I’m wondering if someone could help me understand the advantages and disadvantages of polyurethane glues? I’ve never used them, but I’ve got a reasonably large glue-up coming up with a lot of mahogany and I’m a little nervous about my open time with the Dark Titebond II.
I nearly bought a bottle (titebond) at the local woodcraft last week to experiment, but I couldn’t find a date of manufacture on the bottle. I decided not to buy it after seeing some of the glue hardened in the bottom. Does anyone know how to decode the numbers and letters that are printed on the bottle?
This piece of furniture is being joined almost completely with mortise and tenon joinery and will not be exposed to the elements.
Any recommendations on a brand? Any alternative ideas for my situation?
Thanks for the help.
Replies
FWW did a review on glues a year or so ago, you should check that. Polyurethane has some advantage, such as gap filing and longer open time. But as I recall their strength is not as good as first thought, and the foaming can be a problem. Also a mess to get off of your hands.
Woody
Polyurethane glue will fill gaps as is foams, BUT IT HAS NO STRENGTH WHEN FILLING GAPS!!! If you do have gaps that need to be filled and have strength, use epoxy..-If you didn't learn something new today, you're not looking hard enough!
I've always used poly glues for joints such as sliding dovetails which are tight-fitting. Poly acts as a lubricant where others do not, and makes the glue-up less of a struggle. One other advantage -- the long open time -- seems to be disappearing. For some reason nearly all the big boxes in my area, and LV, stock only Gorilla which has reduced the open time to 10 to 15 minutes, which is the same as LV's conventional glue. Dumb move, in my opinion. Poly is advertised as good for joining different types of surfaces as well as wood, but I have no personal experience of that. Foaming seems to depend on how much glue you use -- sometimes there's next to none. In any case it's not difficult to scrape off. Shelf life can be short after the bottle has been opened, because dampness in the atmosphere can cause poly to cure. It's best to store the bottle upside down after you use it. If you don't have a present specific use for Poly, I wouldn't buy it until it's needed.
Jim
Marti, If I am concerned about open time, I usually use epoxy. You can control your open time, because it requires some heat to kick. I have done numerous projects that took over an hour to get all of the glue spread, before clamping or drawing the vacuum. Some even a couple of hours.
Even then, there may be several hours left. Unlike many other glues that are ruined if they get moved shortly after the initial grab time, epoxy isn't bothered by a little motion as long as it is still fluid.
It is also one acts as a lubricant, which helps get parts together which might grab before getting all of the way home.
Epoxy also bridges gaps, so it doesn't really require extremely tight joints, if thickened by additives, which also can improve its properties, and prevent sagging or running.
I have probably used 50 ~ 75 gallons over the last 20 years. I really don't miss that startled rush of too much blood rushing to my brain in the few seconds or minutes of panic, when trying to get fast grab glued joints together, which grab half way in, or maybe the clamp situation wasn't what I thought. I don't miss that sensation...............
I wonder if anyone has ever done a study of how many woodworkers were found in their shop with strokes which occurred while gluing up. It would be interesting to hear some stories from those who have lost a week or more worth of time, not to mention materials from choosing the wrong glue.
For wood to wood joints, I can think of no advantages. It is not stronger than the normal cadre of woodworking glues, any of which is stronger than surrounding wood in a well-glued joint. (see http://www.titebond.com/download/pdf/ww/GlueGuideTB.pdf ) While it fills gaps, it fills them with foam that has no structural strength; so it does require good fitting. It is messy. It stains your flesh. It requires clamping, particularly in closed joints such as m&t. It has no known solvent, making it both a bother to clean and is not reversible. It has a short shelf life, once opened, and is quite expensive.
It _might_ have some advantage if you need a waterproof glue on dissimilar materials, but epoxy will be 50% (5 minute) to 100% (30 minute) stronger, assuming a good fitting surface, plus, epoxy fills gaps readily for highly porous adherands.
My vote: P.U. on PU.
