Killer Finishes

Every turner wants the perfect finish on a piece, but I took some time out and looked at the potential pitfalls and liabilities.

Introduction

You’ve got the sweetest ogee curve on a bowl, turned it to the ideal weight, and have sanded it to the smoothness of a baby’s bottom. The finish is the cherry on top that makes a piece literally and/or figuratively shine.

The right finish must show off the piece to its best advantage, be easy to apply, and give a resilient coating for whatever the piece will be used for. As someone who only recently learned to turn, I quickly realised what experienced turners know – every aspect of turning has more depth than a novice can imagine, and finishes are no exception. What if that shiny finish on your elegant bowl could make someone sick? It sounds melodramatic, but once it leaves your workshop you can’t control what that lovely bowl is used for and not all finishes are as safe as we might hope. But a few easy steps and you can ensure your turned items are killer beautiful, not killer fatal.

Selling Vs Gifting

When I first started turning, I gave items to friends and family. Bowls and pens and Christmas decorations – all the normal things. Then I set up an Etsy shop, and when I sold my first item (to America!), alongside the feelings of satisfaction and achievement was the dawning realisation that I’m selling items to people outside my circle of trust. This is no longer a hobby where I gift items to friends and family – I’m exchanging money for an item with someone I don’t know. If something went wrong, this isn’t a person I could just have a chat with.

Now, before you all start thinking this doesn’t apply to you, the difference between a gift and commercial item isn’t always that clear cut. I certainly know as a qualified electrician that the Health and Safety Executive don’t differentiate between volunteers and employees – you are always responsible for your work.

“Under the common law, voluntary organisations and individual volunteers have a duty of care to each other and others who may be affected by their activities. Where something goes wrong, individuals may, in some cases, sue for damages using the civil law if they are injured as a result of another person’s negligence.”

And even an accusation could be damaging and cause serious legal wrangles. For those who enjoy a good read I strongly recommend The Secret Barrister.

A few months ago, I was discussing with someone online how to get handmade lamps licensed for sale. Their insurance company had requested a product risk / COSHH assessment was completed. Each risk, some ridiculous, had to be rated in terms of likelihood and a response statement drawn up: warning on the package, certain production technique employed, or specific finish used.

Resorting again to my electrician knowledge I know that the IET BS7671 Regulations 18th Edition, which is the definitive non-statutory regulation on electrical installations, specifies in item 134.1 and repeated in 510.3 that:

“…The installation of electrical equipment shall take account of manufacturers’ instructions”

We’ve all discarded the slip of paper than comes inside every light fitting, packet of pills, tool or cleaning product – these contain those all-important manufacturers guidance. For finishes, most companies seem to make their Product Information Sheets, Test Certificates and/or Safety Data Sheets available online. Risk Assessments and Disclaimers are a thing – should we ignore our responsibilities because it’s a hobby and/or a gift?

Decorative, Toy Safe or Food Safe?

As woodturners we are lucky there is a huge range of products that we can turn to (pun intended). Easy to use gloss finishes, waxes and abrasive pastes as well as a fabulous range of stains, dyes and paints. It’s exciting to see small local companies establishing themselves as the go-to-product for certain finishes as a traditional craft continues to find new methods and techniques. But the range of labelling is baffling for the new turner and a minefield for veterans. Time to de-mystify. There are three common terms that you’ll see on finishes. Here’s the quick guide.

Nothing

The first is nothing. No claims at all. This is surprisingly common, and understandable for small companies, as testing to a standard is expensive. The additional costs of EN71-3 (for toys) or EU10/11 (for foods) tests are likely to be prohibitive to small finish manufacturers. This doesn’t mean that it’s a dangerous finish, it just means it’s untested. But neither does it mean it isn’t dangerous when used in the wrong way.

Toy Safe – EN71-3

This is the standard test for whether an object can be considered toy safe. It looks at potential hazards from sucking, licking, swallowing or prolonged skin contact when the toy is used as intended or in any foreseeable way bearing in mind how children behave. Even items that could be considered toys are included here.

There are three categories of toy material: dry, brittle or power like materials or those of a pliable nature; Liquids and sticky materials; and those that can be scrapped off. The main aim of the tests is to check that heavy metals and toxic chemicals do not migrate from the toy. In 2020 a new version of the standard comes into force with higher standards for Chromium and a better, more repeatable test method.

Food Safe – (EU10/11)

This is a much more stringent test than Toy Safe. The test is in three stages: beakers are coated with a range of finishes and these breakers are then filled with food simulants, namely:

  • A 3% Acetic solution. Also known as Ethanoic Acid is used to simulate acidic food. For reference, Vinegar is 4% Acetic Acid with water being the main ingredient. Another use for Acetic Acid is as a solvent so it’s easy to see how it has the potential to eat away at a finish.
  • A 95% Ethanol solution. This is a very strong alcohol that simulates fatty foods. In industry Ethanol is used as a solvent used to remove oils and waxes so again, we can see the potential for this to interfere with our finishes.
  • Iso-octane. Research has shown that Iso-octane behaves like Olive Oil in contact with other materials, but as it is a more practical substance to test with it is used as a further test to simulate fatty foods.

To perform the test, beakers are kept at 40 degrees Celsius for several days and the liquid is then removed and tested for any plastics that might have leached into it. The tolerances are very low. Terry at Chestnut wrote a blog post about the tests on his products, and says he wasn’t hopeful. As it turned out, many of their products passed two of the three tests with most failing on the ethanol solution test.

