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Strongest wood glue?

Spud

Diamond
Joined
Jan 12, 2006
Location
Brookfield, Wisconsin
Is construction adhesive, the stuff that comes in those tubes and require the use of a plunger, stronger than Titebond and the like?

2 part epoxies are always going to be the strongest??
 
Generally no, to construction adhesives. Plain ol' yellow glue is often stronger than the wood. Epoxies made for wood are super. But the real question here is - is the glue suitable for the particular use you have in mind? There are other reasons beside ultimate strength for selecting a particular glue.
 
Spud, take a deep breath and relax...virtually all adhesives, if used properly, will create a bond stronger than the wood. The term 'strongest' is meaningless without stating what you're trying to accomplish. Unless you're laying subfloors, paneling, etc. you can skip the construction adhesive.
 
Not to mention there are about 20-leben different brands and types of construction adhesive. Or as my brothers sometimes called some of the early versions, "construction evasive".

There are lots of instantaneous "strongest" bond products per advertising and sometimes even attainable. The problem with wood is a bond that is durable for the intended life of the product.

Usually that means Resorcinal, or Phenol-Resorcinals. They mimic lignin chemically and are close to being permanent even in boiling water. But the surface prep has to be perfect and so does the application, pressure, and temperature. Melamines are right up there but not common for retail use. Epoxies formulated for wood are generally next. The thing about epoxies is how forgiving they are. While a perfect Resorcinal bond may be potentially more durable (& stronger), room temp cure epoxy is more likely to form a stronger bond any time conditions and prep are not "perfect". At retail/light commercial, epoxy is also quite a bit cheaper than resorcinal/pheno-resorcinal with similar quantity pricing.

Most constructions glues are not that good, and don't really last long as a bonding agent in shear or tension. Some become like chalk in a year or 2, but i think those have mostly gone off the market. The urethane construction adhesives are quite good and form durable bonds even in areas that are sometimes wet. But as someone else asked, what exactly are you trying to do? There will be a good adhesive for the app, a whole bunch that "seem like they ought to work" but have downsides in certain conditions, and there will be some that just are non-starters even if they are stellar for other apps.

smt
 
As others have noted, an answer would depend on the situation. For all of my regular interior case work, regular old aliphatic "yellow" glue is plenty strong, but I use Lepages PL Premium when I install pre-finished hardwood staircases.

Here on the east coast, most staircases begin with rough stringers of spruce with temporary spruce treads during construction. Then plywood stringers, risers and hardwood treads are laid over the rough stringers like a skin, so to speak. Using the PL Premium gives me a long open time to get all of the components on in one day and then allows the glue to set overnight. The next morning the staircase is as solid as can be and no squeaks. I've been back to stairs that I installed 10 years ago and they were as good as the day I installed them. PL 400 would not work in this situation very well, as the open time is extremely short and the bond would be broken while I worked on the stairs.

This method of staircase construction may seem strange to some of you, as it did to me when I first moved back here from Ontario, but it is certainly a regional preference that shows in even the old houses around here. In Ontario, all of the houses that I worked on, had the staircase built in a shop with traditional mortised stringers and wedged risers and treads, then installed in one piece.

I also used PL Premium to glue some solid concrete blocks together to support a deck and had an extra pair of blocks that the owner tried to pry apart. It only came apart when one block released a chunk of concrete.

Brian
 
construction glue is typically flexible to take wood size changes better as wood dries out. my experience is panel adhesive is extremely strong
.
many, many extremely strong glues with no flex the bond will break as wood changes shape.
.
i had used hot melt glue to glue aluminum to steel to hold in milling machine vise. bond appeared strong and it held up while i machined part. it was slightly warm after machining so i take to sink and pour cold water over it. the glue bond failed and parts fell apart just from size change difference of aluminum and steel at a different temperature.
.
i often hold thin parts with double sided thin foam tape cause it got a little give to it. sure it might move a few .001" under pressure but rarely will the bond fail. if anything it can be a job just separating or breaking the tape bond cause it is slightly flexible
 
Gorilla glue foams out of the joints as it hardens. And,that foam is as strong as a foam plastic coffee cup. They used it in the museum's millwork shop only for outdoor benches,where water resistance was the most important thing.

Epoxies can continue to harden until the joint just cracks and fails. I have had that happen when I was younger,using it to glue on guitar bridges.

I'd have to recommend Titebond or the powdered glues.
 
You can download a nice little informative article that did a simple test of various wood glues in a common joint here (link). The study was done by Fine Woodworking Magazine, but Titebond glue liked the results so much they distribute the article. Bottom line was that generally PVA glues like Elmers or Titebond work best all-around. Other glues have their place too.

