Woodworking Glues (WOOD Mag)

[Chris Padilla]

WOOD had an interesting centerfold in the newest issue about glues.

I am surprised to see that Polyurethane glues to actually be weaker than good old yellow glues. In fact, the new Titebound III is the strongest glue out there except for epoxies!

I was under the (misguided from marketing?) impression that poly glues were pretty strong. Poly has better resistance to heat but other than that, it isn't much better than the Titebound III other than it costs double!

I am glossing over some other points but basically I guess poly ain't all it is cracked up to be! :)

One interesting point I took away:

Moisture delays water-base glues; dry conditions delay polyurethane...from reaching full-strength.

[Dick Parr]

Thanks for sharing the info Chris. I don’t get Wood Magazine any more and that is some interesting information. I was going to pick up some poly this week for my next batch of pens that I just got from Ken, but now maybe I will try out the new Titebond III instead. :)

[Jim Becker]

Thanks for sharing the info Chris. I don’t get Wood Magazine any more and that is some interesting information. I was going to pick up some poly this week for my next batch of pens that I just got from Ken, but now maybe I will try out the new Titebond III instead.
TB III isn't going to be good for your pens...you are joining metal to wood. The poly is still appropriate for the job. You have to remember what the properties of a glue are. PVA (including "new" formulas like TB III) needs to get into the cell structure of the material it's joining to work properly. Choosing the right glue isn't just a matter of strength. Material to be joined counts, too.

[Dick Parr]

Thanks Jim your right, guess I was a little brain dead yesterday. :confused: Just got back from 4 days of camping and was a little tired. :D I do remember about the bonding of the cell structures, after you reminded me. :p

I will still get the poly for the pens as everyone has attested to it being about the best for that process. I have been using ca glue with no blow outs, but it sounds like I have been lucky so far. :rolleyes:

Thanks again.

[Bob Marino]

Interesting pullout and info on the glues. Also in the magazine was a short q & a with a guy who uses only epoxy on his furniture. :confused:

Bob

[Mark Singer]

I was using the Polyurethane glues for a while and had several joint failures at which I stopped using them completely. I use West Systems and Tightbond 2 or Lee Valleys glue for eveything. The poly glues are very messy and short shelf life....why mess with them?

[Bob Marino]

Mark,

Any reason why you choose one glue over another for a particular application?

Bob

[Chris Padilla]

Let's see:

Yellow Glue has 2 year shelf life.
Yellow Extended has 1 year.
Dark Wood has 2 year.
Titebond II has 2 year.
Titebond II Extended has 2 year.
Molding and Trim has 1 year.
Titebond III has 1 year.
Polyurethane has 1 year.
Epoxies and CA have 1 year.

It is true that the poly/epoxy/CA do bond more materials than the yellows. Yellow can bond wood, leather, cloth, and paper. Poly/Epoxy/CA can bond most materials except some plastics.

This is a good issue (June/July 2004, Issue 156) to pick up at a stand somewhere. You can remove the guide and pin it up on your wall.

[Bill Grumbine]

I don't know about those shelf life figures. I have glue that is WAAYYY past its date that I still use regularly and it works just fine. For example, I still have a bottle of Elmer's polyurethane glue that has to be a minimum of six years old, and it still cures and holds like it did when it was new. I only use it for one small job and some occasional pens, but it works and works well. I also have a gallon bottle of Titebond Extend that is years old, but still holds. And as far as epoxy goes, everything I read when I was building my boat says that epoxy has a shelf life that is practically indefinite. Again, I am using epoxy from 1998 and it still works fine.

Bill

[Donnie Raines]

I don't know about those shelf life figures. I have glue that is WAAYYY past its date that I still use regularly and it works just fine. For example, I still have a bottle of Elmer's polyurethane glue that has to be a minimum of six years old, and it still cures and holds like it did when it was new. I only use it for one small job and some occasional pens, but it works and works well. I also have a gallon bottle of Titebond Extend that is years old, but still holds. And as far as epoxy goes, everything I read when I was building my boat says that epoxy has a shelf life that is practically indefinite. Again, I am using epoxy from 1998 and it still works fine.

