Epoxy for Cutting Boards/Lining up Strips

[TomInNC]

I am wrapping up a few end grain cutting boards, and I have some small voids to fill. I also managed to miss a knot hole when I was cutting down the stock and need to stabilize a knot that is on the underside of a board that will only see use on the top. I was looking at David Piccuitto's book on cutting boards, and he mentions several times that you should fill the voids with epoxy. He does not, however, go into the whole food safety debate and suggest what epoxy should be used.

As per usual, the  advice from the interwebs on this is wildly contradictory, ranging from "epoxy on a board will kill you" to "only use FDA approved epoxy" to "just use whatever you have in the shop; once it cures, it's fine." Do any of you use epoxy on your boards, and if so, what product do you use? I have found some of the FDA approved stuff online, but it only appears to come in containers that are about 100 times bigger than what I would need.

Somewhat related question: if you are making an end grain board where you have a particular species running completely north-south on the board but the species change east-west, are there any tricks you use to align the strips in the final glue up? I have made a few of these now, and I always seem to get some minor imperfections in the alignment so that each species appears to "wave" a little bit. I'm not sure if this is from a sloppy glue up or something with the clamping pressure. You can only really see the wave up close. Since I don't have another board to compare mine to, I'm also wasn't sure if this was just something to be expected.

[Chestnut]

On the epoxy, I think judgement would depend on the end user. Some people are way more comfortable with minor risks than others. Those opinions are going to vary wildly here as well, with some being adamant against it and others being ok with using epoxy.

If it is something for sale at a craft fair I'd avoid it just due to any liability issues. I'd be hesitant to also use epoxy on gifts to extended family as I wouldn't want to take any chances.

For immediate family I'd be able to explain what's going on and I'd just tell them to avoid cutting on the epoxy and to make sure to clean it or avoid use with raw meats.

I don't know how big the voids are and any details so beyond above it's hard to gauge any further. If i were spending the time to make an end grain board I'd try my best to avoid epoxy at all costs as iirc, it's going to negate the main benefit of an end grain board, which is knife edge protection.

For the 2nd question pictures would go a long way in being able to help you. I don't understand the question.

[TomInNC]

Thanks. I will try to get some pictures when can and repost.

So if you don't use epoxy, what do you use to fill voids on your boards? Glue and saw dust? These are very small, maybe the size of the end of a pen.

[wtnhighlander]

I would use epoxy over PVA and sawdust. Once cured, the epoxy is pretty much inert. Any "danger", IMO, would be from tiny shards that might mix into the food as it is cut. I prefer to keep the working surface of a cutting board fill-free. The backside, who cares? If you are including feet, or other feature that clearly defines which side goes up or down, I would be OK with the filled knot on the bottom.

[TomInNC]

Regarding the issue with the alignment, I have attached some pictures below that should help clarify. Notice how in the left frame, when you zoom in, the "bricks" are not quite straight. Zoomed out, it doesn't look too bad. 

[TomInNC]

On 9/7/2021 at 10:40 PM, wtnhighlander said:

I would use epoxy over PVA and sawdust. Once cured, the epoxy is pretty much inert. Any "danger", IMO, would be from tiny shards that might mix into the food as it is cut. I prefer to keep the working surface of a cutting board fill-free. The backside, who cares? If you are including feet, or other feature that clearly defines which side goes up or down, I would be OK with the filled knot on the bottom.

Thanks. I am actually putting a rail on the bottom roughly through the knot to catch the sink edge, so it will be very clear which side can be used. 

[Chestnut]

On 9/7/2021 at 9:50 AM, TomInNC said:

Thanks. I will try to get some pictures when can and repost.

So if you don't use epoxy, what do you use to fill voids on your boards? Glue and saw dust? These are very small, maybe the size of the end of a pen.

I don't fill very small voids. To bring in context i haven't done any end grain boards. I mostly do long grain cutting boards mostly because they are faster and easier and 95% of people don't really get the difference. It's also easier to avoid void situations.

So a hole the size of the ball in a ball point pen? that's not much larger than the pore in some woods. I wouldn't fill that. The end grain pores of the purple heart used aren't much smaller.

To your alignment issue, ensuring each piece is the correct thickness during your glue up is critical. If you are relying on a table saw cut you may need to assess your saw calibration. It would be best to use a thickness planer to ensure all of the strips are the exact same width. Also during the final glue you need to make sure the lines are aligned. This can be difficult which is why i often see end grain cutting boards flipped row for row to create a random sort of pattern.