Finishing signs for outdoor weather (Cedar)

[TurtleCove]

I've got a guy that wants me to carve about 50 various signs, that he'll be posting throughout 100 acres of woods.

I don't know the difference between polyurathene, urathene, spar urathene, or all those other "-thenes" out there.

He likes the look of Aromatic Cedar, plus Cedar holds up well outdoors.

What you some of you suggest for a clear finish, on these signs. He'd like to preserve the red color of the cedar. I think almost any of these clear finishes break down in time, and cedar will end up turning brown, but I'm hoping some of you can tell me what works best for preserving your outdoor signs.

[Ike]

I've got a guy that wants me to carve about 50 various signs, that he'll be posting throughout 100 acres of woods.

I don't know the difference between polyurathene, urathene, spar urathene, or all those other "-thenes" out there.

He likes the look of Aromatic Cedar, plus Cedar holds up well outdoors.

What you some of you suggest for a clear finish, on these signs. He'd like to preserve the red color of the cedar. I think almost any of these clear finishes break down in time, and cedar will end up turning brown, but I'm hoping some of you can tell me what works best for preserving your outdoor signs.

In my sign shop I use water based polyurethane called Hydrocote polyshield from Hood products http://hydrocote.com/our_products.htm

It works well and last a good period of time and the most important thing with polyurethane it is non yellowing. So if any of your signs have white lettering it will not yellow the letters. With varethanes and urethanes lacquer, varnish they have an amber tint that yellows or browns white or bright letters.

Marine varnish same thing, I like water based because it is easy to spray with a HLVP sprayer. If you spray anything too thick you will get a quick build up in the letters that will be yellow. To help with that I spray a clear like Krylon clear except I use Walmart clear just on the letters. No do not spray several coats with the WM clear and then the water base. The last coat will peel off been there done that!

Anyway that is what has worked for me for the last 25 years or so!

Ike

[TurtleCove]

ok, Ike...let me summarize, so I'm clear:


You suggest I use a polyurethane.
The particular brand of polyurethane you suggest, is Hydrocote Polyshield
Polyurethane is non yellowing, thus white letters, should stay nice and white.
Marine Varnish will yellow also, along with varethanes, urethanes, and all lacquers and other Varnishes.
You suggest a thin coat, sprayed. Maybe 2 thin coats?
You suggest water based polyurethane for ease of application.
And last, I think you suggest spraying the letters with a light coat of clear Krylon (or Walmart equivalant), and then polyurethane over top of the letters and entire board



Did I get things right, Ike?

[TurtleCove]

Do you konw if polyurathene has a UV blocker, to prevent my cedar from turning brown?

[TurtleCove]

As for application, I usually brush on, or rub on my finishes.
I'd love to spray them on, and I have a 5hp compressor...but I have some questions:

If I use something like this:
http://www.hoodfinishing.com/Products_info/LYNX_Spray_Gun.pdf

Can I keep my polyurathene in the spray cup ? Or do I have to pour it back into the can, and then clean up the cup?

Do I have to clean the gun out someway, after each use, if I'm using water based polyurathene?

[Chief]

Turtle,

For what a good HVLP gun that works with a compressor would cost you, take a look at Rockler's HVLP system. It's about $90 and is so simple to clean that it makes me wonder why Rockler's so smart. It doesn't have the 25' hose that my professional HVLP setup has but I don't have the room to use that in my workshop.

I use a different brand than Ike uses but that's individual preferences. After shooting a coat with your HVLP, wipe the tip clean. Don't open or loosen the paint cup and you're good to go. I do one coat per hour and only when I'm finished do I have to do anything and it's only about 5 minutes of work.

I pour what left back into the can, replace the poly with water and spray for a minute or two. Dump the can and take the gun apart. The only tool you'll need is a pain of needle nose pliers to grab the end of the needle. Just rinse the parts and dry or set aside to dry. You're done. Rockler's whole system doesn't take up much more than my pro system's hose. I don't know whether it's a two stage or 3 stage system but the gun has 2 needles. When I bought a new needle and cap for my HVLP, I think I paid $110. That's not for the gun but one needle and one cap. I wish Rockler had this system out before I bought mine.

