Thanks Dick, I’ll try smearing thin layer of epoxy over the area(s) and try and fill these so called pin holes and once cured check the hull again.
Cheers Alan :zbeer:
Alan,
is rather normal, most of the time the external paint may help expecially if diluted.
Take your hull and present it in front of a windows and look trough, you will see hundreds of small white dots, each one is a potential confirmed hole.
Use several coats of primer and sanding it after each coat will help to close the holes.
As Dick said, this is avoided with the use of a gelcoat but cost weight.
Using a female mould the problem is actually prevented using a wax that accept paints without creating the ‘bull eyes’ - this is wat the french Sicomin company pretend.
This means that you can spray a polyurethane paint on top, once dried and polished, as the first layer and as substitute of the gelcoat and then continue with the classic composite lamination.
The wax is called : Cirex DE 68
from http://www.sicomin.com/
I have to place an order and try myself.
This is what I aknoledged last month.
So, Alan for you : primer + sanding a couple of times and check again !
Cheers
Claudio
a small OT
more then 1800 boats started at the gun shot. Pics from COR - Barcolana race in Trieste Italy
Claudio
Thanks Claudio, I’m now thinking the positives for having a female mould are beginning to out weigh the additional work required using a male mould :rolleyes:
Would not want to be on the lee side of that start line … 
Cheers Alan
I have fought with pinholes on every hull I’ve made. What I use now is drywall mud. After the first coat of primer I rub the surface well with the mud. It is fine enough to go into the pinholes. You will probably see the mud coming through to the other side. Let it dry and sand just enough to take the mud off. If you sand too much you just open new pinholes. The mud allows the paint to bridge the pinhole and another coat of primer seals the mud that’s in the pinholes and you are on the way. If you want you can paint the other side to seal it but it’s not necessary.
Using another coat of epoxy will work if you squeegy it on well but then you have to sand hard enough to get it smooth and that will probably just open new pinholes. More paint doesn’t help because it just beads up around the pinholes.
I know it sounds like a Mickey Mouse fix but I used to curse pinholes and now they are a non-issue.
I think pinholes are the major cause of wet boats, leading to radio failures etc. and this fixes them.
Hope this helps
Don
Don is correct, and I have used same material (also called by various names - drywall compound is another) on external male plugs. It sands very closely to how balsa sands - which can eliminate low spots a much harder filler might create when sanding. It is DUSTY however - not for sanding over a dark blue shag carpet while watching sports ! [don’t ask] :rolleyes:
The epoxy “smear” I suggested was on the inside of the hulls - but again, as noted by Don - the resin is fairly hard to sand - although scraping with the edge of a piece of broken glass does a super job in leveling the surface.
scusate l’italiano ma non scivo e non parlo l’inglese . io per risolvere i problemi di microforature o porosita dello stampo uso mettere il peel play all’interno dello stampo che mi crea uno strato sottile di resina epossidica gia’ pronto per fare delle piccole rasature o stuccature sempre con la resina epossidica mescolata con addensante fino ad arrivare ad un impasto denso tipo gelato. ma siccome e’ difficile ottenere uno stampo perfetto eternamente ( la vernice non fa spessore e se ci sono fori della dimensione di uno spillo questi si vedranno ) io uso quasi sempre uno strato di fondo plastico riempitivo bicomponente ,professionale per carrozieri , che mi prepara anche un’ottima base per la verniciatura. vi assicuro che il peso in piu’ e’ inrilevante , e il risultato e’ garantito.
Importante usate sempre prodotti bicomponenti.
Vi riscrivero per la verniciatura.
Ciao
Don & Dick thank you,
I have applied epoxy smear on inside of the hull, we have very cold temperatures here now (zero degree’s) :shock: so hopefully the very slow curing will help the epoxy fill the pin holes.
Alexus Grazie, ho applicato la sbavatura di expoxy sopra all’interno del guscio, noi ho temperatura molto fredda qui ora (degree’ zero; la s) :shock: così eventualmente il trattamento molto lento aiuterà il materiale di riempimento di expoxy i fori di perno.
:zbeer: Alan
Alan,
I’m afraid that at 0°C the epoxy compound or mixture will not operate as you wish.
As Dick said this problem is encountered very often.
