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Steve Clarkson
12-02-2013, 9:22 AM
I have someone that wants a cake topper cut out of wood........is wood considered "Food Safe"? Does it matter if it is unfinished or finished (with polyurethane)? If not, is there a finish that would be considered food safe?

Steve Baumgartner
12-02-2013, 9:36 AM
I have someone that wants a cake topper cut out of wood........is wood considered "Food Safe"? Does it matter if it is unfinished or finished (with polyurethane)? If not, is there a finish that would be considered food safe?

I believe the answer varies depending on the kind of wood. Some people have sensitivity or allergies to certain species of wood, and there are a few species that produce intense reactions in most people. Lots more info at http://www.wood-database.com/wood-articles/wood-allergies-and-toxicity/

Contrary to myth started by certain finish vendors, most finishes are pretty inert and safe once fully cured. The only issue is in being sure they are "fully cured". For example, some polyurethanes continue to outgas solvents for a very long time.

Mike Null
12-02-2013, 9:59 AM
Food will stain the wood so a finish is in order. Shellac is always a good choice as is mineral oil but I agree with "most finishes are safe once cured".

Kev Williams
12-02-2013, 10:48 AM
I've always considered wood a "vegetable" since it came from the ground. Since it's just going to be a cake decoration and not used for actual eating purposes, I doubt it's going to matter much. But to be safe, I'd either give the whole thing a quick shot of clear spray enamel, or mask & just spray the area that will come in contact with the food. You don't need a heavy coat, just enough to seal the surface of the wood. Works great and it dries in minutes

Mike Troncalli
12-02-2013, 11:18 AM
What species of wood were you planning on using?

To repeat what everyone has already said, YES.. For the most part wood is very safe to use with food.. (Cutting boards, bowls, glasses, etc.) have been used for centuries. There are a few species that are dangerous (hemlock) and many people are allergic to many rosewoods. Most domestic wood, (maple, walnut, oak, etc.) are considered food safe. Also as mentioned above most all finishes are considered food safe once cured. Shellac, mineral oil and carnuba wax are the general "go to" finishes when working with items that will come in contact with food.

Stew Hagerty
12-02-2013, 11:52 AM
"Ever eat a pine tree (http://en.wikipedia.org/wiki/Pine_tree)? Many parts are edible."

Euell Gibbons

A 1974 television commercial for Post Grape-Nuts (http://en.wikipedia.org/wiki/Grape-Nuts) cereal featured Gibbons asking viewers that very question. Although he recommended eating Grape Nuts over eating pine trees. He also said: "Grape Nuts' taste reminds me of wild hickory nuts"

276186

David Somers
12-02-2013, 12:01 PM
Steve,

From a woodturners point of view...Woods are safe as is. The dust from wood can cause allergies in some folks with a repeated exposures. The allergy can be on the skin from contact, or in the lungs from dust inhaled. If you stick with woods like Maples, Ash, US species of Oaks, Cherry, etc you are fine. Avoid using a lot of tropical hardwoods since most of the allergy issues come from them. And if the person were allergic to molds and fungus I might avoid spalted woods...woods that have been allowed to begin the decay process and have those striking black and red and other colors running through the wood. After the turning process those spores will have dried, but people still might have some issues with them. Pick a clean wood with a nice figure to it in that case and avoid the spalted stuff.

In terms of finishes. As someone said earlier, most finishes are safe once cured. But a guideline we tend to follow in wood turning is that if the item is for food use....not just holding a a display of apples and whatnot...if it is for food use we prefer to use an oil type finish. A stabilized walnut oil, or Danish Oil, or a Tung oil variant like Waterlox. Those soak into the wood and cure in the wood itself from exposure to oxygen. This is opposed to a shell style finish like Shellac and Polyurethane and varnish. Those surface shells develop micro cracks over time and food and water gets lodged in there. Once that happens you get staining occurring under the shell which doesn't look good at all, and is impossible for the user to get out without removing and reapply the finish. An oil finish can safely be cleaned with soap and water in a sink and receive a good scrubbing if needed without worry about damaging a more delicate shell finish.

