How did I screw this up?


Texfire

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Hey folks, making my first end grain cutting board with soft maple and mahogany, and it was looking pretty good until it came time to apply the finish.

 

I used a jack plane and card scraper to get the surface flat, I thought, and sanded it with my DX90 with P80 then P440 grit.  After spritzing it with water to raise the grain and sanding a final time, I applied the first coat of finish.  I followed Marc's suggestions and went with a simple wiping varnish of General Finishes Salad Bowl Finish diluted approximately half with mineral spirits and applied generously with a rag for a couple of minutes before wiping off the excess and letting it dry overnight.  

 

The last photo is the blotching that I found this morning.  So what did I do wrong?  Did I not level the surface sufficiently?  The can I took the varnish from has been opened before and is two years old, is it doing something funky because of age?  The shop is insulated but not heated, is it possible it got too cold when curing?

 

I ended up going to Woodcraft to get a bigger sander, and they suggested it was left over glue that hadn't gotten removed.  I purchased an ETS 150/3 instead of trying to sand it all with the smaller 3" sander.  I came back and hit it with a card scraper, sanded it all with P80, then P320, removed the dust and applied more of the wiping varnish.  It looked good going on, but so did it last night.

 

Any other ideas on things I can try or reasons why it would have blotched like that?  I'm coming down to the wire if I want to apply another two layers of varnish and let it dry by Christmas morning.

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I missed that cutting board thread, thanks for the head's up.  I'll go light on the finish so I don't form a film.  I just want to seal the pores.  I'll evaluate after the second coat and see if it needs another.

 

 

I went with Salad Bowl Finish because it is food safe and doesn't require the maintenance of mineral oil since this is a gift.  If I was doing this for myself I would have gone with mineral oil or walnut oil, but I wanted it to be easy to maintain and avoid potential nut allergies.

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I'm with TIODS, I'd suspect that the age of the finish might be an issue.  Don't go "cheap" at finishing time - with all the time and effort you put into a project, you want to make sure you're working with good finish.

 

Another possibility is that there was still water in the end grain from your 'spritzing'.  How much time was there from when you raised the grain to when you applied the finish?  End grain would soak up the water, so you would want to make sure it's thoroughly dry.

 

FYI, pic 4 is post water spritz, but pre finish.  Pic 5 is post finish the next morning.

 

After taking a closer look at the pictures.....it looks like pic 4 and 5 are of opposite sides of the board.  Did you apply finish to both sides?  Is there a chance what you're seeing is more of the finish wicking through the end grain to the other side?

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I'd be very concerned about the salad bowl finish being as old as you mention!  It's a great finish but, has a shelf life.

 

Suggest getting some fresh stuff!  Sand well after it's completely cured and apply the fresh finish.

 

I did pick up a new can because I had the same concerns, but when I opened the older can, there wasn't any change in viscosity or color that I could see.  It stirred up just fine without seperation or particulate, so I decided to use up the older batch.  I'll chuck it and use the newer stuff if I have the same issue again.

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I'm with TIODS, I'd suspect that the age of the finish might be an issue.  Don't go "cheap" at finishing time - with all the time and effort you put into a project, you want to make sure you're working with good finish.

 

Another possibility is that there was still water in the end grain from your 'spritzing'.  How much time was there from when you raised the grain to when you applied the finish?  End grain would soak up the water, so you would want to make sure it's thoroughly dry.

 

 

After taking a closer look at the pictures.....it looks like pic 4 and 5 are of opposite sides of the board.  Did you apply finish to both sides?  Is there a chance what you're seeing is more of the finish wicking through the end grain to the other side?

 

I let it "sit" for almost 24 hours to let the water dry and dust settle out of the shop air before applying finish.  They looked dry, so I don't know if the water was an issue at that point.

 

I finished both sides of the board and let them dry on painter's pyramids overnight.  I'm not sure if that's the backside or not, I actually made two boards but only showed pictures of the most blotchy one.

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Went much better this time.  While still a little blotchy, it's much more uniform.  Attached is a finished applied then what it looks like this morning for both boards.

 

I guess it was a sanding issue, which was made worse by glue issues.  I'm thinking a second lighter coat and it'll be done.  Thanks for your help.

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A couple things come to mind to me. 80 g to 320? Sounds like a huge jump. I don't have a need to sand end grain, but I can't imagine skipping that many grits. Also water shouldn't raise end grain in my opinion. Moisture would go deep into end grain quickly; even all the way to the other side. I could see it taking a while to thoroughly evaporate.

Steve

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A couple things come to mind to me. 80 g to 320? Sounds like a huge jump. I don't have a need to sand end grain, but I can't imagine skipping that many grits. Also water shouldn't raise end grain in my opinion. Moisture would go deep into end grain quickly; even all the way to the other side. I could see it taking a while to thoroughly evaporate.

Steve

^^ this jumped out to me too.  I have done a few end grain boards and found out pretty fast that you should really not skip grits on end grain, my first one I went from 100 - 220 - finish and it came out pretty blotchy, not to mention a fair number of scratch marks... next board was sanded longer and I went 100-150-220, and I really spent some time on the sanding to make sure it was glassy smooth.  I thought about going to 320, but after I finished that 2nd board it looked great do I decided that I didn't need to go that high.  but your sanding may be part of the cause of the blotch - I know it was for me.

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