Dowel Joinery Glue Application Techniques

The standard method is to place a metered amount of glue into the hole, then insert the dowel. November 23, 2012

Question
What is the technique of rolling dowels in a glue soaked sponge to install them?

Forum Responses
(Adhesive Forum)
From contributor R:
I have never heard of that one. All my glue customers just inject it in the hole and push a multi-groove or spiral dowel in the hole. The glue travels up the grooves.



From the original questioner:
I have heard to drill a hole in the sponge, let it soak in a glue bath, and roll the dowel in the hole/glue of the sponge. I have always put the glue in the hole of the substrate. Maybe itís better to glue both, hole, and then dowel?


From contributor M:
Like Contributor R says - dowels are designed to work that way. Glue in the hole first, and then tap in the dowel. The glue will travel up the splines. Your dowel hole has to be the correct depth.


From contributor T:
The sponge trick is new to me, and it seems like it could be ok, however Iíve re-glued hundreds of chairs with failed joints and almost all displaying glue starvation. I take exception to the squirt and shove technique. Most dowels are used long after machining and the resultant oxidation presents a less than optimal gluing surface. To trust any glue joint with unknown glue distribution/coverage is too big a gamble. Glue spread in the hole and on the dowel is the only way to know you've done it right.


From the original questioner:
I believe this was or is a technique that was used in Europe. Regardless, I am switching to dowels, at least for integral panels.


From contributor M:
In Europe dowels are used for everything. The method I described is used by all the manufactures. Even the automatic machines do it this way. You know that the coverage was good if there is a small amount of squeeze-out. If you are using a glue metering system (for small shops the Lamello metering bottle is great) and drill consistent depths you can get great repeatability. After tapping in the dowel you will get tiny droplets of glue showing. The pressure also forces the glue into the material core for a stronger bond. For furniture with large and long dowels it might be different but for carcass joinery donít re-invent the wheel. The sponge method will make it harder to drive the dowel and the glue will not reach the bottom of the dowel.


From contributor U:
We don't dowel much here, but when I have to I use a squirt and dip method. I squirt a little glue into the holes and then dip the dowel in my glue pot before inserting. I do get a lot of squeeze-out that I need to deal with afterwards.


From the original questioner:
Anyone know the optimum fit for a dowel?


From contributor M:
Dowels are sized by the hole. 8mm dowels require an 8mm hole, 10mm dowels require a 10mm hole. If the dowels do not fit in the hole there is a problem with the dowel. Usually they are too tight, and this is often due to improper storage. If the dowels get wet or exposed to too much humidity they will swell and not fit. If you buy dowels that are not fitting their proper hole size, and you are sure it is not due to improper storage, then find a different supplier.