Don’t know if this is a construction technique question, but: I have to paint some pressure treated wood by June 1 deadline. The wood is brand new and damp to the touch. It must be painted and it must be painted by June first. I know from experience that this is a really bad idea, but I have no choice. I have the wood stored on a sun porch right now, in hopes if the sun ever comes out, it will bake it and dry it. Anything else I should do. My dad suggested sponging it with alcohol, but it would take a lot, and I’m not sure that would do much. Thought of covering it with salt or calcium chloride to absorb water, but again not a real practical solution.
Is there a primer that will really stick to dampish PT? I’ve used water based Kilz in the past only to have it peel off after a couple months. I figure water based is my best bet. The other thing is, that this will be overcoated with oil-based varnish (see below). Maybe I could substitute water based poly?
[Okay, for those of you wondering why all the rules and so on, it’s a sculpture for a competition and it must be installed by June 1. We were given the pieces to use and were told they would be marine grade plywood, but when I picked them up yesterday, they are PT plywood (hollow blocks). I’ve already, as part of the rules, told them and got accepted, that I would use varnish (following Zendo’s recommendation for a killer red) as the final finish, so there you are….]
Replies
How long does it have to hold up?
If its only for a short term competition, allowing it to dry for a few weeks should do the trick.
Shouldn't have any problems until after its gone through a few changes of season.
J. D. Reynolds
Home Improvements
Can you get the stock indoors?
"Can you get the stock indoors?"
And make sure it's stickered for air circulation
The US Forest Products Lab says that you can pain PT lumber as soon as it is dry to the touch. Typically 2-6 weeks depending on the weather (if it is outside).
http://www.fpl.fs.fed.us/
Heere is a non-profit group that prints a lot of Labs reports.
http://www.forestprod.org/
You might want to contact them.
Here are a couple of articles from them and they have authors that might be the ones to start with.
http://www.woodweb.com/knowledge_base/Effect_of_water_repellent_preservatives_and_other.html
http://www.woodweb.com/knowledge_base/Best_of_both_worlds__clear_exterior_finishes__in_s.html
And Woodweb has a number of forums with different experts where you might try asking this.
Thanks for the info-- I will check it out.
Just got to say, it is cool the way you research many posts and contribute the links to many threads. Mike
Trust in God, but row away from the rocks.
Painting PT lumber is an exercise in futility regardless of whether it is dry or not. There isn't a paint and primer that can stand up to the wood movement. I would make sure that you put it in writing that you will not guarantee the paint job, period! You can get an attractive paint job on the PT but it won't last. The wood will move, cracking the paint. Once water has a way to get in, it will soon lift the paint and primer. If the homeowner is willing to prep and repaint about every three years, you stand a chance but most will not stick to the necessary refinish schedule. I have a picture of what happens in about five years. This PT was bone dry, mostly clear, sanded, wiped down with naphtha, spot primed with pigmented shellac, top shelf oil based primer, three coats of satin exterior acrylic. The top rails and other horizontal surfaces were the most affected. You would get longer lasting results and easier maintenance by using a solid color oil based stain.
Beat it to fit / Paint it to match
I completely agree with Hammer 1. You can't paint treated wood. There are stains specially formulated for treated wood.
Thanks for the info. The wood is plywood that's been made into hollow blocks about the size of concrete blocks and I have it on my unheated, but enclosed, porch right now. There are 22 of these blocks. I did notify the contact person about being thrown a curve with PT instead of marine grade plywood. She is going to check things out and get back to me. I'll check out the info and web sites Bill Hartman supplied too and see what I can find out.
I was thinking that stain would be best, but we are not allowed to change what we did with the small model, and on the small model I used primer and red colored varnish. Spar varnish without the primer under it may "give" enough with the movement of the wood not to crack and peel, but it would not look as good as the white primer, then metallic gold, then the clear red. Milk paint may also work, but again, that is a change and not allowed--maybe they'll be forced to make exceptions and allow us to do what works. The sculptures are going to be auctioned off and I don't think their buyers will be too happy if all the paint falls off after a year or so!