An oil finish can also be easily reapplied by the user. All the oils I mentioned are available in any store offering paints and finishes, including the big box home stores like Lowes and Home Depot. They can be applied with a cloth with no fuss. My preference is for stabilized walnut oils and waxes like Mahoney's walnut oil finish and wax. Or General's Salad bowl oil. A wax like a simple carnuba is fine as a follow up.

I prefer not to use Mineral oil as a primary finish. It evaporates relatively quickly so you end up reapplying it often, and it doesn't cure in the wood fibers, remaining moist instead. I will suggest it for a touch up to a piece if needed and you don't have a decent oil finish handy. No harm done. But I don't like to use it as the primary finish.

As a rule, the shell finishes are used more for pieces intended for display only, or for light use like holding apples on a table or something like that. But not for regular use holding food to be served.

Hope that helps a bit.

Dave

Chuck Stone
12-02-2013, 1:37 PM
I like tung oil, myself. (not tung oil finish.. those don't usually have any tung in them at all)
Tung oil will polymerize as Dave said.. leaving you with a protective finish. I like to dilute it
with mineral spirits or turps so that it penetrates deeper in the first application. THen wipe
it off and let it dry. Then a coat of pure tung oil, let it saturate and wipe it off and let it cure.
Sometimes on a chatoyant wood, the thinned oil goes deeper into the wood fibers and will actually
carry light in there, like a fiber optic. Just makes that wood glow...
But once cured, it essentially turns into a plastic but instead of a surface coating, it has
now penetrated and become part of the wood. It's not coming off.

Steve Clarkson
12-02-2013, 3:35 PM
Thanks everyone for all the info!

Joe Pelonio
12-02-2013, 8:13 PM
Think about wooden rolling pins, they have no finish on them. We have a marble one, but I engraved one for a woman that was giving it as a gift.

Mike Null
12-03-2013, 8:45 AM
Mineral oil is quite a good finish for wooden food items. It is easy to apply; tasteless and odorless. I've used it exclusively on cutting boards for years. Oils such as walnut oil can turn rancid over time, though probably not likely in this application. Shellac is in common use for edible products and can be applied easily.

I would not use tung oil due to the odor and taste likely to be left on the item. (it is likely that you will find a different formula on every brand of tung oil on the market)

george wilson
12-03-2013, 10:08 AM
I would just use maple with no finish,like bakery tables use. Years ago,our wise FDA decided that wood bakery tables weren't safe,and ordered everyone to convert to stainless steel or plastic. Years later,it was discovered that wood tables actually KILLED off germs,while other surfaces didn't. Wood,like maple,has natural enzymes that protect the tree,and apparently kill germs,too.

For the sake of taste,I wouldn't use walnut. Just stick with maple. Since some foods have water in them,shellac will not stand up well.

David Somers
12-03-2013, 1:05 PM
Mineral oil is quite a good finish for wooden food items. It is easy to apply; tasteless and odorless. I've used it exclusively on cutting boards for years. Oils such as walnut oil can turn rancid over time, though probably not likely in this application. Shellac is in common use for edible products and can be applied easily.

I would not use tung oil due to the odor and taste likely to be left on the item. (it is likely that you will find a different formula on every brand of tung oil on the market)

Good morning Mike!

Although mineral oil is considered safe for food contact keep in mind it is a petroleum byproduct. The reason I avoid it is that it requires frequent re-application because it does not cure in the wood once absorbed. It evaporates, like most petroleum products, and leaves the wood unprotected unless reapplied. Something like a stabilized walnut oil and tung oil will cure in the wood and provides much more and longer lasting protection for the wood without creating the type of surface shell Shellac and other surface finishes create. And a stabilized walnut oil won't go rancid over time. Unstabilized walnut oil, or any organic oil like it that has not been stabilized will go rancid over time. I don't mind using mineral oil for touch ups on pieces that are actively used, but for the primary finish for a utilitarian object i really do prefer something like a walnut oil.

