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Failed Glue Joint - Repair ideas?

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Forum topic by Ivan posted 05-06-2010 04:07 PM 3190 views 0 times favorited 11 replies Add to Favorites Watch
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Ivan

185 posts in 2844 days


05-06-2010 04:07 PM

Topic tags/keywords: question

I moved my laptop the other day and noticed that the boards on the top of y desk were seperating right at the glue joint!

Some history; Jatoba boards glued with Gorilla Glue and Biscuits, Poly finish.

The laptop does give off allot of heat and is not moved, could the constant heat cause the glue to fail? Can I just use some Urea Resin Glue to fill the gap and clamp it back together?

Anyone have issues with Gorilla glue? Should I have wiped the faces of the joint with Acetone first?? I didn’t think Jatoba was that oily to need Acetone for glue to ‘bite’.

Any help would be appreciated.

Cheers,
Ivan

-- "Do it right the first time, you'll just kick yourself later..."


11 replies so far

View MedicKen's profile

MedicKen

1610 posts in 2929 days


#1 posted 05-06-2010 04:16 PM

It sounds like the the joints may have been starved of glue while clamping them. If you over tighten the clamps and squeeze all the glue out it will fail. Another issue may be that the boards were nor complpetely dry when gluing and as they have dried have begun to separate.

-- My job is to give my kids things to discuss with their therapist....medic20447@gmail.com

View richgreer's profile

richgreer

4541 posts in 2541 days


#2 posted 05-06-2010 04:23 PM

Did you use regular Gorilla glue or did you use Gorilla wood glue (big difference)? Regular gorilla glue does not work that well on wood. I have found that the bond from Gorilla wood glue is incredibly strong (stronger than the wood around it) when properly applied.

If this happened to me, I would remove the boards and run them through a jointer to get a fresh, clean edge on each board. Then I would glue and clamp.

I agree that jatoba is not an oily wood that requires acetone.

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

View PurpLev's profile

PurpLev

8523 posts in 3115 days


#3 posted 05-06-2010 04:23 PM

I doubt the heat is the culprit here, more like not enough glue penetrated the lumber during construction as Ken suggested.

I assume you can’t take it apart to redo the top- in which case I don’t think you have many other options than your very own suggestion to drip glue in the cracks, and reclamp to get the boards back together – only this time, don’t over tighthen the boards. as long as the boards are mating with one another thats all the pressure you need to put.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View Gregn's profile

Gregn

1642 posts in 2450 days


#4 posted 05-06-2010 04:48 PM

I assume that when you say separating at the joint, you mean all the way through. Is there anyway you can slip a thin blade down the joint to clear the glue line some? If so great, if not clean out as much as possible with a blade. Then take your shop vac underneath the joint and begin gluing the joint using the vac to draw the glue to the bottom of the joint as you glue along the glue line. Then clamp and let it cure. I have done this to a couple of pieces once and it worked good for me. Only thing I can think of without taking it apart.

-- I don't make mistakes, I have great learning lessons, Greg

View SnowyRiver's profile

SnowyRiver

51452 posts in 2947 days


#5 posted 05-06-2010 05:10 PM

I doubt also that the heat would cause a problem. Typically though with poly glue, it helps to dampen the area to be glued with water. It will help the glue bond and cure better. If the board is loose and can be taken apart, I would suggest removing it, joining it, and reglue like Rich said. Otherwise, you could cut the joint open with your tablesaw or with a guide and circular saw and then join and reglue. If that isnt possible, then you will have to fill it. You could use poly glue mixed with some fine sawdust from the same wood you have and pack it in the crack, and refinish.

-- Wayne - Plymouth MN

View Ivan 's profile

Ivan

185 posts in 2844 days


#6 posted 05-06-2010 05:19 PM

Thanks fo the feedback, I noticed that this ONLY happened directly under the laptop. The joint directly beneath it is more open than the one that was slightly towards the back. This makes me think that the heat was greatest on the joint that opened the most, I didn’t check to see if the joint had opened all the way through, which is why I was thinking it might be a heat issue with the top and bottom having sufficient temperature difference to make the wood movement pull the joint apart. The rest of the top is solid.

I’ll double check it tonight and see if it’s all the way through, then maybe decide to fill it or rip it and re-glue.

I used the regular Gorilla Poly Glue (the one that foams) this top was made about 10 years ago, moved several times, been in the sun, in storage, etc… no issues til now. Back then all I had were Pony Pipe clamps and little experience, so it’s very possible that I overtightened the clamps (as hard as I could for fear of the poly glue foaming and making a weak joint).

Thanks for the help,

Ivan

-- "Do it right the first time, you'll just kick yourself later..."

View Nomad62's profile

Nomad62

726 posts in 2425 days


#7 posted 05-06-2010 11:35 PM

Guess I’d recommend leaving it alone for a couple of days and keep an eye on it. If the laptop was the culprit, the gap may close back up, maybe only partially, when some humidity gets back into the wood; would hate to see it cause more troubles if that occurred after a repair…

-- Power tools put us ahead of the monkeys

View Mark Shymanski's profile

Mark Shymanski

5314 posts in 3179 days


#8 posted 06-03-2010 03:29 PM

Nomad62 may have a point there, the heat from the laptop may not have affected the glue but it may have contributed to unequal drying of the wood proximal to the laptop…warm wood = warm wood moisture = evaporation=drying of the wood. Mind you you have probably fixed this by now as I just looked at the date you posted this :-)

-- "Checking for square? What madness is this! The cabinet is square because I will it to be so!" Jeremy Greiner LJ Topic#20953 2011 Feb 2

View a1Jim's profile

a1Jim

115202 posts in 3043 days


#9 posted 06-03-2010 05:45 PM

Polyurethane glue works great on wood. I suspect you may have a wood movement problem . When making your table did you allow for wood movement when attaching the top. I haven’t used Jatoba but if it’s an oily wood you may have to clean it with acetone first.

-- http://artisticwoodstudio.com Custom furniture

View Ivan 's profile

Ivan

185 posts in 2844 days


#10 posted 06-21-2010 04:48 PM

I have been putting this off as it’s under the laptop and out of sight.

I didn’t fix the top so to allow it to expand and contract with seasonal changes in humidity. The rest of the desk is just fine, but with an unequal drying I suspect the glue joint would survive and the wood would fail.

I’ll have to see when I run out of projects to figure out how to fix this.

-- "Do it right the first time, you'll just kick yourself later..."

View Dragonsrite's profile

Dragonsrite

136 posts in 2863 days


#11 posted 06-21-2010 05:26 PM

My 2 cents:

When I need to disassemble stuff to repair it, I use a heat gun… doesn’t much matter the type of glue (except stuff like epoxy).

Somewhere I remember reading comments from a Tite-Bond “tech” or some such … the general drift was that you can’t over-clamp … as long as there’s enough glue and it’s properly spread, the thinner the actual glue line, the better. These comments may have been somewhere here on LJs or maybe some other forum.

-- Dragonsrite, Minnesota

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