PL Premium...
http://www.loctiteproducts.com/p/12...8/pl_ca_prem/overview/Loctite-PL-Premium-Polyurethane-Construction-Adhesive.htm

note...
it will expand so weight down your plaque till the adhesive is cured....

 

+1 with Stick ( construction grade adhesive)

 

Thanks for the quick replies. I haven't used the PL Premium before, so now I guess my questions would be how much it will expand, and how low will it take to cure? If I clamp the plaque to the board, will the adhesive expand up around the outside edge of the plaque? Then be easily cleaned off with a rag and a sharp chisel or putty knife? Should I "butter" the adhesive into one thin layer, or simply apply a bead to about half of the surface? Please bear with the questions. Thanks.

 

held in place it won't expand much...
read the tube for cure time.....
MS cleans it up really well while it's wet...
dry it will shave/scrape easily..
one side application and more isn't better...

 

Thanks for all of the info.

 

Not a good idea, using some types of pressure treated wood.
Safety information about usage of treated wood - PTW-Safety

 

A good point, but I think most of the pressure treated lumber sold today isn't nearly as deadly as the older lumber preserved with arsenic.

 

Frank I would go with what Stick suggested. I wonder if a few holes should be drilled under the plaque to let water seep out. In the winter if water freezes and thaws that might be a problem. Just a thought I had.

 

No silicon, it will fail within two years my guess. I also recommend PL, either 400 or Premium, both are waterproof. It will expand very little. Rut a small block of wood on top of the plaque. Put similar blocks on either side of it. Lay a board on top. The weight of the board is probably enough.

 

I would question the effectiveness of any adhesive on PT wood. My son-in-law's deck is painted and the paint is coming off. Would adhesive behave in the same manner?

 

PL premium is designed for PT...

 

Here in Australia I would, and have used construction grade liquid nails, I've used it on wood, bricks, concrete and Polystyrene plus materials that I've long since forgotten.

 

Harry..
LN is some pathetic junk/trash/garbage...

 

The Construction Adhesives are absolutely the correct glue to use with wet, icy, pressure treated lumber. It's pretty much the ONLY stuff that works under those conditions.
Been using it for at least 30+ years and I don't recall ever having it fail; it doesn't work like regular wood glues.
In Frank's situation there's no stress on the plaque once it's installed, so compared to laying a T&G plywood deck down in the rain or below freezing weather, this is a walk in the park.
As for PT being unsuitable for a picnic table, how many of you put plastic in your microwave ovens, or eat fruit from the supermarket?
If you want to worry about ingesting toxins, those two are a good place to start... *

"These products undergo extensive testing for so-called “safety” issues that must be done before receiving a label approved by Environmental Protection Agency. So our EPA is saying that this product has met its tolerances of “safety” (the agency does not like you to use the word “safe” in instances like this because it does not guarantee any pesticide is “safe”) and has approved this label. The product is supposed to be at such low levels in the plant that the government considers it safe to eat."
https://www.reviewjournal.com/life/.../life/home-and-garden/systemic-insecticide-affects-entire-tree-including-fruit/

 

Thanks again for all of your replies, and heading me in the right direction. It looks like the PL Premium is the best product for my application. A phone call to Loctite yielded the following info: the product would work well on pressure treated lumber if it was allowed to dry for about 6 mos before application. Evidently the wood is too wet for the best bond, and the bond might not be as strong. So I'm wondering if I could hurry the drying time in the pocket by using a heat gun? I really didn't want to wait that long before installing the plaque. I'm thinking that I'll try that, and if it doesn't work, I'll just have to wait. Comments? Thanks.

 

so when you pick up your wood make sure it isn't sopping wet..
when you cut it shouldn't even shoe wet...
if you picked up your PT from a big box you didn't get what you thought were getting...
sounds like Locktite is covering their butts..
decades of use of PL is talking here... VOE is hard to beat...
just go ahead and set your placque...

what are your reasons for selecting to use PT???

 

I'd never trust the pressure treated wood on the top. Consider using something else up top with the treated stuff forming the legs and support. If there's a chance someone will sit on the seat in a wet bathing (or birthday) suit, a chemical leach might at least become irritating. It's a picnic table, people use them that way. The problem with insects is usually at the point of wood contact with the ground so the treated stuff doesn't have to include the top. If I thought a table was treated on top, I would find another table. Just sayin'.

 

With you on that. Many, many, years ago, my old man made a picnic table framed with square tubing. The top and seats were about 2X12, varnished. That thing is probably still in use today, it was made that well. Not certain, but likely there are plans out there on-line, somewhere.

Took a quick look, found this. https://bradgreenwooddesigns.com/portfolio-items/picnic-table/ Not sure if they are selling kits, plans, or tables. But if I wanted to make one it would be plenty simple enough to make one just from the picture. Not the same style as my old man's table, but there are plenty more sites out there with kits, plans, et al.

