outdoor table, pressure treated pine, never again!

allen levine

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new york city burbs
35x80, using decking for top, 2x4s for legs and aprons.
glueup on legs failed. I believe it might have been my fault, used 12 inch clamps, glued up 2 sets of legs at once, probably not enough pressure?
after 1.5 days, glue wasn't cured, I was able to split the glue up with a spackle blade, so I reglued each set alone.
Table top, end board didn't glue up all the way, split it as much as I could with blade, then poured in as much glue as I could, reclamped.
its 2 days as of this afternoon, overglue is just as wet as first time out of bottle. humidity here is 100%, temps mid 50s, not dealing with this ever again.
I wanted it to look like an indoor dining table, but a poor choice of lumber for gluing up, not to mention its so wet its difficult to plane and joint.
Im going to give it a few days to cure.
I didn't want this project to last more than a week, wait a month, then use some deck paint to give it a nice color.
I have 5-6 total hours into it.

legs will be tapered, and it will all be mortise and tenon between apron and legs.
aprons are planed down to 1.25 inches thick. Top should end up approx. 1 inch thick.
I made the top in two sections so I can handle it better, final glue up will be after drum sander, then Ill give a light sanding by orbital at the one joint.
Elen is off from work Monday, she doesn't know shes going to be helping me run the top through the drum sander.
(Id love to do the drum sander tomorrow while my daughter comes for lunch, she wouldn't mind, but I don't trust the glue with this damp cold weather)
 

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If I just lined up the boards with boards underneath to hold the top together, and used deck screws for legs and aprons, I probably would be close to finished by now. a picnic table like that is a weekend project.
 
I hae used glue on outdoor furniture, but not on major structural components. Gluing the 2x4s together is the right approach, however I would have waited for a warmer day to do the gluing too. Fifty degrees is 10º in my country, and I would want the temperature to be at least 15º (59 US) just to be on the safe side.
 
Allen, I don't know this for sure but I am guessing the 'pressure treating chemicals' are interfering with the glue set up/adhesion. I would try a polyurethane glue, like Gorilla and others. Just a thought.
Best of luck as you go forward.

youre probably right. Im going to give it a couple more days and see if it cured or not.
 
youre probably right. Im going to give it a couple more days and see if it cured or not.

I wouldn't trust glue only at all. Stainless steel screws only way to go. "joining"? The top must have at least 1/2" spacing between boards to allow proper draining even with treated wood. Picnic table ain't fancy furniture, it's a picnic table and is going to take hard knocks.
 
I wouldn't trust glue only at all. Stainless steel screws only way to go. "joining"? The top must have at least 1/2" spacing between boards to allow proper draining even with treated wood...

The wet, treated wood will shrink horribly when it dries, too. I build a deck with it several years ago. Knowing it would shrink, I butted the deck boards tight when I built it. A year later, there are ½" gaps between the boards during the dry season, and about ¼" gaps even during the rainy season (like now).

If you're going to glue up the top 'slab,' then be sure to make slots for the mounting screws, to allow for a lot of movement.
 
thanx, the glueup failed again, so when I attach the pieces, Im going to just use boards underneath to hold together.
I made a solid pressure treated top years ago, it held up pretty well. Gets it small twists and turns, not exactly flat, but no real issues with glueup boards.
It was different pressure treated. I don't remember any pressure treated this wet. The other glueups are fine now.
 
Do you have a moisture meter to see how wet it is? Like Jim Ive done decks that the board were so wet that we just butted them without any gaps and a few days later were 1/4" to 3/8" gaps between after drying out in the sun.

Sent from my SM-G920P using Tapatalk
 
Make it from cedar or redwood and be done with it, it will last many many years, but you know that :thumb:

May I assume that you used this pressure treated wood because of the price difference?

In the long run, maybe a better choice of wood was cheaper, as the time and effort of trying to make this work is not cheap.

Domo
 
redwood prices are ridiculous here. 6 or more bucks a board foot. Not going to build outdoor furniture to sit 11 months a year and not used and spend a lot.

I fully intended to use cedar, white cedar, not red, elen took a ride with me to lowes that sunday,(easter sunday), and we /I could not find one 2x4 or one piece of cedar decking that was straight. I spent 30 minutes going through pallets of cedar, none was straight, so I gave up.
White cedar is only 20% more than pressure treated.

