No core in those 6 boats that i know of either
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No core in those 6 boats that i know of either
yess thats my boat and no core and composite transom as well no wood anyweres its strong as an ox i abuse it every weekend at the river no doubt
i The floor adds a tremendous amount of stiffness to the boat.
yes a well made and designed floor ties the hull from twisting side to side ,for and aft and racking , it needs to be raised as high as is practical and or have a camber built into it and the whole floor well secured to the hull .
I contacted the people at Corelite. Filled out a questionair on their website. I asked them about the corelite board, and their corelite pet products. Told them what I was working on, they responded very fast.
I will send off for a sample of the board and PET. I am curious.
Interesting note they sent back to me:
[quote] Dear James,
Thank you for contacting CoreLite. I will be happy to assist you.
The CoreLite Board in 2” should be stiff enough for a transom. CoreLite Board is commonly used in transoms without problems and comes already sanded and ready to be fiberglassed. We recommend that you perform your own testing as well, as the structural requirements may vary from application to application.
For stringers, CoreLite Board is an excellent alternative. However, if lighter material is desired, I recommend you consider CoreLite PET.
For hulls, CoreLite PET is an excellent solution as it provides great strength for its weight at a fraction of the cost of other foam cores. However, it is important to note that there is also no foam in the world that will be able to compete to the mechanical properties of balsa wood (I guess mother nature does it best). This explains why the majority of the world’s largest boat builders still use balsa wood core (and also racing boats, like Cigarette Racing boats). Balsa should never be a problem if it used correctly during the lamination process.
If you would like to go over more details with me over the phone, we can certainly schedule a phone call sometime next week. I am happy to help. Just let me know.
You can certainly purchase a sample sheet of any of our materials. Epoxy is compatible with all of our materials.
With kind regards,
--
Giancarlo del Cioppo
Business Development Manager
Mobile: +1-305-781-1342 | Fax: +1-305-691-9094 [quote]
A hull without a floor is like a kids plastic lunch box with out a lid it can be twisted very easily but with the lid on an clipped down it instantly becomes ridged !
Cats and tunnel hulls the same !floors always in and glassed before the hull is released from the mold on the ones used to make
[QUOTE=W2F a V-King;2898560]I contacted the people at Corelite. Filled out a questionair on their website. I asked them about the corelite board, and their corelite pet products. Told them what I was working on, they responded very fast.
I will send off for a sample of the board and PET. I am curious.
Interesting note they sent back to me:
[quote] Dear James,
Thank you for contacting CoreLite. I will be happy to assist you.
The CoreLite Board in 2” should be stiff enough for a transom. CoreLite Board is commonly used in transoms without problems and comes already sanded and ready to be fiberglassed. We recommend that you perform your own testing as well, as the structural requirements may vary from application to application.
For stringers, CoreLite Board is an excellent alternative. However, if lighter material is desired, I recommend you consider CoreLite PET.
For hulls, CoreLite PET is an excellent solution as it provides great strength for its weight at a fraction of the cost of other foam cores. However, it is important to note that there is also no foam in the world that will be able to compete to the mechanical properties of balsa wood (I guess mother nature does it best). This explains why the majority of the world’s largest boat builders still use balsa wood core (and also racing boats, like Cigarette Racing boats). Balsa should never be a problem if it used correctly during the lamination process.
If you would like to go over more details with me over the phone, we can certainly schedule a phone call sometime next week. I am happy to help. Just let me know.
You can certainly purchase a sample sheet of any of our materials. Epoxy is compatible with all of our materials.
With kind regards,
--
Giancarlo del Cioppo
Business Development Manager
Mobile: +1-305-781-1342 | Fax: +1-305-691-9094Quote:
The floor/stringers and bulkheads in my HST are the carbon/pvc foam Corelite panels. It is a wonderful product to work with. I used okoume for the transom in 45 degree laminates,
That's a great analogy..got a good visual from that. :thumbsup:Quote:
Originally Posted by tunnels
James
.
If balsa wood has within it sugars and oxygen molecules, then the oxidation of the sugars will create water:
C6H12O6+6O2 → 6CO2+6H2O
even if you vacuum bag the balsa-core material, there will be sugars and oxygen left inside it.
http://biology.stackexchange.com/que...cose-oxidation
I would use composite materials in the core
if the boat is small enough, don't use any core at all.
.
