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All Replies on "Open time" versus "Grab time"

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View richgreer's profile

"Open time" versus "Grab time"

by richgreer
posted 01-18-2012 05:12 PM


17 replies so far

View Bill White's profile

Bill White

3590 posts in 2715 days


#1 posted 01-18-2012 05:32 PM

I have been using Gorilla PVA for a while. Was using TB III until I read (somewhere) about its tendancy to “creep”. Never had a failure with either glue and, like you, I’ve never timed the grab. I guess that I’m a weeny ‘cause try to let my glue-ups rest at least overnight unless I’m usin’ pocket screws.
Bill

-- bill@magraphics.us

View dbray45's profile (online now)

dbray45

2618 posts in 1531 days


#2 posted 01-18-2012 05:38 PM

Just so you know, Titebond III will fail if you heat the joint up. Titebond II is more heat resistant dut is not watter resistant.

I know of what you speak. When I assembled my cart made from ash, there were several joints that had to seat at the same time. It took 4 or 5 dry assemblies to come up with a sequence that I could use to minimize the grab. A cull with a dead blow hammer or a clamp to bring it in tight – again, use a cull so you can add more pressure – makes up the difference.

-- David in Damascus, MD

View kaschimer's profile

kaschimer

89 posts in 1144 days


#3 posted 01-18-2012 05:44 PM

I was watching a WoodWhisperer video the other day, and he was doing something similar, where he needed longer time to make sure everything is aligned. I believe he used Epoxy glue in those cases, and regular wood glue (like Titebond) for everything else that didn’t need longer to assemble.

Having said that, I couldn’t tell you what the “grab time” was of the Epoxy, only that it was enough for him to complete assembly of the complex stuff.

-- Steve, Michigan - "Every piece of work is a self portrait of the person who accomplished it - autograph your work with excellence!" - Author unknown

View Greg..the Cajun Wood Artist's profile

Greg..the Cajun Wood Artist

5283 posts in 2063 days


#4 posted 01-18-2012 06:22 PM

I know what you mean about the grab time being shorter…and that is one reason I also use epoxy on some projects. I also like the epoxy better for gluing miters on my boxes because of better holding power on end grain.

Titebond III is a great glue but you do have to work fast…and I like to take my time to ensure everything is lined up and glued up properly.
I would also like to see a comparison and review of grab times as opposed to open times.

-- Each step of every Wood Art project I design and build is considered my masterpieceā€¦ because I want the finished product to reflect the quality and creativeness of my work

View DS's profile

DS

2132 posts in 1175 days


#5 posted 01-18-2012 06:25 PM

I have discovered that Grab Time varies proportionately with the size of your dead blow mallet.

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

View TheDane's profile

TheDane

3997 posts in 2418 days


#6 posted 01-18-2012 06:32 PM

Rich—I know what you mean … I ran into this when I built my Morris chair. I don’t like to do a partial or sequenced glue-up of a frame … too hard to square up rails and legs/stiles if one end is already glued and dry.

By the time I got the last through-tenon buttered with TiteBond III, the first two were getting tacky and I had a heck of time pulling all four joints together and squaring the assembly.

—Gerry

-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

View DS's profile

DS

2132 posts in 1175 days


#7 posted 01-18-2012 06:35 PM

Gerry, If you dilute your glue slightly, or even pre-wet the joint on the first few joints, it should prolong the amount of time you have to complete the glue up before the glue grabs.

Some glues, when I know the tack time, I start an egg timer and check my progress as I go. This is mostly for complex glue ups.
When I run my veneer press, I always run the timer. I know that from start, to pulling a vacuum in the bag, I have exactly 12 minutes. This lets me know when to stop fussing with it and get busy.

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

View Bobsboxes's profile

Bobsboxes

792 posts in 1419 days


#8 posted 01-18-2012 06:45 PM

I have switched to epoxy on tuff glue ups and use titebond III on all else. I also have got to last joint in a tough glue up and could not get last joint all the way together. But also on softer woods, the longer the wood is exsposed to the glue [titebound III ] the more swelling of the wood fibers. That is what got me changing to epoxy. I also agree that grab time is 1 min. for titebond III. All tough glue ups, I recruite my sweety to help. She has learned that we only have a minute or two, then my atitude starts to deteriate. Also I have been puting some bowties in on some slabs with cracks and I use epoxy, I think it helps fill voids. Also with epoxy, after it is mixed I can stir in some fine sawdust to add color.