Part of a carbon/glass Hull observed with a backlight (window) - 50% of the clear dots are potential leakages holes.
The size of the holes are directly proportional to the Cloth weight/m².
This is why I always suggest to use several layers of lighter cloths for 2 raisons : Smaller holes and added rigidity to the construction.
Unfortunately the lighter carbon cloths are expensive, the use of glass and kevlar, this late never outside, requires to increase the number of layers to achieve the same strenght of carbon.
My question : Is it really necessary to get that strenght ???
This picture is eloquent, is the result after having spray of a paint primer (probably an acrilic stuff)
Since I use often the polyester mastic, I decided to smear every where the compound as suggested by my bodycar painter.
So I did it followed by a good wet sanding. Almost no weight added except the small pinholes. Judge by yourself from the picture.
General appearance show some white filled dots
Hope will help. The Sintomarine is produced in USA and sold everywhere but can be used only above 15°C.
This type of product exist also with glass chipped fibers to repair important bodycar damages. Being a polyester it smell a little , better to ventilate. Available at any paint / tools shops
Cheers
Claudio
Claudio, your right the epoxy smear was not working particulaly in these temperatures, I have found this automotive filler and will be applying it today and sanding again (lighty)
The on-set of an early winter has slowed me down considerably & currently looking around for some heating solutions for my workshop so I will be a little side tracked for few weeks until I get something more comfortable to work in.
Cheers Alan
Because of the cold season, also Gilles of Quebec has stored his ETNZ .
I’m very proud to presents the last pictures I received.
I noticed the nice sails he has made out of Mylar tissue.
Just for record, this boat was specially developped to his request for a lenght of 150cm
Thank you very much Gilles, up to the next season !!!
Don’t let the hull going under zero degrees , it may damages the composites.
Cheers
Claudio
These are pics :
Nice Pictures!
Of course, I like many have been inspired by this thread.
www.quickclic.net/~mranger/boat_0001.wmv
That was a picture for ever plank I put on, taken over several days.
Gravitar
My first model build of any-sort, btw. Wish me luck.
JUST GREAT !
Congratulations to the ART DIRECTOR !
Chers
Claudio
“Don’t let the hull going under zero degrees , it may damages the composites.”
Claudio … are your talking about fibreglass here :scared: or other composites ?
Gillies … pictures of perfection your a master well done !!!
Cheers Alan
Alan,
it is simply my assumption after the discussion about temperatures on composites and resins driven by Dick.
If the uncontrolled over heat disturb the resin caracteristics, I assume that the storage at low temperature may also be not so good.
My remark is just a precaution .
Let see what could be the expert answer.
Cheers
Claudio
In my humble (and non-technical) opinion, I doubt that cold has as much influence as heat on epoxy composite construction.
I base my opinion, only on the fact of how many DN (and other classes) of ice boats are built of composite materials (plywood, fiberglass and carbon/Kevlar) and manage to compete in the dead of winter without failure of the body, plank, tiller and even those who still use wood strip masts.
Failure of any/most of these components are probably due to crashes on the hard ice - or with another ice boat.
ah … thanks for confusing me guys (joking) just as precaution I will kick the missus out the bed and have my NZL 92 kept nice & warm over the winter 
Cheers Alan
Thank you so much Claudio and Allan for your good comments,it’s very encouraging to hear that from you guys.Be sure i don’t take any chance to let my sailboat exposed to cold and humidity,it is stored in my house and by the way,i can look at it and dream about next summer to come fast. Cheers Gilles.
Hello,
Well, this is just an excellent thread!! I have been looking for ages on the net for any instruction about building an RC yacht. I used to own an old Marblehead (built in 1983) but it was ‘lost’ in an accident in the garage (the missus went too far forward in the car when parking!!) Reading this thread, and with the excellent instruction of Claudio I am willing to give building a IACC-120 a crack!!
I have a quick question - if I build a ETNZ design and paint it in Ozzie coulous will that be deemed sacriligious?? 
Thanks Claudio, Kiwi and others for sharing your experiences. It makes it very easy when you understand the ‘learning experiences’ others have had…
Not necessarily Brad, if you don’t pretend to participate to races.
Please read the Rules first, you will get the full answer. Here to go for : http://iacc120cup.altervista.org/Main0E.html
Cheers
Claudio