Deck/Shroud Fixing/Fibreglass repair.

[davidpbo]

How would you repair this:

Some years ago (2004) I think I tightened the shrouds and the deck lifted (not quite so pronounced on other side) We effected a repair by fixing 4 heavy duty stainless angle inside the boat to the knee between the upper and lower shroud fixings (Which were u bolts with their standard backing plate originally)

The face fitted to the knee had a couple of large holes drilled in the angle. Epoxy-woven mat (probably one ot two layers) was applied to the knee, the angle was fixed whilst it was still wet so epoxy etc. would have been pushed into the holes. The angle was screwed with smallish screws to the knee to hold it in place and more epoxy and woven mat was applies over the top.

Epoxy was applied to the top of the knee and the u bolts through the angle used to pull the deck back down. I think I also epoxied some mat over the join between deck and knee.

All in all I felt a good strong repair and an improvement on what was there before. I ground out and filled the cracks with gel coat filler and have kept on eye on it since but it was not the neatest or repairs.

I am not aware of any further movement or cracking and some exploratory poking and drilling a few years back did not show any apparent water leakage into the deck filling. I am presuming this is wood or solid core around the shroud fixings. I think it balsa for the rest of the sandwich.

What would forumites suggest as method of repairing the decks?

I am tempted to mark out a square and remove the fibreglass and see what has happened underneath, however I feel that the main support for the mast is on the angle and knee (which goes some way down the side of the hull boat) and that what needs to be done in mainly cosmetic, in which case maybe a square of stainless to cover the damaged area or strip the fibreglass off and build up several layers of mat with a gel coat finish.

I don't think I could replicate the finish of the deck so would have to accept a flat finish around the shrouds.

Feasible or not?

 

[lw395]

I would only take off the cracked gelcoat in a small area, repair any cracks in the grp and build up with glass cloth and epoxy if necessary.
Provided the connection to the knee is strong, and water is not getting into the deck, the rest is mostly cosmetic.
I don't think most amateurs will be able to make it look 'as new', so go for making it look sorted and stronger than new.

 

[davidpbo]

Yes, I was only talking about taking off the gelcoat/fibreglass over the damaged areas, probably about 300mm square, I would do the same on both sides so they matched.

Suggestions as to how to remove it with miminal dust? boat shares barn with caravans, motorbikes etc. I was thinking mark out and shallow cut the edge to depth of fibreglass with a mulitool then carefully chisel.

 

[lw395]

If you have power, rigging up a vacuum cleaner should get 99% of the dust.
I would try to make the area smaller still if poss.

 

[davidpbo]

The square would be the minimum size to ecompass the cracks.

I am also a little concerned as to how to remove the u bolts as they may have epoxy on the threads.

 

[lw395]

The square would be the minimum size to ecompass the cracks.

I am also a little concerned as to how to remove the u bolts as they may have epoxy on the threads.

Heat the Ubolts to around 100deg and the epoxy will soften locally.
You could do that with a blowlamp if you cobble together some sort of heat shield around the grp.
Or a big old fashioned soldering iron on the nuts. Maybe get a cheap socket and heat it up?

 

[saltylegs]

Hi I had a similar problem but luckily my deck was not textured, some of the deck is balsa cored but around the shrouds and high load fittings it is ply cored.
Water was able to enter down by the chain plates and this caused the ply to swell and raise the deck around the chain plates cracking it.
I took a couple of core samples from the under side to prove this, I then cut away the top skin of the deck and replaced the soggy ply with new and epoxy filler, chamfered the edges and laid up a new top skin and painted, but as I said I do not have a textured deck.
Some photos here. http://s1143.photobucket.com/albums/n630/saltylegs/

on the second page I think.

 

[oldsaltoz]

The square would be the minimum size to ecompass the cracks.

I am also a little concerned as to how to remove the u bolts as they may have epoxy on the threads.

Apply some heat, I have used a large soldering iron and a mini gas flame with good results.

 

[oldsaltoz]

How would you repair this:

What would forumites suggest as method of repairing the decks?

I am tempted to mark out a square and remove the fibreglass and see what has happened underneath, however I feel that the main support for the mast is on the angle and knee (which goes some way down the side of the hull boat) and that what needs to be done in mainly cosmetic, in which case maybe a square of stainless to cover the damaged area or strip the fibreglass off and build up several layers of mat with a gel coat finish.

I don't think I could replicate the finish of the deck so would have to accept a flat finish around the shrouds.

Feasible or not?

The simple way is treat the area and rather than even try to replicate the original finish, simply cover the area with an industrial grade non slip pad.

