Building My First River Coffee Table – Making of and Lessons Learned

Over the last 3 years I’ve fallen in love with woodworking. My journey with woodworking began with our new home. It needs a lot of work. I learned quickly that hiring contractors to build many of the cabinets and things that I wanted was not only quite expensive, but that we wouldn’t be able to get exactly what we wanted. Personally, I prefer to build each of the things as a bespoke piece, rather than a mass produced IKEA type of furniture.

For me, the “river table” or more specifically, an epoxy resin live edge table, was at the top end of the woodworking scale. It was something I aspired to create. I started with cabinets and got quite good at building them, but I wanted to challenge myself to build a river table that could end up being a special piece. They are bespoke art pieces and a coffee table like this can cost at least $1000+. A dining table can cost at least $5000+.

Process

Buying and cutting the wood slab

The original slab. This is curly maple.
The slab, cut into the river table shape. Notice that there are gaps under the right piece. I learned later the hard way that you should use a completely flattened slab.

Building the form

The form was built from spare pieces of plywood. This part is fairly straightforward. Use Tuck Tape on the surfaces that will require water-tightness. As I learned the hard way (see below), make sure that your form is slightly larger than the pieces of wood. The wood should not touch the walls of the form so that it doesn’t push it out. Seal both the inside and outside edges completely with silicon sealant. Water test it!

Doing the epoxy pour

The epoxy pour itself is the easiest part of this whole process. It’s all in the preparation and what comes after the pour that is a PITA.

In this video, you can see how I did the epoxy pour. It became a neighbourhood event with many curious neighbours coming over to see this being done.

Also see below for all the lessons learned in doing an epoxy pour like this. The main thing is to only do the pour when the temperature range is correct. I did it on one of the hottest days of the year, which caused everything to cure much faster than it should have.

The slab after removing the form. Notice all the bubbles – that’s actually really not good and is a sign that the pour went wrong. πŸ™‚

Flattening the tabletop

Flattening the tabletop turned out to be a complete pain in the ass. It was the worst part of the project. See below for all the lessons learned. I can honestly recommend that you should just bring the tabletop to a shop that has something like a Wood Wizz or CNC machine to flatten the table.

Finishing the tabletop

I finished the tabletop by sanding, sanding, and sanding some more down to about 300 grit. I found out later that you can sand the epoxy even more to get it shinier (but it damages easily).

I used a 45 degree router bit to chamfer the edges, so that my kids wouldn’t cut themselves when they smashed their heads into the table. Kids are prone to doing that kind of thing.

I used Osmo Polyx wood oil – satin clear finish. This stuff is amazing and I now swear by it. 3 coats of this stuff, one per day, and the surface was just absolutely gorgeous.

Th finished piece in our living room. Soon to be claimed by our kids and used for building LEGO. πŸ™‚

Lessons learned

Lesson #0: Unless you are a woodworker, just buy one. Really. πŸ™‚

The biggest lesson I learned from doing this project is that I now know why they cost so much. πŸ™‚ The epoxy unexpectedly costs more than the wood, and I’m not using cheap wood either. It is finicky and very time consuming to do this kind of project. You need the right tools, the space, and it’s still a good challenge. I know some people who have seen me do this and now think that it’s simple to do – one even committed to making one for his friend even though he hasn’t got the tools, the space or done one of these before O_o.

Now, if you’re a woodworker and you’re up for the challenge, I think it’s a great project. I’m satisfied with the result.

Lesson #1: The epoxy costs more than the wood πŸ™‚

This will completely blow your mind. Most people just don’t realize that the epoxy resin is extremely expensive stuff. Think “oh it’s just plastic, that’s cheap eh?”. Volume-wise, the cost of the Ecopoxy is generally more than the cost of the wood! It’s freakishly expensive!

Lesson #2: You need a track saw

Originally I was using a circular saw hooked up to a Kreg Accu-cut track. This was fine when cutting plywood for cabinet making. However, for cutting through 2″ thick live edge wood, it was causing the blade and the wood to burn. In one case, it actually caused kickback and damaged the track when the whole saw kicked off the track. This is dangerous and bad.

The issue with circular saws (most of them anyway) is that they do not have a riving knife. A riving knife pushes the wood away from the blade as you saw through it. This minimizes kickback and burning.

I ended up buying a Dewalt track saw system. Why? All my other tools were Dewalt, and it was significantly less expensive than a Festool system πŸ™‚ (to Festool or not to Festool is a whole other discussion!)

