First couple of chain plates almost finished. Just a bit more cleaning up and polishing to do.

I went with 30x5 bar. This is what my rigger would have used if I'd got him to make the chain plates. Yield strength of one of these is about 2500 kgs.

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Microbe said..
First couple of chain plates almost finished. Just a bit more cleaning up and polishing to do.

I went with 30x5 bar. This is what my rigger would have used if I'd got him to make the chain plates. Yield strength of one of these is about 2500 kgs.

Looks great how did you work out the bend ?

They looks tops.

Old vs new

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Microbe said..
First couple of chain plates almost finished. Just a bit more cleaning up and polishing to do.

I went with 30x5 bar. This is what my rigger would have used if I'd got him to make the chain plates. Yield strength of one of these is about 2500 kgs.

That's what I made mine from as well, reinforced with 4 more layers of glass on the inside and used 30x3mm for inside backing plates. Now they also come in handy when taking the boat off the trailer with the engine cranes.

Started working on the deck (the original topic of this thread!). I wanted to at least tackle the area where the new chain plates are going. I suspected there would some rot in the core so cut a section out of the top of the laminate. I was right - the ply was totally rotten.

The photo shows my initial investigation section, but I'm going to take that right out to the toe rail and about 200mm further fore and aft to take out the entire section of ply.

Once that is removed I can epoxy in a new slab of ply and replace the top layer of laminate.

I would suggest when you replace that ply that you have a raised area under the stanchion base. Something like 6 mm or so so that water will not pool at the base.

So, after a bit of a hiatus from boat work because of a sore back I finally managed to epoxy in the bulkheads today. For now its just thickened epoxy between mating surfaces and a bit of a fillet down the edge. Next step will be glass tape layers between bulkhead and hull.

Originally I was planning a bulkhead with timber packing either side to space out the two chainplates by the required 80mm. This would have required me to put the plates on shared 8x100mm bolts. I ended up going with a double bulkhead with a spacer in between, strongly epoxied together. This will allow me to put the plates on their own bolts and spread the load from the bulkheads out on the hull.

Note that the inside surfaces of the bulkheads had to be epoxy coated and painted with two pack paint before being bonded together. The outside will be coated and painted in situ.

That looks excellent, it's not going anywhere.

I need to replace a non structural bulkhead in my boat and was thinking of using this thermo-lite stuff. See link below.

if anyone has used this stuff let me know.
I may in the future also replace the main bulkhead but that is well down the road. Maybe some furniture as well.

www.diycaravans.com.au/shop/thermo-lite-tough-composite-boards/

jbarnes - the thermolite looks good, but I don't know much about foam cores. You might want to find another supplier though - the link you sent says a minimum order of four 1.2x2.4 sheets. They would need to be massive bulkheads to require that much material!

But whilst we are on the subject of core material I'm considering using a pvc core material to replace the rotten ply in my deck. Something like this:

compositeswarehouse.com.au/products/composite-cores/

I'm planning to cut off the top glass lamination, dig out the rotten ply and clean up the bottom layer of glass, then bed in the new core with epoxy and put the old top section back on.

What would I use to glue this sandwich together? I'm thinking epoxy thickened with glass powder. Any thoughts?

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jbarnes85 said..
I need to replace a non structural bulkhead in my boat and was thinking of using this thermo-lite stuff. See link below.

if anyone has used this stuff let me know.
I may in the future also replace the main bulkhead but that is well down the road. Maybe some furniture as well.

www.diycaravans.com.au/shop/thermo-lite-tough-composite-boards/

I have no experience with Thermo-Lite, but was watching the latest video from Free Range Sailing last night, and they have been using it for 6mm deck pads and the like. I think they cut theirs out of the back of an old solar panel. Its rigid stuff.

-gjjQ

PS If you live anywhere near Springfield in QLD, there will be a massive heap of damaged solar panels somewhere, following the hail storm a few weeks ago.

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Microbe said..
jbarnes - the thermolite looks good, but I don't know much about foam cores. You might want to find another supplier though - the link you sent says a minimum order of four 1.2x2.4 sheets. They would need to be massive bulkheads to require that much material!

But whilst we are on the subject of core material I'm considering using a pvc core material to replace the rotten ply in my deck. Something like this:

compositeswarehouse.com.au/products/composite-cores/

I'm planning to cut off the top glass lamination, dig out the rotten ply and clean up the bottom layer of glass, then bed in the new core with epoxy and put the old top section back on.

What would I use to glue this sandwich together? I'm thinking epoxy thickened with glass powder. Any thoughts?

