Filling deck hardware holes - thickened polyster?

I'm starting to remove/replace some of the deck hardware on either side of my companionway. New winches, new clutches and slightly different alignments due to larger winch drums. Etc.

Net of it is, I'll end up filling roughly 30 fastener holes.

I would "normally"
-- drill out the holes
-- ensure that there is clean surface (plywood) inside
-- slightly over-drill the underside
-- tape/seal the bottom of each hole
-- mix up a batch of WEST-system epoxy, thickened to about the consistency of mayonnaise
-- splooge it in there, making sure there are no bubbles or voids
-- when cured, sand/fair/etc.

In *this* case, though, I want to try to have the finished surfaces gelcoated to match as much as possible.
It's an area that will literally be right in front of my eyes every time I'm on the boat, and I want it to look nice. Or at least, not bug me.

I've talked to a gelcoat guy at the local yard, who can color-match it for me. I'm color-blind, so I *know* that's not the job for me.

But he mentioned that gelcoat won't bond with epoxy, so I need to fill the holes with thickened polyester resin instead of epoxy.

.... and I've been using epoxies so long I don't remember what thickening agents are good with polyester.

Old school, I'd buy a half-pound of 1/16" or 1/32" chopped glass strands and thicken to suit. But are there better thickening agents to use? Or is colloidal silica good with polyster? Can I use WEST 406 with polyester? Or... should I use something else?

Bruce

I'll be interested in the discussion.

I have a similar project, and a quick scan seems to suggest a school of thought saying no problem with gelcoat over epoxy.

http://epoxyworks.com/index.php/applying-polyester-gelcoat-over-epoxy/

I have recently used gelcoat over epoxy with no problem using the boatworks site as a back up reference and advice on this site.

https://www.boatworkstoday.com/videos/can-gelcoat-bond-with-epoxy/

My gelcoat over epoxy repair was an 1.5" hole in the toe rail. I posted the pictures recently on this site for advice. For numerous other smaller dings and gouges and small holes I used the 3M filler and the gelcoat on top. I'm still in the sanding and fairing process to make it look as finished as can be, but got side tracked with all kinds of other headaches. (But splash day is very soon).

I have has no problems using gelcoat over small repair except for colour matching. A tiny touch of brown and yellow with a white base seems to give a good match.

I used gelcoat over thickened West epoxy for approx. 50 bolt holes that were +/- 1/4 inch diameter with no problems. This was before I read the Evercoat gelcoat instructions in detail which say to NOT use the gelcoat over epoxy. I bought some polyester resin and drilled out the top of some of my West epoxy filled holes and refilled the top with polyester resin. I can't see any difference in any of the gelcoat fills.

I've since read both the linked articles on gelcoat over epoxy and believe that as long as you scrub and wash the amine blush with water from the cured epoxy fill in each hole your gelcoat will bond just fine. My last 18 filled holes were done with West epoxy. I still have to add the gelcoat.

Mark

Vinylester resin putty is compatible with polyester gelcoat...

1. To Interplastic VE8117 vinylester add Cab-O-Sil TS-720 (about 10% by weight) and stir until consistency is smooth and creamy. The vinylester resin putty can be mixed days before application.

2. To activate the vinylester resin putty add 1.0-1.5% (by weight) MEKP (Hi-Point 90 or Cadox L-50) and stir to mix.

3. After the activated vinylester resin putty has been applied and it has polymerized, activate polyester gelcoat (NPG ISO) by adding 1.0% (by weight) MEKP (Hi-Point 90 or Cadox L-50) and then stir to mix.

4. Apply the activated polyester gelcoat to the surface of the hardened vinylester resin putty. The activated polyester gelcoat can be applied to the vinylester resin putty days after it has polymerized.

Have all the deck hardware off, the holes cleaned out and ready to start prepping for glass. I plan to call WEST tomorrow to ask if their 406 filler can be used with polyester resin (and/or whether there's any issue getting gelcoat to bond with properly prepared epoxy...)

I found about 15 holes on the underside of each area that were not "thru" holes. Not sure if they once went through and were patched from above, or things were once screwed to the underside of the deck. Either way, they all got cleaned out and filled with at thickened paste of epoxy. Gosh I'd forgotten how much fun it is to work with a warm mix of goo, upside down.

I also found a couple of "bonus holes" hidden next to the pad for the double-clutch on the starboard side. They looked (?) from above like they'd been patched and gelcoated, but they were still wide-open from below. Turns out the 'patch' was a small plug of some sort of filler with gelcoat on top, essentially held in place by gravity, I think.

Here's a photo of the now-naked deck area...



Anyone see anything wrong in the photo? Hint - ALL of the fasteners for the deck-hardware were 1/4-20.

Yeah.

The hardware installed by "my" PO all had nice crisp 1/4" holes, drilled in the right places, and the fittings were neatly bedded with butyl. Easy-peasy.

The hardware installed by someone prior (probably the dealer) all had 5/16" holes, most of them crooked and/or oblong, filled with fossilized adhesive (probably 4200/5200), with the 1/4" fasteners effectively glued in place. Some of the fasteners had to be knocked out from below because they were so solidly "bedded" in place that they couldn't be spun out.

Bonus points for the teak risers, which were actually *glued* to the deck and had to be ...uh... "destructively remediated".

It occurred to me, several times, to be glad that I was no longer commissioning Ericson boats for the Newport Beach dealer by the time the 32-III came out. I would be compelled to track down original owners and deliver apologies if I had been responsible for hardware installations like that.

Bruce

PS - the discovery for the day is that a dremel #196 cutting head (https://www.dremel.com/en_US/products/-/show-product/accessories/196-7-32-high-speed-cutters) chucked up in a cordless drill and run at low speed does a great job of chewing out old adhesive and getting to clean fiberglass/plywood without enlarging the holes.