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Repairing A=Cat mast #187574
08/10/09 11:15 PM
08/10/09 11:15 PM
Joined: Feb 2009
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Palm Beach County
TheManShed Offline OP
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Repairing a mast this week.

I started with making a stand to hold the mast level.

A few scraps of biax e glass and the mast taped off with 2 layers of wax paper. Sail groove taped of good to stay clean.

Long view made two clamps of biax on the groove side up so clamps would come off of the mast. This side is also straigh and the taper will not bother the alignment.

Wetted out the glass with epoxy using a cheap throw away paint brush.

Attached Files
Simple Lay-up.JPG (376 downloads)
Long view lay-up.JPG (376 downloads)
Wet out.JPG (373 downloads)

Mike Shappell
www.themanshed.com
TMS-20 Builder
G-Cat 5.7 - Current Boat
NACRA 5.2 - early 70's

-- Have You Seen This? --
Re: Repairing A=Cat mast [Re: TheManShed] #187575
08/10/09 11:21 PM
08/10/09 11:21 PM
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Palm Beach County
TheManShed Offline OP
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The next step was to trim up the clamps then mount them on stands made from scrap wood. I screwed the clamps to wood and put duct tape over the screw heads to protect the mast. I mounted the mast and clamped the base boards to the table to make the mast would not go anywhere if bumped in the shop.

Attached Files
Stands.JPG (370 downloads)
Mast stand.JPG (370 downloads)
Fiberglass clamps.JPG (368 downloads)

Mike Shappell
www.themanshed.com
TMS-20 Builder
G-Cat 5.7 - Current Boat
NACRA 5.2 - early 70's

Re: Repairing A=Cat mast [Re: TheManShed] #187576
08/10/09 11:33 PM
08/10/09 11:33 PM
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Palm Beach County
TheManShed Offline OP
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Last post for the night.

Looked at the break, clean up the area where it was deformed.

Tomorrow I'm building a "bong" for the vacuum pump and mounting it on a base with fittings, Then bagging out the first sleeve in carbon fiber.

The sleeve will have two sizes - on the main mast section the opening is 50mm and on the top part it is 55mm. There was a 5mm hard step at the break. Usually you do not want a hard step (spot) in fiberglass it is better to taper off any size difference. Case in point here at the break. It created a hard spot in the mast. It is not going to be an easy fix but I can come up with something.

Attached Files
Break.JPG (366 downloads)

Mike Shappell
www.themanshed.com
TMS-20 Builder
G-Cat 5.7 - Current Boat
NACRA 5.2 - early 70's

Re: Repairing A=Cat mast [Re: TheManShed] #187577
08/10/09 11:48 PM
08/10/09 11:48 PM
Joined: Dec 2003
Posts: 1,066
Wellington, FL-Singer Island, ...
cyberspeed Offline
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Cool Stuff. Can't wait to see the finished product.


craig van eaton
Supercat 20
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Re: Repairing A=Cat mast [Re: cyberspeed] #187598
08/11/09 08:26 AM
08/11/09 08:26 AM

A
andrewscott
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andrewscott
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Mike, thanks for all the step by step and pics...

Re: Repairing A=Cat mast [Re: TheManShed] #187600
08/11/09 08:53 AM
08/11/09 08:53 AM
Joined: Oct 2002
Posts: 1,226
Atlanta
bvining Offline
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Mike,
I see in the pics you have some fiberglass cloth, and you mention fiberglass in your posts. Are you going to use glass in the final repair? I would recommend using only carbon cloth and epoxy as thats probably what the mast was made from originally.

I'd also recommend taking the diamond wires off so the mast isnt under tension and straight when you repair it.

I've made sleeves to repair carbon masts in the past, it helps align the broken sections and adds some structure to the inside of the mast so you dont have so much of the repair on the outside. I made my sleeves using a bladder, I've talked to other guys that have made molds of the inside of the mast using casting wax.


Bill

Re: Repairing A=Cat mast [Re: bvining] #187603
08/11/09 09:53 AM
08/11/09 09:53 AM
Joined: Aug 2007
Posts: 1,304
Gulf Coast relocated from Cali...
TeamChums Offline
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Just a guess but is that Dr. Ferber's mast?


Lee

Keyboard sailors are always faster in all conditions.
Re: Repairing A=Cat mast [Re: TeamChums] #187622
08/11/09 01:16 PM
08/11/09 01:16 PM
Joined: Jul 2004
Posts: 2,718
St Petersburg FL
Robi Offline
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Originally Posted by TeamChums
Just a guess but is that Dr. Ferber's mast?
Mark Herendeen's

Re: Repairing A=Cat mast [Re: Robi] #187664
08/11/09 08:31 PM
08/11/09 08:31 PM
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Palm Beach County
TheManShed Offline OP
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Few answers;

The repair will be carbon fiber only with west system epoxy and vacuum bagged. Any auxiliary glass work will be scraps of E-Glass. This rig has a cool "on the fly" tension adjustment arm for the diamond wires. They are slacked and the way I’ve supported the mast the diamond wires are in a neutral position if they were not slacked. The mast is level and will be check with a laser to make sure it is straight.

