I have a clear heart redwood sign that I need to clear coat. I am going to laser engrave some detail and my engraver suggested I clear coat first. The entire sign will be clear coated for the final product. I have used mostly marine spar varnish, but I also have shellac available. which is best for long lasting exterior finish?
Thanks!
Posted by Preston McCall (Member # 351) on :
Neither, I have found. I did a heartwood, quartersawn redwood sign, 48x96 in 1980. Goldleafed the letters after sand blasting with four coats of a good primer and gold size. It is still looking good! No redwood sealer at all. Even the gold has kept on there and still a nice sign.
I also restored a 47 Pontiac Woody with major new ash woodwork. Huge money spent on new major structural and decorative ash work. This was a major restoration as the wood was quite rotted. I finished the ash in ten coats of spar varnish and sanded, steel wooled and rubbing compouded the finish out like polished lacquer. The car has been kept mostly under cover and inside over the years, with very little deterioration. It does get outside sometimes, but I have carefully looked it over and see little if any peeling or discoloration.
I also finished an exterior full sun sign using polyurethane clear and isocyanate herdener. Two years later it had darkened and was definitely showing sign of deterioration. After much discussion, someone suggested I use a Sikkens Auto Clear urethane to prevent UV deterioration. Expensive trick, but the new one held up well for another four years, I last saw.
In looking back, I see the raw redwood held up reliably. I might suggest leaving it bare!
Posted by Preston McCall (Member # 351) on :
Exterior use of shellac will not last. Works great on leather 'patent leather' shoes, but as an exterior clear, no way!
Posted by Jeff Wisdom (Member # 6193) on :
The client wants a natural wood color finish. Maybe a clear stain or the sickens clear urethane
Posted by old paint (Member # 549) on :
clear automotive urethane with hardner?
Posted by Dale Feicke (Member # 767) on :
I'm not looking to start any argument, Joe, because I like automotive clear urethane,too.
But, the redwood-type woods "move" an awful lot; that is they expand and contract pretty much.
The catalyzed urethane is very hard and I'd be worried that it might crack as the wood moves.
I'd be tempted to use some type of UV acrylic clear, that will allow the wood to move and breathe. Maybe check with a woodworking shop, or one of the suppliers to home woodworkers, like Rockler.
Posted by Jeff Wisdom (Member # 6193) on :
Great input thanks!
Posted by old paint (Member # 549) on :
dale..........cars are steel and plastic......and iam sure sitting 120 degree sun the plastic parts move at different rate the the steel.....and i dont see any cracking of paint on cars))))))))))))) i would be more concerned with wood.....losing its moisture content....that is why wood cracks......spar varnish on mahogany on boats.....has more to do with keeping the wood from wicking moisture into it.
[ November 05, 2015, 04:48 PM: Message edited by: old paint ]
Posted by Dale Feicke (Member # 767) on :
Joe, cars use different catalysts, hardners, thinners, primers AND flexible additives on the plastic than on the steel....just for that reason.
That's why many sandblasted sign makers use acrylic clears.......so the wood can wick 'out' moisture or absorb 'in' moisture as it needs to.
Posted by Chuck Peterson (Member # 70) on :
I use shellac all the time as a sealer before applying sandblast stencil and sometimes to seal wood before painting but never as a finish.
Posted by old paint (Member # 549) on :
dale......seein as i have painted vehicles plastic & metal parts, the PAINT(color base)has a flexible additive NOT THE CLEAR..........
Posted by Dave Grundy (Member # 103) on :
Dale...I won't make a comment on the original topic....BUT....
Have you not yet learned that Joe will always make sure he has the last comment, whether it is correct or not. It might take 30 posts but Joe will always get in the last comment.
AND IT WILL ALWAYS BE IN UPPERCASE, just in case you missed his previous comments!!!!!!! Posted by goddinfla (Member # 1502) on :
Putting clear on a redwood is a great way to have a nice looking sign for a few months and a piece of crap forever after. Once it starts breaking down you can't remove it to redo it. Use a good stain that's about the same color as the wood. Several coats will seal the wood and can be redone if it needs it in the future.
Posted by Jeff Wisdom (Member # 6193) on :
Great, a stain it is.
