700xs Rebuild Thread 2 - Page 2

kitten · 04-03-2012, 10:46 AM

I agree with JF ( slight pause whilst I spit the bad taste from my mouth!!)
Balsa will not be strong enough with the grain on it's side.

Hydrostream · 04-03-2012, 10:54 AM

I would certainly agree with Jon on this, really don't think the balsa will work in that orientation! It has no compressive strength to counteract the sheer forces on the skins! I know you have done a good deal of work now already, but I would suggest you reconsider before you go any further and have to undo even more!

You should be able to get balsa over there in endgrain pannels, if you can't find it call a local boat builder looks like you'll need only 2 or so sheets! If you get really stuck, I have just ordered a few cases of 19mm and can possibly spare a few sheets!

Burty · 04-03-2012, 12:20 PM

where was the damage on the outside Jurry?

Ph@ntastic · 04-03-2012, 03:48 PM

The problem is everything is already in and cured

To take al out will be a real drama i think , what is if put on an other layer using end grain balsa on top of what is have been building so far ?
The problem was i couldn't find any boat builder or wood shop who could suply me with end grain balsa so i went this route , also informed what route to go but no one could point me in the right direction ......

As for the outside , there will be two more layers of woven 220gram mat on top of the scm mat i laminated in yesterday to be sure the sturcture is okay , the problem was that i could not get the woven mat in nicely enough/flat enough , so i switched to scm mat .
On the inside there is only woven mat used for the repair .

@Burty , the damaga was slightly out of the midle of the hull , about 2/3cm next tot the small pad .

Jon Fuller · 04-03-2012, 04:08 PM

Jurry, I'm sorry, when we traded PM's about this, it didn't occur to me to check that you knew about the orientation of the balsa grain.
We tend to use the generic term 'balsa core', but in reality this is an abbreviation of the full title, 'end grain balsa core', which is quite a bit more specific.

I can't comment on the idea of adding another core and laminate within the existing one. My feeling is that the one you already bonded in could still crumble, even with the added layer/rigidity. I guess you'll have to decide for yourself if that's a risk you are prepared to take.

Ph@ntastic · 04-03-2012, 04:25 PM

No nothing to do with our pm conversation Jon you and others on here have been very helpfull and suplying me with good info

I was talking about some boat building companies over here which i contacted for advice since balsa is new for me , i have done quite some rapairs on various hulls and transom's but never worked with balsa before .
I think taking all of the new work out will piss me off more than first testing and finding out you gents were right from the beginning so i think i will give it a shot by putting in a extra layer of end grain on top of what i already did and see what will happen .

Hydrostream · 04-03-2012, 04:51 PM

Hi Jury, I really wouldn't bother adding any more material over your existing work, it will be only more to pull out when you have to. If you feel you must test this!

I know it's not what you want to hear but I feel it has to come out and be replaced with a core material of some sort!

Ph@ntastic · 04-03-2012, 05:07 PM

What do you mean by "test this" , to take her out and see how it wil hold (or not) or as in take it out this instand and put end grain in ?

Btw i really appreciate all of the advice given

I wish there was that much people with info on these kind of things over here .

Hydrostream · 04-03-2012, 05:44 PM

Sorry, what I meant was don't bother putting any more material over the work you have done if you are not going to redo with end grain balsa. It will just be more work to pull it all out to replace the long grain balsa with end grain.

http://www.scottbader.com/locations/...n-network.html

Call one of these guys, first one is in the Netherlands they should be able to help, if you get stuck I will probably have a few sheets to spare out of the cases I just ordered.

Ph@ntastic · 04-03-2012, 05:51 PM

The top one in that list is 10km from my homeadres

Thanks i will call them first thing tomorow !

Jon Fuller · 04-03-2012, 06:20 PM

They may want you to buy a whole box (expensive), if that's the case, either Alans offer, or, I think Nick has some 1/2" (12mm) Baltek left over and he might be persuaded to send a bit of that over.

Jon

Ph@ntastic · 04-03-2012, 07:00 PM

Okay thanks for that Jon .

glen76 · 05-03-2012, 02:15 PM

Quote:

Originally Posted by Jon Fuller

They may want you to buy a whole box (expensive), if that's the case, either Alans offer, or, I think Nick has some 1/2" (12mm) Baltek left over and he might be persuaded to send a bit of that over.

Jon

ewwwww. How much has he got?

Burty · 05-03-2012, 04:52 PM

Jurry, just make sure it ends up being the same thickness as before or that will in turn give you more problems as you will find that the fuel tank / clamps / ski pole etc won't fit!!!

Ph@ntastic · 05-03-2012, 05:53 PM

Thanks for that Rob , but if needed the tank wil be modified so that wont be a problem

Got in contact with http://www.advancedplastics.nl/ thanks to the link Hydrostream provided they are only a fem miles from my place and they sell end grain balsa scrimmed and scored , normaly at 27pannels (20,07m2) but they are willing to make an exception so i now got 2 pannels of 12.7mm end grain balsa 150kg/m3

Big Dutch · 05-03-2012, 06:09 PM

Modifying the tank.
I have seen tanks with lugs on that rest on top of the stringers
I wonder if that could take some strain off the repaired area ?
Just a thought.

Ph@ntastic · 05-03-2012, 06:37 PM

My thought as well

Goane test fit the tank tomorow to see how it all fits , if it doesn't the tank will be modified to lean on the stringers with 2 strips wich will suport the tank on both sides .

Ph@ntastic · 08-03-2012, 06:56 PM

Well i hurt but i got the grinding disc out again and cut out the balsa and the layers on top

Had to be sure i didn't have to redo things this winter .
Put in end grain balsa as i should have done from the begining .
Today i test fitted the tank and it still fits like befor , better yet i have a spare of 10mm between the stainless steel bar that holds the tank in place so i will fit a rubber mat underneat the tank when she is finaly installed .
Also made a new floor to fit under the tank .
Still thinking about getting the lumps on the botom off or have them cut in the same angle the floor underneat is .
I now have 20mm distance between the hull and the tank and after the rubber mat that will be ca. 30mm .
Anny advice is welkome !
Also put the boat on the trailer today , hapy moment because i dind't now if she would fit , but after adding two keel-rolls she will be on just the way i like it

Also got the new pullup lighting in today , pullup cleats got in on monday

Ph@ntastic · 08-03-2012, 07:46 PM

Btw thanks for you advice/coments on the balsa gents

mad_4_h2o · 09-03-2012, 07:40 AM

You did the right right the thing sort the repair out properly, theres nothing worst than taken your boat and and spending the day worrying if your repair will hold. Rubber under the tank is a good idea, just make sure that the tank tight down on it as you want it solidly mounted with no movement. The trailer worries me as it doesn't fit the boat very well and all your hard work could be damaged. Ideally the trailer should have a bunk or roller underneath the transome taking the weight of the engine.