Glue creep

Glue creep · 01-16-2006, 10:31 PM

Glue creep: What is it? Why does it happen? How do you prevent it?

Reason I ask is: I've noticed that some (not all) of my projects have developed a little tiny ridge in the glue lines over time (weeks to months). Feels like glue squeeze-out, but on a microscopic level, if you can imagine that. It's very easy to knock off with #0000 steel wool, and the jointery is still smooth/level, so I don't think it's all due to wood movement. I don't want to have to go around buffing all my projects after I've finished them!!!

I've been using either plane yellow wood glue or titebond II for my projects.

D L Ames · 01-16-2006, 10:35 PM

Interesting.......I don't believe I have ever experienced something like that before. Does it occur with any particular wood species or all species that you have used? Is your glue beyond the recommended shelf-life?

D L

Monty · 01-16-2006, 10:38 PM

I don't buy large quantities of glue, so the stuff I have generally is pretty fresh - like less than a year old max. I have heard people talk about "glue creep", but I'm not sure if this is what it means.

D L Ames · 01-16-2006, 10:46 PM

Well, I am certainly stumped by it. Hopefully someone will know what is causing it.

Does it only happen once per joint or does it keep repeating itself every couple of months?

D L

Big Mike · 01-16-2006, 10:58 PM

Monty, sounds like the classic symptoms of glue creep. Sometimes it is more pronounced depending on what the wood is that you use in your glue ups. For instance if you join a flat sawn edge to another board that is more or less quartersawn or rift sawn the creep will be more pronounced. Look at the ends of your boards and try to match the annular growth rings so that similar ring patterns are adjoining one another. It will help but not completely eliminate your problem. I have no conclusive evidence but I think that Titebond II is more susceptible to creep than plain old Titebond. I am sure others will straighten me out.

DaveO · 01-16-2006, 10:59 PM

I have had similar situations occur with several panel glue ups. I have a Mahogany table top that was dead smooth and now you can run your hand across it and feel where the joints are. Also a similar condition on some Oak tables. I am the only one who notices it, but I knew what it felt like after I finished it. I don't know what caused it. But I do know how it can be prevented. Plastic resin glues will never creep, but they are expensive, messy and not readily available at Lowes

I would also like an explaination as to the reasons behind the creep.
Dave

woodguy1975 · 01-16-2006, 11:05 PM

Like Big Mike said it is from a slightly different rate of expansion-contraction between the boards. Yellow glues don't have a ridge enough bond to prevent the boards from moving independently so you feel the glue line. At certain points in the year it will be more pronounced or less pronouced.

Dave O is right PRG is the way to go. I be using that on my dovetails of my chest to prevent this from occuring.

Good Luck,

John

Monty · 01-16-2006, 11:06 PM

Yea DL, it just happens once or twice. Like on that mallet I turned a couple of weeks ago... a hair line emerged on the joints that I buffed back out, now there are a couple of areas that it's happening again, but not as much. I suspect that probably 2-3 buffings will take care of it, but I don't want to have to do this to a project that has a fine finish on it!!!

(as if I'm capable of a fine finish!)

Steve D · 01-16-2006, 11:38 PM

From personal experience Titebond II is more susceptible than regular Titebond. I only use II on projects that will have direct moisture exposure and for iron applied veneer.

Mountaincraft · 01-17-2006, 12:34 AM

From my experience, tightbond 3 will expand somewhat quickly after curing, then not move much.

NCPete · 01-17-2006, 01:00 AM

I thought that was the guy they couldn't get out of the adhesives aisle in Lowe's

SteveColes · 01-17-2006, 09:42 AM

I thought that was the guy they couldn't get out of the adhesives aisle in Lowe's

DavidF · 01-17-2006, 10:08 AM

I agree with everybody on the reason, but what to do? Maybe some of the cause is that the join was not perfect, maybe excessive clamp pressure was required to close it and when that pressure was released the microscopic gap with an elastic glue in it is causing the problem. How about too thick a glue line; again possibly caused by a less than perfectly flat edge join - sorry Steve not running down your jointing skills

SteveColes · 01-17-2006, 11:07 AM

Originally Posted by DavidF

....sorry Steve not running down your jointing skills

Wasn't me, I have no skills to run down

Monty · 01-17-2006, 12:13 PM

Joints are all machined flat with the planer prior to glueup. Glue was applied to both sides, spread very thin (just to wet the whole surface). Also happened on a dovetailed joint, where the fit was perfect (honest!) and the glue was only on one side.

Wondering about too much pressure on the glue line - dovetail maybe too tight (it WAS snug), mallet handle trapped in the middle of 4 pieces of rosewood...

What do ya'll think?