Laser - nonslip tread Gelcoat repairs

[Kessica]

Not sure if this is in the right forum, but here goes.

I have been asked to repair a Laser. There are considerable cracks and crazing in the which I intend to grind out completely and restore the glass through the layers finally finishing off with gel coat. This has already been a successful repair process on a glass hull and apart from the slight variation in pigment colouring, you cannot see where the repair was made.

Anyhow back to the Laser.... All around the laser is a non-slip surface which Im pretty sure was formed when it was first moulded. Im wondering how I can replicate this coarse pattern in the gel coat. My inital thoughts are to make a reverse copy of it using a gel or resin and placing a a fine layer of cling film between the two when making the mold to stop the resin from sticking to the original surface.

Once Im ready to do the final coat of gel coat on the hull, I can then use the mold that I have used to make the impressions before it goes off hard. This seems to be a be a bit of a hit and miss affair. Im wondering if anyone else had to do similar repairs and how they achieved a reasonable finish on the non-slip tread.

If I can get to the club later Ill take some pictures and attach when I get back.

Thanks.

[PI Design]

Hi - do you want an exact match of the non-slip pattern or will any non-slip do?

A friend of mine had the same problem - he ended up using an ink stamp (one that rolls rather than stamps, if that makes sense) that was a very similar pattern to the Laser non-slip. He got it from one of those out of town arts and craft shops.
Alternatively, if you have any old copies of Dinghy Sailing Magazine there have been several articles on repairing Lasers and I'm sure one of them would have covered the non-slip decks. Those articles were mostly written by Pete Vincent, who can be contacted at West Country Boat Repairs.

[Kessica]

Id like to get as close as possible to the original. Im afraid Im a bit of a perfectionist and even more so if the thing Im working on is not mine. I know that the guy said that as long as the deck doesnt flex he will be happy, but I think if a jobs worth doing, its worth doing well and I have a reputation to keep lol.

If the Laser were my own, Id give it a complete renovation as its a bit tatty, but getting the deck so its structually sound is all thats required at the moment, but a good finish too.

[Phil Stevo]

take a mould of a piece of the deck large enough to cover the repair. then make up a thin plate with the gelcoat texture and a layer of choppy underneath. once your structural repair is done and filled/faired, make up a jig of sorts and trim down the 2mm or so, to allow the piece you made up to sit in flush. glue down and flowcoat the join neatly. that will get you a pretty good job.

its a lot of extra work, so quote/estimate and offer a brushed flowcoat finish

[Kessica]

A couple of pics from the Laser. The cracks go quite deep as you can flex the deck here and see them open up. Unfortionately its right where you sit so this will need not just gelcoating, but structural work too.

[mark_m]

I had a nasty accident in my Laser a couple of years ago where an FD T-boned me, taking out about 200mm of gunnel and digging into the deck about 200mm. It was covered under insurance and repaired professionally by Laser UK.

I was extremely dissappointed when I got the boat back. The gunnel was matched up very well but they had just stippled the gelcoat and the texture is nowhere near the same. They warned me it wouldn't match up exactly, but I thought they were refering to the joints, not the texture itself.

This is more annoying because I was working for a small composites shop at the time and probably could have done the repair myself. If I was doing it I would have taken a mould of the original deck, either in GRP or with something soft like silicone.

It would be interesting to know how Laser made the texture originally. I bet it wasn't cnc cut. I'd guess they used a textured roller to make the plug's texture, then made the molds from that.

If you work out how to do it please post with pictures 'cause I might have a go at redoing mine before I sell it.

[Kessica]

I had a play with making a mold using some cling film and gelcoat as mentioned in my first post. Although it worked the cling film ( very thin film of plastic ) creased a little and there wasnt a great deal of depth to the tread pattern, so using this way is not really ideal.

After scratching my head a while I decided it might be worth trying some liquid latex. I believe this method will be the best and will give the best mold. It went well today however when working with this unusual stuff you really have to be patient. The first few coats set very quickly, but as the thickness increased, the time for it to go off, got progressively longer. The final coat had only just formed a skin when I eventually left after waiting around 3/4 hour.

I first cleaned the sample tread with soapy water then degreased it. After masking off with tape I then went around the boundary with plasticine so create a pliable wall so the liquid latex wouldnt slop everywhere.. After wiping down with a drop of liquid vaseline to stop the latex from sticking too much thereby easing removal without tearing I then laid about 6 layers. see the attachments. Hopefully, tomorrow Ill be able to peel the mold off and let you see the results.

Once the mold is ready I can then make some small panels or tiles to inly into the repaired decking. They will be seen of course but I think with a neat thin border around them they wont look too bad. I think it would be better to make a feature of them in a small way, than try to merge them all together so it looks botched.

Whilst waiting for the latex to go off, I sat around the lake and was amazed at the procession of Canada Geese and their families.I just had to include these

[Kessica]

After peeling off the rubber mold which incidently came off very easily and without leaving any residue or staining, I took a sample cast from it. It looks exactly as the original non-slip tread on the deck; which is was I expected

Its now a simple case of making up a few small tiles to fill the areas where the tread will need to be replaced. I intend to gind out the fractures, lay up with glass and resin and then fill with gelcoat, but leaving it about a 2-3mm short of right level. Once its gone off Ill be able to fit each tile and secure using gelcoat. The alignment will be crucial for a neat job, but I might just leave a thin smooth border around each tile to take up any inaccuracies. I think it would be better to make a small feature of this rather than try to hide and end up with a botched looking repair.