I’m making a sleeve but it is not such a straightforward operation. From the break down towards the foot of the mast the ID of the mast section is 50mm and the wall thickness is 5mm so using a 1:10 taper the outside skin will taper out to 50mm for the repair. This brings me into the slot for tang for the mast hounds. From the break towards the top of the mast it has an ID of 55mm and a skin thickness of 2.5mm. Using the same formula a taper of 25 mm. It has a hard spot that took the skin thickness from 5mm to 2.5mm with a hard drop and this is where it broke. My goal is now to sleeve the mast, which will take two different size sleeves where one will almost fit inside the other and try to eliminate the hard spot. There is also another sleeve further up where I can see some fatigue starting.

The repair will be inside and outside. My plan of lay-up will be in the area of the crack to taper all the way to the sleeve. At least one layer of cloth in the taper at a 45 degree angle to the break in each direction to form a X to try and mend the area around the circumference, all other lay-up will be with the fiber oriented with the mast from top to bottom. Because this mast is broken my main concern is to have a good repair and be strong. You can have the lightest mast in the world but when it is in two parts what good does it do you? Once they break you have to fix them stronger.

Another interesting note is the mast looks like it was spun carbon strand then covered with a carbon cloth exterior lay-up. I’m not sure if I’m looking at a factory mast or modified. I’d be interested in actual construction / lay-up of the mast.


Mike Shappell
www.themanshed.com
TMS-20 Builder
G-Cat 5.7 - Current Boat
NACRA 5.2 - early 70's

Re: Repairing A=Cat mast [Re: TheManShed] #187672
08/11/09 09:30 PM
08/11/09 09:30 PM
Joined: Jun 2001
Posts: 12,310
South Carolina
Jake Offline
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Mike,

Tons of fun watching - thanks for the updates. The mast is probably woven fabric on the inside and outside with a bunch of uni running vertically on the inside. Interesting that it has such a huge thickness step there - no doubt that created a stress riser leading to the breakage.

What brand is that stick?


Jake Kohl
Re: Repairing A=Cat mast [Re: TheManShed] #187696
08/12/09 08:04 AM
08/12/09 08:04 AM
Joined: Oct 2002
Posts: 1,226
Atlanta
bvining Offline
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Mike,
Is this the mast for the Tri?

Or is it going back into the Acat class? If its an Acat mast, the current trend is toward stiffer masts. The big top sails need stiffer masts. Most guys are adding uni on the outside, oriented top to bottom to stiffen up the mast. If you knew the age and make of the mast, you might be able to get an approximation of the stiffness.

Bill

Re: Repairing A=Cat mast [Re: bvining] #187749
08/12/09 04:25 PM
08/12/09 04:25 PM
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Palm Beach County
TheManShed Offline OP
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I have a special mast for the tri it is still a virgin!

This is for a A-Class cat. So after my repair the mast will be updated! I was working on the resin bong last night. My first bongs were made of bamboo in the late 60's and now they are PVC.


Mike Shappell
www.themanshed.com
TMS-20 Builder
G-Cat 5.7 - Current Boat
NACRA 5.2 - early 70's

Re: Repairing A=Cat mast [Re: TheManShed] #187793
08/13/09 12:29 AM
08/13/09 12:29 AM
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I have the vacuum bagging bong ready. These works as a vacuum reservoir so I can pull a vacuum and turn the valve then turn the pump off. It also collects any run-off resin and keeps it out of the pump. All the materials were purchased at Home Depot except for the pump and the gauge; they were purchased at Harbor Freight Sales.

Attached Files
Vacuum pump Handle removed to get at fitting.JPG (178 downloads)
Removing AC fitting
AC fitting replaced with tubing barb.JPG (175 downloads)
Now I can use Tubing

Mike Shappell
www.themanshed.com
TMS-20 Builder
G-Cat 5.7 - Current Boat
NACRA 5.2 - early 70's

Re: Repairing A=Cat mast [Re: TheManShed] #187794
08/13/09 12:32 AM
08/13/09 12:32 AM
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Palm Beach County
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more:

Attached Files
Holes PVC tubes bogged in with west epoxy.JPG (171 downloads)
Hole bogged in with West and 404 filler
Inside bogged.JPG (173 downloads)
Inside bogged

Mike Shappell
www.themanshed.com
TMS-20 Builder
G-Cat 5.7 - Current Boat
NACRA 5.2 - early 70's