You might want to test it first. The PVC might not stick with the glass. Not sure if thats a problem or not but they layers might move as the boat flexes.

you could maybe just do a whole bunch of layers of glass if it's small areas. there might be better people than me to comment

the other thing I thought about was fibreglass panels or carbon panels to use as backing plates. www.ebay.com.au/itm/324313781962

www.ebay.com.au/itm/Green-Glass-Fibre-Sheet-FR4-Epoxy-Fibreglass-Plate-Sheet-3-6mm-Thick-200-200mm-/133384127345?_trksid=p2349624.m46890.l49292

Interesting thoughts there. To comment on Microbe's SS22 local to the chain plates deck repair only;

Imho it is far better to stay with the plywood core and glass each side lay-up as per the original. To introduce a foam core sandwich panel into this localised area for a 70s built boat with a glassed ply deck is not wise imho and won't work.

Leaving aside the glass layers each side for the moment, the ply core and foam core materials on their own have vastly different properties in bending, tensile and shear strengths, and stiffness in all these three. So placing foam core into the routed out rotted ply will immediately created strength and stiffness mismatches in all these. Even if the foam is bonded well to the underneath original polyester glass layer left in tact, with epoxy resin maybe fortified to glue strength with filler, the perimeter bond would be subject to question as regards strength of the ply edge to foam edge bond. Then the top grp laminate needs to be added to fill the void - epoxy resin based suggested - and then more laminate to create continuity with the existing polyester laminate - say at least 50mm overlap all round.

So I am not talking about the merits of foam cored deck construction versus ply with each sandwich panel having glass each side - I am only talking about repairing a 70s built ply deck with glass each side, with a foam cored insert. I would never contemplate this.

So imho suggest cut out and chase out all the rotted ply, taper it at least 4:1 from the inner glass layer to the outer upper glass layer, epoxy glue in new marine ply with the at least 4:1 taper, laminate top layer of glass fabric with epoxy resin - firstly to fill the void of the ground out initial area, then add more epoxy laminate so that the added top laminate overlaps the void in at least 2 glass pieces tapering outwards, and leaves the location where the chain plates pierce through higher than the surrounding deck so as to avoid a ponding issue as per Ramona previously. Added overlap laminate at least as thick as initial deck laminate on top of the ply.

I have used the International HT9000 epoxy resin and associated fillers for many similar laminating and gluing projects in the past and can recommend it.

Thanks for the suggestions. I had been thinking about PVC core to remove the chance of rot in the future, but hadn't considered the difference in strength and flexibility. Marine ply will be cheaper and easier to find, so I'm happy to use that.


The deck is only partially cored. The core was added as reinforcement in high load areas. There is a section the full width of the deck around the chainplates and a thinner section running fore and aft from there. I will remove the whole chainplate section core ply (about 300x700) and replace with new ply. I'll feel happier knowing I've definitely got out all the rot and solved delamination issues.

Having done this there will be no need to taper or scarfe the new ply in to the old, so no edge bonding issues.

Thanks for your detailed reply r13, I like the idea of building up a new top laminate rather than reusing the old. More work, but a better repair.

Pvc core rots just as much as ply if water gets in. Probably worst as the core takes up water the pvc gets soggy!.

Thanks Microbe.

As regards pvc core rotting - there are many types of pvc core materials and just as with end grain balsa cores the lamination of the inner and outer skins to the core is the key........effusive article here spruiking end grain balsa

www.yachtsurvey.com/core_materials.htm

and a forum here

forums.sailinganarchy.com/index.php?/topic/155138-longevity-of-foam-cores/

Divinycell if done well during the initial build, and not tampered with after, is a top shelf core.

blog-fgci.com/tag/divinycell/

Gurit work in all cores;

www.gurit.com/Our-Business/Industries--Markets/Marine/Case-studies

Finally some progress after holidays, a string of bad weather and a sinking dinghy that needed to be repaired.

I managed to cut out the old ply and bed in a new ply core on a bed of thickened epoxy.

I pre-wet the ply and the old glass with unthickened epoxy, then spread a bead of thickened epoxy then temporarily screwed the ply in place until the glue dries.

The big holes in the ply are where the chainplates will pass through. I'm going to fill the holes with epoxy and then cut the correct through deck holes. This way there will be no ply exposed to any water ingress.

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Zzzzzz said..

Microbe said..
First couple of chain plates almost finished. Just a bit more cleaning up and polishing to do.

I went with 30x5 bar. This is what my rigger would have used if I'd got him to make the chain plates. Yield strength of one of these is about 2500 kgs.

Looks great how did you work out the bend ?

Hi Microbe.
Could you tell us how you bent the chain plates?

Select to expand quote

Bundeenabuoy said..

Zzzzzz said..

Microbe said..
First couple of chain plates almost finished. Just a bit more cleaning up and polishing to do.

I went with 30x5 bar. This is what my rigger would have used if I'd got him to make the chain plates. Yield strength of one of these is about 2500 kgs.

Looks great how did you work out the bend ?

Hi Microbe.
Could you tell us how you bent the chain plates?

I didn't need to bend the chainplates - they are just flat bar. The camera might be making them look like they are curved I guess.

With the chainplate extender/wobble stoppers I need to have a 90 degree twist in them. I did that by clamping the bar in the vice and then using some mole grips to apply brute force. Seems to have worked out OK. These are just temporary until I learn how to mill some out of round bar.