Another poster mentioned cutting boards? For those surfaces I prefer mineral oil provided it is frequently applied. The wood fibers are being cut all the time so a finish that cures down in the fibers is less of a benefit than a more typical utilitarian piece. Mineral oil simply keeps the piece from absorbing water, and keeps the appearance of the wood up.

And for folks who don't normally pay attention to finishes....baby oil, while made with mineral oil, has stinky stuff added to it (perfumes) that make it completely unsuitable for food contact....Unless eating a salad scented like a baby's bottom is appealing to you. Hmmmmm? Might be the next foody trend? Baby bottom beet and Arugula salad anyone?

Tung oil, or a product like waterlox which is part tung oil, also cures and once it has cured doesn't impart flavor. Prior to curing it can impart flavor though. Waterlox can also be built up to create a shell finish if you want. A few coats work as an absorbent finish though provided you wipe off any wet finish that doesn't absorb fully into the wood. I have used waterlox as a friction finish on a lathe mounted piece as well with good results. For those of you reading not familiar with lathe applied finishes, a friction finish is like a French friction polish. It is a finish applied and cured through rubbing rather than air drying/curing. Thin applications are built up through this method to get the thickness and gloss you want. The finish can be quite attractive and durable. The advantage on a lathe is you can spin the piece and avoid all the elbow grease of a french finish applied to flat stock. We lathe workers are a lazy lot after all! <grin>

Finishes are pretty fascinating. So many aspects for each type and product! And so many personal preferences. Keep in mind my choices are governed largely by my work on a wood lathe, producing both utility pieces and display pieces. There are lots of other priorities for finishes.

Dave

Dan Hintz
12-03-2013, 4:02 PM
Think of it this way... (some) cutting boards are still made from wood. If it's safe to prepare food directly on, you're good with a topper. Just remember to wash if you reuse, and I won't get into the potential bacterial issues if you do.

Mike Null
12-03-2013, 5:16 PM
David

It appears you have done your homework. I will stand by my mineral oil for cutting boards with about a twice a year or less application. I have 3 in the kitchen which receive regular use. I also have a masher I turned from maple and which I finished with polyurethane. It gets occasional use and still looks pretty good after 15 years.

John Bion
12-04-2013, 3:31 PM
On a slight tangent: what about plywoods, especially Baltic Birch and Marine Ply for food?
Thanks for your comments.
Regards, John

Michael Hunter
12-04-2013, 7:08 PM
I think that baltic birch would need to be well sealed or it would pick up stains instantly and look awful (and it doesn't look that good to start with).
Interior grade birch that can be laser cut won't last long in a kitchen!

The reddish marine ply normally sold in the UK has a very open grain and so would also need sealing.
It is made of sapele or similar tropical hardwood : As David Somers says, the dust from these woods is considered hazardous by many woodworkers (either toxic or irritant or both), so I would not want a chopping board made from it.
Marine ply won't cut cleanly because of the glue.
Also consider the resin that comes out when engraving.

David Somers
12-04-2013, 8:58 PM
John,

I have never tried to deal with the use of a plywood for food service. I don't see why it would be an issue though. The main worry I can think of might be if i were a material that was meant to be sliced on. A cutting board or plate or platter? I am not sure what the characteristics of the glue between the laminates is after it has dried. What kind of use were you thinking of? I can dig a bit and see what is out there.

I do mostly woodturning so I don't deal with Plywoods at all.

