Water in my balsa core!

[Colvic Watson]

OK, this is far outside of my skill and knowledge base (which is confined to training Labradors and teaching children), but I've got a problem. An area about 18 inches by 12 inches on the foredeck is springy, makes a sort of cracking sound and water comes out of a tiny hole when you step on it. Got the yard to look at it and they reckon its water in the balsa core. The thing is, they want £1000 to cut the section out and redo it, obviously the materials are peanuts so its down to labour, lifting out and back-in etc; but is that a fair price? Has anyone done this themselves? Any recommendations for other yards on the Kent coast? Does the boat have to be under cover? Sorry if I sound a bit dumb, but like I say, this is outside my area of expertise.

The boat is a 1978 Atlanta Macwester 28.


Simon

 

[adelaidem]

i would do it for $500 cash but u have to bring the boat 2 me.

 

[Colvic Watson]

Good, that's my summer holiday sorted then!

 

[adelaidem]

why do they have to lift the boat from the water? if it is in ur deck area it would possible rain water thats entered through a deck fitting can u establish where the water is getting through the laminate?

 

[Colvic Watson]

It was from an old deck fitting that the previous owner removed and didn't seal correctly and we didn't check. Is the under cover bit to help with epoxy/grp curing? I thought not?

 

[cliff]

See here for instructions.
Please remember it is as important to find out where the water is getting in as is the repair/replacement of the core.

As for 1K to have the job done "professionally" - if that includes the lift and demasting and remasting and 2nd lift it is not too bad although perhaps a little on the high side however bear in mind once the "pros" start cutting the top skin off there is no telling how far they will have to go to do a proper repair - perhaps 4 times the size of the soggy bit. I personally would have a go myself afloat with a temporary tarp tent over the job incase it rained.
----------

“Artificial intelligence is no match for natural stupidity”
Skype id:cliffillupo

 

[adelaidem]

if u can drill the some small holes under the deck and drain some or most of the water out,drill some small holes on top deck then cover with plastic then put small fan heater in bow section,if it all seems fairlly dry after a week or so patch the lower holes ,with 2 pack filler or gelcoat then inject with syringe through holes in top vinylesta resin. if this method is not possible yes u will have to cut and replace the core.

 

[Colvic Watson]

The £1000 is plus £300 for lift in and out - just checked. £1300 seems a lot!

 

[mainshiptom]

there is an area on my boat which I need to do!

I read lots about it and seems easy enough to do ! I am about to start soon, where are you moored?


Tom

 

[oldsaltoz]

G'day Simon,

This is not a difficult project, well within the average DIY persons ability.

The water coming up through the hole is the most likely point of entry, but you will have to double check to make sure (more on this later)

First priority is stopping more water getting in and to remove what moisture is still trapped between your deck and inner layer. So you need to cover the area, a simple plastic sheet taped to the deck will do the trick.

The water will have caused the core material to fail, sounds like it’s Balsawood, but it may be some other core material that is not a ‘closed cell’ type, that is, it will take up moisture.

This type of repair is best done from below to preserve the top deck, no mater how good you are a repair on the topsides will show, if not now, it will later as the new gel coat fades at a different rate to the material around it.

I have done this a few times over years and find the simple method is to:-

Use a drill fitted with a depth stop and drill up through the underside of the deck, check the material that falls from the drill for any sign of moisture, each time you get a wet hole move an inch or so and drill again, continue this till you have established the extent of the problem, mark only the holes that have no moisture showing in the cuttings.

You should end up with a number of marked holes that effectively indicate the total area to be treated. At this point I use a grinder to cut a hole along the line of the outer wet holes; take care not to cut the underside of the deck, then remove the glass and dig out the core material around the edge till I find dry core.

Then recut the hole to leave about half an inch (12 to 15 mm) ledge of glass all round.

Now you can check the deck layer for holes, cracks, leak points, sometimes the colour change from water staining will help find them. Next remove all traces of the old core material from the underside of the deck and give it a sanding to provide a good surface to glue onto later.

Gat some ‘closed cell foam’ in sheet form, it’s very easy to cut and shape, if you need to curve it to fit the underside, just make saw cuts 5 mm apart but inly cut to within 10 mm of going through, the sheet will now bend along the cut lines.

Make up 2 halves to fill the area, so you can slot them in over the ledge we left earlier. Dry fit both halves to ensure they are a snug fit before you start mixing any resins.

When you are sure you can slide the two halves in without problems, drill them from the uncut side with a 5 mm drill in a grid pattern about 25 mm apart over the entire foam sheet, more on this later.

Mix a small batch of epoxy resin (Half a cup) and hardener, and then add some closed cell Microballoons, ‘Q’ cells, or Microsphears and mix to about a toothpaste thickness. Apply a layer on the cut side of the sheet and work it into the cuts so that when the sheet is curved, the mix will squeeze out, leaving the cuts full, then add about 10 mm to the smooth uncut side of the sheet, now fill the ledge on the underside of the deck so that filler will contact the edge of the sheet when placed and squeeze out and air gaps, now place the first half in position (Smooth side up) and then the second sheet after coating as above, you may to hold the sheets in place to retain the correct curve, do this with a prop from the cabin floor, put a small of plastic sheet over the end to prevent it sticking, note, do not put the sheets up till you are ready to place the prop, only then should the sheets be pushed up and any air trapped behind them should come out via the holes drilled in the sheet, in fact expect to see some of the resin mixture come out of most holes.

