White Oak vs Ash

[Steve Ambrose]

With ash becoming nearly impossible to find (locally) in appropriate lengths for rail stock, I'm turning to white oak which is readily available in long clear lengths here in the SE. Both of my local sources for ash claimed the availability problem was due to "bugs" (Emerald Ash Borer). TN got hit by the EAB last year which is where most if not all their ash was sourced.

I know white oak has been used by OT and others for decks and thwarts but is it an appropriate material for rails and stems?

Also found a couple of 20' clear douglas fir but wanted to ask about its suitability for rails before I had the mill rip the boards into rail stock.

 

[H.E. Pennypacker]

Steve,

White oak is outstanding. Excellent rot resistance in the heartwood (mill stock free of sapwood), and excellent steam-bending capability. The rails on many old Canadian all-wood canoes are white oak. Stems too.

Douglas fir seems brittle, esp. kiln-dried, and it doesn't steam-bend well. It is said to have good rot resistance, but I have no experience with that.

Hidalgo

 

[john hupfield]

White Oak is a go. Douglas Fir is good structurally and is used as Planking Stock on many boats (seldom canoes) but splits easy, not recommended for rails. Also it tends to wear unevenly and really should be epoxy sealed.
John

 

[Mark Neuzil]

It is notable that white oak will be 10 to 15 percent heavier than most ashes; green ash is probably closest in density.

 

[kamkaotm]

Straight grained spruce is available in appropriate lengths for rails, bends easily, and is recommended for rails. Old Town used it for both inwales and outwales on their canoes and square stern boats. I've never hear of it being used for stems. I think you could get some ash from Rollin Thurlow at Northwoods Canoe. It's great stuff for stems. Oak is used, but it is difficult to bend and I'd bet you'd have to pre-drill for every tack and nail.

 

[Dylan Schoelzel]

True, ash bends well but White Oak (Quercus alba) ranks among the best for bending. It can be bent to some of the tightest radiuses with the least amount of tension failure. From the U.S. Forest Service:

Stock Selection

The U.S. Forest Service has evaluated 25 hardwood species for relative bending quality. In their testing, the best 17 woods were:

Hackberry (Best)
White Oak
Red oak
Chestnut oak
Magnolia
Pecan
Black walnut
Hickory
Beech
Elm
Willow
Birch
Ash
Sweetgum
Soft maple
Yellow-poplar
Hard maple (Worst)

This ranking represents the results from one evaluation; variation in the results can be expected from tree to tree and site to site.

 

[Howard Caplan]

Could somebody give me some tips on steaming and bending a 1"X1" strip of white oak? About to make outer stems for a Penn Yan.

Howard

 

[Dylan Schoelzel]

I would start with a piece 1 inch thick by 1 1/8 wide. A little wider than the thickness will help prevent the piece from wanting to twist over while being bent.

Using a compression strap with blocks on each end will help with the tension stress on the outside of the bend. Space the blocks apart about 1/8 of an inch greater than the overall length of the piece being bent.

Steam it for about an hour to an hour fifteen and make sure the temperature inside your steam box is as close to 212 degrees as possible.

Doesn’t matter whether you are bending kiln dried or air dried material. Kiln dried wood is still subject to losing and gaining moisture. If you are using kiln dried stock and it has been sitting around for awhile, chances are it is at the same moisture content as a well seasoned piece of air dried lumber (of the same species and thickness).

If your lumber is too dry, say below 12% moisture content (MC), you can soak it for a few days to help raise the MC.

If your lumber is to green and has bound water in it, it will be easy to bend but you will have to wait for the piece to dry after bending. During this drying period you could experience drying defects such as splits and cracks. The act of steaming wood in this application does not dry the wood to acceptable MC levels.

 

[Howard Caplan]

Thanks Dylan. I bought a kiln dried piece a month or so ago. It is laying around now and will until late winter, early spring. I think I will still soak it for a while and hope my recently built box can heat up to really hot.
Do you leave the piece clamped on the form for several days?

howard

 

[jchu]

I couldn't bend kiln dried, it always blew out on me, I got recent cut air dried about 25% moisture and it was a charm to bend. White Oak is a wonderful boat wood.

 

[ppride]

Hi Steve, I used red oak on a Chestnut V stern for outwales, transom, and seat frames. It worked fine, looks great, though probably heavier than ash. The boat has always been stored upright on a trailer when not in use so rot is not an issue.

 

[Jerry Fruetel]

Howard,

Yes, you should leave the piece clamped on the form, preferably for a couple weeks or even longer.

 

[Dylan Schoelzel]

Leaving the bent piece on the jig for days to weeks (or so) can help minimize spring back, so yes I personally like to leave pieces on the jig as long as I can afford to.

Some observations I have had along the way are:

The drier the wood is to begin with, or lower the MC is, the more spring back there will be.
The greener, or higher the MC is, the less spring back there will be.
The hotter your steam box is the less spring back there will be.
If your steam box does not achieve high enough temperatures, spring back will be a problem.
The aid of a compression strap with blocks at each end helps minimize spring back.