 

The old treated lumber was CCA which stands for Chromated Copper Arsenate. The replacement is ACQ which stands for Alkaline Copper Quaternary (ammonium compound) which is water based. Preservers don't like treating very dry lumber because dry wood soaks up more of the treatment compound which costs them more money. Because of that some of the PW you get has pretty high MC.

 

Franklin is my weapon of choice...
Titebond - Product

All this negative hype about PT is leftover from the CCA 40 and CCA50 era. There is no ARSENIC in the current PT retail products (you can still get the old stuff for industrial; purposes...marine pilings etc. Even then it seems that the preference is still for creosote treatment).
https://sutherlands.com/resources/article.php?id=13
The active ingredients in the ACQ treated lumber are Copper and a Quaternary compound. If I had any concerns about the Quats, I'd stop using them as disinfectant-cleaners. For goodness sake, nobody is eating the PT lumber!
Please folks, stop criticizing PT lumber; we have this ACQ stuff because of greatly exaggerated concerns over the old CCA product being used in playground equipment.
I've been using a lot of both types in construction for four decades, as have a a lot of other members, for the most part we're still alive and kicking. Arsenic poisoning is nasty and I'm sure some of us would have been stricken before now. Keep in mind Arsenic, in small doses, used to be/may be prescribed as a medication.
https://www.webmd.com/vitamins-supp...ientmono-1226-ARSENIC.aspx?activeIngredientId=1226&activeIngredientName=ARSENIC

 

Titebond doesn't say it's for use with metal where PL Premium specifically mentions it.

 

It's the uniformed propagating myth...
you'll never get around that...

there is a time and an application to fit the need...
so will any read this PDF...

.

 

As for PT being unsuitable for a picnic table, how many of you put plastic in your microwave ovens, or eat fruit from the supermarket?

I do plus I get stuck in traffic and have to be in traffic with vehicles that wouldn't be allowed on the road in a lot of European countries.

 

"...with vehicles that wouldn't be allowed on the road in a lot of European countries."
That works both ways. John.
There are Euro vehicles that you can't import into Canada. Works for me! LOL!!

 

The latest obsession is getting rid of every bit of asbestos 'contaminated' building material in a house.
All those years of being exposed to street dust containing Asbestos fibres from brake linings apparently is irrelevant when they grind pavement, and relay the asphalt. When was the last time you saw the road crews wearing full Asbestos protection gear? (Never?)

 

so go w/ redwood..
there are plenty of plan ''B''s...

.

 

Thanks for the charts. An interesting read. Honestly, price is a consideration for this project, so I'm kind of stuck with less costly options.

I did purchase some rough cut white oak for a pickup truck bed project which I ran through my planer. Used a dado blade in my table saw along with a router and an edge guide to finish the edges. Except for a couple of loose knots, I think it ended up looking pretty good. It wasn't a show truck, so it didn't require clear lumber. The actual price of the boards was about 1/3 the price of a mail order finished kit.
I didn't want to use a film type finish, so I tried something from Izzy Swan at Think Woodworks. Minwax is my choice for stain and varnish, so I used that in my mixture. Mixed 70% Teak Oil and 30% satin Helmsman Spar varnish over Minwax Golden Oak stain. Yearly maintenance requires a little roughing up with some steel wool, then a reapplication of the mix. Let it soak in for 15 - 20 minutes, then rub with a rag. Doesn't take a lot of time to do, and lasts for the whole year. Much, much easier than stripping and re-varnishing, at least in my opinion.

 

You and I will have to agree to disagree on this point Marty unless America hasn't found the Australian secret of making construction grade liquid nails.

 

LN here is straight up worthless....
I've used it...
PL series is leagues ahead LN......
LN there might be the best you have but if it's anything like the LN we have here it isn't much...
I'm addressing N America...
potential users here need to know not to waste their money...

 

"LN here is straight up worthless...."

Could you be more specific like what you have used it for and what has been the problem/s.

 

really Harry...
please...
it's a marginal item..
it failed to perform 100% of the time...
over the years.. many different applications...
simple as that...

 

you have a planer...
can you get any of those outdoor woods in rough sawn...

price considered..
you want something you are just going to again or do you want something that will last for an extended period of time and the longer it last the lower the cost...
you've heard the saying...
we never have the time nor the money to do it right the 1st time but we do the 2nd time...

you never did say why you selected PT or what grade/level you had available to you...
just trying to dort fact from myth...

 

I'm only going to make the table once, and it will last long enough if I proceed like I'm planning to. In post #28 I provided a link to the product I'm leaning towards using, and I'm thinking it'll be the best to meet all of my requirements.

 

it's wood to metal holding sucks...
as does wood to masonry...
and no, it doesn't bridge well...
good point.. it is very runny and flashing it is a mistake...

 

That's why I like the Titebond...you take your finger off the trigger and it stops at the spout. Now.
I hate it when you put your caulking gun down, come back a few minutes later and there's a little (or big) mound of glue that's escaped from the tube. Did I mention that I hate that?

 

This is what we in Australia use.

http://www.selleys.com.au/trade/building-products/construction-adhesives/liquid-nails-high-strength/

 

same manufacturer...