Finishing advise...

[KevTN]

I hope everyone is doing well. I am building an epoxy sign out of Hard Maple. This sign will be outdoors near the Tennessee River (moisture). I was thinking of finishing with 3-4 layers of Shellac. I am doubting myself but what finish would you use? Thanks

[Grandpadave52]

For a one-off project, my choice would be THIS.. It's also available in quarts. I think you can get matte finish in the quarts. The rattle can is only available in gloss and semi-gloss.

 

@kmealymay have other suggestions.

[PeteM]

House paint is my #1 choice for anything outdoors, but I agree once you've invested in maple, seems sad to hide it.  For this year, anyway; 5 years from now when you're tired of fussing with peeling finishes, might have a different take.  There are outdoor "clear" finishes such as various "spar" products (I'd get it in a non-spray for cost control).  If you were planning on staining colors into the wood before finishing, UV exposure might change the colors in spite of whatever top coat you use.  Also, you probably have to renew the top coat every 2~4 years anyway.  It "resists" UV, but does not defeat it.

[lew]

Doesn't shellac react with water/moisture? I'm thinking about how a wet glass can make a "ring" on shellac finished furniture.

 

Is the sign very large? Maybe use a poured finish like they use on restaurant bar tops? 

[DAB]

spar urethane?

[Fred W. Hargis Jr]

You don't want to use shellac on anything outside. It's just not good outdoors. Any outdoor clear finish will need to be maintained, none of them last forever....some of them don't last very long at all. It you want it to be absolutely clear, you'll need a waterbased finish. I have no suggestions since I've not tried any that ever worked that well...I'm not saying good waterbased exterior finishes aren't available; just that I don't know which ones they are. If it was my sign paint would be the ultimate long lasting finish....but if I had to have it clear I'd probably choose a true marine spar varnish. You don't want anything that says "urethane", urethane resins don't do well in the sun either, a good consumer level marine spar might be McCloskey's Man O war, I've used it with good success. Otherwise the ones at marine suppliers (Epifanes comes up often as a good one) would be a good choice. They (marine) will also be quite expensive and probably take many coats for max protection. Any of these oil based finishes will shift the color, the maple itself will also shift over time....so maybe paint wouldn't be a bad choice after all. That said, some years ago when you could buy it exterior oil based paint with no tint would cure looking very much like varnish, and last a very long time. This would be the exterior tint base for the darkest colors, I always used Olympic base #5. Left untinted it was a very good outdoor finish. Somewhere in the intervening years it became unavailable and I haven't found another paint base that worked as well. The first can of Olympic I bought at Lowes was when they had the mixing paint behind a chain link fence with a gate for the employees. I told the young lady I didn't want it tinted...she replied "we can't sell it like that". Rather than argue, I waited for her to walk away and snuck back and grabbed a can.

Edited July 3, 2024 by Fred W. Hargis Jr

[DAB]

as you may be gathering, there are very few finishes that are "apply once, it'll last forever outside"  even bare wood will change color over time (pine goes from honey colored to grey).

 

weather is tough on everything, including wood.

 

i have a wood beam outside my back door, and i have to refinish it with Spar urethane every 3-4 years, sanding to bare as needed, then putting on 3-4 coats.  it faces east.

 

so....you want it to look good (sealed maple), or do you want it to last (stamped metal).

 

even carved marble weathers over time, go visit any graveyard.

[Ron Dudelston]

I’m with DAB, marine spar

[KevTN]

On 7/3/2024 at 11:12 AM, lew said:

Doesn't shellac react with water/moisture? I'm thinking about how a wet glass can make a "ring" on shellac finished furniture.

 

Is the sign very large? Maybe use a poured finish like they use on restaurant bar tops? 

The sign is 15 x 24. I wasn’t sure about shellac. I have not an outdoor sign for someone before and just feel kinda lost lol.

