Finish for railing in historic building

[Richo B]

We have handrails/banisters in a historic building that need to be recoated prior to cleaning everyday for COVID while open. The surfaces were finished with shellac back in the 1960's but most likely never since. I've done tests on the surfaces and it appears anywhere that hands most likely touched no longer have much shellac except in the pores. The other sections where hands do not touch still retain most of the shellac applied in the 1960's.

There is shellac like I make in the lab which is a mixture of shellac flakes in denatured alcohol and there is the commercial shellac that you can buy, like Zinsser Bulls eye, that contains additives that I use at home on my own woodworking. Normally in Conservation we don't use anything that can't be easily reversible or could harm the materials involved. However in this case we may need something that will work without easily coming off either with sweaty hands or with the solution I will be using to clean against COVID which consists of a surfactant in water which will break apart the envelope that contains the virus, killing it. So whatever is used has to be able to withstand some water but not as powerful or hard to remove in the future like polyurethane.

Any ideas? I'm not as knowledgeable on modern varnishes, lacquers or shellacs as I am on other areas.

 

[Mike Davis]

Only thing that comes to mind is marine spar varnish.

 

[KenOfCary]

Not sure how well Lacquer would hold up to the usage element. It is pretty water resistant though.

You have a unique situation there. Might be a good question for an expert at one of the woodworking magazines. Although there are some pretty experienced people here. I'm not really one of them.

 

[Charles Lent]

I too, would like an answer to this, since a significant portion of my home was finished with orange shellac. It's easy to repair the worn areas or make remodeled areas match, but not at all great for high wear or places that need to be cleaned frequently, especially if the cleaners contain alcohol. I have a railing that needs refinishing now.

Charley

 

[Joe Scharle]

I'd favor more shellac. It's easier to slap on more shellac (no sanding required) than to sand and re-coat with varnish.

 

[Jeff]

The old shellac probably contains the wax from the lac bug (there wasn't dewed shellac in the 1960s) so I'd suggest Zinsser Shellac from Lowe's or HD. That old shellac is about 50 years old.

What is the name or brand of the cleaning/disinfecting product that you'll be using ?

 

[Graywolf]

The real question is do you want to stay true to the history of the railing. With that you incur a higher level of maintenance. Or do you change the finish to a more durable but inappropriate coating with lower maintenance. I don’t envy that decision.

 

[Jeff]

I will be using to clean against COVID which consists of a surfactant in water which will break apart the envelope that contains the virus

Many of those are quaternary ammonium salts so they shouldn't have any effect on the shellac.

 

[Richo B]

What is the name or brand of the cleaning/disinfecting product that you'll be using ?
[/QUOTE]
I am making a solution of Orvus (sodium laurel sulfate) in water at a very diluted percent. Orvus is a common conservation surfactant with a neutral pH primarily used with textiles but I have also successfully used it for cleaning marble and limestone statues. For this application you only need about 1% of the Orvus for the water as it is pretty powerful stuff. For obvious reasons I can't use alcohol, ammonia or some of the other materials used in standard disinfectants. I did some experimentation with hydrogen peroxide 3% in water that did work and didn't disturb the finish but I've not seen enough supporting evidence on this from other museums and peroxide can be damaging to any metals or fabric that are near the surfaces being treated. It might be fine for me to use in a controlled situation but I wouldn't hand it off to someone else with less training to clean with.

 

[mdbuntyn]

I'm not sure if this will be of any help, but I poured out some of the disinfectant from a container of Clorox wipes onto a (failed project) board that has several coats of 1½ lb cut shellac that I mixed from flakes and 190 proof grain alcohol.

After close to 10 minutes, I wiped the puddle away, and the only "damage" was hazing beneath the puddle. The shellac didn't feel sticky, and I couldn't detect any humps, for lack of a better term, at the transition from hazy to normal areas.