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Microbe said..
Finally some progress after holidays, a string of bad weather and a sinking dinghy that needed to be repaired.

I managed to cut out the old ply and bed in a new ply core on a bed of thickened epoxy.

Nice work. Looks like your using Microballoons as a filler which will work pretty well. I'm using the same as a fairing filler on my plywood deck repair. It sands easily and leaves a good finish.
www.ebay.com.au/itm/Microballoons-Lightweight-Phenolic-Filler-5-Litre-FREE-FREIGHT/141092454271?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649

For glueing and seriously strong filler, I'm using Aerosil with epoxy. This makes a very strong glue and a tough filler that has to be ground with a 36 grit disc in a grinder. It is dangerous though and it's best to avoid the dust. It does not slump and is good for overhead fillets.

www.ebay.com.au/itm/Aerosil-Filler-for-Polyester-Epoxy-Resins-5Lt-FREE-FREIGHT/131022059016?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649

For other glueing stuff I'm using Selleys Durobond and Selleys exterior PVA. I have a sneaking suspicion that the Durobond maybe a stronger joint than epoxy and Aerosil mix. I have made a test panel with the 3 types of glue and will test to destruction in a few days.

I also use the galvanised self tappers to hold the job while the glue sets. Next day remove the screws and fill the holes with epoxy and filler.

Thanks Ramona, I'm using boat cote epoxy with their fillet and glue powder. It sets very strong and is a bit hard to sand.

To avoid spreading dust everywhere I wet sand by hand. Machines like belt sanders get the job done quickly but throw fine dust over everything.

A sanding block with a cut off piece of a 40 grit fabric sanding belt works well and leaves behind a slurry that can be wiped up with a cloth. Much more elbow grease though.

Select to expand quote

Ramona said..

Microbe said..
Finally some progress after holidays, a string of bad weather and a sinking dinghy that needed to be repaired.

I managed to cut out the old ply and bed in a new ply core on a bed of thickened epoxy.

Nice work. Looks like your using Microballoons as a filler which will work pretty well. I'm using the same as a fairing filler on my plywood deck repair. It sands easily and leaves a good finish.
www.ebay.com.au/itm/Microballoons-Lightweight-Phenolic-Filler-5-Litre-FREE-FREIGHT/141092454271?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649

For glueing and seriously strong filler, I'm using Aerosil with epoxy. This makes a very strong glue and a tough filler that has to be ground with a 36 grit disc in a grinder. It is dangerous though and it's best to avoid the dust. It does not slump and is good for overhead fillets.

www.ebay.com.au/itm/Aerosil-Filler-for-Polyester-Epoxy-Resins-5Lt-FREE-FREIGHT/131022059016?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649

For other glueing stuff I'm using Selleys Durobond and Selleys exterior PVA. I have a sneaking suspicion that the Durobond maybe a stronger joint than epoxy and Aerosil mix. I have made a test panel with the 3 types of glue and will test to destruction in a few days.

I also use the galvanised self tappers to hold the job while the glue sets. Next day remove the screws and fill the holes with epoxy and filler.

That Aerosil looks like fumed silica to me or cabosil. I bought some from this place. I am pretty sure the 250g bag at $9 was about 5L making it very cheap. Very hard stuff.

trojanfibreglass.com.au/product/fumed-silica/

Someone should start a DIY boat hacks page. I am pretty sure half the paints are just house paints but many times more expensive.

Someone told me the bilge paint is just concrete paint.

Fumed silica aka cabosil etc is a good laminating epoxy filler as it absorbs the resin so is less likely to be squeezed out of tight joins for less accurate joinery or big fillets glue powders like chopped glass are good, and a mongrel to sand to save some pain I brush the fillet with un thickened epoxy before it sets hard to smooth it

Getting closer...

Have covered the ply core with three layers of 420gsm glass saturated in epoxy and then a few layers of epoxy/silica powder mix to bring it level with the deck.

More progress. Got the deck primed and gloss applied around the chain plate area. Have fitted the chainplates, so this is where I'm at (see photos). Looking forward to standing up the mast. Still a lot to do, but mostly cosmetic.

That looks sublime and better than new, well done all round. You must be pleased with the result and looking forward to getting back out sailing.

Finally I got the mast raised today so I'm back to where I was 5 months ago, albeit with new rigging and a firm new section of deck. I was pretty pleased that the shrouds and stays all fitted perfectly, as I'd had them made up by a rigger onshore who had never seen the boat, and I'd changed the chainplates too. I can't believe the mast lift went so smoothly. I'm still waiting for something to go wrong - I am accumulating 'temporary work arounds' though which need effort to rectify asap. Things like using a bolt when I didn't have the right size rigging pin... ok for holding the mast up on the mooring, but will need to be sorted before sailing.

Super result. It went so well due to your planning and efforts including having a plan b for bolts to use temporarily for rigging pins.