The big danger is the boom reinforcing may no longer be where the boom is!!! Especially if you have the boom high.
The other problem could be mast extender, it's not going to fit as far up the mast as before, so a long extender may not be usable on lower settings.
I think cutting the bottom off doesn't alter stiffness or curve significantly.

if you do cut your mast were a face mask carbon dust KILLS

Cool I`ll check that my extension will still fit,,and if it happens to break where boom is I`ll cop it on the chin,hopfully not,,,thanks for the reply,,,saw the forcast for Sat and will get down to Inverloch to see how it goes,,Mistral flow 105lt my board trying to get back in to this great sport,,,,Laurie

decrepit said...

monster said...

if you do cut your mast were a face mask carbon dust KILLS

Do you have anymore on this monster, for some reason I thought carbon dust wasn't as bad as fiberglass

Hope this helps

The effects of carbon dust inhalation on the bone marrow-derived (B) and thymus-derived (T) lymphocyte populations of spleen and mediastinal lymph node (MLN) cultures. The concanavalin A (Con A)-responsive cell population (T cells) in the spleen was found to be depressed after 7 days of pre-exposure to carbon dust. However, this effect was transient, and after 14, 21, and 28 days of pre-exposure to carbon dust, the Con A-responsive cells exhibited a 30 to 40% enhancement over control group responses. Conversely, Con A-responsive cells in the pooled MLN cultures exhibited depression, ranging from 22 to 33% below control group values, after 7, 14, and 28 days of pre-exposure to carbon dust. The lipopolysaccharide (LPS)-responsive cell population (B cells) in the spleens of carbon-exposed mice was found not to differ significantly from control group values after all times of pre-exposure. LPS-responsive cells in the MLN cultures exhibited enhancement, ranging from 49 to 74% above control values, after 14, 21, and 28 days of pre-exposure to carbon dust. The ability of carbon spleen cell cultures from carbon-exposed mice to undergo antigen induced blast transformation after sensitization with Mycobacterium tuberculosis H37Ra was also determined. Mice exposed to carbon dust inhalation 2 weeks before and 3 weeks after aerosol or subcutaneous immunization exhibited significantly enhanced ratios of transformation upon culture of their spleen lymphocytes with purified protein derivative of tuberculin.

hi decrepit i have ducati monster and there is a web site for ducati owners like sea breeze any how we have lots of carbon on our bikes and people cut and shut there bikes any how there was a warning on there about carbon dust arfter a fella died in the us from carbon dust ill see if i can find but when any one now talks about cutting carbon people start jumping up and down something to do with dust particales sticking into the lungs regards bazz

lozza38 said...

Is it ok to cut down a mast say a cheap low carbon 2 piece 460 and cut it down(off bottom of cause) to make a even cheaper 430,or does it change the whole dynamics of the mast.I ask this as there are some cheap 460`s around but I already have one and am after a 430...I thought I might put down the hacksaw and ask first,,,,,Laurie

Cut 15cm off the top.....
Cut 15cm off the bottom
Problem solved..............

yer carbon dust isnt good for u but if it was as bad as ur making out monster i should have been dead long ago.
in 06 i swear i had was persistent coughing up **** for almost 3 months. a dust combination of car bog, fibreglass, carbon and regular dust wasnt the best. even though we used dust masks when sanding and cutting the shear volume of dust around the workshop while we hung out and did other stuff was the killer in my opinion. propper dust extraction and segregated "dirty" rooms that can be easily fully cleaned are the go in my opinion.
but if ur just cutting a mast u dont have much to worrie about.

I've been told if you smoke and inhale lots of dust in ur occupation ur the most likelt to wind up with cancer. Without smoking ur lungs have "some" ability to repair themselves, but thow smoking into the mix and ur rooted.

I think you'll find it will be too stiff. If its a 460 it will most likely be IMCS 25. When you shorten it it will still be close to IMCS 25 whereas most 430s are IMCS 21. Actually because you're removing from the stiff end (the bottom) and keeping the soft end the stiffness will change a bit. It would be interesting to know how much but it certainly wouldn't bring it anywhere near 21.

Lozza, In 1998 I cut down a 460 fiberspar mast (30cm off the bottom) and used it on my ezzy wave sails all this time no worries at all, I do run my boom real low (at bottom of cutout), only broke it last month, it broke at the ferul join on the botttom half, now I have a new 430 powerx mast I do notice that I am using a lot less downhall than previously for the same shape in the leach so yeh it must be a bit stiffer cut down, never noticed any difference in performance though, I say go ahead and grab the hacksaw.

I've done it a few times before i started useing skinnys.Was going through so many masts i bought whatever i could find cheap.I always cut 10 off the bottom and 10-15 off the top .Couldn't tell the difference in performance compared to an uncut mast .Most masts i broke at the boom ..cut or not.....

just re-read my earlier post. I cut off the top section of the mast at the BOTTOM end. You need to check it doesn't taper in too quick to still fit of course.

Also I was told by the shop assistant when I was replacing a mast that broke at the boom it's because the boom chafes away at the outer sealing layer of the mast with salt sand etc and then the water gets in and it breaks down. Dunno if its true but since I then I have slipped a short length of bike inner tube over the mast to where the boom fits and the mast is still like new. Inner tube only lasts about 10 sails though which I guess means its doing its job