Let this cure over night and sand any high spots off and fill any low spots ready for re glassing, grind the of the repaired area to form a taper, it should be about 30 mm wide.

After sanding the area apply your glass, best to have this pre-cut to save time and more mess. You will need 3 to 4 layers, the first should finish only just inside the outer line of the ground area, the next layer should finish 10 mm inside that and so on.

I only use epoxy resins when repairing as the bond is very good and you have a pot life around 30 minutes, so no need to rush it. Avoid using glass cloth that is not designed for use with epoxy resins, or you will use more resin and get no benefit for the extra cost.

No mater who does this work it will be dusty and will make a mess, so remove whatever you can to reduce cleaning time, and protect the cabin floor with covers.

Needless to say you will need some personal protective gear, goggles or safety glasses, a good respirator, ear plugs, a box of disposable latex rubber gloves, and the list goes on.

If you have power on board, or are in a marina there is no reason for a lift out.

Measure twice and cut once, rush and you will loose time doing it all again, take a break before mixing resin and think about the sequence of work you are about to do, some can and should be done before mixing, like pre cut glass, having cleaning pots reedy, spare clean pots to collect material squeezed out and so on, plan your attack, it will save time and money.

I hope this helps.

Andavagoodweekend......

 

[Colvic Watson]

Thanks for the advice so far. I hadn't realised (cos I don't know much about GRP) that we don't have to take the top GRP off, only the bottom layer of the 'sandwich' - hence it's all done from below. We're going to give it a go. The worst is that we get it wrong and still have to pay £1300, the best is that we save well over £1000 !

 

[boatmike]

I would entirely endorse what oldsaltoz says. I would only add the obvious. Don't breathe the dust when grinding out the bottom skin and wear a respirator and protective clothes. I personally would use a vinylester resin rather than epoxy because they are easier to work with but it's not a bad bit of overkill to use epoxy as long as you realise that the H&S risks with epoxy are very high so don't get it on your skin or breathe the fumes. Working overhead with any GRP work is messy so try to impregnate the material first, downhand on a piece of polythene and then offer it up wet with a roller from the underside. Let the resin go off for about 1/2 hour then rip the polythene off. Hell if it stays there it won't matter and it's better than getting it in your hair....... Go for it. If you have not used GRP before, practice a bit off the job first to give yourself the confidence.

 

[woody001]

Had the same done on my boat about 7 months ago, exactly the same method..about 1 meter long. 1 ft high.
Cost me nothing

 

[William_H]

I agree totally with Olldsatoz and his description is terrific. yes vinylester resin is good stuff, if however you want to do a shoddy job or make do. It may be possible to open up a hole where the fitting was previously fitted. The deck surface is probably damaged or mared any way so cut a hole in the upper deck layer. gouge out the core as far as possible sideways and replace with foam or if it is a small hole resin with some chopped up glass. Smooth out the resin or if you used foam cover with several layers of glass. Use gell coat or a pignment for the last layer or paint it. Just one hole fixed will give support presumably to the middle of the damaged core.
The reason for working from unnderneath is to maintain the outer layer which especially if it has a non skid pattern is impossible to return to original looks. However of course if the deck surface is tatty or damaged then you may as well curt it out from the top and accept you will have to do a smooth layer of glass then paint with non skid paint. Obviousy it is far easier to work from above.
So the fix depends on how bad the core damage is, how well you want to fix it and what condition the cosmetic look of the deck top is.
regards olewill

 

[oldsaltoz]

G’day Olewill,

The problem with drilling a hole from top and just repairing a small area will mean water is still trapped and the rot will spread, the original post indicates this is not a small spot but an area of deck.

Also note that repairs done from the top will not only be easy to spot but will also reduce the resale value, by far more than the effort or cost of repairing from the underside. Yes it’s dusty and messy but when finished invisible. And, all the moisture has been removed so it’s a long term fix.

It will take half an hour at most to drill the holes and cut out the bottom, 20 minutes to dig to dry material. Say an hour to cut and shape the 2 bits of foam, another 30 minutes to install them, 20 minutes to sand and fill lows, another 20 minutes to sand and glass, another 20 to fill and fair, then 10 minutes to flowcoat.
Total: 4 and a half hours spread over a few days, hardly hard work.

Andavagoodweekend.

 

[boatmike]

And three days to get the resin out of his hair afterwards if he doesn't wear a hat! /forums/images/graemlins/smile.gif /forums/images/graemlins/smile.gif /forums/images/graemlins/smile.gif /forums/images/graemlins/smile.gif /forums/images/graemlins/smile.gif /forums/images/graemlins/smile.gif

 

[oldsaltoz]

G'day Mike,

Well I did say it was a dusty messy job and to cover the floor, but I must admit I never considered bonce contamination, would look like a rooster with a rubber glove in his head. (Wife calls out "what are you laughing about? looking at joke sites are you).

You can remove 'most' of the uncured epoxy resin with vinegar, Acetone might be a bit of an overkill.

Avagoodweekend......