Filling and drilling holes using West System Epoxy

[Sid at SailAway]

My cat suffered some wind damage this winter on the Chesapeake. The binimi and framework were ripped off the boat by high winds. All the screws in the baseplates were basically ripped out of their holes. Fortunately, the frame was not bent.

My plan of attack was to oversize the holes to 1/4 inch. The holes as they are about an 1/8 inch. Number 8 selftappers came out. After that, I was going to take a bent rod and hog out some of the core to insure enough epoxy was introduced back in. Let it harden, pilot drill and then re-screw the frame back on.

I thought it was a good plan but wanted to get West Systems blessings on it. So, gave them a call and the tech told me the epoxy would be so hard that I wouldn't be able to screw the screws back in even with a pilot. I will be using 105 with the 205 hardener. I'm not buying it. Why wouldn't I be able to screw into the epoxy?

So, here's my question. Has anyone done this successfully? I would think this would be a common fix. Do I need to use a filler such as 404? If I hadn't called, I'd be fillin' and drillin' but he's got me scratching my head. What am I missing?

[rwidman]

Originally Posted by Sid at SailAway

My cat suffered some wind damage this winter on the Chesapeake. The binimi and framework were ripped off the boat by high winds. All the screws in the baseplates were basically ripped out of their holes. Fortunately, the frame was not bent.

My plan of attack was to oversize the holes to 1/4 inch. The holes as they are about an 1/8 inch. Number 8 selftappers came out. After that, I was going to take a bent rod and hog out some of the core to insure enough epoxy was introduced back in. Let it harden, pilot drill and then re-screw the frame back on.

I thought it was a good plan but wanted to get West Systems blessings on it. So, gave them a call and the tech told me the epoxy would be so hard that I wouldn't be able to screw the screws back in even with a pilot. I will be using 105 with the 205 hardener. I'm not buying it. Why wouldn't I be able to screw into the epoxy?

So, here's my question. Has anyone done this successfully? I would think this would be a common fix. Do I need to use a filler such as 404? If I hadn't called, I'd be fillin' and drillin' but he's got me scratching my head. What am I missing?

Take a piece of scrap wood, drill a hole in it, fill it with epoxy and let it cure, drill a pilot hole and see if you can drive the screw in. In other words, test your plan on a piece of scrap wood. You will have your answer.

[katsumi]

Hi Sid
Have you considered drill and tapping into the west system then use machine screws? I have done this in places where it is impossible to get a nut and bolt in place in the past and found it a much stronger option than self tappers. If you are in the US, I used a product called marine tex, which you can drill and tap, worked well. Use a little bit of 3M, 5200 between the fitting and structure as well for extra strength and leaks.

[boatman61]

Sid.. you need to make a paste with microballons or fibres if using WS..

[Stumble]

The problem is that epoxy isn't just hard it's brittle. It maybe possible to drill into it (it is absolutely possible) but screws don't hold very well. Much like trying to screw into a sheet of glass. It may be possible, but it's a terrible idea.

If you can get to the back side then thru bolting is always prefered. Though instead of using a bent piece of tubing I prefer to use a Forster bit to bore out the underside larger than the top hole and fill the entire plug with epoxy, then thru bolt into this.

If you cant get to the back side of the repair then make an epoxy plug from the top and tap the plug.

[John Boor]

Sid I have filled many holes on my rebuilt boat. What I did was drill a 3/8in hole through the top glass, I then inserted the 3/8in dremel circular cutter and drilled out the core sealed the lower small hole with tape then filled with epoxy, after hardening I drilled and tapped to the size I needed for the fastener.

John

[skipmac]

Of course you can drill a hole in West epoxy and you can put a screw into it with no problem. Have done it with dozens of holes in the decks of my boat.

BUT, as Boatman61 says, if you want to screw into it then add microballoons or some other filler.

AND as Stumble says, much better to through bolt if you can do so.

Forstner bit to enlarge the hole is good but not always an option. I use an old allen wrench to ream out the holes if the core is soft enough to do it.

[Greenhand]

You should use a filler to thicken the epoxy. We cheat and just use the Six-10 premixed, prethickened. However, we believe we have also through bolted everything we have drilled and filled so far.

[Cheechako]

Use a filler with fibers would be best, and drill and tap if you cant thru bolt. I pretty much Drill and Tap for all applications that cant be bolted.

[psneeld]

I' m thinking bolting rather than screws so it doesn't happen again. If no access, can access be made?

If access can't be made, how about blind fasteners?

More expensive but it may be worth it and you may not even have to fiddle with the holes.

[Weyalan]

Just add microballons to the epoxy until you get a consistency like, hmm, somewhere between molasses and toothpaste. This will harden up nicely and be drill-able and tap-able but not brittle nor over-hard

[MarkSF]

Originally Posted by Sid at SailAway

My cat suffered some wind damage this winter on the Chesapeake. The binimi and framework were ripped off the boat by high winds. All the screws in the baseplates were basically ripped out of their holes. Fortunately, the frame was not bent.

My plan of attack was to oversize the holes to 1/4 inch. The holes as they are about an 1/8 inch. Number 8 selftappers came out. After that, I was going to take a bent rod and hog out some of the core to insure enough epoxy was introduced back in. Let it harden, pilot drill and then re-screw the frame back on.

I thought it was a good plan but wanted to get West Systems blessings on it. So, gave them a call and the tech told me the epoxy would be so hard that I wouldn't be able to screw the screws back in even with a pilot. I will be using 105 with the 205 hardener. I'm not buying it. Why wouldn't I be able to screw into the epoxy?

So, here's my question. Has anyone done this successfully? I would think this would be a common fix. Do I need to use a filler such as 404? If I hadn't called, I'd be fillin' and drillin' but he's got me scratching my head. What am I missing?

Yes, I did exactly this, 2 days ago. West System's 105 with 206 hardener and colloidal silica additive. No problem.

[JeffBurright]

You might also consider a filler of wood flour, which is essentially fine sawdust. Coat the area with neat epoxy first to make sure the area is really sticky, then glom in a batch of thickened epoxy at around peanut butter consistency. It ought to drill and hold together nicely, and it sands down well too. I use this mixture when conducting cold molded hull repairs. Talcum powder (the main ingredient in baby powder) also makes a great fairing filler, but I don't know that I'd seat screws in it, just for uncertainty's sake. Good luck!

[Ziggy]

Originally Posted by katsumi

Hi Sid
Have you considered drill and tapping into the west system then use machine screws? I have done this in places where it is impossible to get a nut and bolt in place in the past and found it a much stronger option than self tappers. If you are in the US, I used a product called marine tex, which you can drill and tap, worked well. Use a little bit of 3M, 5200 between the fitting and structure as well for extra strength and leaks.

Yes, best would be to thru-bolt, but if that's not practical, mix in some colloidal silica (aka cabosil) into the epoxy as a filler, then drill and tap for machine screws.

[Terra Nova]

Do NOT use microballoons! This creates a very weak mixture that is easy to sand but has very little strength. Instead use colloidal silica and microfibers.

OP--your original installation was inferior. Through-bolt the mounting.