pre-glued dowels vs. naked dowels

[Packard]

My google search did not really answer my questions on pre-glued dowels.  It did indicate that it was less messy and quicker to use pre-glued dowels.  It did show that the fluted (straight grooves) performed much better than the helical groove dowels (in pre-glue).

But it did not show the relative strengths of the pre-glued vs. site-applied glue dowels.  It may be a non-question.  Perhaps both are strong enough.
https://www.google.com/search?q=pre-glued+vs+non+glued+dowels&client=firefox-b-1-d&ei=zVMdYMnLFMWo5gKZ_4D4Cw&start=20&sa=N&ved=2ahUKEwiJ5t__99LuAhVFlFkKHZk_AL84ChDy0wN6BAgIEDg&biw=1384&bih=786

Anyone have experience using pre-glued dowels?

 

[Svar]

This seems handy. However, when joining with dowels, glue is also usually applied to the mating surfaces. This partially defeats the advertised benefits of pre-glued dowels.

 

[Packard]

From what was available online it seems that the pre-glued dowels have found these advantages of pre-glued:

1.  Faster
2.  No squeeze-out that might affect finishing
3.  less labor = less expense (not a factor for hobby-builders)

Pre-glued requires a properly fitted dowel/hole.  Pre-glued will not fill voids left from oversized holes.

While the instructions vary, most call for filling the hole 1/3 full with water.  The dowel pin then forces the water up through the entire length of the hole.  The water softens the glue and allows the dowel to absorb the water causing it to expand for a tighter fit.

The glue is " uncatalyzed, water-activated, PVA (Polyvinyl Acetate) glue".  Once the glue is dissolved I would assume it makes contact with the mating surfaces.

For cabinets pull-out strength of the pins seems less of an issue than shear and racking forces. 

I am not defending the pre-glued dowels.  I am trying to learn if the advantages are offset by some unknown to me disadvantages.

So far I have not found much on the downside.

 

[Packard]

Additional web search found that putting excess water in the holes can cause damage to the panels and compromise the strength of the joint.  Something to think about. 

Automated dowel insertion machines accurately meter out the water.  That would be a slower process by hand. 

Several sites recommended against soaking the dowel itself.  So an accurate method of metering out the water is desireable.

 

[AlexThePalex]

I didn't even know pre-glued dowels existed.

What I do know is I always use wood glue that can stand water, so I would never use pre-glued dowels.

 

[Packard]

PVA glue, which they all seem to use, is similar to white glue (Elmer's).  I don't think it is water-resistant, but that would not normally be an issue in cabinet work.

 

[ferrij]

I have used both with the VS 500 (which dates me). I initially used pre-glued dowels and was glad when I used them  all up. I switched to plain fluted dowels and am much happier. I found wetting the dowels to be a pain in the butt.

 

[Packard]

Really?  Wetting is a pain in the butt?  In my mind, wetting seems much easier. What was your process?

 

[Cheese]

A rather interesting idea for production shops. Not so much for the hobbyist. With an automated water dispensing mechanism you could really fine tune the amount of water injected into each hole and maintain the hole-to-hole consistency.

I think the largest issue for the hobbyist is accurately measuring the water doses and filing the dowel holes...I think a syringe with graduations would be a big help. Too much water and the glue gets too diluted, too little water and the glue doesn't soften up and flow like it should.

I also wonder if there are guidelines on assembly times for different wood species as I assume cedar absorbs water at a faster rate than hard maple?

 

[AlexThePalex]

I don't think it is water-resistant, but that would not normally be an issue in cabinet work.

In my mind, constructing anything that can dissolve with a few drops of water is an issue.  [tongue]

 

[DeformedTree]

pre-glued would make more sense to me if they used a glue that was set via thermal.  Either you put it together and run a heat gun by it for a moment, or the friction of being pounded together makes enough heat to activate the glue, like coated sinker nails that the heat from the friction activate the glue on the nail.

 

[blues]

Recently i built a cabinet using pre glued dowels. It was amazingly easy and quick. I use the ddf40 and i have a squeegee filled it with water. You are supposed to fill up half the hole with water and insert the dowel. You are not supposed to keep a bowl of water and dip it before you insert it. It's not required to use regular glue along the edges. So what i did was to use the water bottle with a pointed spout filled water and inserted my dowels. Glue up was quick. Used clamps to force pieces together, 20 min it was done. No squeeze out or clean up. Super strong. I used helical grooved pre glued dowels. The helical grooves are only there for the excess water to squeeze out. Flueted dowels may be good for regular glue up. All future builds are going to be pre glued dowels.

 

[ferrij]

When I started working with dowels, I thought pre-glued dowels sounded like a good idea. I bought a lot of 6 and 8mm dowels. I tried all the methods you mentioned and found them to to be more complicated than I anticipated. Try them both and see which you prefer. Dry fitting joints with pre-glued dowels is particularly irritating. It is all too easy to transfer some of the glue to the work dry or wet. The water as well I found hard to control no matter how carefully I prepared.

 

[Packard]

Thanks for all the replies.  I guess I will have to try them out both ways.

I would note that the one site I found online that had some actual data clearly showed that the fluted dowels were stronger than the helical ones. 

I know that the fluted dowels are compressed along the flutes and swell when wet.  I'm not sure if the helical ones are machined or not, but they looked machined. 

In the event I try out the pre-glued, they will be the fluted versions.

Packard