Bill

Bill,

I think that I would reconsider the use of the glue to far beyond the shelf life that is stated. Sure, there are always exceptions to the rules.But, why spend so much time on the details of a project to then have a joint failure or table top split loose becuase of poor quailty glue? I have always been a little paranoid when it comes to this. I buy the smallest bottles I can find that way I no I always have the freshest glue I can get my paws on. The last thing I want to have happen is to finish a project only to have a leg fall off becuase the glue failed.

Donnie Raines

[Chris Knight]

I have been doing a bunch of strength tests on glue joints for a recent project. Basically making the joints, gluing them, then testing to failure with stress applied by clamps, or hammers!

It has become very clear that the type of grain to grain contact is an issue (eg is it long grain to long grain, end to long, end to end etc?) Also, in every case, whilst some wood failure takes place (ie the glue is stronger than the wood), the real issue is how the glue has wetted the wood.

So far, each glue has performed differently but Regular Titebond has done best overall.

I would emphasize that these are informal/non-scientific tests and no measurements were made, other than guesstimating the percentage of the joint that failed in the wood, versus that that failed in the glue line.

I made no attempt to regulate clamping pressures and these are clearly important - but how many of us do that when we are clamping up a project? I just tightened the clamps as I typically would in my assembly sequence. In some case, it was way too much I guess and in others, not enough.

[JayStPeter]

I usually buy glues in smaller containers to keep shelf life out of the equation. I'll buy a couple of med. size containers before a project.

Mark,
I disagree with your assessment that poly glues are messy. I find myself using poly glue to avoid mess/hassle. As a hobbiest, I often work in the shop until bedtime. Lots of times, I'll clamp up something and go to bed. I find it much easier to clean up the squeeze out of poly than titebond. I use titebond when I know I'll be able to clean up the joint within an hour later or less. I do try to use the right quantity and wipe it off initially, but there's still some latent squeeze out. I've also found that if there is a little poly glue left, finish and stains stick to it and don't leave a little white spot. If you let titebond dry hard for a week and try to scrape it out of a corner ... good possibility of white spot.
So far, I've had good luck with all my glue joints. I do test them often to ensure good technique and quantity is being used. I try to break my cutoffs over my knee to see if the joint fails or the wood. Always been the wood with both glues. What brand of poly were you using that failed so badly?

Jay

[Mike Circo]

I agree with whose who disagree with the statement that poly glues are messy.

Everyone I've seen who has a "mess" problem is using too much. You can typically use about one-third the amount of poly glue as would be used for yellow. Plus you only apply to once surface. This also stretches its use and defrays part of the higher cost.

I find that the foamed out part doesn't stick to the work and when scrapped off doesn't effect the subequent finish.

I use it when long open time is required (like for bent laminations or big glue ups), or when an odd material is used.

[Larry Browning]

If the shelf life is expired, what is it about the glue that goes bad? Is it that the glue get weaker? Is the open time reduced? Won't cure properly?? I'm with Bill on this one. I have some glue that is at least 5 years old and I can't tell the difference from new. It wouldn't surprise me to learn that the stated shelf lives are just made up times the the manufacturer puts on their products to get us to buy more glue. Have there been studies done to verify these stated times?

Hey! this could be one of those things like electric motor horsepower. I could be onto something here :)

[Glenn Kiso]

I stopped using gorilla glue after my benchtop started delaminating a bit here and there. Another benchtop made a year later using the same construction techniques and yellow glue is still perfect. I haven't seen the wood mag article, but I think the poly's are overrated. If titebond won't be strong enough, then epoxies are my next choice.

[Chris Padilla]

One nicety I've learned from poly is the ability to heat it up in the microwave slightly (10-15 s on high) and have it spread so nicely and thinly. It helps you to not use too much thereby saving money and squeeze out. I've also found that the amount of water you use on the mating piece for poly is directly proportional to the amount of foaming it does. Keep the water to a minimum--one wipe with a damp sponge works for me. Poly also has a slightly longer open time so it is good for laminations.

To avoid "Gorilla Fingers" for a week (i.e. black fingers from dried poly on 'em), I now wear disposable gloves or I just try to be extra careful. Yellow does peel nicely off ones hands, however...clothes, too.

Bill and Larry...excellent points/questions. How is shelf life of a glue determined? Could it be marketing?! :) I've read many times that fresh glue is the best but I've never heard why old glue is bad. I have some 2-3 year old Titebond II. Seems to work just fine.

