polyurethane glue for doweled joints

Assembling a rather large cabinet that I used dowels to join a panel to a large corner post. the panel is about 48" high and has 12 dowels over the 48" span. I'm afraid I wont be able to get the pieces joined and clamped before the glue sets, so I normally use epoxy, (but I am out) which gives me plenty of working time and acts as a lubricant, allowing the joint to easily come together. I'm considering polyurethane, but have never used it. Never heard anything good about it either. If I use it, will it act as a lubricant like the epoxy and give me plenty of working time? Do I absolutely have to use water? :confused:

Polyurethane glue will act as a lubricant, will give you more open time, and will foam more if you dip the dowel in water.

If your dowels fit tightly dry then there is enough moisture in summer air to cure the glue [unless you live in the desert].

I experimented years ago with polyurethane glue and biscuits. Glue in slot, a quick biscuit dip in water [no glue on biscuit], and plenty of time for assembly. If I soaked the biscuits for any length of time they swelled too soon, and foamed more than I liked.

Why not try a couple test joints, make sure your procedure workes for your situation.

FWIW, I built a secretary with lots of sliding dovetails, and 8 years later I couldn't be happier with how the Titebond-polyurethane glue performed for me.

You don't have to use water; it will set up with the slight amount of water in the wood and air. I prefer PVA glue for most jobs but use polyurethane occasionally, no issues other than stained hands.

Make sure you wear gloves with the polyurethane glue. It makes a terrible mess on your skin.

Doc

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Originally Posted by jim mills

considering polyurethane, but have never used it

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I wouldn't want to make my first use of polyurethane glue on a complicated glue-up. Polyurethane glue has it's use in the workshop, but I've found for wood to wood contact there are much better glues available.

Thanks, this batch of dowels is extremely tight, hence the difficulty getting things together with PVA. I'm glad that water is not required, it's plenty humid here. I'm gonna go grab a bottle and experiment as suggested.

I would not use dowels that are tight,too easy to split the wood. I like to drive the dowels through a thick steel plate with counter sunk edges ( to prevent cutting the dowels ) that compresses the dowels for easy fit in holes. Yellow glue is thinned a little with water which will make dowel enter easily without splitting the work. Dowels will then swell and make tight fit needing very short time in clamps.

Thanks Mel, I 've actually had good luck with dowels from Grizzly in the past, but I got this batch from Jessem, along with a new jig. They are supposedly "compressed" dowels, but I think maybe they forgot to compress them?!?!

Yep, no extra water is needed for the poly glue despite what the bottle says.

Polyurethane glue is one of those glues that can stick together an amazing amount of varying materials BUT it is messy...do wear gloves or you'll have black hands for a good 3-4 days. :)

I've only used the Gorilla Glue polyurethane glue but it is a wonderful glue...messy...but a nice glue. It is my only hope to try and glue oily and difficult-to-glue ipe.

Well, glad to be of help,Jim. It's possible the dowels were improperly stored ... or made. I like using my homemade plate made from junk yard steel. You can test a joint made by method mentioned in my earlier post by band sawing lengthwise a dowel glued in a block and hanging out . The half dowel will break but not separate from hole in which it is glued.

'Bout the only thing I remember being discussed in the past besides the mess, was that PU glue didn't have any strength.

I did teak boat trim years ago (80's), and resourcinal resin was always my go-to glue. I know some of that stuff is still in service.

The foam has no strength but the glue is plenty strong, I assure you.

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Originally Posted by jim mills

Thanks, this batch of dowels is extremely tight, hence the difficulty getting things together with PVA. I'm glad that water is not required, it's plenty humid here. I'm gonna go grab a bottle and experiment as suggested.

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Put the dowels in the oven at 275 deg. for an hour. This will get the moisture content to just about zero and they won't be tight any more. Works for biscuits and dominos, too.

Thanks John, I'll give that a try and report back