Drilling cured epoxy?

Stellina

Stellina

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Is there a problem or something to watch out for if you drill cured epoxy? I'm going to use oversize holes for the studs of an anchor winch but the West System help pages seem to suggest leaving the studs in place and using a release agent rather than re-drilling.
 
If you are using studs (that is, threded right down) you can cast in epoxy. The release agent will allow you to unscrew the studs after the epoxy has set. Drawback is that you have to get them exactly right. If you are using through bolts then drill the normal clearance holes using the template that comes with the winch if it is new. I assume if you are needing to drill epoxy, you are making a cored deck solid in way of the fittings. Personally I would prefer through bolts as this allows you to fit a backing pad to the underside to spread the load.
 
It's not a cored deck; just that West System advise it as a stronger fastener. I am using through studs and a backing plate but I am unsure how to put the studs in place in the epoxy, apply loctite for the thread in the winch and get the winch base plate and winch in place. I guess the worst case if I screw it up would means extracting the bonded studs with heat.
 
Slightly confused here. Am I right in thinking that the studs are screwed into the base plate of the winch? In this case you will not be able to thread them into the epoxy. Therefore just drill a clearance hole as you would for a bolt or machine screw. Assume you have a nut and washer on the other end bearing on the backing plate. If this is the case then the use of epoxy is overkill. The key issue is to strengthen the deck area to spread the load and epoxy may be used to bond a pad on the underside of the deck. The use of epoxy as a fastening as described in Chapter 14 of the West manual is mostly for setting fastenings into wood or composite. If using through fastenings there is no need to use an epoxy plug, unless the panel is cored and the epoxy prevents crushing.

Hope this helps
 
Why are you using studs? Is it because you can't get access to the underside of the deck where you are bolting the anchor winch?

Assuming you can get access, and you say it isn't a deck with a balsa core, I see no advantage in drilling oversize holes and using any epoxy at all. If its a solid deck, drill the holes, and bolt the thing down on a suitable bedding compound with a suitable backing plate underneath. A Rolls Royce job would include bedding the backing plate onto an epoxy/fibre mix, but you'd get away without doing this on most decks and it would be a perfectly workmanlike job.

If you can't get access, then drilling holes into a solid base (hardwood or VERY thick GRP) and casting studs into the holes is a viable alternative. Professionals mount engines on studs put in engine bearers and winches onto cockpit coamings in this way. When I have done it, I have never bothered with releasing compound on the studs. If necessary you can unscrew them out relatively easily with a couple of nuts and a little heat.
 
Yes, the studs are screwed into the base of the winch; I've come to the same conclusion that oversizing the holes will be too difficult and will use epoxy to seal the wood first. I will also take oldsaltoz's advice about bonding the backing and base plate.
 
Even more confused now. Where is the wood? I assume this is on a GRP deck, in which case John's advice is good. Re-inforce the deck if necessary with a pad and bolt the winch down using a sealer. If the pad is wood or ply then epoxy it and bed it down in thickened epoxy. Do not use epoxy between the base plate of the winch and the deck as it will serve no purpose.
 
Sorry about the confusion, this might explain or make it worse... I am mounting an on-deck winch (Quick Genius) over a chain locker with a lid. The two rear studs and the wiring pass through a thickened shelf at the rear of the locker and into the forepeak space; thickened I reckon with ply but I won't know for sure until I drill it. This pad is not large enough for the windlass (and there is no chain chute) so the front two studs and the chain hole are in a thick ply base I have tailored to fit in the rear of the space over the open part of the locker. To keep these two parts of the base together I have a plate which will go under the winch. This will be bonded, rather than the winch base itself.
 
Thanks. Makes sense now. My only concern would be whether the extension to take the front of the winch is strong enough without being bonded to the front of the plinth. You might want to consider glassing (with epoxy and cloth) the extension to the vertical face of the plinth. Better still, triangulate it with a knee as well. Otherwise the whole load will be on the rear two studs. There are huge loads on a winch, particularly if you don't transfer the load, when anchored, to a cleat. I use a chain hook and a strop to a cleat.

Hope this helps.
 
Yes, although the extension is tailored to fit in the taper towards the bow in the locker (to wedge it in) I have an option afterwards to put a strut forwards to the roller base in the bow if it doesn't get enough support (or my tailoring job is not up to it.)
 
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