I just made a mast similar to the Fed 5 mast this week. It cost about half as a carbon mast. It weighs 23 lbs . The carbon is about 10 lbs with 5 or more lbs stiffener in it. It is stiffer than the 80% carbon mast. I installed a 6' aluminum stiffener in the carbon mast too for the test. The test consisted of suspending a 45lb weight in the middle of the mast supported by saw horses.
The alum mast sagged about 1.375" less than the carbon one. I also rigged it up and couldn't get the blocks as close as the carbon mast by about the same distance as the weight test sheeting in as hard as possible. The rigged pis show what each mast looks like. The over bend wrinkles are a less and little smaller with the Alum mast. We have found that the 520 80% carbon masts are getting harder to find. Naish (? forgot the model) Power x and Joystick are the same masts built a while back are pretty much unavailable anymore in 80% carbon. Unifiber is still in production. The only source I know for Unfiber is Sailworks. We found the Uni fiber to bend more at the base than the Naish. We also feel the carbon masts lose there stiffness after a period of time. We will be forced to change to alum masts in the Mini Skeeter Class. 100% are still made and cost $900.00 usd. Not the direction I want to see the class go. I made the aluminum one for about $260.00 through online metals and my local Pacific Steel distributer. Its a mixture of tubing and pipe all 6061 T6. The Fed 5 mast is all 6061 schedual 4 pipe. they are manufactured back East in the US for about $600.00. The 1.25" pipe that they use for it has to milled down to be able to sleeve. I found a way around that by using 40mm od. I had to resort to using some tape to make up (shim) for the wall discrepancies. I went through one roll taping rings every 6'' where needed.
I cut an additional 4.5" off the top of the aluminum mast because I went to a low profile mast crane. I also made it a three piece so I can remove 21" off the tip for the small sail. I used machine screws instead of rivets so I can change out the inner sleeves to manipulate the stiffness. It took about 2 hours to build.
Not trying to hijack your thread John,
Here is a sample of the cost to build a Fed 5 mast of your own. I'm afraid these prices are for U.S. only.
$64.98
Aluminum 6061-T6 Bare Pipe Schedule 40
1.5" nom. (1.9" OD x 0.15" Wall x 1.61" ID)
108" L
$82.40
Aluminum 6061-T6 Bare Pipe Schedule 40
1.25" nom. (1.66" OD x 0.14" Wall x 1.38" ID)
$24.01
Aluminum 6061-T6 Bare Pipe Schedule 40
1" nom. (1.32" OD x 0.13" Wall x 1.049" ID)
Cut to: 96"
US Sub-Total: $171.39
Cut Fees $22.50
Shipping $0.00
Taxes $16.00
Total: $209.89
That's cheap for any mast. I get 100% CF sdm 520 32 mast's from China for $167 USD, shipped! But I bought six to get that price. Sold two for $300.00 ea.
I just listed the raw materials, not the necessary machining.
I chuck it up in my lathe and use a live center.
Round nose cutter then finish it up with 80 grit emery cloth.
Your drawing of the Fed 5 mast is correct.
