# Under mount Kitchen sink and sealing Maple counter, help.



## Greenbush (Jan 10, 2011)

Hello Gents and Ladies-
Because of time constraints I am posting my own topic in hopes of getting some strong feedback and suggestions on my situation.

I purchased an old 2 1/2" Maple bowling lane to cut up and make my 11' "L" shaped kitchen countertop and undermount my kitchen sink. I've had numerous issues with this beautiful chunk of wood. First, discovering that each board is nailed to the next with tempered twist shank nails and not glued. :thumbdown:. So, the planks flex and as if the old maple was not enough of a blade eater already, I then had to cut through them, which was like grinding metal in an auto shop.
I chased the no glue issue around a bit. I injected glue where I could and then routed out numerous channels on the bottom to run hardwood inset stringers across the underside and clamped, clamped and clamped. I seemed to do well but after moving the monster 11' counter a couple times the top side of the counter seemed to open a bit. So, I then bought an 1/2"x16" Ship Auger bit, drilled through the middle and forced glue in and then 1/2" dowels, especially on each side of the area for the 22"x33" undermount sink. I then ran a very old piece of Beech as the face trim and put in a 1/2" Black walnut dowel every 12" at an average of 5" deep. I all looks awesome. But the cutting out of the sink opening for the undermount was a complete B to the Itch. 
Due to the sink I got a great deal on is 22" deep and the counter is 25", it has weakened it. Also, I did not want to have a major drop from the counter surface to the sink, went with 5/8", was 3/4" but a nail got in the way of the router. :furious:
SOOOOOOOOOO. Here are my issues that I want to hear on;
1) Looking for input on what to use went setting the sink into the opening and sealing it to the wood. Obviously the remaining 5/8" overlap is not going to be the support of the 100 lbs sink, but need to make sure it seals really well. I will make blocks and anchor bolts to hold the sink in place. Do I just use almond silicon or? I don't want to commit the sink to be completely permanent to the counter.

2) What do I use to seal up the underside and around sink mount area? 
As for the top of the counter, has anyone used Rubio Monocoat? I don't plan on using the counter for cutting but counters get dented and wouldn't want to have to fix a dent/chip in a hard finish.
THANK YOU ALL for making it this far in my ranting post. I'm a bit hesitant right at this moment. I'm ready the mount the sink.

Thanks... I will post pics in a bit.


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## cabinetman (Jul 5, 2007)

Wood countertops around a sink in a kitchen can be touch-n-go. I would rather use a drop in sink. But in your case if you are making mechanical fasteners to hold the rim to the wood, you may only need a silicone caulk as a sealer. For many undermount installations a two part epoxy can be used.

I would thoroughly seal the inner exposed edge and the underside using an oil base polyurethane...several coats.












 







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## Greenbush (Jan 10, 2011)

Cabinet Guy-
Thanks for your input. I was thinking of the Poly I have to use in that area.
Here are some pics. Sorry they're upside down, but the counter is at this moment.


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## cabinetman (Jul 5, 2007)

That sink looks like a drop in...not an undermount.












 







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## Greenbush (Jan 10, 2011)

cabinetman said:


> That sink looks like a drop in...not an undermount.
> 
> 
> 
> ...


It could be if I was tiling it in or creating a trim piece to cover the sink rim. Plus, I got it great used condition for $65 at our local Habitat for Humanity Restore. But it has a shallow chip on the front rim that needed to be covered. 
It has square corners and slightly tapered edges.


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## Greenbush (Jan 10, 2011)

cabinetman said:


> Wood countertops around a sink in a kitchen can be touch-n-go. I would rather use a drop in sink. But in your case if you are making mechanical fasteners to hold the rim to the wood, you may only need a silicone caulk as a sealer. For many undermount installations a two part epoxy can be used.
> 
> I would thoroughly seal the inner exposed edge and the underside using an oil base polyurethane...several coats.
> 
> ...


What do you think of using wax free Shellac for the inner and under surrounding areas over Poly? I'm wonder if it would soak deeper into the grain and maybe more if thinned a bit with alcohol. Your thoughts?:huh:
Thanks


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## cabinetman (Jul 5, 2007)

Greenbush said:


> What do you think of using wax free Shellac for the inner and under surrounding areas over Poly? I'm wonder if it would soak deeper into the grain and maybe more if thinned a bit with alcohol. Your thoughts?:huh:
> Thanks


I would not use shellac at all. The first application or two of an oil base polyurethane can be thinned 25% for the benefit of penetration, but full strength for subsequent applications.












 







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## 240sxguy (Sep 13, 2010)

I am doing the same thing you are working on. I am not using a bowling alley though! That looks pretty neat. 

I plan on using Waterlox to seal and 3m 5200 to glue the sink to the underside of the edge grain butcherblock. 3m says the stuff can flex up to 1350% before breaking the seal. It's commonly used on boats, and will make removal of your old sink difficult or impossible (keep this in mind). 

Unfortunately this time of year its too cold to use waterlox in my garage, so I am considering doing tung oil heavily then waterlox in the spring when I can get good ventilation going. My timing was bad on this one!


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## Greenbush (Jan 10, 2011)

cabinetman said:


> I would not use shellac at all. The first application or two of an oil base polyurethane can be thinned 25% for the benefit of penetration, but full strength for subsequent applications.
> 
> 
> 
> ...


Sorry to belabor this topic. But I tried some of the WB poly I have on a spare maple piece. It doesn't seem to want to penetrate. I kinda did the old soak the chalk in the fluoride style test, if you'all remember those commercials. I was thinking of thinning some Boiled Linseed to apply pre OB poly. Thoughts? I'm just a bit nervous about this counter, being it was not glued like a countertop plank would have.


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## cabinetman (Jul 5, 2007)

Greenbush said:


> Sorry to belabor this topic. But I tried some of the WB poly I have on a spare maple piece. It doesn't seem to want to penetrate. I kinda did the old soak the chalk in the fluoride style test, if you'all remember those commercials. I was thinking of thinning some Boiled Linseed to apply pre OB poly. Thoughts? I'm just a bit nervous about this counter, being it was not glued like a countertop plank would have.


Read post #7 again.












 







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## Greenbush (Jan 10, 2011)

cabinetman said:


> Read post #7 again.
> 
> 
> 
> ...


Okay. LOL. I am just very nervous because the lack of glue between the boards. Thanks for your patience. How is OB Poly resin for the job? I have some, otherwise I need to go purchase more. Or I have exterior Spar Var.


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## cabinetman (Jul 5, 2007)

Greenbush said:


> Okay. LOL. I am just very nervous because the lack of glue between the boards. Thanks for your patience. How is OB Poly resin for the job? I have some, otherwise I need to go purchase more. Or I have exterior Spar Var.


If your top pieces aren't glued together you are going to have a problem. I suggested oil base polyurethane...not shellac...not BLO...not spar varnish. But, you can use whatever you want.












 







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## Greenbush (Jan 10, 2011)

So, the counter and sink are in. I applied lots of OB poly around the underside of the opening and the end grain. As well as soaking the entire bottom of the counter with 3-1 diluted tung oil and after dry a layer of OB poly as well. 
I then made some wood chocks(2"x 1 1/4"DF and 3/4" oak) that run the length of each end of the sink, cut at an angle and leveraged into the bottom of the sink edge by 3 (1/4") anchor bolts on each chock. Sealed with kitchen and bath silicon.
Now in place I set out to sand and apply OB Poly to the top.


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## 240sxguy (Sep 13, 2010)

Looks very cool! Nice job. I started on my tops yesterday.


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