EM9000 Problems on live slab

[Elliot Faust]

Hello All,

I tried searching but didn't find anything quite like this. Long story short I'm building a small basement bar and the top is a live edge walnut slab. I left a can of soda on the bar top today for about 30 minutes and got my first water ring. I was a bit disappointed as I thought my finishing schedule would be more durable than this. I'd appreciate any advice on either what I did wrong, or how I could make the top more durable.

My finishing schedule was as follows:

-Sanded to 220 grit
-2 coats of dewaxed shellac
-5 coats of Target Coatings EM9000 sanding with 320 between coats

[John TenEyck]

That's not good. Target's data sheet says water and a whole bunch of other liquids have no effect on EM9000. It's supposed to be KCMA rated. I've done studies on GF's products, and with all but one I've tested you can leave a wet glass on them for days, until the water dries, with no ill effects. Was your slab kiln dried? If not, was the moisture content less than 10%. When you finished it, did you follow the minimum application temperature guidelines? Curious, but I don't see what temp. that is when looking at their TDS. With many WB topcoats it's around 65F. How long had the top been finished before you put the soda can on it? Most of these products need at least 7 days to fully cure. How old was the can of finish?

What to do to make it more durable? Talk to Target Coatings first and see what their take is on it.

John

[Elliot Faust]

I applied with shop temp between 60-65. Slab was 7-8% I checked it before starting to work it. Can of finish was brand new just shipped.

Slab had finish applied for about 4 days. It feels a little soft to me. I can scratch it with my finger nail.

[John TenEyck]

You need to find out what the minimum application temp. is for that product; maybe it needs to be greater than 65F. Otherwise, I think the finish was bad, or maybe it froze during shipping? The GF waterbornes I use are very hard; you cannot scratch them with your finger nail.

John

[Elliot Faust]

John,

If I scuffed the surface of my em9000 and applied a few coats of GF waterborne or Arm-r-seal would that solve my problem? I'd hate to sand the slab all the way back down to bare wood but I'll have to do something. Otherwise I'll have rings everywhere.

[John TenEyck]

Elliot, either of those would not get water rings. But if you can scratch the Target finish with your finger nail something is wrong with it and putting another product over the top might not and probably won't be a durable solution. I think you need to discuss the problem with Target and get their opinion before deciding what to do about it.

Personally, with no other information, I would strip off what you have and start over - with a different product.

John

[Elliot Faust]

Thank you. I'll put in a phone call tomorrow and see what they have to say. I'll report back.

[Elliot Faust]

I spoke with Jeff this morning. He didn't see a problem with my finishing schedule but did recommend using the cross linker product. I will be looking into this next time. He also said that, more than likely, the 9000 just hasn't cured yet. With the colder temperatures and the shellac underneath it may take longer to cure. I'm hoping this is the case. Either way Jeff was very pleasant to talk to and very knowledgeable.

[John TenEyck]

Add the cross linker will make a harder, more durable film, but the finish should resist scratching with your finger nail w/o the cross linker. How long had the top been finished before you had the water ring problem? What's the temperature in your basement where the slab is? If the answer is more than 3 days and more than 65 F then I don't buy it that it hasn't had long enough to cure. Shellac gets hard by evaporation, temp. has little to do with. If the problem is related to your shellac then it's more likely the shellac was old and didn't cure properly than due to low temperature. That's easy to prove. Just put a little of the shellac on a piece of plastic, etc. If it cures to a brittle film the shellac is fine. If it remains flexible even after 8 hours or so, the shellac is bad.

Did Target tell you what the minimum application temp. is? If you applied it below that temp. I don't think it will ever cure properly. If the shellac was bad, it's never going to get better. I don't think we're at the end of this story yet.

John

[Elliot Faust]

The top had been finished for 4 days prior to the water ring problem.

Shop temp was between 60-65 degrees during application and drying. Jeff said proper temp is anywhere between 60-80.

I'll try a shellac test and let you know. Other than that... I'm going to hang tight and see what happens. It's my home bar so if I run into more problems down the road I'll just remove it and sand it down. For what it's worth, the water ring has since disappeared. Which Jeff said it probably would....

[Elliot Faust]

I just wanted to update. It's been about 1.5 months now. I've hosted a few gatherings and more than a few cold beverages have been placed on the top. I've been very careful to use coasters but inevitably some cans have been set on the top. I'm happy to report that no circles are visible. I think that the finish just took longer than expected to cure. Possibly from the shellac or possibly just from the numerous coats applied. Either way, so far so good.