First amongst Equals?

Just because one product passes certain tests, it doesn’t mean that every product with the same name is manufactured to the same standard. It’s important to have documented evidence of the quality of a product if it’s going to be used or marketed as Toy or food safe, as a verbal confirmation wouldn’t hold up in a court of law. When I spoke to Terry at Chestnut, he emphasised that it is not just the product itself which has to be safe.

There are many grades of the same product (e.g. pharmaceutical / cosmetic, general use/industrial grade, organic (cosmetic or general use) and raw) and the process and handling system could result in a safe component becoming contaminated. What if a previously Toy Safe product has the grade of a component part downgraded in a cost saving?

I spoke to Liberon about their Black Bison Wax. Their Bison Wax used to have EN71-3 status, but they told me during a phone conversation where I was asking about the safety data sheets that although the composition is the same, it is no longer being marketed as Toy Safe because of the company isn’t prepared to pay the three yearly retest fees.

But the internet tells me that any product once cured is safe?

There are many articles in circulation on the web suggesting that any product (including Polyurethane Varnish) is safe once cured. In one example, the ‘cure test’ described is whether you can smell the finish. On the basis that my nose is terribly inconsistent and unreliable I’m not sure how scientifically robust this is and whether it would stand up in a court of law.

“I smelt it your honour!”

If we specifically consider whether Polyurethane finishes are toy/food safe, I found several published articles that almost exclusively claimed the same safe cure theory. However, an article published by the Centre for the Polyurethanes Industry in 2016 says something slightly different:

“…Food Contact Substance Notifications (FCNs)… establish clearances for some food contact applications associated with polyurethane formulations. Your polyurethane supplier can provide you with a list of any clearances applicable to its products… If it can be demonstrated through laboratory tests that no uncleared components migrate into food during the use of a specific formulation under its intended conditions of use… FCNs are not generic. An FCN is proprietary to the supplier and/or converter and may only be relied on by the manufacturer and its customers.”

If we put aside the chlorinated chicken differences between the FDA (U.S. Food and Drug Administration) and EU Regulations, I can safely say I would prefer to see a varnish on sale in my local shop that comes with a EU10/11 test approval completed. And for the record – I couldn’t find one or one that was available commercially at least.

One further comment – my research would suggest that Polyurethane is only conditionally resistant (depending upon the specific formulation used by a company at the time of manufacture) to Ethanol (the hardest test above) and could weaken the finish, especially when warm, causing cracking. I recently was lucky enough to dine at a local Michelin star restaurant who served my starter on a once varnished wooden platter. The varnish surface now had a certain ‘patina’ and I wondered where all those varnish flakes had ended up…

So just use Food Safe?

It’s tempting when faced with this information to just opt for the safest finish and disregard the plethora of excellent products that give your work the perfect finish. But that would be missing out. You can have it all!

I have put together a handy table which I keep printed off in my workshop that I follow for many finishes but specifically anything I intend as a toy or for use with food.

But if an item is purely decorative, I don’t for a second feel restricted and allow myself to indulge in experimentation!

Final Thoughts

When I asked other turners how they dealt with the issue of finishes and liabilities on the woodturning group of a popular social media platform I was met with responses that were disheartening. One person responding with a sick face emoji, another claimed they thought they had left this madness behind when they retired, and there was much agreement with this position. I’m going to suspect many of these people would run to the gutter tabloids if a child was accidentally poisoned by nuts in a meal. But in their hobby, many turners choose to ignore that they might be at risk of causing harm

Simple things you can do:

  1. Use reputable finishes of known quality.
  2. Keep a copy of product information and data safety sheets for the products you use.
  3. Keep a record of the finishes you use on the products you make.
  4. Be clear when you give or sell an item what it’s intended use is.

Nothing can save people from themselves. But when peace of mind is as easy as a little piece of paper, surely that is worth it.

References

  • Health and Safety Executive Website )https://www.hse.gov.uk/voluntary/when-it-applies.htm)
  • The Secret Barrister can be found on Twitter @BarristerSecret or https://thesecretbarrister.com/. The Book ISBN: 9781509841141 is for sale on Amazon and in all good book shops!
  • The Institution of Engineering and Technology BS7671 18th Edition (https://electrical.theiet.org/bs-7671/)
  • Wood Central – Food-Safe Finishes – Garrett Lambert (2003) (http://www.woodcentral.com/articles/finishing/articles_497a.shtml)
  • Popular Woodworking – Is Polyurethane Food-Safe? – Published in American Woodworker (June 2002) (https://www.popularwoodworking.com/techniques/q-a-is-polyurethane-food-safe/)
  • Made from Wood – Is Polyurethane Food Safe For Your Kitchen? – Scott Curry (https://www.makefromwood.com/is-polyurethane-food-safe-for-your-kitchen/)
  • Wood Magazine – Is Your Finish Food Safe – Editorial (https://www.woodmagazine.com/materials-guide/finishes/is-your-finish-food-safe)
  • Center for the Polyurethanes Industry – Guidance for the Use of Polyurethanes in Food Contact Applications (2016) (https://polyurethane.americanchemistry.com/Resources-and-Document-Library/10355.pdf)
  • Chestnut Products – Food Safe Finishes Special – Terry (2018) (https://chestnutproducts.co.uk/food-safe-finishes-special/)
  • Iso‐octane as fatty food simulant: Possibilities and limitations (https://www.tandfonline.com/doi/abs/10.1080/02652038809373680?journalCode=tfac19)

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