Posted by James Donahue (Member # 3624) on :
Shellac is a very interesting product. Made from bug juice and tree sap. Collecting it is a source of extra income for people in poverty in the countries where it is produced. I use it quite a bit for interior wood projects. Actually a number of interior painting projects. For wood, it brings out the color of the wood very nicely. I then topcoat with varnish. The nice thing about shellac is that it seals the surface quickly (keeps other products from soaking in). Shellac dries very fast. You know how it is, if a product takes 4 hours to dry laying on the surface as a second coat, it will take twice as long to dry soaked into wood as a first coat. Enter shellac. Looks great, saves time. It comes as shellac, which is waxed, and sealer, which is unwaxed. If you read the smaller writing on the can of sealer, it will say unwaxed shellac. That's what to use under varnish or other finishes. I guess you're not supposed to use the waxed kind under other finishes. Good stuff, I like it, but no, the bug juice doesn't cut it outdoors.
Posted by old paint (Member # 549) on :
i ll never forget the smell of shellac. took wood shop 8th, 9th, 10, 11th & 12th grade.......and the place REEKED of it. i dont think a wood project went outa there without 3-4 coats.....steel wooled between coats.
Posted by Rick Sacks (Member # 379) on :
I love shellac, but not under a clear outdoors. It's great for sealing knots and for interior signs. A clear oil seems like the best choice for your needs. Leaving the redwood raw will allow it to darken and turn grey.
Posted by Dale Feicke (Member # 767) on :
I gotcha, Dave! It would almost seem as though he maybe believes that I'd never painted cars before...lots of them... And actually, it depends on the brand of paint you're using. Some use the flex additive in clear; some don't. But then, how would I know?
At any rate, Jeff, I still go back to my original post, where I recommended that you consult the experts....those who work with, or sell products, designed just for this purpose.
[ November 06, 2015, 09:14 AM: Message edited by: Dale Feicke ]
Posted by Raymond Chapman (Member # 361) on :
My best results with redwood that needed to be left natural is a semi-transparent stain. It evens the natural color of the redwood but does not cover the wood with a clear. I've never been a fan of clears for exterior use. High quality paints are more durable than the clears.
I'll leave the automotive argument to the experts. I paint signs, not cars. And my materials are wood, PVC, and HDU.
Posted by old paint (Member # 549) on :
well dale, the one thing i did learn as an outside sales person for MARTIN SENOUR PAINTS, as i was trained by what is called "factory reps." these are people trained by the MANAFACTURE of the paint company. is ther are a lot of variables in paint, application and final product. when i started with NAPA in 1969, we had 2 paint mix products, LACQUER & SYNTHOL ENAMEL. couple years later they came out with ACRYLIC ENAMEL. then they started with hardeners and clears. metal flake was big then. the clears tended to yellow over time. then they came out with urethanes, single stage and 2 stage. and who woulda ever thought we would be painting vehicles with WATER BASED PAINT. things change.......https://www.facebook.com/basfrefinishna/videos/638731532896346/?fref=nf
[ November 06, 2015, 11:05 AM: Message edited by: old paint ]
Posted by Dave Sherby (Member # 698) on :
The best stain I found for redwood, and used a LOT of it years ago before switching to HDU, is SignLife Stain. They have a color called Sunset Brown that is much closer to natural clear coated redwood. I had a redwood sign that I had clear coated with their clear, and it lasted longer than any clear I ever heard of, but when it came time for some sprucing up, I noticed the sunset brown matched the natural color of redwood better than their redwood colored stain. To me, all redwood colored stains are way too red. Anyway, it' an oil based stain that lasts a very long time. And it makes a great base coat for oil based paints. My very first redwood golf course tee signs were flat redwood with routed out letters. I stained these with SignLife and on the ladies tees I painted a flower border with One Shot (back when One Shot was really good, like 1981) The paint over the SignLife never failed. Looked brand new until the day we retired the signs. I thought it should be used as a preferred primer on wood over traditional primers. They still make the stuff but I checked with Midwest Sign Supply and they no longer stock it. I'm pretty sure you can still order it factory direct though. Their number is (419) 526-1695.
Posted by Rick Sacks (Member # 379) on :
There are clear oils we put on redwood houses here that maintain the fresh milled color for several years and then require pressure washing and re oiling.
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And actually, it depends on the brand of paint you're using. Some use the flex additive in clear; some don't. But then, how would I know?