Jeff
 
You can download a nice little informative article that did a simple test of various wood glues in a common joint here (link). The study was done by Fine Woodworking Magazine, but Titebond glue liked the results so much they distribute the article. Bottom line was that generally PVA glues like Elmers or Titebond work best all-around. Other glues have their place too.

Jeff

That test is so frickin flawed, it annoys me every time it comes up. I could take the same procedures and change the order almost any direction I wanted, except for the almost worthless Poly-urethane glues.

It pretends to be "scientific" and has something of the trappings of same. But a very really factor is that different adhesives require different surface prep in different woods, to maximise performance.

It is also a snap shotof freshly made glue joints, not the performance of a given system over time.

I do think "yellow" glues are one of the strongest and even "best" glues out there, especially for cabinets and, well, perhaps for bridle joints or similar assembly type joints like dovetails and M & T's for internal work.

Nor did they test some of the best glues (resorcinals and melamines)

The FPA has done reams of testing on glues for most of the past century. They usually do both aging, and accellerated aging tests, keep long records of a wide range of very controlled conditions, and do things like boil and salt expose the assemblies. If you take the time to read much of that data, what comes out is that gluing is a complex subject with multiple correct and incorrect solutions and that successful solutions are specific to the problem.

smt
 
Stephen,

After reading this forum for some years, it's quite apparent to me that you've forgotten more about woodworking that I'll ever know, so it's in that spirit that I reply. I thought the linked article was generally illuminating, though obviously not a scientific treatise.

I respectfully request that you provide some links or otherwise point to some data that would be informative for a hacker to read and learn, and that could be digested in a few hours. I searched for "FPA" and came up empty. Wikipedia is a good source to figure out acronyms, and this page gave nothing of use. Perhaps you meant the Forest Products Society, but I went to their website and searched both the main page and the bookstore for "glue" and came up empty on both, though probably that terminology is too basic.

From your post I gather that there's a heck of a lot more to it, not exactly a news flash, but beyond that?

Jeff
 
Jeff -

Curmdgeonliness aside, what the FW article "tests" is the performance of bridle joints, not glue per se. It uses uniformly machined (I presume well qualified "equal" samples) sets of wood components with various fits and glues them up and breaks them after a very short period of time (anything short of a few years under varying reasonable but real climatic conditions is "short")

It shows that if you want good performing bridle joints, machine them accurately and with close fits and tolerances. Within that standard, several glues (adhesives) will work for your bridle joint, at least in the short term.

To test for glue strength, each joint would be prepped for the glue as it was designed to be used. This might include a rougher surface for epoxy (even coarsely sanded), appropriate fillers, (few epoxys perform well in wood bonding "neat"/without fillers because the wood wicks the epoxy away before it sets. Short setting epoxies seldom have as good a bond as long setting epoxies due to the shorter molecular chains. Oily/resinous wood such as Ipe is supposed to be rinsed with lacquer thinner a few times, then a neat coat of epoxy spread and left to absorb & thicken slightly; then a fresh batch of epoxy mixed with the correct filler is applied and the work fitted together. Epoxy does not require a lot of pressure for bonding. For some woods (maple e.g.) excessive pressure which would be necessary with hot hide or resorcinal glues is counter-productive.

Conversely, hot hide glue should have a hand planed type surface and fairly close but not starved glue joint. Liquid hide glue works pretty well as the tests show, but IME many are not very resistant to humid weather (for get "wet"). Your source of flake hide glue and its gram strength makes a difference, for liquid hide glue, the source and formulation makes an even bigger difference.

What is obvious is that for assembly joints "aliphatic resin"/"yellow glues" are is very forgiving. They will routinely give excellent joints under less than perfect conditions. They are or can be very water resistant. They may or may not be more durable than other adhesives "depending". :)

Some glues, and I have experienced it with yellow, is softening over time. Not tested, but some urea glues like "plastic resin" glue can actually chemically degrade over about a 20 year period, at least per some of my FPL literature. Essentially, some have an inherent half-life.

I have posted about "usually" using "yellow" glue for edge gluing maple, myself, & that it often gives better bonds on smooth, freshly planed hard maple than epoxy. I believe I could make an equal bond in hard maple with the specified sanded joint, and adding perhaps a pre-soak period with neat epoxy as is specified by WEST for oily/resinous woods. Sometimes it is very tough to decide for critical applications or work in public spaces. Often the dark glue lines of a resorcinal would rule that out immediately, and perhaps if the material required sand/soak joints for epoxy in light wood, that would create wide or "obvious" glue lines. So you settle on yellow glue which has a huge track record, and "hope" :)

Overview of FPL:

Forest Products Laboratory - Wikipedia

A portal to get you started searching the database, I did not take time to go glue specific.

http://www.fs.fed.us/research/forest-products/
 
Stephen,

After reading this forum for some years, it's quite apparent to me that you've forgotten more about woodworking that I'll ever know, so it's in that spirit that I reply. I thought the linked article was generally illuminating, though obviously not a scientific treatise.

