Proper way to Seal an Exterior Sign... HELP!

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Forum topic by Proflemoi posted 12-03-2015 02:46 PM 1020 views 0 times favorited 18 replies Add to Favorites Watch
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37 posts in 1225 days

12-03-2015 02:46 PM

Hello All,

I am sure this has been covered (but I can not find it) so I will ask here…

I have a Carved Maple Sign (See below) that I need to seal so it stays all nice and pretty. I have applied 3 coats of stain in the areas you see but the rest of the sign is just bare wood. Can you tell me what I should seal this sign with to protect it from the elements? The sign will be outside in Maine, they get a lot of SNOW, rain, wind, etc… so I will hope to find a sealer / process that will keep the sign protected from that rough environment.

Thank you!

Prof L

-- Probotix Asteroid

18 replies so far

View pjones46's profile


1001 posts in 2844 days

#1 posted 12-03-2015 02:53 PM

I would use a good quality Spar varnish such as those from where they urge customers to periodically refresh a varnish finish with a maintenance coat or two, the frequency depending on amount of direct exposure to UV generally.

By the way, great sign.

-- Respectfully, Paul

View Proflemoi's profile


37 posts in 1225 days

#2 posted 12-03-2015 02:57 PM

Thanks Paul, I had thought about that but after asking a friend who went to the Boat School in Eastport, Me he suggested that Spar Varnish might yellow over time…

They sell Spar Varnish at Home depot… I was really hoping to find something great that I could buy from either Lowes or HD, but if in the end I have to order online something I will…. just running out of time as this is a Christmas Present…

Prof L

-- Probotix Asteroid

View Fred Hargis's profile

Fred Hargis

5176 posts in 2695 days

#3 posted 12-03-2015 04:07 PM

If you really want to be crying in a years time, buy a spar at a box and use it. Any of the oil based finishes will yellow over time. The with urethane resins will flake and peel quickly. If you want to avoid the yellowing, you’ll need to go with a waterborne. There are several good ones, the one I have3 the most experience with is the General finishes HP, it’s UV stabilized and a very good finish. You could also use an untinted exterior paint . The link I provided talks about oil based paints, and they will yellow…but some of the waterborne formulas also work, and dry crystal clear….SW exterior A-100 is one as well as Olympic Premium gloss exterior. Bear in mind, any outdoor finish will need renewing over time, do it soon enough and the job is easier. Also, the wood itself may change color over time unrelated to the finish.

-- Our village hasn't lost it's idiot, he was elected to congress.

View Fettler's profile


200 posts in 2198 days

#4 posted 12-10-2015 10:30 PM

I second epifanes marine varnish. Don’t waste your time with a Home Depot varnish. If it’s not sold at your marine supply shop you probably done want anything to do with it.

The problem with using something like a poly is that in a year or two (in the PNW more like 6 months) it will need to be refinished. Epifanes layers tells to flake off when they begin to fail and some light sanding easily removed the bad layers. More layers equals better protection.

Epifanes will definitely add an amber tone. Whatever finish you end up with make sure it has a good UV additive to prevent fading.

-- --Rob, Seattle, WA

View AandCstyle's profile


3179 posts in 2459 days

#5 posted 12-10-2015 11:30 PM

Prof, I used Cetol Door & Window on a west facing door in north Texas about 4 years ago and it still looks like the day I applied it. It will darken the wood to some extent so test it on scrap first. It is available in sample size containers.

-- Art

View MrUnix's profile


7050 posts in 2400 days

#6 posted 12-10-2015 11:40 PM

Might not be applicable, but I’ve made quite a few house signs (names, house numbers, etc..) that are destined to live outdoors in full weather without any cover. Dark areas get an exterior grade paint, and the exposed wood just gets water sealant. I’ve been using Thompsons as that was what I have on hand, but I’m sure there are other brands that work as good or better. We don’t get snow down here in FL, but lots of rain and some pretty strong sun.


-- Brad in FL - In Dog I trust... everything else is questionable

View BurlyBob's profile


5983 posts in 2467 days

#7 posted 12-11-2015 02:29 AM

Check out Jamestown Distributors. They have a lot of marine epoxy finishes and are very helpful to talk with about anything. I’m thinking a coat of that fiberglass top coat resin might be an option. I know it’s pretty darn tough. You won’t want to do it anywhere near the house. It’s got a pretty powerful odor.

View ThomasChippendale's profile


244 posts in 1134 days

#8 posted 12-11-2015 03:50 AM

Maple is going to require serious protection to survive in an outdoor environment, especially in Maine. Epoxy is a good protection but will need an overcoat of spar varnish so it can survive UV. Cetol will require constant overcoating and if left unattended, will cause the sign to degrade rapidly. Water based finishes will not last in that environment and over a wood that is just not meant to be outdoor. Conclusion; thick epoxy coating on all surfaces with a spar varnish overcoat .

-- PJ

View TiggerWood's profile


271 posts in 1808 days

#9 posted 12-11-2015 04:38 AM

I use teak oil for anything outdoors. It tints it a slight golden brown but the protection it gives is amazing.

View Harry's profile


80 posts in 1381 days

#10 posted 12-11-2015 05:03 AM

A friend in the sign business turned me on to Permalac. Bulletproof on wood, metal and stone.


-- Harry - Professional amateur

View Tennessee's profile


2893 posts in 2716 days

#11 posted 12-11-2015 12:16 PM

Boy, I’ll say one thing…I learned more about outdoor finishes in the last 15 minutes reading this post than I could have visiting multiple stores!

-- Tsunami Guitars and Custom Woodworking, Cleveland, TN

View dhazelton's profile


2793 posts in 2498 days

#12 posted 12-11-2015 01:04 PM

Just be prepared to throw in the towel and paint that in a couple of years. You could use gold leaf or something on the letters so it doesn’t have to be considered a fail.

View Proflemoi's profile


37 posts in 1225 days

#13 posted 12-11-2015 01:51 PM

So much great information! I the end I have decided to try the Waterbed EXTERIOR 450 SATIN Varnish. I went to the General Finishes website and read up on all their finishes….the Exterior seems like it might be worth a shot. I will put on 3 coats as that seems to be the magic number. I have used the General Finishes products in the past (especially their Gel Products) and have been VERY pleased …

Since I will be doing a lot of signs in the future can you guy point me to the wood you recommend for outside signs. Teak is really more expensive then I can afford… so what are your other recommendations?

Thanks again ALL! I have learned a great deal!

-- Probotix Asteroid

View TiggerWood's profile


271 posts in 1808 days

#14 posted 12-11-2015 02:51 PM

Cedar. It’s naturally bug resistant. I made my mail box stand with it and a coat of teak oil five years ago and it’s still just like the day I made it.

View ThomasChippendale's profile


244 posts in 1134 days

#15 posted 12-11-2015 03:57 PM

Having been around boats for 45 years the best wood is Teak but as you mentionned, it is costly and you may not get the contrasts you want. The Maple, beech, birch type woods are not meant to be outdoor, I have used some in the past and rapidly they developed rot and did not resist whatsoever in an outdoor environment.

White Oak is commonly used in boatbuilding, it will resist outdoor even if neglected. Most mahoganies will also be good and they take varnishes and stains so well that they are easy to maintain. BC Fir would also be a good choice, I hear Locust is also good but I haven,t used it.

-- PJ

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