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[Garabaldy]

If all goes to plan i'l be sealing my hull this weekend.  Whats the best way to go about this?

It has been suggested to me to put on a layer of resin (inside the hull) then put on tissue then 'dab' the tissue on with more resin.  I have some fasglass stuff from halfords, will this be any use to me?

Thanks

[boatmadman]

I use fastglass for the inside of my hulls, the only difficulty is that its a little viscous so you end up with quite a thick coating. The cloth that comes with it is too thick for this use.

If you have glassed and clothed the outside, then you prob dont need cloth inside. The only place I have used cloth internally is where a join needs stiffening.

There is a thread on thinning epoxy here  http://www.modelboatmayhem.co.uk/forum/index.php?topic=11218.0

Ian

[Garabaldy]

but as i have used p38 to fill in the holes around where the shafts rudder etc im lead to believe the p38 is porus and there for needs some kind of sealing done to stop it leaking.  Will painting the outside of the hull be enought to seal it or do i need to do somthing on the inside aswell?
 

[boatmadman]

I have used p38 before without porosity problems, but it is always best to seal it.

I would strongly recommend sealing the outside of the hull with a couple of coats of epoxy, if you think the hull is strong enough, then no cloth/tissue would be ok.

I would use a laminating type epoxy for the outside, its thinner and easier to apply. Also, after application, scrape over it all with a bit of flexi plastic (an old credit card is ideal). You will remove lots of excess and end up with a better finish.

Good paint is waterproof, but I always think that a good seal coat or two, rubbed down with wet/dry then painted is better.

Stavros is the paint expert on here.

Ian

[DickyD]

Ian do you think he needs to seal the outside of the GRP hull would not paint be enough and epoxy on the inside ? :-\

[boatmadman]

DOH!

No he doesnt need to seal a GRP hull, inside or out! That will teach me to read the title better!

Ian (feeling stupid)

[Garabaldy]

epoxy round the areas its likely to leak around the shafts and then good paint on the outside?

If its going to be that simple then im a happy man! 

[DickyD]

As long as your shafts and rudder tube are a fairly tight fit, roughen them up where they go through the hull and roughen up the interior of hull round them with glasspaper, get rid of the dust and apply epoxy resin round shafts and tube. P38 and paint is OK on the exterior.

[Garabaldy]

What if they are not a tight fit?

[DickyD]

Can you do a photograph showing what you are talking about in the way of gaps etc.

[Garabaldy]

yeah i probably could over the weekend.  I have filled all the gaps in with p38 and its all smoothed off ready to paint on the outside of the hull its just i was under the impression i would have to do somthing on the vulnerable areas inside the hulll.

[DickyD]

If there is not to much filler you can coat the inside with epoxy then do it a couple of times more to build up the thickness.

[boatmadman]

Trying for a sensible contribution here....what I do at the entry point of the rudder tube and prop tube is build a little damn around them using wood, then fill with epoxy. This seals and strengthens the area. I usually go about 25mm all around the entry point and 6 to 10 mm deep.

Ian

[DickyD]

Better than the last one Ian 

[boatmadman]

Wasn't difficult was it? ::)

[Garabaldy]

thanks everyone. ive got a good enough idea what to do now.

not long until she gets wet!

[DickyD]

Bail out 

[John W E]

hi there

with regard to bonding to a fibre glass hull using either polyester resin or epoxy resin - the area to be bonded on the hull must be firstly, roughed - up with either coarse emery or sand paper, breaking the fibres in the fibreglass layup - the reason for this is that the hull is what is know as past its green state - it is now cured.  Any further laminations must be - what is known as 'mechanical' rather than 'chemical'.

Failing to abrade the area, you will find, after a period of time, the applied Epoxy or Polyester resin will possibly pull apart.

You say you have used P38 filler to bond in the propeller shaft - this is ample - there is no need to put a coating of any epoxy resin over thetop of this on the inside and normally, you would be painting the filler on the outside and therefore preventing any water impregnation.   The only time I would worry about sealing fillers on the inside of the hull, is, if you know the inside of the hull is going to be constantly wet. Or, indeed, subject to glow/petrol fuels.   The other thing is rather than pour Epoxy resin around your rudder tube where it enters the hull - cut a piece of one eighth plywood - say 1 1/2 inches square and sand it so it fits neatly to the shape of your hull.   The epoxy this to your hull - and then drill through the plywood through the existing hole in the hull for your rudder tube.  Doing it this way, is a far easier and better way to dissipate the stress on your hull.

Avoid pouring copious amounts of polyester or epoxy resins - into these areas.   What happens on vast amounts of resin without matting added - and poured into the hull - it shrinks/expands at a far different rate to the actual hull itself.   There delaminating itself.

That is how you always tell a bad fibre glass hull build - you will see where folk have added resin to either the bottom/side of the hull and it forms 'pools' - apart from being an utter waste of resin it actually does more harm than good.

A good fibre glass hull should have a matt appearance and when you rub your fingers over the hull, you should 'just' be able to feel the strands of glass.   There should be no evidence of dry areas - e.g you will see the glass show up as white.

Hope this is of some help.

Aye
john e
bluebird

[wallace]

Always used fibre glass to bond prop shalf and any platforms you put to hold things also under the wood at the side of hull  that holds the top deck no water will get into the boat just put throw away things on to your hands use your fingure to push it up into the side