A Safe Non-Toxic Sealant for a Wooden Highchair?

updated Jul 17, 2020
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Q: What is a safe, nontoxic sealant for a wooden highchair? We have an old wooden highchair that has a tray with all the finish worn off. The tray had also broken in half where it was seamed together. I glued it together again, but I’d like to refinish it to make it easier to clean. It is in otherwise perfect condition and we want to use it for our grandchildren.

Sent by Pam

Editor: Here’s what our friends at Green Home Guide have to say:

Answered by Kirsten Flynn of Sustainable Home.

You bring up a very interesting issue with wood finishes for preserving green furniture. Wood finishes break down into two categories:

  • newer urethane finishes that basically are a strong layer of plastic that sits on the wood, and traditional oil, and
  • wax-based finishes that sink into the wood.

Oil and wax-based finishes tend to need renewal and replenishment. People started using urethane finishes because they are waterproof and low-maintenance, which would be a priority for a highchair that is wiped down time after time. However, there are pros and cons with each option.

Urethane finishes On the plus side, plyurethane finish is waterproof, and water-based formulatiopns can be low-odor low-voc. One obviously needs to wipe down a highchair frequently — I have seen rice cereal fly! This coating would most sponge-friendly.

  • The AFM Safecoat product line has three options of clear finishes. They are a paint and finishes company that originated to provide non toxic finish and coatings for those who were concerned about or sensitive to chemicals.
  • Another choice would be the Vermont Natural Coatings Poly Whey product. This is an interesting product because it uses whey proteins as the bonding agent, thus using less petroleum-based plastic. The whey is a renewable byproduct of the Vermont cheese industry. The product seems to have gotten good reviews from woodworkers thus far, although it is a fairly new company. I am eager to try their products myself!

On the minus side, polyurethane finishes are not traditional, and for that reason should never be used to refinish heirloom-quality antiques. Also, because the plastic coating is impervious and inflexible, it does not allow you to replenish the oils in the wood. Wood does tend to expand and contract, and polyurethane can crack, especially along seams. If this occurs, it is possible that a child might end up consuming a few flakes of the product.

Natural oil or wax-based coatings

The natural oil or wax-based coatings feed the wood and give it a more natural finish. The grain tends to show more than with urethane finishes. These finishes both coat and sink into the wood, but they are not impervious. I guess you could say they would be water repellent rather than waterproof. Since this kind of finish is used on wooden cutting boards or wooden food-prep surfaces, it is food safe.

  • Osmo, which makes natural floor finishes, also has two products that are good for furniture: the Wood Wax finish, and the Top Oil.

  • Another option is a pure oil finish, such as natural Tung oil.

These finishes require multiple coats to be durable, but are extremely easy to touch up. If the item gets scratched, just apply another coat of the oil and it will fill in the scratch. Re-coating also helps maintain the finish.

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