# Glue Joints Failing



## GeorgeC (Jul 30, 2008)

Has anyone worked with Iroko wood? It is a teak substitute.

Two years ago I made some drawer units for my boat. I made two units of one contained two drawers and one contained three drawers. The basic carcases were birch plywood and birch lumber. The fronts of the drawers and the visible trim was made of Iroko.



I have now had two failures of the glue joint that holds the drawer front to the basic drawer. I used epoxy throughout the whole project because, even though it was in a cabin, the project would be on a boat. I originally only but jointed the drawer front to the carcase because I assumed the eposy glue joint would be very solid.

The two joints that have failed exhibit soft epoxy. I am wondering if the oil in the Iroko could, combined with the summer hear in the boat cabin, be softening the epoxy. The first joint failed last summer and the second a couple of days ago.

Has anybody else ever worked with Iroko?

No other joint in the whole project has failed. All of the epoxy that I examine seems solid.

In rejoining the drawer fronts I am using dowels and Tight Bond II. Time will tell if these will hold up. 

George


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## cabinetman (Jul 5, 2007)

Oily woods can be difficult to achieve good glue joints. The mating surfaces should be wiped with acetone and a two part epoxy should be used.

In your case, your drawer construction was on the lazy side. You depended on the glue alone to be the fastener instead of the two woods being fastened. What likely happened is that you didn't get a good bond, and the glue lost its hold probably from one or both of the surfaces not being entirely prepped for gluing. All the opening and closing forces were on that glue joint.

At this stage, dowels would be one method, or routing a spline in the front edge of the drawer side and the back side of the drawer front. Either way, there has to be a good alignment. I'm thinking that a spline might be easier to line up and give more gluing surface. You have to clean off the old glue and prep both surfaces before assembly.

For dowels or splines, I would use TB III.


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## GeorgeC (Jul 30, 2008)

Yeah, I was lazy. Should have used a mechanical joint and then the glue. I did clean the Iroko thoroughly before assembly.

However, the glue is still firmly adhered to both sides of the joint. When I pulled the pieces apart there was actually a "string" of glue stretching between the pieces. It took me a lot of work to get the residual off both sides of the work before I could reglue. The expoxy in these joints is actually soft. 

George


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## mics_54 (Oct 28, 2008)

> The two joints that have failed exhibit soft epoxy.


sounds like bad epoxy


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