My first try at fibreglass repair...

[Greenheart]

...didn't really warrant photographing, sadly...it's pretty poor. But...I'm delighted, finally to have realised that it's not terribly difficult to do.

Very possibly my work will immediately flake, crack, come loose from the deck and generally be a disaster, but after many weeks of pondering, then buying, then returning different products, it actually seemed much simpler and more effective than I was expecting, to saturate layers of the thin tape, lay it along the crack and add more of the resin...and after an hour in today's sunshine, it had dried and hardened up nicely before I went home.

Granted, it doesn't look slick - lumpy, uneven, some fibres sticking out - very sloppy - but when it's all dry and hard, I'm thinking it'll easily sand smooth. That being the case, my concern about the old boat's imperfections appears to have a solution.

Not sure if I used too much of the catalyst in the mix...I hope not, because it's only a tiny pot. Is there anything available to clean the mixture off brushes?

 

[Wansworth]

acetone

 

[Greenheart]

acetone

Damn! I should have remembered that, after a longish thread on acetone here, less than ten days ago... Thanks, anyway.

 

[prv]

Buy multi-packs of the cheapest brushes you can find, and don't bother cleaning them. Resin doesn't need a quality brush like varnish etc does, and at 20p each or whatever it's not worth your time.

Pete

 

[Greenheart]

I know that's probably true, but the brush I used today was brand new and seemed surprisingly good for a cheapie - of course, an hour later it was like a piece of wood.

Is there a reasonably accurate way to measure out the tiny amount of resin - 3ml I think it is - so that ten drips of the catalyst is neither too little, nor wasteful?

 

[prv]

Not sure you'll get far with only 3ml of resin, but in general for measuring out small quantities of fibreglassing substances (wax in styrene etc) I find disposable plastic chemistry pipettes handy. I bought a pack of 100 of them on eBay a couple of years ago for two or three quid.

Note the "disposable" theme here

Pete

 

[Lakesailor]

Told you to use GRP repair paste...............

 

[Greenheart]

Told you to use GRP repair paste...............

I'm jolly glad I took the repair paste back and bought the tape & resin instead, to be honest Lakey. The damaged decking is only millimeters thick, so there wasn't much to 'fill'...what I needed was something that overlapped the damaged parts with a really solid bond, but without much thickness...

...and hopefully even my cack-handed first try today will provide that. The photos aren't very clear, but the split in the deck ran about 18", turning through 90º. Before:

View attachment 32179

...and after...

View attachment 32180

SWMBO almost wet herself as I applied the stuff, because it looked so sloppy - tufts of tape sticking up and the gloves sticking to everything, but it ended up quite tidy.

Having had a go, I'm much happier about the boat in general. Where there are bendy bits that ought to be rigid, I can see how a few extra layers of tape & glass will stiffen it, without adding shed-loads of extra weight.

I'm starting to look at things all over the place at home, which would benefit from reinforcement with a little fibreglass...

 

[William_H]

Well done on your repair.
A few points. Sanding down the job willl be very difficult unless the GRP has cured. It just clogs the sand paper.
If you needed max strength of glass over that crack with min. bulk you would have done better with Kevlar rather than glass.
However it is very difficult to cut or sand kevlar. The ends just stick up as you sand away the resin. But it is tough. Much tougher than glass. You can just use it like glass ie saturate it with any resin. If you are doing polyester resin you will knopw if you have put in too much hardener cos it will get hot in the pot and go hard too soon. So smaller quantities for a quicker lay up job mean you can put in more hardener. good luck olewill

 

[Greenheart]

Sanding down the job will be very difficult unless the GRP has cured. It just clogs the sand paper.

How soon till the cure is complete, do you think? The glass felt dry and hard after 60 minutes. It was warmish today (by English May standards - 18º).

I'm hoping ordinary polyester resin will be fine for this job...I'm not concerned about slick results or a little extra weight here and there, and the decks were probably pretty standard glassfibre originally - the boat's 40 years old - so if I've slightly thickened the damaged area with more of the same stuff, I reckon that ought to suffice.

 

[lustyd]

I generally leave 24 hours before sanding in a sort of "one for luck" type way. Extra layers can be added as soon as it's hard, and there's no reason not to sand earlier if you're in a hurry. The surface will be the last to harden if you didn't cover with something like clingfilm, and without covering or wax it may always feel tacky until you clean it up.

 

[Lakesailor]

I'm jolly glad I took the repair paste back and bought the tape & resin instead, to be honest Lakey....

Just pulling your pisser. You're making progress, but it looks like you've missed summer now. It was yesterday.