With all this in mind, it is good to have an arsenal of ashesives at our disposal...just learn how to use them.

[Kirk (KC) Constable]

I agree with those who feel that overall, the poly glues are the least 'messiest'. The trick is to ise the right amount, and keep a gallon jug of orange hand cleaner around (and use it frequently).

I believe I've tried every poly glue out there...or at least the 'top four'...Gorilla, Titebond (Franklin), ProBond (Elmer's), and System III. In my experience, all poly glues are NOT created equal. They 'foam' differently, and at different speeds. They 'clean up' differently, with some squeezeout literally 'crumbling' away, and some that usually require chiseling to break loose. My preference of the four is Gorilla because it seems to have a longer 'no foam' period, and spreads easier. I use poly glue exclusively on the mortise/tenon joints in chairs (and anything else), and it's easier to get a 'proper' coating of glue in the mortise with the Gorilla. I tend to use too much of the others simply due to the 'spreadability'. I distinctly dislike the ProBond for this reason. Occasionally I'll use a teensy bit of glue on the shoulder of a tenon, but as a rule, no glue at all.

When working with mesquite (usually around 15% MC), I've never wetted either surface. Early on, I would wet one surface when working with cherry, but I've quit doing that. I think the moisture accelerates the curing...which may cause premature foaming...which may lead to the common feeling that the poly glues are messy and hard to work with.

I've never intentionally tried to break a M/T joint, because I think I could break it whatever glue I used. What I can say is that I've used it on something around 150 chairs in the past 5 or 6 years, and with the money people are paying for the chairs, I strongly suspect they'd be coming back if there was a problem. We have done some minimal testing with edge-glue material and found that the poly breaks easier...which is why I seldom use it for edge-gluing.

KC

[Jim Becker]

One little important tip about Polyurethane Glues...GLOVES ARE NOT OPTIONAL unless you like having "black" fingers for about a week. The stuff just does not come off easily and largely needs to wear away. Invest in a box of nitrile or other "medical style" gloves to use when you are using this type of glue as well as other messy things in the shop. It will save you a lot of time and possibly "embarasement"...;) DAMHIKT!!

[Mike Circo]

KC...
I agree that too much water usage could be the reason for the messy label on the Poly glues. I have heard that the moisture from your breath in a mortise is enough to initate the curing process in most woods. (don't try this on large areas or you end up hyperventilating. DAMHIKT)

Also, wet Poly and still wet foam-out can be cleaned up quite nicely with mineral spirits. Once it sets, you are SOL, but while wet, cleanup is not difficult.

[Bob Marino]

Kirk,

Did you ever use epoxy for the m & t's?

Bob

[Tim Sproul]

taking a wet rag and running it along the glue joint is enough moisture for polyurethane glues. The joint doesn't need to be sopping wet.....just adding a bit more water helps the curing.

[Bill Grumbine]

Hi Donnie

Like Larry says, what is it about glue that makes it expire? Like an idiot, when I first started out I thought I was going to need lots and lots of glue, so I bought a gallon of Titebond. It lasted forever - well, a good five years anyway. I thought I was going to lose most of it because it was well past the expiration date. Well nothing I have ever built has come back to me for a glue joint problem (or any other problem, for that matter). So, about five years ago I bought another gallon of Titebond Extend or whatever it is called. I did not really want a gallon, but I needed the extra open time, and gallons were what was available.

I am still using that gallon, and I check the glue on a regular basis to see how it is holding up. It still has its proper consistency, it still has its advertised open time, and things I have built with it are still going strong. Two examples are some benches I built three years ago, and a towel rack I built about 18 months ago for our own use. All of these pieces get hard daily use and there have been no joint failures yet. As an aside on the towel rack, I was sort of panned by some people for it being too high and narrow. It has not even come close to tipping yet, and again this is seeing daily use in our bathroom, and with three kids to boot.