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Noli, not trying to argue, but i have a 1981 Eliminator Daytona which is all original and the balsa core is visible through the top layer of glass plain as day and is literally perfect. How so?Quote:
Originally Posted by noli
wow that's new !! why because someone did right for a change !!Quote:
Originally Posted by capteliminator
.
Checkout these impact tests ==> http://www.fram.nl/faq/how/SP_CoreCell_comp.pdf
"... an impacted balsa panel often shows no outward sign of damage, lulling the boat owner into thinking there is no serious damage. Yet impacts are readily transmitted from the outside skin to the inside skin, the end grain splitting parallel to the grain and causing local skin delamination ..."
http://i1238.photobucket.com/albums/...mpactTests.png
...thus if your floor looks like the pic below, and upon visual examination of the surface only shows no visible damage, there could be other things wrong that is not readily visible. Also, surface only inspections will show the balsa that have been embedded and dried into the resin but will not show damage below the surface-balsa-skin.
Don't get me wrong, I luv Elim boats, I'd like to own one someday. A surface-only inspection does not mean that the composite laminates are all good. It most proly is, but to be sure one has to do an invasive inspection, something that I wouldn't do...not for the purposes of these forums anyway :)
If I were to build a cored bottom, I would proly use CoreCell, as someone already mentioned
http://i1238.photobucket.com/albums/...reFlooring.jpg
What we forget about balsa is that it has to be dried properly before it is installed. Yacht factory I once worked at stored all the balsa and foam core in a room with a de-humidifier running 24/7.
yes have seen all that sales guff for the last 25 years ! some of those photos are repeated by lots of other companies as well .
I never believe 1/2 of what you see in print and even lease told by a sales man with a smile and a order book in his hand .
I have always done my own testing of cores and different glasses that are used and proven that most is either not true or just sales bull dust ,
Have a look at number 3 photo and see how cleanly the balsa has come off the GLASS skin !!!AND WHERE IS THE RESIN PENITRATION INTO THE BALSA END GRAIN ? THERE IS NON ON ANY OF THE SAMPLES ! WHO EVER MADE THAT SAMPLE DIDNT KNOW WHAT THEY WERE DOING THATS FOR SURE!! ALL LIES !!
in all my years have never seen balsa do that never. Balsa doesn't come off any skin if its done properly
also have in all my nearly 4 years never seen balsa shear !!
DONT BELIEVE ALL YOU SEE ! WHEN MAKING SAMPLES YOU CAN BUILD SAMPLE TO DO WHAT EVER YOU WANT THEM TO DO TO PROVE A POINT!!
Many people have used balsa over long period of time and never had problems
I did a lot of boat collision repair and re-construction. What I saw with balsa, it just breaks the outer skin and pushes the core away from the outer skin in the impact area. Balsa being saturated with resin is more solid and is therefore more likely to transmit the impacts force further from the impact site than the foams also. Foam has impact absorbing qualities, and is a softer, less resin saturated material that actually absorbs impact. The pics show what I am referring to.
http://www.yachtsurvey.com/core_materials.htm says it all !Quote:
Originally Posted by XstreamVking
Yes, it shows that surveyors do not build boats.........
being a surveyor is one job I could never do ! So i am into Composite forensics IS MUCH MORE INTERESTING finding the reason for the causes of problems .99.9%is bad workmanship and poor understanding by the people doing the job can then trace that back to there supervisors that most haven't got a clue what day of the week it is !Quote:
Originally Posted by XstreamVking
My test panels did not break like that when I busted them up. The glass was much more reluctant to release from the balsa. But like already said, we do not know how they constructed the panels they used and I used a BFH with the test panel across 2 - 4x4's.
you are right ! believe 1/2 of what you see because is all false advertising ! and as for it happening to a whole balsa panel that is a blatant lie!! even using PVA glue would stick better than what ever they used
I have used it,,,worked well for us,,
How thick is the actual fibreglass skin on the cored hulls ?
what is the thickness of skin under the core and above the core ? say at middle of boat and 2 feet out from the centreline/keel area.
lets say this is on a 18ft v -hull that will take a 200hp motor ?
.
That's a very good question and I to will be very very interested in the answers you get !Quote:
Originally Posted by phillnjack
There could be quite a few variables of boats with cores ,and those without, plus boats with stringers, and those without , The laminate glass will consist of chopped strand matt and woven rowing !