 

[Greenheart]

Extra layers can be added as soon as it's hard, and there's no reason not to sand earlier if you're in a hurry. The surface will be the last to harden if you didn't cover with something like clingfilm...

Ah...that makes me nervous again...it was a week or two since I bought the resin & tape kit, supplied in a minimalist polythene package...and having opened it and left the components on the boat, any instructions which may have been supplied are now lost...

...so, I just mixed the catalyst and resin in a very approximate way (in an off-cut squash-bottle base) and applied several layers of the very thin woven-roving tape, all in the same quarter-hour period. I didn't wait for one layer to cure before adding more. I also didn't give a thought to covering with cling-film.

I hope it's not still gungey and soft underneath? Thinking optimistically, the thickness of the roving-tape and the completed job was so small, perhaps it could be regarded as no thicker than a single laminate in other uses.

Still, it seemed to have hardened up successfully in a very short time - I had expected I'd need to keep the boat-cover from sticking to the area, but it was tack-free by 5pm.

How volatile is the catalyst, as long as it's kept in its bottle? There must be an alarming combination of chemicals on board my little boat, as aboard most others: acetone, pre-eco-regulation paint, resin, catalyst, lighter fluid for the BBQ...I hope it stays cool under the cover!

...you've missed summer now. It was yesterday.

It was beautiful at lunchtime. Damn chilly by late last night. I hope summer's yet to come, I haven't even bought a pair of sunglasses yet.

Haven't had a pair for fifteen years. Note to self: search forum for best sailing sunglasses thread.

 

[jon711]

I would use a well sharpened cabinet scraper, one of the best tools in the tool box

 

[prv]

I hope it's not still gungey and soft underneath?

I think it will be fine. It's only the surface that has that effect, due to contact with the air. I also believe it is only a gelcoat problem, not something that happens with resin. At least, I don't remember encountering it.

Pete

 

[lw395]

Just pulling your pisser. You're making progress, but it looks like you've missed summer now. It was yesterday.

Summer was today down here.
Blue sky and 18knots.
Still haven't finished my winter refurb on the dinghy, luckily I have a spare one to go racing in...

 

[martinteeluck]

...didn't really warrant photographing, sadly...it's pretty poor. But...I'm delighted, finally to have realised that it's not terribly difficult to do.

Hi Dan and well done dude! We did our first grp repairs this weekend aswell - pretty happy with how it ended up but at one point we mixed up too much 2 part and the cup ended up being too hot to hold and started melting!!!! Good learning curve though

 

[Greenheart]

I think it will be fine. It's only the surface that has that effect, due to contact with the air...

Cheers Pete (and others...). No surprise if yesterday's work turns out imperfectly, but if it hardens up & assimilates with the split deck, it'll be good enough to sit on.

Also yesterday, the batten I bought last month was finally cut in two, to reinforce the thwart which is divided along the centre-line by the centreboard.

I'd hoped it was just a matter of doling out Sikaflex onto the right-angle faces of each batten then clamping them into the corner positions required, for a few hours...

...but it turns out, the underside is not smooth - lots of fluffy outcrops of old glassfibre, which aren't as easy to shift as they initially feel. No good pulling with pliers.

So the seat may turn out to be another glassing job, because I can't get the very rigid, perfectly straight iroko battens to sit flush up against the uneven surface.

 

[Bobobolinsky]

I use standard margerine tubs for small jobs. 300ml and one cap full of hardner is perfect. (Hardner came in a kit and the small cap gave a perfect measure) Cold day two caps. I use a measuring jug, put 300ml of water in the marg tub (about 2/3) and mark the water line with a marker, empty and dry, then fill to line with resin. Large jobs I use large paint kettles or the buckets from the florist and multiply up (1.8 Litre)

 

[Lakesailor]

Cheers Pete (and others...). No surprise if yesterday's work turns out imperfectly, but if it hardens up & assimilates with the split deck, it'll be good enough to sit on.

Also yesterday, the batten I bought last month was finally cut in two, to reinforce the thwart which is divided along the centre-line by the centreboard.

I'd hoped it was just a matter of doling out Sikaflex onto the right-angle faces of each batten then clamping them into the corner positions required, for a few hours...

...but it turns out, the underside is not smooth - lots of fluffy outcrops of old glassfibre, which aren't as easy to shift as they initially feel. No good pulling with pliers.

So the seat may turn out to be another glassing job, because I can't get the very rigid, perfectly straight iroko battens to sit flush up against the uneven surface.

It's a job for epoxy. It'll bond well to the existing grp (with a bit of roughing up) and soak into the wooden battens. May need thickening to bridge the uneveness. I prefer wood dust, others seem to like microballs.