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Exterior Sign Clear Finish / Polyurethane Question

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Forum topic by Notbrick posted 08-27-2018 02:58 PM 1144 views 0 times favorited 9 replies Add to Favorites Watch
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Notbrick

42 posts in 528 days


08-27-2018 02:58 PM

Hello everyone. I am making a sign (first one) for my father to be placed on a dock shed. The board is laminated oak, and will paint the letters red. I am curious about the correct polyurethane finish to use on this. We are located in Missouri, however this will not see direct sunlight or weather, being covered by the dock roof.

Exterior-oil based ? Drying time, as I want to finish it before the weekend, also has tendency to yellow.
Exterior-water based ? Never used it before.
Interior-water based ? Concern that it may not handle the humid environment. Use inside with good results.

I understand that oil-based is primarily the way to go being outside. I just want to ensure no mold will come about, being in a rather humid climate.

Thanks for the input.
-Adam


9 replies so far

View BuffaloBrewer's profile

BuffaloBrewer

73 posts in 1237 days


#1 posted 08-27-2018 03:43 PM

Nice sign!

Take a look at spar polyurethane finishes. They are formulated for dealing with the outdoors. There are other products that are also good for exterior used such at Cetol (I use this on my boat and it holds up well).

View Fred Hargis's profile

Fred Hargis

5585 posts in 2912 days


#2 posted 08-27-2018 03:54 PM

You want to avoid anything “polyurethane”. The resins just don’t hold up in a high UV environment very well. If you want to use a spar, go with a true marine spar, such as Epifanes. Be aware, any clear finish is going to need maintenance over time….the key is to do it before the finish actually fails. You could also consider an untinted paint. If you get a deep color paint base (sometimes called #4) in an oil based exterior paint, it will look much like an oil based varnish (complete with the amber color shift) and hold up very well in an outside application.

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

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Notbrick

42 posts in 528 days


#3 posted 08-27-2018 06:31 PM

Thanks for the input. I will certainly take a look at the untinted paint, seems like a nice alternative after reading up a bit more on it. I appreciate the kind words on the sign as well. It was quite fun to make. About 54” wide, 12.5” tall

View DrDirt's profile

DrDirt

4577 posts in 4161 days


#4 posted 08-27-2018 07:33 PM

article I saw in wood magazine, said that you want to use the “Base 4 or 5”
the one for being tinted super dark.
The Base 1 is much more “White” as a base, and doesn’t dry as clear.

**I have not done this personally…. just reporting what I read about using base.

-- “The two most important days in your life are the day you are born and the day you find out why.” Mark Twain

View John Smith's profile

John Smith

1879 posts in 581 days


#5 posted 08-27-2018 07:48 PM

how did you laminate the oak panel ?? what adhesive, dowels, biscuits, etc.

from experience, polyurethane is not an adequate finish for ext. signs.

seal with the following:

and apply 5-10 coats of either Pettit or Epifanes: following the directions on the product.

any sign that is on or near the water will be exposed to 10 times more UV rays
than one that is not. totally your call as to how much you want to put into it.
but – oak is not a really good choice for an exterior sign: lots of pores and lots of movement
in the wood that will break down any finish in a very short time. (2-3 years).
also – red paint will fade pretty quickly if not top coated with the Pettit.
apply the same number of coatings to all sides: front, back and all edges.
nice work !!!

Edit: I just noticed you said you want to get this done before the weekend.
well – to push it through quickly using oak, you will be redoing the entire sign
in the near future. . . . sealing and finishing for prolonged outside exposure takes time – - –
my suggestion would be to just put on the sealer coats and install it for the weekend.
then, when you get ready to come home, bring the sign home with you and finish it properly.

.

.

-- I am a painter. That's what I do. I paint things --

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Notbrick

42 posts in 528 days


#6 posted 09-04-2018 02:25 PM

Thank you for the help everyone. I ended up using the a non tinted deep oil base from Sherwin Williams. Strangely enough, the salesman could not sell it to me without it being tinted, and had to call his manager for approval. Used a 0,0,0 paint code, which I found humorous. Like mentioned above, it looked like a watered down chocolate milk in the can, but dried nearly clear, with a nice amber shift. The colors popped quite well. Used my Critter for application of 3 coats with a day to dry between.

The sign painted and hung. My father was very surprised and loved receiving it.


View Fred Hargis's profile

Fred Hargis

5585 posts in 2912 days


#7 posted 09-04-2018 02:36 PM

That circumstance (not selling it without being tinted) is a common reply by the counter folks, and pure BS. It also depends on the store you visit. I’ve picked it up off the shelf and carried it out, and also had to argue the point.

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

View John Smith's profile

John Smith

1879 posts in 581 days


#8 posted 09-04-2018 02:49 PM

very nicely done!
it took a few minutes and increasing the scale to see what the sign says.

M.A.R.C. Aritaville a spinoff from Jimmy Buffett.

.

.

-- I am a painter. That's what I do. I paint things --

View Notbrick's profile

Notbrick

42 posts in 528 days


#9 posted 09-04-2018 03:09 PM

Thanks John. Yes, my father used a spin off of our first name initials. He also very much enjoys his margaritas.

Time will tell how it holds up. We plan to take it down during the winter time when boating season come to an unfortunate break. It should help keep a little extra life to the sign. I was quite fun to make.

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