To dowel a hole or not?

Today I have started the process of filling screw holes on our deck that are left over from floor covers installed by a previous owner. I am going to use West Systems Six Ten to fill the lower part of the hole, the Marine Tex or a dab of gelcoat to make it white. Should I just use straight epoxy or drop a small piece of dowel rod in there to fill the major part of the void?

Thanks.
Tom-

I would forget the dowel and use thickened epoxy in this case.

jleonard said:

I would forget the dowel and use thickened epoxy in this case.

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I agree. The dowel would just be something else to rot.

Drake said:

I agree. The dowel would just be something else to rot.

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Thanks you guys!!! After starting in on the project, I kinda thought the same thing, however, my thought process was more about two dissimilar materials expanding and contracting at different rates and breaking loose the bond to the surrounding core material.

Epoxy only it is.

Tom,
If you use thickened epoxy, you will need patience and good technique with a toothpick to "burp" the air bubble out of the bottom of the hole (assuming they are blind holes).

If that doesn't work try a syringe with a tube-needle to fill the holes from the bottom up, but those don't work with the high viscosity of thickened epoxy, you'll have to try it without fillers.

GoneFarrell said:

Tom,
If you use thickened epoxy, you will need patience and good technique with a toothpick to "burp" the air bubble out of the bottom of the hole (assuming they are blind holes).

If that doesn't work try a syringe with a tube-needle to fill the holes from the bottom up, but those don't work with the high viscosity of thickened epoxy, you'll have to try it without fillers.

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That is pretty much the plan. (I hope)

Make sure that whatever you fill the hole with and whatever you use to make the repair white are compatible.

Place a strip of masking tape with a hole punched in it over the screw hole. Any mess will be easier to clean.

Use west system 404 adhesive filler. It will end up being fairly white, so you may not need anything other than this. I would also suggest getting some west system syringes to carefully fill the holes. If you do it right, this may be a simple job.

Finally, and this is a bit tricky, but if you go after the filled hole with a rag wetted with denatured alcohol, you can "shape" half cured epoxy and flatten it. If you use MEK you can take down a bit of excess epoxy.

I've used hypo syringes, larger ones 30ml on up, even with fillers. Yes you will have to push hard and you will use a few hypos but they can be cleaned with acetone if done before the stuff stiffens too much.

The needle need not always be used. Carefull checking of various flex. tubings should net one that will jam into the Luer lock on the hypo end. That tube can then be fed into the hole bottom and then lifted as you fill the hole so the air is excluded as you go.

Sometimes I have shot some unthickened epoxy into the hole allowing it to soak into the core for a few minutes before sucking it out and then shooting in the thickened material.

Some of the blue 3m 2090 tape has helped limit the mess around the hole. The epoxy does not seem to weld itself too badly to the tape.

A good way to mask holes is to tape over and hit it briefly with a counter sink bit.
Cuts the tape and breaks any sharp edge on the hole.

Are these through holes, that is, open to whatever's below? Are we talking about repairs to a cored structure where the core is exposed within the bore of the hole?

If it's a through hole then the epoxy dripping onto whatever is below might be undesirable. A dowel would stop the drip; coat the hole, coat the dowel and knock it down below the upper thickness of 'glass. Fill the remaining hole with thickened epoxy either shy or flush having considered how hard you want to work to patch the gelcoat.

If it's just a hole into the core, then the dowel could be considered solely to save you some epoxy; proceed as above.

If it's just a hole into the core, then fill it with thickened epoxy and get on with the surface repair. Poking the epoxy with a bit of wire, toothpick or similar is necessary to pop the inevitable air bubbles.

As has been mentioned before elsewhere, be sure you've got the bore clean and the shattered gelcoat removed. Drill it out a smidge and use a countersink.

I would just caution to use the correct thickening agent. I filled a bunch of deck holes on my sailboat with West System and filler. I don't recall the filler I used (other then it wasn't a light weight filler nor was it colloidal silica...but after a few years in the sun I guess, they had shrunk just a little and was separating on one side of the hole.

I wish I could be more specific, just a caution to make sure you do it correctly

So at the end of the day, I stuck with my original plan. The holes were blind and into a cored deck floor. After dirring out the threads and tapering the top of the hole, I filled the holes as best as I could with the Six Ten, poked it around the inside of the holes with mechanic’s wire, cut a dowel below flush, then added more Six Ten. Once I got started, it really looked and felt right. In fact, I started without and went back and added the dowel. I plan on tapering one more time with a countersink, then add Marine Tex white to level it off with the deck. All I need to do is stop the water and this should do it. As long as it is white, they should disappear from eye-level. It should’t be a problem and I will watch it for a while.

Thanks for your input yall.