Re: Repairing A=Cat mast [Re: TheManShed] #187795
08/13/09 12:34 AM
08/13/09 12:34 AM
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Palm Beach County
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Attached Files
Intake to pump routed up.JPG (170 downloads)
Routed up to keep resin away
Waste exhaust tube added.JPG (168 downloads)
Added tube for waste to run down into the bong

Mike Shappell
www.themanshed.com
TMS-20 Builder
G-Cat 5.7 - Current Boat
NACRA 5.2 - early 70's

Re: Repairing A=Cat mast [Re: TheManShed] #187796
08/13/09 12:38 AM
08/13/09 12:38 AM
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Palm Beach County
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Attached Files
Building manifold.JPG (169 downloads)
Manifold, vacuum guage fitting, shutoff valve, connections
Resin Bong back.JPG (169 downloads)
Front view
Resin Bong front.JPG (168 downloads)
Front

Mike Shappell
www.themanshed.com
TMS-20 Builder
G-Cat 5.7 - Current Boat
NACRA 5.2 - early 70's

Re: Repairing A=Cat mast [Re: TheManShed] #187797
08/13/09 12:39 AM
08/13/09 12:39 AM
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Palm Beach County
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Starting to work on the Mast. Tomorrow I will start on the sleeves now that I can vacuum bag.

Attached Files
Starting to reshape the spar.JPG (167 downloads)
Reshaping mast around the hound.

Mike Shappell
www.themanshed.com
TMS-20 Builder
G-Cat 5.7 - Current Boat
NACRA 5.2 - early 70's

Re: Repairing A=Cat mast [Re: TheManShed] #187816
08/13/09 07:35 AM
08/13/09 07:35 AM
Joined: Jun 2001
Posts: 12,310
South Carolina
Jake Offline
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Jake  Offline
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Mike,

Nice setup on the vacuum. Note, however that the pump will not hold the vacuum on it's own if you turn it off - it will bleed back through the vanes and discharge your reservoir.. a check valve at the discharge of the pump, or better yet, a electric 3-way mac valve will seal off the vacuum pump when it's off. By nature, the check valve with it's ball and spring will cause a slight reduction in the ultimate vacuum you can pull (which I didn't like when I used one) - so I now use an electronic three-way mac valve to disconnect the pump from the system coupled through the same relay I used to cycle the pump on and off...which then leads to another issue where you need some additional electronics to make everything work together....

A vacuum controller switch coupled with a relay will automatically turn your pump and the valve on and off at a set vacuum level...I've even got one wired into a small PLC controller so I can control all the timing of the valve, pump, switching on and off, and I even programmed in a timer controlled by a series of switches (in a binary fashion) so I can set the controller to not turn the pump on after 1 to 9 hours (so I can go to bed or leave town and rest assured that it won't stay on indefinitely). The next step is to connect a modem to the PLC so it will call me if my pump stays on for more than 15 minutes (indicating a leak occured in the bag)...


just kidding on that last part although it IS possible!.

If you put a small reservoir between the pump and the mac valve, the pump will also have the opportunity to start from ambient pressure instead of being hit with vacuum immediately.

Lots of plans and all the pieces parts needed can be found here:

http://www.veneersupplies.com/default.php?cPath=60_36

One last thing...I had my vacuum switch powering my relay with AC power initially but I had a lot of trouble with bouncing of the switch (making the pump turn on and off very rapidly for a second before it reached steady state). I would recommend using a 12VDC relay (instead of 120VAC) and a wall mounted power supply for the vacuum switch and relay. The relay then can switch the 110VAC to the pump and the valve. Apparently the amount of AC current needed to switch the relay creates magnetic currents that disrupt the sensitive vacuum switch.

I know this is complicated, but compared to the alternative of leaving the pump on full time, it is amazing once it is all together.


Then again, these pumps are designed to be left on for extended periods...so it's not a big deal if you leave the sucker on for hours (although mine does tend to overheat).


Jake Kohl
Re: Repairing A=Cat mast [Re: Jake] #187824
08/13/09 08:38 AM
08/13/09 08:38 AM
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Palm Beach County
TheManShed Offline OP
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Jake,

Great idea I'll have to explore that I may pick your brain some more. With the check ball I held a vacuum for a hour with the pump off last night.


Mike Shappell
www.themanshed.com
TMS-20 Builder
G-Cat 5.7 - Current Boat
NACRA 5.2 - early 70's

Re: Repairing A=Cat mast [Re: TheManShed] #187843
08/13/09 09:40 AM
08/13/09 09:40 AM
Joined: Jun 2001
Posts: 12,310
South Carolina
Jake Offline
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I didn't realize you had a valve after the pump - that should work well.

I've never had a bag that was completely sealed - I've been close where the pump would come on only once every 30 minutes for about 30 seconds...but it was something that I would otherwise have to constantly monitor.

I do like your resin separator ability in your reservoir - I'll be copying that!


Jake Kohl
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