nida-core questions

[donjames]

fast and to the point... About nida-core

1. I like what I've researched... Who of you have used it ? And any input
and opinions about it on ....
a; structural
b; interior, Lamination of wood veneers,cores for.. counter tops and furniture structures.

Any of you who have field experience with it , any and all would be greatly appreciated.

I like every thing except for Fire rating and shear strength....
are there products that can be used to achieve a higher rating as to
the flash point a retardent possibly.

And I understand that when using balsa core they sometime use 2 x 3/8''
with a frp lay-up in between to add for impact strength.
Can this also be done with for ex;

1/2'' nida-core + 1 layer of mat + 1/4'' balsa core to acheive a higher shear rating with of course the balsa being on the int. and all being above W/L.

I still achieve a ligter build ( I believe ? )
As far as cost ... well ,I've wanted this project for some time I'm not going to cut here . Its got to be right and I'm surly not going to let excitement
get the best of me on the water.

Does this make since ? I hav'nt seen it done this way in my reseach. I'm sure it has been and thats why I ask .
donjames

[tja]

We use Nida Core exstensively in our boats. If you want good results from this material in structural aplications I've found that the more glass on each side of the panels the better from impact and compression views. As far as interior aplications I would use Nida Core with wood laminate already applyed from Nida Core.

[Ilan Voyager]

Life is already complicated...so I wouldn't begin to glue different cores. Too much work for little results. Calculate the intended impact resistance and add the fiber needed on the outside skin. It's simpler and more effective.

The lone boats I know able to resist high impacts are the old destroyers with skins of 1 to 2 feets of ol'good high strength steel. Do not be fixed on impact resistance (a fear I've found among a lot of amateurs). A good rubber or hard wood rail protection screwed at the good place is more effective to protect your boat from the other boats than 200 kg of GRP...

Whatever the cores or thickness of skins if the boat is grounded on rocks during a 60 knots gale and 6 feet waves, it will be destroyed. It's like cars, if you hit a tree at 100 miles/hour, the car will be destroyed. So the requirement is to have enough resistance in a normal use and withstand a litle abuse.

I have not used Nidacore in hulls, but in decks, roofs, panels etc...with fibers and/or plywood skins. Good price, very easy to use (see their internet site filled of very good tech infos) because of the polyester mat screening. Very good results.

Nidacore has a good engineering team able to answer to your questions.

A general tip about getting useful info:

As naval architects and engineers, and material providers are plagued by "amateurs" (in the bad meaning of the term) who spoil their precious working time, show you are a serious amateur with a project for what you're asking tech advice. That means that the great lines (purpose of the boat, size, displacement, general calculations) and some drawings are already done.

A good precise question receives a good detailed answer.

[donjames]

Thank you for the information, I understand what you are saying in your general tips
I'm working very hard at obtaining good info and trying to hold on before asking ??'s
on design. I try to obtain as much as possible and there are times when I simply run into block walls. I've recieved alot from there web site (nida-core) And was more interested in field applications . Your thread and the previous helped answer some of the ??'s . I hope that I can recieve more from the hands on point of view and opinions of others.
I have just recieved Element of boat strength this weekend and it has
a wealth of answer to some of the ??'s Ive been asking. Thanks for your patients and
Thanks for the responses.
donjames

[Ilan Voyager]

Originally Posted by donjames

Thank you for the information, I understand what you are saying in your general tips
I'm working very hard at obtaining good info and trying to hold on before asking ??'s
on design. I try to obtain as much as possible and there are times when I simply run into block walls. I've recieved alot from there web site (nida-core) And was more interested in field applications . Your thread and the previous helped answer some of the ??'s . I hope that I can recieve more from the hands on point of view and opinions of others.
I have just recieved Element of boat strength this weekend and it has
a wealth of answer to some of the ??'s Ive been asking. Thanks for your patients and
Thanks for the responses.
donjames

You're welcome. Do not hesitate to ask again.
You have bought a very good book.
I counsel to buy the Pierre Gutelle book "Design of Sailing Yachts"
ISBN 0-948646-54-3 even you're designing a power boat. This book gives clearly a methodology of design. Maybe the english edition has like the french edition examples of sheets. The maths needed are secundary shool level.

The shareware MDSolids ( www.mdsolids.com) may give you some good notions about the main notions and calculations.

Useful links:

some good courses of strength of materials on the web:

*Very basic and very well done. All you need to have the minimal basis to understand the stresses in a boat, and the choices of materials : http://physics.uwstout.edu/StatStr/Strength/index.htm

*Strenght and a bit more; very good http://www.samconsult.biz/Science/BET.pdf

The site the author, a consultant in NL, has many intersting things and tools
http://www.samconsult.biz/Index.htm
************************
Composites Links from a thread (http://www.boatdesign.net/forums/sh...28008#post28008) about laminations and composites some "extracts"

------
...To understand better composites and how it works.
http://callisto.my.mtu.edu/MY472/index.html
A course about composites engineering.
You do not need to make the math exercises...
------
...Another link if you want to calculate composites properties, after having understood the course on composites given in my precedent thread :

http://www.eng.hawaii.edu/~nejhad/
---------------
For some people internet acces is costly or difficult or you may want to have the soft in your hard disk. A very good shareware (29 US$) Laminator v 3.5 at http://www.thelaminator.net/

A trial is worth, this soft is good. 20 years ago a such soft under DOS and ANSI ugly design would cost a few thousands bucks plus a annual maintenance fee...

As always with engineering, calculations are good only if you use good data...

Cheers and best wishes for your project.

Ilan

[Jeffrey]

What about using the scored nida-core for hull sides in an open mold lamination. Do all of the score lines need to saturated with resin or is it better to use nida-bond or core bond to glue the nida-core to the sides. The hulls were previously cored with balsa but the slamming loads were transfered to the inner skin causing cracks and the eventual water penetration and rot.
Thanks in advance
Jeffrey