Edited 3/5/2009 8:57 pm ET by byhammerandhand
One possible solution is to work through the glue up sequence again. Instead of needing a long open time, it might be that a sequential glue up can be arranged so that it proceeds in stages. This can, if successful, both eliminate the need for long open times and, at least theoretically, reduce the heart attack inducing nature of the glue up. In a sense, this makes hide glue, which is both reversible, if things really go awry, and "adjustable" for a relatively long time, a sensible choice. Those 18th c. cabinetmakers could get massive secretaries together in that way. It kind of changes the way of working, where a piece is built--step by step, rather than assembled, after all the pieces have been cut and joined.
I will say I have found this hard for a person with modern sensibility, despite good intentions, managed to increase my "assistant's" vocabulary during the glue up process, while only narrowly avoiding the necessity of alimony.
Marti,
I don't have much experience with PU glue, but have done some research. As others have noted, the only real pros for it are that it's waterproof and is good at bonding dissimilar materials. The open time isn't any greater (sometimes even less) than other glues and its gap-filling capabilities are overrated. The foam doesn't have any strength, which seems to be a common misconception.
I believe the number on Titebond bottles is a batch number, and to the consumer has no meaning.
Chris @ www.flairwoodwork.spaces.live.com
(soon to be www.flairwoodworks.com)
- Success is not the key to happiness. Happiness is the key to success. If you love what you are doing, you will be successful. - Albert Schweitzer
The Titebond code is as follows.... 2Gxxxx (2=last digit of year made; G=7th letter of alphabet=7th month of the year=July
................................................
Men will never be free until the last king is strangled with the entrails of the last priest.~ Denis Diderot
Good to know. Thanks - I stand corrected.Chris @ http://www.flairwoodwork.spaces.live.com(soon to be http://www.flairwoodworks.com)
- Success is not the key to happiness. Happiness is the key to success. If you love what you are doing, you will be successful. - Albert Schweitzer
I would not even consider polyurethane glue for your project. I think Gorilla is mostly a marketing gimmick. Weldwood plastic resin glue would fit the bill in your application or as Steve commented liquid hide glue. Titebond makes a premixed hide glue, so it is not all the mess of the past. You were smart to pass on the glue you saw in the store because it was way out of date. Most hardware and lumberyards have all out of date titebond. One day I checked about every bottle in a large lumberyard and some of them were three years old. When dating Titebond, as somebody said, the code 9B4561 means 9-the year 2009, B- second letter of the alphabet for second month of the year February 2009. 4561 are the batch numbers and the factory in which it was made. Franklin Adhesives advises one year shelf life on it's PVA glues. Lowes usually carries the freshest Titebond III (all I use) I have got some there that was made earlier in the same month, but usually a month or two old. Plastic resin glue has unlimited shelf(if you keep it dry) life because you mix it with water for the batch you need. I use plastic resin glue in all my laminations because of the open time and it doesn't creep like PVA's.
Thank you all for your comments. It will be particularly helpful to know how to decode those manufacture dates.
As far as completing the glue up in stages goes, that's what I'm doing. Each stage has a number of mortise and tenons to be joined. Truthfully, I might have enough time to glue it with the titebond, but I've done a lot of work to screw it all up now because I was too cheap to spring for some epoxy.
I'll drop by the local Woodcraft and grab some epoxy today.
I'll let you know how it turns out.
Well,
I ended up using Titebond III for the glue up after the sticker shock for the epoxies sent me looking for other options. Mainly because I didn't need a pint of resin and a quart of hardener or whatever order it comes in.
The T3 worked really well and I have to say I might have discovered my new favorite glue. Open time was great and this stuff really lubricates the joints well during assembly, making the process a little more convenient. What little squeeze out remained cleaned up easily.
Thanks for all of your comments.
You made a good choice. Woody
I would be interested in hearing what the price of epoxy was, and for what quantity.
