Yes yes yes. I think we only did a couple of coats on the underside but several in the sink cut-out.

yes, waterlox everywhere. it helps regulate the moisture exchange and keeps the wood from warping.
the top part will be sanded in between coats. the other sides need not.

What is waterlox? I'm planning to use butcher block on my island which I want to be able to chop on. Do I have to use this waterlox also?

http://www.waterlox.com/
highly recommended finish on this forum (and I agree). It is great for DIYers. I have done many projects, counters, floors, cabinets etc in this finish. my favorite for exotic hardwoods.
Downside - very very smelly when you put it on. after a while the smell will subside.

Thanks so much for the quick responses. My next question then is should we treat it with waterlox before we cut it to size or do it when the butcher block is one big piece? I think I've read things on Ikeafans that warned that warping may occur if not sealed in a certain order.

bickybee- ask around but I don't think you want to use waterlox unless you are not planning on cutting directly on the butcher block.

Breel, you'll need to do the sides so I think we treated ours once all the pieces were cut. Otherwise you'd have a raw edge without treatment, kwim?

megsy, that's what makes the most sense to me. I guess we just `need to get going and make the cuts and start applying the waterlox. I've heard you should wait at least 12 hours in between coats of waterlox.

Waterlox is not what you want if you are going to cut on it.

We Waterloxed our IKEA BB top after we had it cut and routed. I absolutely love the finish! We used about 4 coats of Original (the really stinky one) and followed it with about 3 or 4 coats of Satin (not too stinky). It did take a several days because we waited 24 hours between the Satin coats.

Alright, it seems like we cut it first and then use the Waterlox. Sounds like a plan. I was surprised that Lowe's and similar stores don't carry it. Luckily, I found a place nearby that has it. What did you use to apply it? I've heard everything from a rag to a roller.

We're thinking about this too, so I went over to the Woodworkers Forum -- there are some really good posts there about how to apply Waterlox.

Wood Craft carries it.

I used an old tee shirt, as that was the easiest to me, and really provided for a nice even finish.

Do all the work in your garage. Make sure there is no dust in the air.
Apply with a rag. I used a sponge brush. you can get them cheap at harbor freight.
wait 24 hrs between coats.
sand lightly
wipe thoroughly
then apply next coat.
repeat this at least 4 times.
if you want a matte finish, apply 3 glossy coats and one matte coat.
DO NOT rush the process. I would allocate at least 2 weeks for this project.

let dry for several days or until the smell disappears.
Then bring inside the house and install.

Then ogle your work and post photos here :)

You've gotten good advice!

I applied 2 coats of Waterlox Original to the underside of the Ikea slabs before they were cut to size. (A carpenter was cutting and installing them and I didn't want to have to move them afterwards.) I tried every application method I could think of - old t-shirt, foam brush, lambswool applicator, brush, etc. The foam brush (a wider one, 2" or so) worked best for me. Use a new brush for each coat. Do let it dry well in between coats, and be generous with the first few as it will be absorbed into the wood.

You're going to want lots and lots of coats around the sink area - and probably a vapor barrier between the dishwasher and the underside of the butcher block. I ended up applying 2 coats of Original to the bottoms, then 3 coats of Original and 4 coats of Satin for a total of 7 on the tops and sides. I'd suggest more at the sink.

Good luck - the Waterlox will make it look rich and honey colored!

Finishing the underside of a countertop (or tabletop or what have you) has no effect on warping of a board.

"Understanding Wood Finishing" by Bob Flexner exlains the science of wood movement and how it cannot be affected by any finish whatsoever.