They can be cut to any shape or size, can almost any colour and last for many years and cost a fraction of that needed to replicate the original finish.

Good luck and fair winds.

 

[TQA]

Making a mould with some silicone is not difficult.

Find a good piece of deck, make a dam with plasticine, paint deck with mould release, spray was will do, pour in some moulding silicone. [ Silicone sealer will do at a pinch.

Use mould to replicate deck pattern.

 

[davidpbo]

Thank you everyone for the comments.

Saltylegs that looks like a bit of a project, I could not find a date on the photos to see whether it is finished. Kave you finished?

How did you remove the fibreglass to get to the wood by the shrouds?

Did you consider fitting a plate around the shroud fixings that couold be bedded down on Sikaflex or similar to stop future water ingress?

I have considered trying to match the texture but don't think it is feasible for me or a professional for that matter. What I would like to end up with is a nice smooth square the colour of which is similar to the surrounding. If that looks too bad the option of covering it with a non slip pad as suggested by Oldsaltoz may come into play.

 

[maby]

Making a mould with some silicone is not difficult.

Find a good piece of deck, make a dam with plasticine, paint deck with mould release, spray was will do, pour in some moulding silicone. [ Silicone sealer will do at a pinch.

Use mould to replicate deck pattern.

I watched a professional gel coat repairer do this and the results are fantastic if you take just a little care!

 

[saltylegs]

Thank you everyone for the comments.

Saltylegs that looks like a bit of a project, I could not find a date on the photos to see whether it is finished. Kave you finished?

How did you remove the fibreglass to get to the wood by the shrouds?

Did you consider fitting a plate around the shroud fixings that couold be bedded down on Sikaflex or similar to stop future water ingress?

I have considered trying to match the texture but don't think it is feasible for me or a professional for that matter. What I would like to end up with is a nice smooth square the colour of which is similar to the surrounding. If that looks too bad the option of covering it with a non slip pad as suggested by Oldsaltoz may come into play.

Hi David, boats are never finished but that was all over the winter 2010 / 2011, spray hood and heater going in this week.
I cut with a 4" diamond disc but any stone cutting disc is fine as you need to chamfer the edges to relay the skin.
I started close around the chainplates cutting only to the depth of the inner core and the top skin lifted off easily, I then gradually increased the width of the opening to get back to dry core, in my case it was just the ply that was wet as the filler seemed to have stopped the water getting to the balsa.
There is a cover plate on the deck which was part of the problem as it was screwed to the deck and only sealed with silicon, I refitted with sikaflex and no screws and no leaks so far.
best of luck.

 

[davidpbo]

I have now opened up the deck around the port shroud fixings and removed the rotten balsa.

I have also removed the backing block and U bolts which came out relatively easily.

I intend to repair this using a ply backing plate to the size of the newly excavated area, actually it will be larger as I have dug out under the cabin wall to solid fibrglass and removed a small section of the cabin roof to get back to firm balsa. I would still like to know what moisture readings I should be looking for the wood I have gone back to is <20%. I will probably take some readings of balsa core elsewhere on the boat.

Can people suggest some good modern books on fibreglass repairs please?

I am fairly confident with fixing the wood and building up, it is just what to do with the final layer/gel coat or whatever I use.

More pictures here

 

[oldsaltoz]

Can people suggest some good modern books on fibreglass repairs please?

I am fairly confident with fixing the wood and building up, it is just what to do with the final layer/gel coat or whatever I use.

Hi David,

I assume you will be using an epoxy based resin?

It's a good practice to drill 6 mm holes through the ply backing sheet om a 50mm grid pattern, this method ensures good contact with no trapped air behind it.
Adding Micro-fibres to the resin will ensure good strength and adhesion as well.
Glassing is made a lot easier if you have well rounded corners and edges, you can use the resin and micro-fibres to fill and internal corners and the area the balsa was filling.
For best strength yo need a ration of one part mixed resin to one part cloth, so lots of rolling is not only good makes it cheaper and stronger.
Use latex gloves and put on two pairs, so that if things start getting a bit sticky, tear one off and keep going. Only mix resin in shallow wide containers to avoid exothermic heating, one litre ice cream containers are great.
Always wash down BEFORE sanding or you will end up just spreading contaminants.
Allow a minimum of 24 hours for curing, and even then do a thumb nail check, if you can make a mark it's not fully cured.
Temperature should be above 20*c and humidity below 73%, this means starting mid morning and finishing mid afternoon.

Good luck and fair winds.

 

[davidpbo]

Thanks for the advice, I have also come across this West System info sheet
Fibre Glass Boat Repairs

I intend to use marine ply as the core, the area is not much bigger than the backing pad required anyway, does that seem sensible?