Lesson #3: You need a completely flattened wood slab before attempting to do an epoxy pour

I was very excited about having a piece of wood, and I assumed that it was already flat because the place I buy it from generally sells already flatted slabs. This slab was not flat (not entirely anyway :)). The issue with a non-flat slab is that once you pour in the epoxy, it can lock in the air in certain spots, then suddenly when you are waiting for it to cure, the air can escape as bubbles. This is exactly what happened. I was certain there were no bubbles after pouring and leaving it for several hours, then when I came out the next morning to check, there were huge bubbles encased in the epoxy! 😦 Lesson learned: really make sure that the slab is really completely flattened. For the next project, I bought 2 slabs of wood and got them to flatten them both on the Wood Wizz.

Lesson #4: Do not pour when the temperature is out of range (especially when it’s too hot)

I did my pour on 1st July, which turned out to be one of the hottest days of the year. It was 30+ degrees celsius with high humidity. This caused the epoxy to cure much faster, which resulted in bubbles not having enough time to dissipate. I ended up getting huge bubbles in the epoxy.

Lesson #5: Do not try to remove bubbles by torching them

Combined with Lesson #4, I attempted to remove the bubbles by torching them. The idea was that it would heat up the air which would cause the bubble to rise up. Yes, it does work for surface bubbles but definitely not for the big bubbles that are in the middle of the epoxy. What ended up happening was that the epoxy got heated up and cured much faster, which sealed the bubbles in the epoxy. Hot weather plus torching is not a good idea.

Lesson #6: To avoid leaks, use silicon inside AND outside to really completely seal the form, make your wood slightly smaller than the form

My form leaked. I had water tested it. I had sealed it only on the inside.

The issue was that the wood was the exact correct size for the form, and when I put the wood in, it must have pushed the form out one end, which caused the seal to break. Epoxy went everywhere and I was scrambling to hot glue, tuck tape and seal the leak. Not good no.

For the next project (which was successful), I completely sealed the form inside and outside, water tested it, and also cut the wood slightly smaller than the form so that it would not even touch the walls of the form. Yes, it means that some epoxy will run around the wood, but that’s better than having epoxy leak everywhere!

Lesson #7: The pour is the easy part, flattening the piece after is extremely challenging

As I discovered, doing the epoxy pour itself was the easy part. You just pour it in! As long as you follow all the steps correctly, you can just leave it for 3 days and generally it will settle and give a very good, bubble free finish.

The hard part was flattening the table afterwards! I went to the trouble of building a router sled, then planed down the table using this.

My first pass completely ripped up the epoxy and left huge chunks cracked out of it. 😦 I learned that you can’t just use any router bit. You have to use a special surface planing (bottom cleaning) bit used on CNC machines ($$$). I bought one on Amazon.ca and it worked much better but it was also only 1.5″ diameter so you end up doing many passes. When you are hunched over flattening a large piece with a 1.5″ bit, you really end up questioning your life choices!

Also, a router sled comes with its own set of problems including:

  • Ensuring that the guide rails are really very very flat.
  • Ensuring that there is no vertical movement on the guide rails.
  • Dust/shavings collection. You need excellent dust collection. I use a cyclone hooked up to a shop vac.
  • Overheating bit. When the bit overheats, it can cause damage to the epoxy that you’re trying to plane down.
  • Going too fast and too slow. When you go too fast, it damages the epoxy. When you go too slow, it overheats which also damages the epoxy.

I tried doing this on the garage floor, then realized that the garage floor itself wasn’t flat. O_o

In the end, I did manage to flatten the table after messing with it for several days, and swore never to do it myself again, especially for larger pieces. My back was very sore.

I found out that my wood shop KJP Select Hardwoods has Wood Wizz machines that could just flatten the tables and it wasn’t that expensive either. For the next project, I would use this service instead of attempting to flatten anything myself.

Lesson #8: The vast majority of people don’t notice your mistakes πŸ™‚

Despite all the problems that I had with this table, the saving grace was that everyone who has seen the table is unable to tell any of the mistakes. To them, it just looks amazing. They see the bubbles encased in the epoxy and remark “Oooh there’s bubbles in here! How did you get that effect?” πŸ™‚

Which goes to show that only the artist sees their own mistakes. Everyone else looks at it and enjoys the finished piece.

Links and Resources

If you want to learn how to make a river table properly, check out these links:

Jeff Mack Supply: How to Use Ecopoxy Liquid Plastic – This is the best written tutorial I’ve come across on how to do it.

Ecopoxy: How to build a river table

This video by Ecopoxy is good for explaining the overall process and using the Ecopoxy product, which is actually the easiest part πŸ™‚ The hardest part is all the preparation and what comes after the pour. I recommend having a relationship with a shop that has the right tools to properly flatten slabs like this.