Ive attached a couple of macro pictures of the mold and cast. Note that they look inside out. This is because I couldnt be asked to get out the better flash gear and do a proper job on the photography Lighting can really change the look of a bump textured surface.

The rubber mold :


A test gelcoat cast from the mold:


Ill upload some pics from the finished repairs later this week once they have been completed.

[Kessica]

Its been a few days since I last woed on this project, mainly as I was busy finishing off a workbench which I had been building for the Sea Cadets at the Unit, and also spending a day with Tim B saling from Southampton to Cowes in his Lark.... Fantastic Day out despite needing a short tow on the way back as the wind became non-existant and the GPS reported a speed of 0.0 for about 20 mins

Anyhow, after grinding away slowly and following a few cracks in what I believed to be a structural problem area, I discovered that after going down a depth of a couple of mm, I came across what looked like either a foam base or some glass matting which looked dry and rotten. Going deeper and ending up making a small hole, it could be seen that it was in fact a rigid foam. What made matters worse was the fact that the it had dropped by about 3/8 inch away from the skin. This explained all too well why the fault had occured in the first place and why the deck was very flexible with stress lines forming easily.

I decided to grind away and prepare for some major glasswork. The idea here is that I will build up a number of thick layers between the foam base and the skin so that the skin will be much better supported and become more rigid allowing for a person to sit on the deck in the right place without cause more flexing and structural damage again. This problem, now exposed really does explain why the stress marks have appeared in the first place and why the decking is so flexible. What amazes me, is how thin the skin is. The single layer of glass matting is not enough in my mind. The laser really does rely on the foam for structural strength and if this fails, goes rotten or comes away from the skin, then the deck will flex so easily and after a short period of use will fracture and eventually break.

This is the underside of the skin and you see where the foam has detached from the skin. This looks like a manufacturing problem as I dont think that water ingression would have affected the underside of the deck on one side of the boat while the boat has always been stored on a trailor in its normal position ( Cant be guaranteed of course ).



This next shot shows where I have ground out the cracks going right down to foam on the upper stress lines. The lower ones I have prepared as square holes ready to take the glass to build up the gap between the foam and skin. You can almost see the gap here.



Here is a close up showing clearly the structural problem. Once it has all been glassed, the intention is to fill to within 2-3 mm of the surface and then drop in some pre-made casts of the tread so that there will be a good coverage of non-slip tread where the repairs have been done. There will be a few stress lines, filled as normal, that will show, but that is acceptable to the owner

Ill be spreading the glass matting as far as possible under the skin covering as much area as possible. If other parts of the deck still flex and could cause this problem again then Ill consider cutting more holes in the skin and getting a wider coverage of infill.



Ill be there again tomorrow glassing up, will post some more pictures when I can.

[lazeyjack]

if you are going to grind out a crack, drill a 1/16" or 2 mm hole at the end of it, then fill, that way you will stop the crack spreading

[Kessica]

Originally Posted by lazeyjack

if you are going to grind out a crack, drill a 1/16" or 2 mm hole at the end of it, then fill, that way you will stop the crack spreading

Perhaps, but the best way to grind out a crack is to go beyond the crack in the fibre glass/gelcoat and remove the complete crack, both along the crack and beyond its depth. This way it will never go any further as there are no cracks left. Achieving a good bond with the new glass is paramount for a good repair which will be as good as the original if not better. Its also best to feather the edges too which also helps against new stress marks appearing. Which is the proper way of doing it

[lazeyjack]

Originally Posted by Kessica

Perhaps, but the best way to grind out a crack is to go beyond the crack in the fibre glass/gelcoat and remove the complete crack, both along the crack and beyond its depth. This way it will never go any further as there are no cracks left. Achieving a good bond with the new glass is paramount for a good repair which will be as good as the original if not better. Its also best to feather the edges too which also helps against new stress marks appearing. Which is the proper way of doing it

no, not perhaps!! it is basic engineering standard, sure you can take the crack right out BUT you will leave a sharp place(even though you can not see it) so drill a hole where you finish

[Kessica]

I use a smooth minature conical grinder which has a 5mm radius at the sharp end. This actually gives very smooth results. Using a sharper instrument which can pull itself through the thin skin and create an unwanted hole in my mind creates more problems than it solves, even if its an engineering standard.

A useful tip when using these to keep a good smooth surface after grinding is to use plenty of fine chalk dust on the stone. This prevents the stone from clogging and getting high spots which can cause additional stress to the working material. The resulting finish from grinding is exceptionally smooth, and a bonus from this method is that the stones life is extended as it harldy ever needs dressing. After grinding and cleaning with a good degreaser you can almost see your face in it.

The pictures I have posted are of the rough grind, they will be finished off tomorrow which will include feathering.

[lazeyjack]

ok thats fine)

[fiberglass jack]

dont over do it with the grinding u dont want a super smooth shiney finsh that you can see yourself in. u wont get a good bond and the new resin may lift, u should leave a 80 grit finsh so if i was you i would sand the area after you grind with some 80 or even 40 grit, the trick to this type of repair is to get the gelcoat to match with the old, try your best, if the new repair blends in well thats half the battle, nonskid repairs are the worst to do very hard to make them invisable, i have a job coming up very simalar to yours but instead of trying to patch the repair we will be resurfacing the deck with algrip makes the job go faster