Installing deck hardware

[Guest]

Hi,

I am finally taking the plunge and buying some nice new shiny self tailing winches and I plant to position them so I can sheet in without having to leave the tiller. According to some books on the subject I should drill the holes seriously oversize, plug them with epoxy and then drill the correct size holes through this plug.

I seem to remember an article in PBO suggesting that the core material should be removed for the entire footprint of any new deck hardware.

Opinions, anyone?

Regards



Fred

 

[vyv_cox]

I assume you are talking about bolting right through a balsa or foam cored deck? If it's just GRP you only need to ensure that there are some decent load spreaders behind, like ply, aluminium plate or at the least, large washers. It also depends to some extent on how the load will be applied. A winch takes load in shear and large pads are not really needed, whereas turning blocks take vertical loads, in which case a large pad is essential. My genoa winches, seriously oversize, only have 1 inch washers beneath the bolts and there is no sign of any problem.

For a cored surface I would not drill a large hole right through, only through the inner skin and the core. If doing this on a decorative inner skin it's worth considering what will show inside. You can buy plastic caps, e.g. from DIY shops, that will cover holes of about 1 - 1.5 inch diameter. Drill the hole accordingly. Leave the outer skin intact. Then fill the hole with epoxy paste to a depth that the bolt heads or nuts will not protrude through below. Drill out for the shank when cured. Make up with the biggest washer that will fit inside and put on the plastic cap. I fitted my windlass like this very successfully.

If you have a cored surface where it does not show internally it could be worth cutting out a large area to fit a pad. I did this on my boat when I fitted beaching legs, using a Tufnol pad about 8 x 6 x 1 inch thick bonded to the hull with Sikaflex.

 

[Guest]

Hi,

> For a cored surface I would not drill a large hole right through, only through the inner skin and the core.

Hmmm.. and fill the void with a syringe loaded with epoxy?


I wonder if I can persuade my local adult education centre to run an evening course on GRP work and boat repair during the winter?

Regards



Ian

 

[John7]

Use a bent nail or something like it to clean out the filling if you have balsa wood. As much as you can get out so as to prevent compression of the two layers of fibreglass as well as add strenth. If you dont expect to have to remove the fitting you can epoxy it in place. But this will be as difficult to remove as using Sikaflex. If you are intending to remove it a sealant that is not also an adhesive, neoprene sheet cut for example.

 

[John7]

You do have to fill with epoxy, or it will not do much! I found making the hole larger than needed made it much easier to fill the void.

 

[kgi]

you cannot use epoxy on its own you must thickenit with something so it will bind together, raw epoxy will crack and splinter and on its own it is relatively soft keith

 

[oldsaltoz]

G’day twohapence.
Assuming you have balsa, foam or other composite in the area you plan to fit the winch, the following is the method I have used with no problems: -
1 Drill a small pilot hole through to the inside from outside first, then check that you have access from inside, if not, you can measure what clearance you require and fill the original pilot hole/s.
2 From inside, use a hole saw (Good quality only) and run it up the pilot hole, but do not cut the deck layer.
3 Remove the material from between the layers of GRP, you should also remove at least ½ an inch of material past the remaining edge of the lower / larger hole.
4 Place some tape over the top hole to stop filler getting squeezed out and paint the cut area with epoxy resin and when it’s tacky fill with epoxy mixed with fibres to a consistency that will not sag. Have some timber plugs handy made by cutting scraps with a hole saw that fit into the bottom hole, wrap them in glad wrap and push them into the hole far enough to finish the nut flush inside, secure them with more tape till cured, you can fit a cover over this later.
5 With the blocks removed, you can remove the tape from the deck and drill the required size holes and install the bolts (With sealant) and fit a large flat 316 s/steel washer, tighten and fit caps.

I hope this helps.

Andavagoodweekend Old Salt Oz.

 

[vyv_cox]

Not sure what you are saying/asking here. Don't use clear epoxy, use somthing you can trowel into the hole. I use some stuff used to repair concrete, it takes muscle to mix the two components but I can then fill any vertical hole from below and it is very strong in compression.

 

[Robin2]

A large volume of West System epoxy (eg 5cm diam by 1cm deep) will get VERY hot while curing - enough to melt a plastic mixing beaker.

If you want to fill a large space it would probably be advisable to do it is stages - but don't let the first layer cure fully before applying the next - see the West System literature or web site.

 

[Guest]

Hi,

Great advice so far, thanks. I went out and bought some west system filler and hardner and some colloidal silica. Now I'm even more puzzled than before. After hunting high and low I can't tell whether the west epoxy is air inhibited or not.

It isn't going to matter for fitting the winches but I plan to repair a deck hatch while I am mixing. If it isn't air inhibited then fine, if it is then the repair will need to be covered.

Regards


Fred

 

[Robin2]

See it all on www.westsystem.com

If by "air inhibited" you mean that it needs air to cure - I don't believe it does - just mix and stand back - this advice is based on consuming about 200kg of the stuff.