Quote:
Originally Posted by phillnjack
Drilled a few 1/16" holes in mine....Curiosity got the best of me, and another member here asked me the same question. So out came the drill! These areas are getting re-glassed anyway. Inside and out.
The skin below the core is a fuzz over 3/8", so that's 10 mm. Same in all three test holes, pad center just in front of the transom, center of the V next to the pad, and up past the core was the last hole....all 10 mm.
Core was 1/2" ....Maybe 5/8... not 100% as most all of it was rotten. And swollen in some spots.
Glass covering the core was CSM, then foam filled between the core and pad, well 1/2 filled anyway.
Everywhere other than the cored area has what looks like a double layer of DB 1700 or there about, hard for me to tell with it fossilized in resin. But there is an edge that was left where the core ended and the rest of the hull continued, and it is about 3/16 to 1/4" in .
This is on a 79 V-King
James
You are talking about the corelite PET in comparison to the Divinycell H80? Can it make a contoured slight bend, like a 45 degree? Like scribe one side to get it to turn? Or did you use the cut sheets?Quote:
Originally Posted by 1BadAction
Got my stringer set up all mocked up and ready to order the materials. Going with the same Corelite Board 2" transom and tying my stringers into the transom and motor well bottom.
Thank you,
James
If you scribe it, it will just break right there (this is actually how I cut it, scribe lines with a razor then snap it off). It is somewhat flexible though, depending on the radius you might be able to get it down with some work. Maybe even warm it up with a heat gun then form it.Quote:
Originally Posted by W2F a V-King
There is a little trick the wrapping 18 mm thick H80 sheet core we learned when we were making racing yachts in South Korea and you could roll it round a 100mm radius or smaller without it even looking like it was going to break !! And no heat was not used !!!Quote:
Originally Posted by 1BadAction
WE made 16 full length sheets of bendy core for port and starboard sides that was needed for the 8 yachts we were making ! small radius one end and got bigger radius as it went aft !!
Only took me 5 minutes to understand how it could and had to be done !!very simple and very effective !!
Now that is going to make a few skeptic's raise there eyebrows and cough a whole lot and shake there heads !!:confused::cool: NO IT CANT BE DONE !! but yes It can be done !!:D
Understanding the materials you have to work with is the key to what we did !
Consider a balsa core. It has been used for decades with proven results and is much more cheaper than foam products (that do not provide the same strength). I get my balsa from CoreLite Composites. They have great customer service and good pricing.Quote:
Originally Posted by W2F a V-King
Makes me smile reading all these posts !! Why not use a combination of cores for your transom ! Balsa and foam or a honey comb ??!There is no need to use the same all the way across !!Quote:
Originally Posted by composites_marine
Problem with balsa in a lot of boats is "IF' it gets wet...it's done, it will rot and get weak. It doesn't matter if it gets wet from the top side or the bottom side...wet is wet and the enemy of wood. Save for maybe teak?Quote:
Originally Posted by composites_marine
"Some" of the boat manufactures do not adhere to proper glassing techniques ( read cheap and fast production= poor coverage with proper sealing ) which allows moisture to get in at some point, and over time these hulls rot.
Guessing if it properly put down and sealed properly and completely in glass with no places for moisture to get in, one would be OK. Tunnels could better address this area of proper installation of balsa.
For most boats, this may not be an issue, however on a light fast hull that could be a recipe for disaster. Especially in hulls that have floors covering the core...out of site, and out of mind, until something happens.
Tunnels, If balsa is cheaper, lighter and stronger, why bother with the composites at all ?? :confused:
James H.
Sorry to say but any timber including teak will rot when it gets wet and is semi sealed away from the air !!Quote:
Originally Posted by W2F a V-King
The word stronger and strong have many different interpretation's !! you can say a window is strong but when hit smashes quite easily !! A steel bar is strong but bend it ,it will break !
SAME with thick fiber glass is seen to be strong but could snap like a carrot !
Then there is flexural strength and that is a really interesting subject !! fiberglass that will bend 360 degrees and let it go just straightens out flat again and this can be done a 1000 times with no effect on the fiberglass what so ever . with the use of different types of Glass fibers Glass fibers can be manufactured to do almost anything at all !! S glass is even stronger and has way better properties than carbon fiber that to me is very highly over rated ! and has some terrible habits !!