, with unidirectional and biaxial carbon as above.

Doing either of these repairs will take time and effort and probably cost you $200+, and carbon can be a pain to work with, so you may want to consider buying a used or new mast instead, especially if you value time, the warranty, or lack tools and experience in composite repairs. But it's winter, sometimes a good time for projects...

Re: how do you repair moses silente mast?

Posted: Fri Dec 07, 2018 9:56 am
by grandeand
very interesting answer, certainly the most complete.
I asked for quotes and for both options they asked me from 200-250 euros.
this break was in May, I immediately bought a Moses vorac-e fr 101 with 590 and 330.
much higher in all, but sorry to leave this mast in the cellar or throw it away.
definitely 200-250 euros is not worth spending, if I can create a boxed tuttle box to fit the mast and then I create the box in the table.

Re: how do you repair moses silente mast?

Posted: Fri Dec 07, 2018 2:54 pm
by grandeand
this video is very interesting ....
I could:
cut the mast;
create an attack suitable to contain the mast (similar to a tuttle);
put the mast inside the box and pour resin with microsfete also putting some pieces of fiberglass.
once hardened, I make a hole with the cutter on the table, and I create the box using the mast as a mold.