Pokher Ace

I have my Fountain cabin gutted and close to rebuilding all bulkheads and stringers and just curious what I should use? The MDO was suggested by a friend that owns a boat shop and said its waterproof and easier to cut than marine plywood its what they use to make road signs heres a quick read http://lumberjocks.com/reviews/965 Also how much resin, tape, biax, and wood do I need? I would guess maybe a dozen 4x8 sheets so if I were to use coosa I would lose roughly 400#'s but how would that affect cog? I also am losing about the same #'s in the bilge.. saddle tanks, iron heads, q&q/ iron exhaust etc. I dont mind the $$ doing coosa and epoxy but if its going to affect other stuff then I would rather rebuild it with plywood. Ill post a pic later of cabin

Pokher Ace

heres a old pic all I have left to do is rough sand with 40 grit then clean then glass

glassdave

iTrader: (1)

You will love working with Coosa doing a project like this. It is very easy to work with and well worth the money. Theres a bit of a split on its use in transoms though. Personally I'm still old school and prefer a wood transom, done properly there are no longevity issues. If you plan to use epoxy you will need to use 1700 or 1800 bi ax fabric without the stitched mat. Its far stronger and lighter the using 1808 or 1708 with epoxy not to mention much easier to wet out. The only reservation with using epoxy is you cannot use and poly or vinylester products from there on out. Really shouldn't be to much of a problem other then it makes final finishing the bilge a bit more time consuming and a bit more labor intensive but its a good trade off for the added benefits. If you do wish to use Coosa for the transom i would triple up three layers of half inch. You will also need to treat your method of mounting the engines to the stringers differently. You can no longer simply through bolt them. You will need to build a custom saddle type of mount to spread the load over the top of the stringer.


COG you can always play with if you have to, you are trimming weight but can always place some ballast if need be. Its tough to estimate a project like this where much of it is custom. What length Fountain?

I have not used MDO in any marine application. I have heard it is heavy.

Pokher Ace

42' its mainly only the cabin and bulkheads the engine stringers are solid and so is transom. Can I do coosa with vinyl ester resin? I always here the epoxy is hard to wet out the cloth. I agree on cog I have 4 sealed stereo batteries that weigh 60#'s each and before I had them placed up close to the vberth so thats plenty of weight to move around. Also the cabin was stripped before, no mirror, bathroom, cabinets etc. which I ahd no issues with ride so this will only be a little lighter than that. Also would you do all 1/2" coosa and double where needed or use sum 3/4" also approx how many sheets?

glassdave

iTrader: (1)

Its hard to wet out the cloth because generally most people use the wrong cloth and for some reason places like UScomposites have a great epoxy but dont sell matless laminates. Industry standard for marine fiberglass is 1808 (or 1708 which is virtually the same thing) Those laminates with the stitched on mat are difficult to wet out solely because of the mat, which is useless and actually a weak link in an epoxy system not to mention hold a ton of excess resin. You can certainly use vinylester with Coosa, should be good for any of the marine resin systems. I would double up the half inch where 3/4 is needed because its easier and (i feel) stronger to stagger the joints and manufacture long stringers.


I'm in the process of doing a 26 Velocity in all Coosa, all the superstructure.

JRider

iTrader: (1)

The MDO looks like it would be the ticket for marine speaker boxes.

ezstriper

MDO (medium density overlay) is what we use in the sign industry, have a covering over, 1 or 2 sides depending on if it's 1 or 2 side good, now it's NOT waterproof and must be sealed like any other wood, it's surface is stabalized for use with viynl lettering as reg plywood will pop the lettering off in most cases. there is also a MDO they use for suffits on homes, lower quality than the one we use, if you are glassing over see no use to use MDO as you would have to grind into covering to get to adhere...