Chief

[JDPratt]

ok, Ike...let me summarize, so I'm clear:



Polyurethane is non yellowing, thus white letters, should stay nice and



Did I get things right, Ike?

Don't assume that all Polyurethane is non-yellowing. some brands are and some are not. Check the label. I believe the brand that Ike is recommending is a non-yellowing brand. The krylon Clear is definitly non-yellowing (from past experience) and of course it says so on the side of the can.

John

[Rocky]

In my sign shop I use water based polyurethane called Hydrocote polyshield from Hood products http://hydrocote.com/our_products.htm

It works well and last a good period of time and the most important thing with polyurethane it is non yellowing. So if any of your signs have white lettering it will not yellow the letters. With varethanes and urethanes lacquer, varnish they have an amber tint that yellows or browns white or bright letters.

Marine varnish same thing, I like water based because it is easy to spray with a HLVP sprayer. If you spray anything too thick you will get a quick build up in the letters that will be yellow. To help with that I spray a clear like Krylon clear except I use Walmart clear just on the letters. No do not spray several coats with the WM clear and then the water base. The last coat will peel off been there done that!

Anyway that is what has worked for me for the last 25 years or so!

Ike


I have a HLVP sprayer but have never used it. Never could figure out how to get the right paint consistency. Can you use the Hydrocote right out of the can without having to thin it?

[Ike]

I have a HLVP sprayer but have never used it. Never could figure out how to get the right paint consistency. Can you use the Hydrocote right out of the can without having to thin it?

Rocky, yes you can spray it without thinning or the need for a sealer first. It is self leveling and I don't just believe it is non yellowing it is non yellowing. Urethane on the other hand is yellowing, now I haven't checked every can of polyurethane, but all the the ones I have used and seen are non yellowing.

Exterior use of polyurethane varnish may be problematic due to its susceptibility to deterioration through ultra-violet light exposure. It must be noted, however, that all clear or translucent varnishes, and indeed all film-polymer coatings (i.e., paint, stain, epoxy, synthetic plastic, etc.) are susceptible to this damage in varying degrees. Pigments in paints and stains protect against UV damage, while UV-absorbers are added to polyurethane and other varnishes (in particular "spar" varnish) to work against UV damage. Polyurethanes are typically the most resistant to water exposure, high humidity, temperature extremes, and fungus or mildew, which also adversely affect varnish and paint performance.

However there are products like marine polyurethane varnish that contain an amber tint that will yellow white paint.

Krylon yes is clear and does state is for exterior use, but from experience is not a good finish for outdoor signs.

Ike

[Rocky]

Rocky, yes you can spray it without thinning or the need for a sealer first. It is self leveling and I don't just believe it is non yellowing it is non yellowing. Urethane on the other hand is yellowing, now I haven't checked every can of polyurethane, but all the the ones I have used and seen are non yellowing.

Exterior use of polyurethane varnish may be problematic due to its susceptibility to deterioration through ultra-violet light exposure. It must be noted, however, that all clear or translucent varnishes, and indeed all film-polymer coatings (i.e., paint, stain, epoxy, synthetic plastic, etc.) are susceptible to this damage in varying degrees. Pigments in paints and stains protect against UV damage, while UV-absorbers are added to polyurethane and other varnishes (in particular "spar" varnish) to work against UV damage. Polyurethanes are typically the most resistant to water exposure, high humidity, temperature extremes, and fungus or mildew, which also adversely affect varnish and paint performance.

However there are products like marine polyurethane varnish that contain an amber tint that will yellow white paint.

Krylon yes is clear and does state is for exterior use, but from experience is not a good finish for outdoor signs.

Ike


Thanks, Ike.