Boat Building Forum

Find advice on all aspects of building your own kayak, canoe or any lightweight boats

Re: Material: Carbon Fiber
By:Bill Hamm
Date: 12/7/2009, 12:45 am
In Response To: Re: Material: Carbon Fiber (Larry C.)

: Bill,
: Your right, discussing is good, arguing is not.

: The reason I suggested a removeable coaming is I feel a first
: timer,laying bias cut strips on his existing coaming could
: quickly create a disaster. Apparently you don't realize 6-8
: total layers of 4oz.glass & 6oz.carbon are only about 1.5 MM
: thick at the most. This lay-up is a very thin, flexible and
: extremely easy to remove, even from a non plumb or curved riser.
: In fact till it cures it's rubbery, and quite fragile. Triming,
: shaping, and adding more fill coats are mostly done off the
: boat. If the final result is not what's expected, nothing is
: lost. The boat has not been damaged. If the layup is directly on
: the existing coaming, everything has to be right the first time.
: This may seem like extra steps, but I think it's worth the
: effort.

: Most of my past experience with coaming reinforcement only, has
: been on very thin and weak race boat coamings, 1MM or less, and
: this method worked great. I recently used a variation of this
: method on an old downriver boat that had severe cracking, and
: chiping of the gelcoat on the lip. It created sharp edges that
: wern't very nice. I actually cut the lip completely off, leaving
: just the riser.I could have just belt sanded the gelcoat off
: down to the glass, but the damage required more radical surgery.
: The new lip was made with 12 layers of 4oz. S glass with white
: pigmented epoxy for fill coats.The finished product was less
: than 3mm thick, the same white as the original and plenty
: strong. I would normally use carbon cloth is in the layup
: because the number of layers can be less with a much
: stronger/stiffer result. This boat wasn't worth the extra
: expense.

: In my original post, I was trying to open up discussion on
: alternate methods of coaming repair or complete coaming
: replacement. As I stated earlier, there are many methods to
: accomplish this task, your suggestions and concerns are valid.
: However, from someone that has actually built and repaired
: several composite layup coamings, I feel my methods are also
: valid. You are correct, I have no way of knowing what Dan's
: coaming looks like or do you. I was merely suggesting a possible
: repair from my actual experience, Closer scrutiny may alter my
: suggestion, however I still feel it's a safer method than a
: direct layup, especially for a beginner. Discussing different
: methods is how we all learn, wouldn't you agree?

: Larry C.

Hi Larry,

Yep, discussing various methods here is one of the things that makes this forum great. Btw, I've built lots of coamings and one of glass/carbon. The thickness that results will depend entirely on how heavy the fabric is that you're using, you are obviously useing very light weight cloth. With the current price of carbon fiber that's understandable. I don't use it often, it's just too pricy to play with for me at least. I do though have an NDK boat and know what their coamings are like, specially the older ones. NDK just uses way too thick gelcoat on the whole boat and it has a stress cracking problem due to it's thickness. It's mostly cosmetic since most any glass coaming will flex a little in use.

Your method will work too, just seems like too many extra steps to me.

Bill H.

Messages In This Thread

Material: Carbon Fiber *PIC*
danp -- 11/26/2009, 12:31 am
Re: Material: Carbon Fiber *PIC*
Larry C. -- 11/26/2009, 2:04 pm
Re: Material: Carbon Fiber
Bill Hamm -- 11/27/2009, 12:26 am
Re: Material: Carbon Fiber
Larry C. -- 12/5/2009, 7:35 pm
Re: Material: Carbon Fiber
Bill Hamm -- 12/6/2009, 9:24 am
Re: Material: Carbon Fiber
Bill Hamm -- 12/6/2009, 1:58 am
Re: Material: Carbon Fiber
Larry C. -- 12/6/2009, 5:55 pm
Re: Material: Carbon Fiber
Bill Hamm -- 12/7/2009, 12:45 am
Re: Material: Carbon Fiber
Roy -- 11/26/2009, 8:09 pm
Re: Material: Carbon Fiber
danp -- 11/26/2009, 6:08 pm
Re: Material: Carbon Fiber
Don Goss -- 11/26/2009, 9:56 am
Re: Material: Carbon Fiber
danp -- 11/26/2009, 10:43 am
Re: Material: Carbon Fiber
Bill Hamm -- 11/27/2009, 12:21 am
Re: Material: Carbon Fiber
Bill Hamm -- 11/26/2009, 6:35 am
Re: Material: Carbon Fiber
Bill Hamm -- 11/26/2009, 6:32 am