In a recent issue of Fine Woodworking magazine (July-August, 2007), they tested the strength of six types of glue

“most commonly used for furniture making.” Amongthe glue types missing from this report were slow settingurea formaldehyde (plastic resin) glues. These are gluesthat I use primarily for bent laminations and veneer work,although there are times when I get into some challenging

assemblies that I fi nd these glues to be the answer.

Urea formaldehyde glues have several qualities that makethem superior to all other glues:

1. Long open working time (30-45 minutes in coolerweather.

2. These are rigid glues that will not creep over time.

3. Gap fi lling ability, which means that they will workwhen uniform clamping pressure is diffi cult.

4. Resistance to moisture, solvents, fi nishes, etc.

5. An ability to glue oily woods (such as a number ofexotic woods).

Most important is that these are “rigid” glues. For bentlaminations and veneer work (as well as general joinery),the wood will stay where you put it, and the glue lineswon’t cold creep or open up. This is a big deal when youcompare it to PVA glues, also known as yellow glues. Yellow glues are very, very strong, as was evidenced in the

Fine Woodworking article, but they are semi-rigid. Overtime, woods that are under stress can exert some force orpull on the glue lines, causing them to expand. I have seenmeticulously crafted pieces of furniture glued exclusivelywith yellow glue, which later exhibited joints that havepulled open. Veneer, either commercially cut at 1/32″ orband sawn veneer cut to 3

/32″, still can exert enough forceon a glue line to cause it to open over a period of time.

One of the demonstrations that I do for a lot of the classesthat I teach is to show students two dried glue fi lms. Oneis some yellow glue that I have poured out onto a piece ofplastic, and the other is some urea formaldehyde glue. Bothof these glues were left to cure for a week or more, so thatthey could reach maximum hardness. In the demonstration,I put the sample of yellow glue in one hand, and the sampleof urea glue in the other hand.