Ive built several tables and close to 50 Adirondack chairs out of pressure treated. It twists and turns, but for the money, its ok for outdoor pieces.

I don't think the colder 100% humidity days helped much.
 
I was out most of the day, didn't get into the garage until 3:30 but I got the legs all sized up, but couldn't use my tapering sled because the legs were too large, the blade didn't go up enough on the TS. I built a quick jig to hold them in place on the mitre saw, then tapered them a bit.
 
The last stuff I got was so wet it's splash when you drove a nail into it. Really nasty stuff!

Often treated wood when delivered to the lumber yard can still be dripping. And, it is impossibly heavy. Carrying a 3/4" sheet of plywood is a chore for two men.
Another choice is composite material. About twice the cost of treated lumber but is (theoretically) a 'forever' material. My son has a 15 year old deck made from it and it looks like new. In the long run it is very cost effective.
 
I would bolt the legs to the seat cross pieces as well as to the bracing under the top. I would never use treated lumber for areas that might get food or or skin contact, but for the legs and framing, it's likely the best. I built my son a picnic table this way in 1998, using white pine 2 by for the top and seats, but treated for the legs. It gets a tarp cover in the Winter, but it's left uncovered the rest of the year. All of it was given several coats of linseed oil after it was built, and a couple of coats have been added since, every few years. The top and seats are about ready for replacement, but the rest of it is still doing OK. This time it will use stainless hardware instead of galvanized. I didn't expect it to do this well and for so long.

Charley
 
I would never use treated lumber for areas that might get food or or skin contact,

The notion that skin or food contact with treated lumber is dangerous, in a word, is nonsense. I worked at large campground years ago. By law, they were not allowed to have picnic benches, or any furniture made with treated lumber because of this overblown concern. Supposedly, a child laying a hot dog on the wood could become poisened. A little research found with the amount of chemicals in the wood a child would have to EAT twelve picnic tables to ingest enough chemical to harm him. BTW, in the wooded campground, tables seldom lasted more than one season. Building new tables was an ongoing nearly full time project.
 
pressure treated pine today is not the same chemical methods used 15 years ago. Its pretty safe today.

this table will not be sitting outside exposed, it will be under an awning, overhang, don't need to worry about wood drainage. And if I need to keep it outside until then, Ill cover it.
top glued up, mortised the legs today, made the tenons and glued up the base. One leg again didn't seem to glue up strong, while the others did, maybe it was just a bad surface, even though I planed them flat, maybe I didn't clean it well, whatever, I decided to place deck screws on the inside of all the legs so if glueup becomes a problem outdoors, the screws are in place and I can always add more.
I also put on deck screw through each tenon on the aprons. My only concern is that the top, 3 sections, glues up strong. I don't know why 3 boards glue rock solid and one end one I can break off with a chisel. My guess is I didn't joint it good enough, and left too much dust on it.
Ill know in two days.
For 10 or so hours, its not a back breaking miserable project. Quick, easy, just some glue up problems.
If I still have problems, Ill junk it and go purchase cedar. Id rather not.
Ill add some support in the center, use my bisquit cutter and use z clips to hold the top on the base, and I should be finished with sanding and assembly by weds or Thursday. A quick sanding with 120 grit, not worried about a smooth perfect finish, not important since its a raw outdoor table.
probably throw a few coats of deck sealant on it in a few weeks.
this table should seat 8 comfortably, 80 inches long.
 

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My response was made from personal experience, and I know that the chemicals used for wood treatment have changed to safer compounds, but I have built many pieces of outdoor furniture, not just my son's picnic table, using both the older style and newer style treated lumber. In all cases, when the members of my family have come into skin contact with the old and new treated lumber I've received complaints. My most recent problem was with Adirondack chairs that I made 3 1/2 years ago from the new style treated lumber. After the complaints I replaced the seats, arm rests, and backs with untreated yellow pine and then finished both the old and new wood with linseed oil and then one of the opaque outdoor paints that they call a stain. Everyone is now happy to sit in them. Only the legs and cross braces remain of the treated lumber, so there is no skin contact with it any more.

Charley
 
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