Bushed Holes

[Don Silsbe]

These have been a source of irritation with me for years.  They are an awesome thing to have, but a miserable thing to make.  At least for me.  It seems that every time I attempt to make them, half the epoxy drizzles out onto the floor.  I can show you the puddles.  Does anyone have an effective way of sealing the underside, when pouring in the neat epoxy?

[Captain Tim]

Secure a block of wood with packing tape on it under the hole. The tape keeps the epoxy from sticking

[Mike Vacanti]

I just use blue masking tape well burnished to ensure leakproof contact. The adhesive side of the tape releases reliably from the epoxy.

[Don Silsbe]

My latest fiasco was with sprits.  The curved surfaces were a problem.  Next time, I’ll try extra rubbing/burnishing to get a better contact.  In the past, my tape has released.
Any other tips?

[Captain Tim]

On a round piece you can wrap the tape around it then cut the opening to pour the epoxy in. 

[Steve W]

I always use clear packing tape. It sticks good and you can see the air bubbles are out. I thicken with cabisol and use a room key card to squeegee and come back after it sinks a bit and re squeegee.  

[Andy B]

Just for this rookie's education, what you are talking about is drilling a larger hole in the wood, filling that with epoxy, and then drilling a screw into it or drilling a hole for a bolt?  All to keep any water out of a wooden hole?

 

Also, how important is this, and in which locations?  I don't believe any of my deck hardware has this.  Is a good sealant (butyl or lifecaulk) adequate?

[Mike Vacanti]

If you use the bushing technique (which you have described accurately) then you are nearly certain that you won’t rot the plywood around the fastener holes. If you only use sealant there is always the possibility that it could fail and water ingress will rot the plywood.

 

There was a fellow out near me in Rio Linda, CA who built a very nice Marples/Brown Constant Camber trimaran over a period of many years. After he took off with his wife and cruised for a few years he had to do extensive repairs to the deck because of water getting through the sealant on many of the bolts that held on his deck hardware. This is on a boat that lived in the water, a trailer boat doesn't have as hard a life. But this example does show what can happen if water is allowed to get into the end grain of plywood. 

[Jknight611]

Gorilla duct tape…..

 

I made some bushings today in the Looper keel today with this tape, and it seems to be holding. 

[Don Silsbe]

@Jknight611— That’s what I use, but sometimes it releases.