Here's a price list for the stuff I use (not very often). Makes polyurethane look like a bargain. I imagine you might get a better deal buying in bulk. http://www.leevalley.com/wood/page.aspx?c=2&p=20011&cat=1,110,42965&ap=1
Jim
Hi Jim, While I still have not heard back from the OP, but just for comparison, you may want to read what I posted to Metod, and Rick. Just for comparison, I have tried to use the gallon price to keep the field level, but LV doesn't show gallons. The smaller the container, the higher the price per oz. I believe there are 16 cups in a gallon, so an 8 oz cup cost $3,15, which is probably enough to glue up a table or walk-through door.
Keith,
Check out http://www.clarkcraft.com. I used their epoxy for two strip built kayaks, and always keep some at hand.
Best wishes,
Metod
Hey Metod, That looks like a pretty reasonable price, especially if you buy in larger quantities. I don't buy less than gallons, and sometimes 5 gal. when have larger projects. Just for comparison, your source was $114 for a two gallon kit. The supplier that I use is $94 for two gallon kit of 1-1 ratio. This is a higher viscosity than you may want for wetting out glass, but I am not using it for that. Although, this source does have many different resins and hardeners. http://www.fgci.com/
Keith,
Thanks for your link. I glanced at it, but one needs to call for pricing.
As a hobbyist, my glue usage is rather small - but the kayaks were really 'thirsty'. For quick and small applications (when only a few drops are needed), a 5-min epoxy (expensive!) is just fine.Take care,
Metod
A good source of epoxy is http://www.jamestowndistributors.com
I get mine from a local guy and can get those prices lower. He will UPS to you if interested. I use System 3 and buy gallons of it. It doesn't go bad so there is no time issue like PVA and super glues. Also have a good bulk source on super glue. I've bought it by the 5 gallon jug on occasion. Half the price of Fastcap super glue which isn't priced to bad either.
Hi RickL, Am I reading the price list correctly? $172 for a gallon starter kit? I guess that would be 1.2 gallons though. That is just too expensive for my liking. I have been paying around $46 per gallon for resin, and $48 for activator, which is also one gallon, for a 1 -1 mix. It is a higher viscosity , although I still thicken it when I use it for an adhesive. Here is the source that I use. I had to call for the price, they are working over the website.
http://www.fgci.com/
5 gallons of Super Glue? Really? I'm lucky to go through an OUNCE in a year. Are you a practical joker?Chris @ http://www.flairwoodwork.spaces.live.com(soon to be http://www.flairwoodworks.com)
- Success is not the key to happiness. Happiness is the key to success. If you love what you are doing, you will be successful. - Albert Schweitzer
Never joke! Commercial woodworking and millwork business and often use it for filling feather checks on antique lumber for flooring before running it through moulder. We often have jobs of 5,000 bd ft of flooring for a single house. Saves thousands of dollars on wood that would be ruined otherwise. $500 for 5 gallons of super glue is a bargain. Much cheaper and faster cure time than 5 minute epoxy which we also go through gallons a year.
Playing with some of the industrial cyanocrylic ("super") glues opens up a lot of possibilities, or at least it has for me. Really simplifies a lot of tough-to-clamp glue ups, tiny bits, etc. The industrial one I've use is http://www.fastcap.com/products.aspx?id=232. Like most, it's a two part mixture. "Glue" on one piece, activator on the other. Press together for 10 seconds and you're done. Viscous formulations (gels, etc.) for wood joints where regular "super glue" just soaks in. Another tool for the tool kit, anyways.
Cheers
Peter
You might want to take a look at this discussion on the WoodNet forum:
http://www.forums.woodnet.net/ubbthreads/showflat.php?Cat=&Number=4191163&page=6view=collapsed&sb=5o=14
For anything with a lot of glue joints that need aligning etc. I always use Titebond liquid hide glue. It cleans up with water but is sticky like honey and is a little more difficult to wipe off than Titebond I, II or III. It gives you about 20 minutes open time but I have never had the joints open that long but in their positions and I could still shift them. This glue has a shelf life of 1 year per Franklin Glue Co. and the problem is most stores carry out dated bottles of it. Guess it is not a big seller. It is like the old LaPages fish glue.