As far as the polyurethane glue goes, how's this for a hard use situation? I use it for gluing threaded inserts into the tap handles I make for a local micro brewery. The inserts are knurled and not threaded on the outside, as they are being inserted into end grain. I used to just press them in, but some were coming back loose because of hard use. About four or five years ago, I started using a drop of polyurethane glue on each insert. At the time I started using it, the expiration date had already passed on the bottle, but I have not had one failure in hundreds of handles. Keep in mind that these are going in bars and restaurants where they are being yanked on all day long every day of the week. If something were going to fail, these would be prime candidates.

I have had some poly glue go bad, but it is real easy to tell. The whole bottle solidifies. It is like a rock, and no glue comes out. But other than that, I have never had a problem with glue not sticking as advertised.

Bill

[Chris Padilla]

Great information, Bill. I'm beginning to think it is a marketing thing. Perhaps if we are diliget about capping the glue bottle when done, we keep out the nasties that starts the curing process. I have a gallon of II and two of the larger Gorilla Glue bottles (found on sale). I only open these when I need to transfer them into smaller bottles for ease of application. Other than that, those larger bottles/jugs are rarely open for longer than a couple minutes every few months.

[JayStPeter]

Regarding wetting joints:

I read in a magazine somewhere that there was no need to wet the opposite side of the joint when using poly glue. There is enough moisture content in wood to cure the glue just fine. You should do it for some other materials though. That's been my MO for the last couple of years and I think I get better joints from it. Initially I was using a wet rag on one side and getting all sorts of foam out. Those joints were definitely weaker than the ones I get now (although I was probably using too much clamping pressure also). I use poly and titebond pretty willy-nilly. If I want my clamps back in an hour to clamp something else ... titebond. If I'm worried about squeezeout ruining finish, or am not going to get the piece out of clamps today, poly. If I run out of one, I use the other. I have to admit, I probably use more titebond. But, I haven't had any problems, period. Well, OK ... I'm pretty bad about leaving the caps open on my glue. With poly, you're finished. With titebond, you can peel off a layer and still use whats underneath :cool:

Jay

[Mark Singer]

Mark,

Any reason why you choose one glue over another for a particular application?

BobBob,
West Systems(Epoxy) for all waterproof applications such as doors (exterior) patio furniture. Or where strength is really important...chairs, cross grain joinery, mortise and tenon with smaller surface area. Also for wood movement.

Tightbond....Long grain joints...cabinets...carcass construction, drawers, dovetails...Lee Valley GF2002 is similar and very good.


Hide Glue filling joints in combination with sanding does not change appearance of finish (I never have to fill any joints...yeah right!)

Roo Melamine Glue....Pre finished appleply...or prefinished Baltic birch for drawers or melamine

[Kirk (KC) Constable]

Kirk,

Did you ever use epoxy for the m & t's?

Bob

I've used epoxy a couple times on a complete rocking chair, and still use it for the 'leg post to rocker' joint. When using epoxy I use System III T-88.

KC

[Terre Hooks]

I was using the Polyurethane glues for a while and had several joint failures at which I stopped using them completely. I use West Systems and Tightbond 2 or Lee Valleys glue for eveything. The poly glues are very messy and short shelf life....why mess with them?

I agree with you. I have only used TB Poly glue one time. I did not like it. What a mess. Only time I will ever contemplate using it again is if I build something that I think will need to endure extreme weather condtions. Even then, I might consider expoxy or some kind of Marine adhesive.

I am on my 3rd gallon, been through several quarts and pints of Titebond 2, and I have been very pleased with it. I wouldn't have bought the second full gallon if I didn't like it.

[Chris Padilla]

This has been an interesting thread.

What I take from it is that we all have different experiences with different adhesives.

Glue is a tool and as such, will be used in many ways. Be thankful that we have the selection we do and learn to use the tool to your advantage.

Happy Woodworking to all! :)

[David Rose]

One bottle of Titebond that I bought a couple of years ago smelled strongly like skunk. It was still within the expiration date code. I tried it on a sample edge glueup and it worked fine as far as I could tell. When I contacted Franklin (the makers) they said that it "might" be a bad batch. They would make no other comment as to servicability. All the glue that both local borgs had were the same expiration date and same smell. Next trip to Greg's store in Tulsa I replaced it. I really ought to go through my bottles of outdated stuff. It may be OK, but for what the pint bottles cost, is it worth the chance? I would not feel too positive about it unless I occasionally tested it in a break test. If I had a lot, it would probably be worth periodic testing.

David