Dave

John Bion
12-05-2013, 1:41 AM
Hi Michael and David,
Thanks for your replies. I was thinking of cheeseboards. Not lasercut but engraved for advertising.This has been on the back of my mind for a while so I thought I would ask the safety question when this thread came up.
Thanks and Kind Regards,
John

Stew Hagerty
12-05-2013, 10:39 AM
Something no one has mentioned (I apologize if you did and I missed it) is wax. Good ole beeswax. Dissolve it in some mineral spirits (I use the "low odor" variety) so that its consistency is like mashed potatoes, then use your hand & fingers and rub it into the wood. The warmth from your skin helps to work it in. Scrape off any excess. Let it sit and dry then use a scraper, with a light touch, to remove the majority of what is sitting on the surface. Finally, buff buff buff.
The beeswax is completely safe of course. It is also very durable, it's repairable, and it is water repellant. I keep a jar of this in my finishing cabinet.
Another alternative is to apply a thick coat and leave it all on. Once the mineral spirits has evaporated, set the item in a low oven (my lowest setting is 170). The heat will allow even more of the wax to be absorbed into the wood fibers. I usually leave items in for 20 minutes or so, but it will depend on the size, mass, and wood species you are using. Let it cool then scrape and buff as before.
Straight beeswax is the oldest wood finish. And it's still one of the best for in the kitchen.

David Somers
12-05-2013, 12:18 PM
Hey John,

Thanks for the info! I did some digging and odds are quite good that the glues used in a hardwood plywood like you would encounter with a laser/engraver will have a urea-formaldehyde glue. Those glues are considered inert once they cure. I have not seen anything that says this is specifically rated "safe for food contact" yet but I have some feelers out to see. It is considered inert though which is a decent sign it is OK. For that matter, all of the glues I see used in plywood manufacture are considered inert once cured. (there are 3 basic types of glues.)

For example, a urea type glue is often used in vacuum forming industries where they are laminating hardwoods thins together in various shapes, typically for food service items. That is considered a safe use. Though again, I have to say I have not found any "food contact safe" designation on them yet. Just based on this peripheral info though I would feel OK producing something with this material for my own use at this point. I might prefer to see the Food Contact Safe designation before selling to the general public though.

Hope that helps!

Dave

Alan Sweet
12-05-2013, 12:30 PM
I believe that finishes are inert after they have been cured properly. I also believe that no matter what is used to finish a wood surface, there are people out there somewhere that will have some sort of physical reaction to it. And given the state of the legal system these days, three lawyers will file suits for everyone that do have a reaction to something you sold.

John Bion
12-05-2013, 12:32 PM
Hi Dave,
Thanks of your helpfulness and effort in research. I have seen a few things around-about made of these laminates (for food), and had wondered about the safety for human consumption off of them, putting aside for a moment the gasses potentially given off at engraving on a laser (although it is likely i will use a cnc router for this). Your comments have been encouraging.
Kind Regards and Thanks again, John

David Somers
12-05-2013, 12:59 PM
John,

I am being dense. I just noticed you are in the UK? Keep in mind I am in Seattle and have been looking at our designations for things? Our designations may have no bearing on where you live. I know there are often differences between what we consider safe and what the UK's or the EU's regulators consider safe. And then of course we have California, where distilled water will receive safety and health warning labels. They represent the very far end of the spectrum! <grin>

I am afraid I have no idea where to turn in the UK or the EU for information like this. For a product being sold they would be the folks I would want to run all this through. Not some New England Yankee transplanted to the left coast of the US! <grin> I will let you know when the info comes in from my queries though!

Dave

David Somers
12-05-2013, 1:13 PM
John,

So....info is starting to come back. Two plywood manufacturers have both replied saying they would NOT recommend their products for food contact. Still waiting to hear from my contact in our Public Health Service who has contacts with our FDA (Food and Drug Administration).

This is pretty interesting since I see Plywood products used for food stuff all the time. Though to be honest, now that I think of it, most all that I can think of appear to have been vacuum formed specialty shapes of hardwood or bamboo plies. They may be using specialty glues that are not being used in the primary manufacture of hardwood plywoods. I have also not noticed where the products were made....here in the US or somewhere else? Will have to look next time I am in that type of store. That will not be really soon though.