I respectfully request that you provide some links or otherwise point to some data that would be informative for a hacker to read and learn, and that could be digested in a few hours. I searched for "FPA" and came up empty. Wikipedia is a good source to figure out acronyms, and this page gave nothing of use. Perhaps you meant the Forest Products Society, but I went to their website and searched both the main page and the bookstore for "glue" and came up empty on both, though probably that terminology is too basic.

From your post I gather that there's a heck of a lot more to it, not exactly a news flash, but beyond that?

Jeff

try this

Search Forest Service Research & Development

but wood glue is at best statistical....works most of the time :)

dee
;-D
 
Jeff -

Curmdgeonliness aside, what the FW article "tests" is the performance of bridle joints, not glue per se. It uses uniformly machined (I presume well qualified "equal" samples) sets of wood components with various fits and glues them up and breaks them after a very short period of time (anything short of a few years under varying reasonable but real climatic conditions is "short")

It shows that if you want good performing bridle joints, machine them accurately and with close fits and tolerances. Within that standard, several glues (adhesives) will work for your bridle joint, at least in the short term.

To test for glue strength, each joint would be prepped for the glue as it was designed to be used. This might include a rougher surface for epoxy (even coarsely sanded) appropriate fillers, (few epoxys perform well in wood bonding "neat"/without fillers because they wood wicks the epoxy away before it sets. Short setting epoxies seldom have as good a bond as long setting epoxies due to the shorter molecular chains. Oily/resinous wood such as Ipe is supposed to be rinsed with lacquer thinner a few times, then a neat coat of epoxy spread and left to thicken slightly, then a fresh batch of epoxy mixed with the correct filler is applied and the work fitted together.

Conversely, hot hide glue should have a hand planed type surface, and fairly close but not starved glue joint. Liquid hide glue works pretty well as the tests show, but IME many are not very resistant to humid weather (for get "wet"). Your source of flake hide glue and its gram strength makes a difference, for liquid hide glue, the source and formulation makes an even bigger difference.

What "aliphatic resin"/"yellow glues" are is very forgiving. They will routinely give excellent joints under less than perfect conditions. They are or can be very water resistant. They may or may not be more durable than other adhesives "depending". :)

Overview of FPL:

Forest Products Laboratory - Wikipedia

A portal to get you started searching the database, I did not take time to go glue specific.

http://www.fs.fed.us/research/forest-products/

beat me to it :)
 
Thanks Stephan for the detailed response, and dcsipo for the link. FPL-FPA, 220-221, whatever it takes. Some light bedtime reading is just what I need.

Jeff
 
After reading all the replies and watching YT videos on wood glue, I bought some Titebond 2.

The glue is just to augement Torx flathead Power lag Spax screws . This is to secure a 2x4 to 2x6 on a shipping pallet. A 620 lb printer will be bolted to two 2x4 and the 2x4 are glued and screwed to 2x6 deck boards. I'll post a picture soon.
 
All do respect, I know you're concerned about the strength of this pallet based on your other posts, but this seems like massive overkill. I've palatized and received quite a few machines between 1000-3000lbs and the only concern is making sure the load points of the machine are transferred/supported at the pallet. Instead of lag screws the framing members are bolted together. A side note about adhesives...the ideal thickness for a strong titebond glue joint is only a few thousandths of an inch thick, generally not more than .004", whereas urethane construction adhesives can fill gaps up to 1/4-3/8". If you're using 2x4's from the store they're probably not very flat, unless you plan to joint them, so the strength of the titebond will only be the points that directly contact the other member. In this application I think construction adhesive would be better, although I don't think you'll have any issues using titebond. As a general rule bolting framing members is substantially stronger than lags. Regardless, due to your meticulous nature, I'm quite sure whatever you decide will be more than sufficient for the 650lb printer, especially if the load is supported where it meets the pallet.
 
After reading all the replies and watching YT videos on wood glue, I bought some Titebond 2.

The glue is just to augement Torx flathead Power lag Spax screws . This is to secure a 2x4 to 2x6 on a shipping pallet. A 620 lb printer will be bolted to two 2x4 and the 2x4 are glued and screwed to 2x6 deck boards. I'll post a picture soon.

It'll be great. You're making a much better pallet than most.
 
In case my last post came across as being critical, that wasn't my intent. You mentioned you're not charging for crating so I was trying to articulate (probably poorly) that you don't need to go overboard with the construction and still be confident in its safe arrival. If the extra steps give you piece of mind, there's nothing wrong with that. I built houses for years and overbuilt many times when I wasn't confident because of lack of experience. In hindsight I wasted plenty of time and money, but in the moment the extra steps kept my mind at ease.
 








 
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