[KevTN]

On 7/3/2024 at 1:52 PM, Fred W. Hargis Jr said:

You don't want to use shellac on anything outside. It's just not good outdoors. Any outdoor clear finish will need to be maintained, none of them last forever....some of them don't last very long at all. It you want it to be absolutely clear, you'll need a waterbased finish. I have no suggestions since I've not tried any that ever worked that well...I'm not saying good waterbased exterior finishes aren't available; just that I don't know which ones they are. If it was my sign paint would be the ultimate long lasting finish....but if I had to have it clear I'd probably choose a true marine spar varnish. You don't want anything that says "urethane", urethane resins don't do well in the sun either, a good consumer level marine spar might be McCloskey's Man O war, I've used it with good success. Otherwise the ones at marine suppliers (Epifanes comes up often as a good one) would be a good choice. They (marine) will also be quite expensive and probably take many coats for max protection. Any of these oil based finishes will shift the color, the maple itself will also shift over time....so maybe paint wouldn't be a bad choice after all. That said, some years ago when you could buy it exterior oil based paint with no tint would cure looking very much like varnish, and last a very long time. This would be the exterior tint base for the darkest colors, I always used Olympic base #5. Left untinted it was a very good outdoor finish. Somewhere in the intervening years it became unavailable and I haven't found another paint base that worked as well. The first can of Olympic I bought at Lowes was when they had the mixing paint behind a chain link fence with a gate for the employees. I told the young lady I didn't want it tinted...she replied "we can't sell it like that". Rather than argue, I waited for her to walk away and snuck back and grabbed a can.

Thank you for this information. I would like to keep as clear as possible as the customer said liked the wood color with the epoxy. I have tried to read up on it but got overwhelmed. 

[KevTN]

On 7/3/2024 at 2:08 PM, DAB said:

as you may be gathering, there are very few finishes that are "apply once, it'll last forever outside"  even bare wood will change color over time (pine goes from honey colored to grey).

 

weather is tough on everything, including wood.

 

i have a wood beam outside my back door, and i have to refinish it with Spar urethane every 3-4 years, sanding to bare as needed, then putting on 3-4 coats.  it faces east.

 

so....you want it to look good (sealed maple), or do you want it to last (stamped metal).

 

even carved marble weathers over time, go visit any graveyard.

I agree. I can finish it with spar and I can write down instructions for care for the customer.

[KevTN]

Thank you for everyone who spent the time to answer my question and give insight I do appreciate it.

[lew]

https://www.bestbartopepoxy.com/blogs/ultraclear/will-epoxy-hold-up-outside

[Grandpadave52]

This was in my email today. Wood Magazine eNewsletter: Breakdown of outdoor finishes HERE. 

[kmealy]

On 7/3/2024 at 1:52 PM, Fred W. Hargis Jr said:

You don't want to use shellac on anything outside. It's just not good outdoors. Any outdoor clear finish will need to be maintained, none of them last forever....some of them don't last very long at all. It you want it to be absolutely clear, you'll need a waterbased finish. I have no suggestions since I've not tried any that ever worked that well...I'm not saying good waterbased exterior finishes aren't available; just that I don't know which ones they are. If it was my sign paint would be the ultimate long lasting finish....but if I had to have it clear I'd probably choose a true marine spar varnish. You don't want anything that says "urethane", urethane resins don't do well in the sun either, a good consumer level marine spar might be McCloskey's Man O war, I've used it with good success. Otherwise the ones at marine suppliers (Epifanes comes up often as a good one) would be a good choice. They (marine) will also be quite expensive and probably take many coats for max protection. Any of these oil based finishes will shift the color, the maple itself will also shift over time....so maybe paint wouldn't be a bad choice after all. That said, some years ago when you could buy it exterior oil based paint with no tint would cure looking very much like varnish, and last a very long time. This would be the exterior tint base for the darkest colors, I always used Olympic base #5. Left untinted it was a very good outdoor finish. Somewhere in the intervening years it became unavailable and I haven't found another paint base that worked as well. The first can of Olympic I bought at Lowes was when they had the mixing paint behind a chain link fence with a gate for the employees. I told the young lady I didn't want it tinted...she replied "we can't sell it like that". Rather than argue, I waited for her to walk away and snuck back and grabbed a can.

Agree with this.  

"Spar Urethane" always seemed a bit of an oxymoron to me -- urethanes have very low UV resistance.  Spar generally means a higher percentage of oil in the varnish recipe so it's softer and more flexible.  Which also makes me wonder why people like it so much for inside projects.  I was at a doctor's house once doing some other work and they asked me why there were so many pen impressions on the new built-in  desk.  I asked if they knew what finish had been applied and they went to a closet and pulled out the can of Helmsman.  QED
 

 

If you want untinted paint you might just say that you have UTCs and make your own colors.

Edited July 5, 2024 by kmealy

[KevTN]

On 7/5/2024 at 12:33 AM, Grandpadave52 said:

This was in my email today. Wood Magazine eNewsletter: Breakdown of outdoor finishes HERE. 

Very interesting article. Thanks.