Losing my head

In my previous post I noted how I clamped down the planking with drywall screws and wooden blocks. This can be seen here.  There's also a strapped 1x4 to help with a slightly bulging plank.

I think there were about 200 screws in all, that I used for clamping the planking.   A disaster hit when I started to remove the screws.  The epoxy and the tough white oak that many were screwed into held tight and caused the screw head to snap off.  In total, there were 8 screw shafts embedded with no easy way to remove them.  In addition, because I planned to countersink and plug each hole, the metal shaft prevented it.  The look of the deck would be compromised if I couldn't get a plug into the hole, so I had to get them out.

I spent most of a day figuring out how to get them out.  Normal screw extraction techniques do not work because the shaft is so thin and the metal is hard and brittle so it can't be drilled out.  In my first attempt I messed up the the countersink hole which will now require a slightly larger bung than the other countersunk holes. 

Here are the key tools I used:

The small router bit for the Dremel tool on the right let me create a little hole around the shaft.  This was important to guide the countersink bit on the left.  If there wasn't a starting hole, the bit would wander.  This is what messed up my first attempt.   The countersink bit is part of drill/countersink set where I removed the drill part leaving a hole in the center.  This let me drill a 3/8" countersink hole around the embedded shaft as shown here.

This is what I had to work with.  I then used the router bit again to clean out more wood around the shaft to hopefully reduce the grip on the shaft.   I still could not get the shaft out because my pliers kept slipping.  So, my next step was to use the tapered grinding stone to flatten one side of the shaft.  Besides creating a flat spot, it also heated up the shaft which helped loosen the epoxy grip.  Epoxy, when heated, gets soft and loses it grip.  

I could then get a needle nose pliers on the shaft and slow turn it out.  It was a tedious and frustrating process, but I succeeded in getting them. 

The moral of the story is not to use drywall screws for clamping epoxy assemblies if it is critical they must be removed.   I could have used two options.  One, I could have countersunk the planks before epoxying and used the final silicon bronze screws. Or, two, I could have used regular zinc plated screws for clamping which have a thicker shaft and would have not broken upon removal. 

Anyway, on to finishing the deck and plugging the holes.