Dave

John Bion
12-05-2013, 1:20 PM
276382David, Many thanks, the principle is a guide though. California and Europe are about equally daft - in Europe it is illegal to advertise bottled water as an aid in rehydration of the body! The EU is also home of legislation as to how straight a banana must be in order to be sold. I am something close to a Texan in England :)
I look forward to hearing what you find in any case.
Kind Regards,
John

David Somers
12-05-2013, 1:26 PM
Stew,

Very true, I also keep a variant of this around. 5 parts Mineral Oil and 1 part Beeswax, melted and stirred together in a double boiler, then cooled and stored as a paste. Works great for many things. Only reason I use mineral oil rather than mineral spirits is the lower flammability and no odors or flavor to impart. I don't use it as often as I should. The walnut wax I use a lot is a similar makeup. (silly, but I just like the smell of that stuff)

Thanks for the reminder about this!!

Dave

Matt Turner (physics)
12-05-2013, 2:02 PM
As far as food-safe plywoods go, the folks at our local Rockler told me that their bamboo plywood is made with a food-safe soy glue. There's also a formaldehyde-free plywood that Home Depot sells called PureBond that is made with glue "derived from food-grade soy flour plus a wet strength resin used in printed currency and milk cartons." I don't know if this means that it is food-safe, but they do say "the soy flour in our glue is both kosher and halal."

Stew Hagerty
12-05-2013, 2:28 PM
Stew,

Very true, I also keep a variant of this around. 5 parts Mineral Oil and 1 part Beeswax, melted and stirred together in a double boiler, then cooled and stored as a paste. Works great for many things. Only reason I use mineral oil rather than mineral spirits is the lower flammability and no odors or flavor to impart. I don't use it as often as I should. The walnut wax I use a lot is a similar makeup. (silly, but I just like the smell of that stuff)

Thanks for the reminder about this!!

Dave

Dave,

I actually keep two varieties around. One is the wax & mineral spirits I mentioned before; and the other is 1 part wax (approximately 4 parts beeswax to 1 part carnauba wax), 1 part BLO, and 1 part mineral spirits. This is my variation on the traditional beeswax/linseed oil/turpentine blend. I altered it because BLO dries, turpentine has that odor, and carnauba wax is hard. I've used this on a few projects and I especially like it on my workbench.

Mel Fulks
12-05-2013, 2:31 PM
Interesting info about not using plywood. Since the plys are rotary peeled off maybe they infuse or spray something to make the wood cut better. Or they could just be giving cautious liability proof advice. I don't see how cured glue could be much of a factor.

Dee Gallo
12-05-2013, 3:12 PM
Steve,

I always cook with wooden spoons and spatulas, they are safe for handling food. I also eat with wooden chopsticks.

For a cake decoration, I imagine it has to handle being wet-ish so a finish is in order as you don't want oil on your icing. The amount of time it will be in contact with a tiny percentage of the cake will not cause a problem in my opinion. If you are really paranoid, attach it to an acrylic base.

Stew Hagerty
12-06-2013, 11:49 AM
Steve,

I always cook with wooden spoons and spatulas, they are safe for handling food. I also eat with wooden chopsticks.

For a cake decoration, I imagine it has to handle being wet-ish so a finish is in order as you don't want oil on your icing. The amount of time it will be in contact with a tiny percentage of the cake will not cause a problem in my opinion. If you are really paranoid, attach it to an acrylic base.

Dee,

I used to use wooden spoons and spatulas for cooking as well. But then I discovered Bamboo...
They are AMAZING!!! They don't pick up stains or get discolored, food doesn't stick to them, They last way longer (I don't know exactly how much longer because I haven't been able to wear mine out yet), and best of all you can put them in the dishwasher!