Are These Laminates Too Heavy? Advice On Pvc Honeycomb Cores.

[VIKING]

HI,

I am building 15 ft to 23 ft sports fishing boats and feel I am overdoing the layups as they seem very thick/ heavy.

Exampls of my laminates are :

23 ft Hull:

a) 1 * Gelcoat
b) 1 * Surface tissue
c) 1 * 300 g/sqm Mat
d) 2 * 450 g/sqm Mat
e) 1 * 350 g/sqm Woven roving
f) 2 * 450 g/sqm Mat



15ft hull

a) 1* gc
b) 1 * surface tissue
c) 1 * 300 g/sqm Mat
d) 2 * 450 g/sqm Mat
e) 1 * 350 g/sqm Woven roving
f) 1* 450 g/sqm Mat

Am I wasting money?

I am convinced these are too heavy but am afraid to lighten this as I do not know what the minimum laminates would be. Is there perhaps some literature available out there on this that would provide guidelines?



I also intend to use Nidacore pvc honeycomb vacuum bagged for my decks to lighten the laminates and save on resin (without compromising quality.

Does anyone have any comments on this product?

I am also using Cray Valley gelcoats and flow coats and am finding the quality is not consistent.- Any one else out there finding the same?



Thanks,

VIKING

[War Whoop]

Use one of the Foam or Balsa cores... That material is not intended for any Structural use. and it is not PVC Material...i

[tgundberg]

Assuming that these are hull laminates, one would need to know what you stringer setup and spacings are to determine if the laminates are too thick or not. Personally, I think you might be using too much chopped strand and not enough structural material (woven roving).

As for bagging polypropylene honeycomb, I would watch out for filled the open cells with resin. I agree that a more closed cell foam or balsa would work much better.

[VIKING]

Hi

This polypropyline honeycomb material comes with a scrim backing which is attached to it by the manufacturer. I have since visited the www.nida-core.com website and they reckon it can be used for hulls even. I only intend to use it to stiffen the decks. It is cheaper than balsa or Airex too. Have you had any bad experiences?

Regarding the skin thickness/ layup issue I have no stringers only plywood frames which form a grid supporting the floor and hull. These plywod frames are filled with foam, laminated with one 450 csm and covered with a ply flooor. This is all tabbed to the hull.

I suppose only a construction drawing would help you comment?

Thanks,

Viking.

[BCPower]

Viking,

As I understand it, you're essectially creating a plywood female plug and filling with 2-part foam to create the male mold, right? If so, how are you parting the plywood from the foam?

[BCPower]

I just re-read your post. I think I'm wrong, your plywood and foam get lam'd together.

[slneatboat]

I wouldn't want to make them any lighter my self or use any less chopped strand matt in fact i would want to use a heavier woven roving say 600 or 800 grm. As for a core i have nearly always used balsa in decks i have made and in my opinion is the best.I was using pre-mixed white cray valley gelcoat at my last place of work for a few months and ,it went on well {we brushed it on}with even consistancey and could apply a nice even coat, had no problems with qaulity{ in fact we loved it ,it was a joy to use what more can i say! } at the time we also used cray valley resins quick cure 30 and encore 30 both nice to use with no quality problems, however the encore 30 has a high wax content so quikecure was mostly used.

[jimslade]

Nida core is a great product. Do a sample and find out its strength. I met someone that built race boats in bermuda out of this stuff. hull deck and transom. He said the boat was bullett proof. Experiance is far more valuable than speculation. I'm in the proccess of building a 29 ft offshore out of Nidacore. if you have any questions about lamination PM me and I will give you my # .

[War Whoop]

Personally I would not build any offshore powerboat out of Nida Core and yes by all means do a test LOL then do the same with a REAL structural core. I guess the raving is based solely on the COST factor!

Look I have used about every material out there and Personally Like the foams now that said in the Middle East we built a number of Gun/Patrol boats the specs called for Balsa so I ordered from the states Pro Balsa to make a long story short one of the boats in fog ran up a rock break water @45-50 MPH a tug boat was used to drag the thing back into the sea and to the base.

The damage was to the outside Laminate and some core that took a hell of a beating but stayed in place, we repaired this quickly and the boat was back on duty in 2 weeks Now had that been the miracle Nida core the boat would have been a total loss..

[JR-Shine]

Originally Posted by War Whoop

Personally I would not build any offshore powerboat out of Nida Core and yes by all means do a test LOL then do the same with a REAL structural core. I guess the raving is based solely on the COST factor!

I second that, and I am a fan of Nida-core. We use it for decks and soles mostly. I would never use it in the hull, transom, or stringers. Maybe in some less important frames or bulkheads.

Choose the core that best fits the application. The next boat I build with have an Okoume plywood core in the hull (epoxy and directional glass), PVC foam cored stringers/frames/transom, and a mix of wood and nida-core for the decks and sole

[jimslade]

Sorry the cost factor is not valid in Canada. Nida-core is alot more money. I would never put wood in a boat again. It does'nt matter how carefull you are resin will absorb water and wood will rot. Smart builders avoid wood like the plague. I have a deck that I'm working on, It's 14 years old never seen a lake, only sat outside in the elements. There are many places that the balsa core has rotted. WHAT A JOKE! Balsa suppliers will tell you that water will not migrate through the core. LIARS! I have done pressure tests sheer tests and delamination tests on structural foam and nidacore and I would go with nida in all cases. Remember the promises made by manufacturers of two part urethane foam for flotation. Its won't absorb water or is affected by gasoline. I just finished taking out the floor on a 13 year old bowrider that must have weighted 200 Ibs more due to water and oil absorbsion. Nida core will not absorb water or rot like balsacore. The only thing I would build out of balsa core is a model airplane. Check out [on the web]some problems that marine surveyors have had. My moto has always been. DO IT RIGHT THE FIRST TIME.

[War Whoop]

Balsa shop practices relate more than the material itself sloppy work hand contact lamination and the rest of the lazy systems would equal a substandard part and performance. Nida core the impact resistance is completely non-existent Period unless an ridicules amount of laminate is used NOW for that very reason it has NO Like none… ABS blessings for hull shells decks bulkheads stringers or anything really that holds the water out!!!!!!

Personally I prefer the plastic foams Airex or Corecell (check the peel on Airex) and have had great success with them. When you are out there on a lightweight Powerboat running over 120 MPH in open sea one will quickly understand.

The Airex coupons use a 10# Sledge to impress customers now for Nida LMAO Use your foot!

[jimslade]

airex will delaminate not nida core. I tried.

[War Whoop]

Yeah I tried too! BUT My Airex Boats have Many National/International World Offshore Titles Not mentioning the allied awards and being LIGHT also have most importantly NOT killed anyone, when you can claim the same come back and we can talk as for your second rate sub standard cheap material I would never EVER Build anything with a core system prone to instantaneous and catastrophic failure .As for your test I suggest a course in remedial fiberglass lamination and Most importantly reading THE Materials instructions.

[buckknekkid]

wazzup Steve? giving any lessons on building? Im going to break down and think about a large cat soon. I have to finish off the sporty first. how about 40 feet with diesels. something like those tour boats Errol built