 

[Richo B]

I've contacted a couple fellow furniture conservators who are among my mentors in the field and they have made a strong suggestion: Reshellac the surface with traditional shellac first and then adding Mohawk Finish Up (water clear urethane) getting either gloss or matte and possibly mixing the two up to get the right sheen. The shellac will hold up to water but the urethane will be even more resistant. The first banister that is being done is a more practical servants stairs and not a grand staircase, though that will have to be done at some point as well.

I've got an account with Mohawk and shouldn't have trouble acquiring some but that takes time. Is there something that might be an equivalent that can be purchased at one of the big box stores instead?

 

[Richo B]

I'm not sure if this will be of any help, but I poured out some of the disinfectant from a container of Clorox wipes onto a (failed project) board that has several coats of 1½ lb cut shellac that I mixed from flakes and 190 proof grain alcohol.

After close to 10 minutes, I wiped the puddle away, and the only "damage" was hazing beneath the puddle. The shellac didn't feel sticky, and I couldn't detect any humps, for lack of a better term, at the transition from hazy to normal areas.

Very interesting. Clorox wipes generally tend to have a little less of the nasty stuff in them and tend to contain more water. They are meant to be used by anyone who probably aren't wearing gloves or other safety protections. I had originally told the custodians that it was ok to use them on the banisters in some of the historic houses where I knew the shellac was from the twentieth century. Clorox used in small doses or on the surface without aggressive rubbing shouldn't cause any issues but long-term usage over time could add up. When I was initially working on researching this back in March I was thinking we would be doing this for several months. Now I have to consider that this cleaning system and the surfaces involved may be done for several years, with or without a vaccine. I can't take chances with our surfaces with just anything.

 

[Jeff]

I will be using to clean against COVID which consists of a surfactant in water which will break apart the envelope that contains the virus, killing it.

Orvus probably won't kill COVID it's a mild surfactant cleaner used by conservators. Clorox hand wipes are a mysterious mixture that don't contain "bleach" but they do contain isopropyl alcohol which could harm shellac over time.

 

[Oka]

Here is an Idea I did this once on some cabinets. They came out bullet proof. I used the clear coat hybrid poly/enamel used on a car. It was 2 part and I shot a tack coat then reduced and shot 2 more coats. The cabinets looked like new 10 years later. Check with Sherwin Williams or PPG professional finishes divisions. They might have some suggestions.

 

[Richo B]

Orvus probably won't kill COVID it's a mild surfactant cleaner used by conservators. Clorox hand wipes are a mysterious mixture that don't contain "bleach" but they do contain isopropyl alcohol which could harm shellac over time.

Sorry I didn't write this out completely. I'm not using the Orvus to "kill" the virus directly like alcohol or bleach would. The Orvus is used to break apart the viral envelope that houses the virus. The virus cannot live outside of that envelope.

From National Center for Preservation Technology and Training:
All viruses are bits of genetic code bundled inside a collection of lipids and proteins, which can include a fat-based casing known as a viral envelope. It’s this fatty envelope that makes COVID-19 susceptible to soap and water, which washes it away and causes the virus to fall apart.

They suggest the use of Orvus or Ivory soap to do this work. Since the use of alcohol or bleach is not possible for us conservators in this instance, Orvus is something we have and can use in small diluted doses with distilled water, using distilled water to then rinse it away. This method is suggested by the NCPTT (see above), Canadian Heritage, National Park Service, and American Institute of Conservation. I've also run it by some healthcare and surgery professionals and they agree as well.

 

[Jeff]

They suggest the use of Orvus or Ivory soap to do this work. Since the use of alcohol or bleach is not possible for us conservators in this instance, Orvus is something we have and can use in small diluted doses with distilled water, using distilled water to then rinse it away. This method is suggested by the NCPTT (see above), Canadian Heritage, National Park Service, and American Institute of Conservation. I've also run it by some healthcare and surgery professionals and they agree as well.

Thanks. That's useful information.

 

[Graywolf]

Richo thanks for the useful research and info. I learn new stuff everyday from everyone. Thanks!

 

[Oka]

Also can use Thymol oil. It is from the Thyme herb, I believe that is what is in Meyers organic soap. It is also FDA approved for killing viruses and disinfecting.