Is the shelf life 1 year from manufacture or 1 year from opening?Chris @ http://www.flairwoodwork.spaces.live.com(soon to be http://www.flairwoodworks.com)
- Success is not the key to happiness. Happiness is the key to success. If you love what you are doing, you will be successful. - Albert Schweitzer
According to Franklin Co. tech rep. he said one year from the date code on the bottle. That was about 6 or 7 years ago when they printed the date on the bottles of liquid hide glue. I still ues it even when it is 18mo old and have never had a problem as long as its consistancy is essentially the same as new. After 18mo out it goes used or not.
For a long open time, you can use plastic resin glue. Ace hardware, among many online sources, carries Weldwood Plastic Resin Glue. I use this exclusively when doing monster glue-ups, like bent laminations. It has a very long open time, so no panic attacks, like Keith said. It also has some lubrication value, as well.
$8 for a small container, last time I bought it a few months ago. My local ace hardware stocks it.
Jeff
If you cherish what you build and intend for it to last a few generations, then you should also then consider the person who may have to repair it in the future. Fine furniture is made with glue that is reversible - expoy, poly, Titebond type III are not easily reversible.
I have repaired a couple of hundred chairs/furniture pieces over the past 20 years or so - when I run into epoxy or poly or something similar (usually applied by someone who is looking for a quick repair), my price goes up very quickly. Suddenly the owner realizes how expensive Gorilla glue reallly is.
Well let me say this about that. I think you are getting great glue advice. I used Gorilla to glue up my purple heart work bench and while it was fresh it worked great as far as invisible glue lines. For key joints in the vises where there could be a gap here or there I used epoxy. That was the way to go there.
NOW. After two years after opening the bottle I used the same Gorilla to glue up an eight quarter bubinga table top. Bad idea ! The glue was too thick. The strength still seemed to be fine but I could see the glue lines even though I went to extremes for invisible glue lines when no glue or clamps.
I glued up the top and could see the seams. The glue acted like mini balloons and kept the joint apart even with lots of high quality clamps and gluing up one joint at a time ! ! !
I cut the whole thing apart and rejointed. While planing off the old joints I could plane down to a definite layer of glue. Bad news. Just a layer of bubbles that it took a few plane swipes to remove.
I don't think the thickened Gorilla would have been a problem for your mortise and tenon joinery. Still would go together and still would cure and be strong enough.
I was careful to clean the bottle tip and squeeze out most of the air etc. I wound up throwing out half a bottle of glue. For Gorilla if you want to use it I recommend the smallest bottles.
Expensive this way but less atmosphere in the bottle. I like epoxy especially for your mortises. It is a true gap filler with strength where as the Gorilla has no gap strength.
If time isn't a factor regular white or yellow cabinet makers glue is just fine for strength.
I used Poly because I was using these "oily exotic" woods. Tests have shown recently that the regular white or yellow cabinet makers glue do just fine for strength with these as well so with poly it is just a longer open time or water proof advantage. The Gorilla is easier to plane off and may take finishes better also.
And another thing. If someone decides to use up some older/thicker Gorilla in a non glue line/hidden joint I recommend stirring it up. I used an old chop stick. I found I had much less foaming (for what ever that is worth ) if I just used it from the bottle unstirred. If I stirred it up there was more foaming for the same ambient temp ~65° F. In both cases I wet both sides of the joint first with water and let "dry" so there was just a bit of water down in the pores. Then put very thin layer of glue on both surfaces in both cases. This is the way I did my work bench and it worked great when glue was fresh. I think I read in the Gorilla literature this is the best way to go with the oily exotics.
roc
Give me six hours to chop down a tree and I will spend the first four sharpening the axe. Abraham Lincoln ( 54° shaves )
Edited 3/12/2009 7:59 am by roc
Edited 3/12/2009 8:02 am by roc
Edited 3/12/2009 8:04 am by roc
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