I have some SP epoxy bought some years ago and some gelcoat. It has been stored in a detached unheated garage. Is this usable, should I do some tests with it or just dispose of it?

The moisture content of this small sample of core which I removed yesterday has dropped from 19% to 12%
overnight.

If I was to use a polyester resin as opposed to epoxy would I then be able to add gelcoat as the final coat and sand and fair it? Am I right in thinking Gel coat will not bond to epoxy? I am still looking into final finish.

 

[cimo]

If I was to use a polyester resin as opposed to epoxy would I then be able to add gelcoat as the final coat and sand and fair it? Am I right in thinking Gel coat will not bond to epoxy? I am still looking into final finish.

correct.
you also asked for book recommendations earlier.
I can recommend Don Caseys well illustrated guide.
http://www.amazon.com/Sailboat-Hull...41344655&sr=1-1&keywords=hull+and+deck+repair

(All you'll need to know, although I believe there is a newer edition to the one I linked here).

rgds
c

 

[davidpbo]

Thank you, I also found the West System guides quite informative, obviously geared towards their products.

 

[davidpbo]

Yesterday I bought the resin etc. to effect the repair.

The gent in the shop said I could using Plastic Padding Gelcoat repairer as the gel coat is this correct? I need to cover an area approx. 350mm by 200mm, presumably by applying it then sanding. Can I ?

I didn't buy it as I think it is not liquid enough, I would be adding on top of the epoxy rather than using a mould

Other suggestions were Toplac and an epoxy colourer which is added to the epoxy.

I actually bought the epoxy colourer thinking that I can use that for the time being and sort out the final finish after. Can I leave the finish for a while or does it all have to be applied together?

Firstly the colourer is West Systems the epoxy I have is SP, is that likely to cause a problem?

Has anyone used it?

Do I need to put something else on top to

waterproof? I think not, it is epoxy

prevent UV degradation (During this summer, Cumbria).

Can I use West system coloidal silica to thicken the epoxy to a suitable consistensy to glue and fill voids, core (proably marine ply) to existing fibreglass? Are fillings from one manufacturer compatible with epoxy from another?

The original filling is a greeny grey colour so they maybe used something a bit more like filleting compound but I only have a small area to repair and don't want to end up with a lot of materials left over that I won't use but on the other hand want to do the repair right.

Should I be OK using Marine ply for the core for the whole of the repair which goes under the deck (accessed from the cabin about 1/3 as much again. Marine ply I would have to buy. I also have Brazilian mahogany in the garage minimum 25 yrs old. could I use that? That would save buying anything.

Does epoxy bond to it OK?

 

[oldsaltoz]

Yesterday I bought the resin etc. to effect the repair.

The gent in the shop said I could using Plastic Padding Gelcoat repairer as the gel coat is this correct? I need to cover an area approx. 350mm by 200mm, presumably by applying it then sanding. Can I ?

I didn't buy it as I think it is not liquid enough, I would be adding on top of the epoxy rather than using a mould

Other suggestions were Toplac and an epoxy colourer which is added to the epoxy.

I actually bought the epoxy colourer thinking that I can use that for the time being and sort out the final finish after. Can I leave the finish for a while or does it all have to be applied together?

Firstly the colourer is West Systems the epoxy I have is SP, is that likely to cause a problem?

Should be no problem at all.

Has anyone used it?

Do I need to put something else on top to

waterproof? I think not, it is epoxy

There are few products more wter or chemical proof than epoxy so no you don't

prevent UV degradation (During this summer, Cumbria).

Can I use West system coloidal silica to thicken the epoxy to a suitable consistensy to glue and fill voids, core (proably marine ply) to existing fibreglass? Are fillings from one manufacturer compatible with epoxy from another?

Silica will only thicken the resin, adding Micro-fibres will do the same thing but be a lot stronger as a glue and more rigid.
You could also chop up some cloth to make it thicker and stronger.

The original filling is a greeny grey colour so they maybe used something a bit more like filleting compound but I only have a small area to repair and don't want to end up with a lot of materials left over that I won't use but on the other hand want to do the repair right.

Should I be OK using Marine ply for the core for the whole of the repair which goes under the deck (accessed from the cabin about 1/3 as much again. Marine ply I would have to buy. I also have Brazilian mahogany in the garage minimum 25 yrs old. could I use that? That would save buying anything.

Does epoxy bond to it OK?

The old Mahogany should be fine, but will need several coats of epoxy resin (wet on tacky to avaid sanding between coats) make sure you lots into the end grain edges and round them off before wetting.

Good luck and fair winds.