-- Bob, Lewistown, Montana. Kindness is the Language the blind can see and deaf can hear. - Mark Twain

View TheDane's profile

TheDane

3997 posts in 2418 days


#9 posted 01-18-2012 06:47 PM

DS251—Hmmm … never really thought about that.

It would seem that diluting the glue could weaken the joint, and pre-wetting the joint might cause the wood to swell. No?

—Gerry

-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

View DS's profile

DS

2132 posts in 1175 days


#10 posted 01-18-2012 06:52 PM

Gerry, correct on both counts. But it is a matter of degrees.

You are just trying to shift the glue up a bit more in your favor. Slightly diluted, lightly wetted. Glueing wets the joint anyway. We’re talking a small percentage more wet. That’s all.

Experimentation on scrap wood is totally acceptable also. I usually mock up my joints with scrap as I setup my tools. That same scrap can test your glue’s tack time.

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

View TheDane's profile

TheDane

3997 posts in 2418 days


#11 posted 01-18-2012 07:02 PM

DS251—I see what you mean. I do actually do experimentation … sometimes to the extent of building prototypes if I am getting into something that is new to me.

We’re downsizing a bit (getting ready to sell the house and move), and while clearing off a shelf in the storage loft above my wife’s car, I found a set of frame and raised panel doors I made over four years ago when I was building my entertainment center. Usually the prototypes are just cut up for other work or go into the scrap bin, but these (must have) turned out so well I dry-assembled and wrapped them in plastic. Now I’m trying to figure out what I can build that would use a set of pine raised panel doors!

—Gerry

-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

View DS's profile

DS

2132 posts in 1175 days


#12 posted 01-18-2012 07:15 PM

FWIW, I use Titebond II almost exclusively. Titebond III is probably superior in many ways, (especially for joints exposed to weather or moisture), but 1 to 2 minutes tack time? That sounds rediculous.

T2 usually gives me quite a bit more time. Wish I could say exactly, but there are so many variables that a range is probably better suited. I’d guess 6 to 10 minutes. Once it is under clamping pressure, full tack time is about 15 minutes—hard to get apart by that time.

Glue ups are like a stage play. I rehearse them to minimize wasted movements. It is preplanned. All the cauls are ready, all the clamps set at the right distances and there’s no interruptions once there’s glue open.

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

View Jim Bertelson's profile

Jim Bertelson

3686 posts in 1919 days


#13 posted 01-18-2012 07:22 PM

Having dealt with these issues recently, appreciate the discussion. Using Titebond III I leave a little water in my glue brush to help wet the glue when I anticipate problems.

-- Jim, Anchorage Alaska

View richgreer's profile

richgreer

4525 posts in 1829 days


#14 posted 01-18-2012 07:30 PM

This is excellent input. Thank you.

I have never considered Epoxy for woodworking. I will now. Also, I never would have expected TB2 to have a longer “grab time” than TB3. TB3 has the longer open time.

I had also not considered diluting the glue with a little water. Does anyone know if that weakens the joint to any significant degree?

This discussion proves the value of our website. Raise an issue/problem and you almost always get good feedback and insight. that can be of value to many.

-- Rich, Cedar Rapids, IA - I'm a woodworker. I don't create beauty, I reveal it.

View pintodeluxe's profile

pintodeluxe

3580 posts in 1568 days


#15 posted 01-18-2012 08:25 PM

I have gone to Titebond II Extend for all of my complicated glue-ups. It has an open time of 20 minutes, and it will allow you to reposition the joint as needed. It is a little runny compared to regular Titebond II, but for me it is worth it to know I can relax and glue-up assemblies with a dozen mortise and tenons at one time. Glue strength in my testing is stronger than the wood fibers of white oak (same as regular Titebond II).
Titebond II Extend comes in a white container, and is available in several sizes, including gallons. It is available through Amazon.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View Viktor's profile

Viktor

448 posts in 2174 days


#16 posted 01-18-2012 10:04 PM

“It would seem that diluting the glue could weaken the joint”

- Titebond is waterbased PVA emulsion. Diluting it will not affect binding per se. The only negative side is more shrinkage and running out of loose joints.

View ToddTurner's profile

ToddTurner

144 posts in 2078 days


#17 posted 01-19-2012 03:19 AM

Hi Rich. Hope your doing well. The grab you reference may be induced by friction. Some adhesives react to the friction caused by the tightness of joint such as the dovetails. Also, if the surface is really flat and there is virtually no air between the joints, this may present itself as grabbing.

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