Outdoor dowels!

[Bm101]

Dowels are easily made in the workshop from scraps using tooling you make yourself. Paul Sellers has demonstrated one variation where you literally just bash the wood through a washer!

You can get a little more sophisticated than this using other homemade dies, e.g. made from the body of an old plane iron. But even mild steel is capable of holding up well enough to make enough dowels for a handful of projects.

Don't doubt it Ed, not in the least. Just on my 'personal time available' multiplied by 'things I'd rather be doing' divided by 'total cost' it just doesn't equate old son.

 

[Woodchips2]

I use a Joint Genie with bought 8mm beech dowels for external joinery and have had no problems. I use waterproof glue. Biggest problem is cramping the joints up when I use 3 dowels per joint but that's just old age.
Regards Keith

 

[DigitalM]

I've already got the Join-Genie craftsman setup Sunnybob. It's the issue of using them for outdoor work that I'm querying.

 

[Steve Maskery]

No-one has addressed the issue of why dowels are an inherently poorer alternative to a M&T joint.

It's to do with surface area of face-grain.

In a M&T joint, we have two areas where the face-grain of the rail is in contact with the face-grain of the stile. Face-to-face is a strong glue bond.

With dowels, there is nowhere near as much face-grain. You could argue that there is NO proper face-grain contain involved at all, and even averaged out, you couldn't argue that it is more than 50% of the dowel's surface area. The rest is in contact with end-grain, which has no structural strength.

Now it is true that many commercial doors are held together with dowels, but their life-span is nowhere near that of a proper M&T. If water does get in, it is far more vulnerable to failure than a true M&T would be.

Face-to-face = good
Face-to-end-grain = waste of glue

 

[DigitalM]

Those little liddl Irwin type japanese saws leave a perfect finish. Used it to repair my oak engineered floor. Flawless.

Yeah I've got a Trend flush cutting saw that is brilliant. Seeing as I have the dowel jig, which works so well for quick projects indoors, and a good flush cutter, it just seems like an obvious thing to do to use it for outdoor stuff that isn't critical load bearing. I'd rather save hand making proper load-bearing joints for when they're actually needed as I have so much other stuff to do...

 

[dzj]

Best not to use them outside.
Like with all floating/ loose tenons, it's only good as long as the glue holds.
And as Steve says, dowels have a small glueing surface, so...
Felder uses dowels for their window set, but that's heavily reinforced with hardware.

 

[Jacob]

Trad windows nearly always have dowels pegged through the M&T joint. Nearly always just split square section but hammered into a round hole so you can't always tell. They get squeezed into a taper as they are forced through so the hole will be squarish (or have 'ears') on the near side but will be round on the far side. Painted with linseed oil paints and they last until the paint has been neglected for too long say 20 years.
Then what's interesting is that intermittently they start absorbing water, loosening and expanding. Being tapered this tends to force them very slightly out of the hole, but they don't find their way back in. Eventually you can end up with the dowel almost completely sticking out of the hole, just 1/4" holding it.
I found this quite often and it took me some time to work out how it could happen.

 

[Steve Maskery]

I'm confused.
Are we talking about using dowels in place of a M&T joint, or are we talking about using dowels to peg a M&T joint?

 

[DigitalM]

Just for the record, I started the topic talking about using dowels outdoor for quick non-load-bearing projects. I was primarily concerned with the issue of durability rather than strength – I wasn't advocating using them for huge double glazed doors or the like.

 

[Jacob]

Just for the record, I started the topic talking about using dowels outdoor for quick non-load-bearing projects. ....

Widely and extensively used and have been for thousands of years https://en.wikipedia.org/wiki/Treenail

 

[powertools]

No-one has addressed the issue of why dowels are an inherently poorer alternative to a M&T joint.

It's to do with surface area of face-grain.

In a M&T joint, we have two areas where the face-grain of the rail is in contact with the face-grain of the stile. Face-to-face is a strong glue bond.

With dowels, there is nowhere near as much face-grain. You could argue that there is NO proper face-grain contain involved at all, and even averaged out, you couldn't argue that it is more than 50% of the dowel's surface area. The rest is in contact with end-grain, which has no structural strength.

Now it is true that many commercial doors are held together with dowels, but their life-span is nowhere near that of a proper M&T. If water does get in, it is far more vulnerable to failure than a true M&T would be.

Face-to-face = good
Face-to-end-grain = waste of glue

I am more than happy to discuss the best joints with you but it is my opinion that there is no best joint it all depends on what you are making and how you are making it.

 

[DigitalM]

It needs to be added that it doesn't need to be the 'best' joint ... just one that's plenty good enough for the job in hand.