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View Full Version : Comparing pinus ellotti to douglas fir?



PeterSibley
04-25-2012, 07:09 AM
Slash pine (p.elliotti) versus douglas fir? Strength, glue-ability, durability? What do our experts think? Google seems to indicate a lot of similarity.

The reason is that I've been reading Bruce's "Building my Venus Ketch" thread,
http://forum.woodenboat.com/showthread.php?115780-Build-of-my-34-Venus-Ketch.
I don't have any douglas fir( well a little but not much) whereas I have several dozen very good 60 year old p.elliotti .Certainly sufficient for my needs.

Your opinions welcomed!

Sayla
04-25-2012, 01:33 PM
I've read that slash pine is certainly more durable than radiata or other similar species, with better dimensional stability, but less gluable by the same amount - being the resinous/greasy nature of the timber that gives the durability in the first place - I've seen it last outside a fair while. I have more specific data on it at home (I'm currently at work), and will post what I have after getting home. From working with it in building homes I found it a bit heavy, could be brittle and split with wegde type nailing, or split along the grain if stressed enough, slower to dry than, say, radiata, but eventually does.

sayla

cybuilder
04-25-2012, 03:43 PM
WoodenBoat's regular wood columnist, Richard Jagels, had a good article on southern pines in last Sept's issue #222 (p99). As with many woods, growth rate is one of the main criteria for a good boatbuilding wood. Most southern pines (today) growth too fast. Jagels recommends applying the old southern yellow pine lumber grading rules:

no less than 6 rings per inch
at least one-third to one-half summer wood (the dark denser part of the annual ring)
a sharp contrast (boundary) between spring and summer wood
evidence of resin staining (color and smell)

As a forester who used to grow slash pine, I can say you will never meet those criteria with lumberyard plantation-grown or open-grown trees. A slash pine pretty much has to grow very old under crowded natural conditions (and/or infertile soil) to produce rings that tight. If your 60 yr-old trees grew under those conditions, they could be useable. Check knot size too.

PeterSibley
04-25-2012, 04:30 PM
Steve, my trees run around 7 or 8 rings per inch, they were close grown but not thinned as widely as some would thin them to. Most of them are 18" diameter at chest height or less diameter. Some of the smaller trees of the same age are thinner, around 14".

Good lengths of clear log, 30 or 40 foot in most trees.

wizbang 13
04-25-2012, 04:53 PM
I see a wood mizer in your future.
For strip planking one does not need "boat building " quality wood.
That is one of its' many advantages!

PeterSibley
04-25-2012, 05:15 PM
I used to own something considerably better than a WoodMizer but unfortunately it's gone now.

http://pic40.picturetrail.com/VOL282/9443996/17245530/396465990.jpg

WX
04-25-2012, 05:15 PM
I see a wood mizer in your future.
For strip planking one does not need "boat building " quality wood.
That is one of its' many advantages!
Given that some strip planking is being done with paulownia I would have to agree.

Bob Smalser
04-25-2012, 06:41 PM
Unlike Doug Fir, none of the yellow pines begin to grow heartwood until their mid to late teens in age. Hence when harvested at (typically) 30 or 40 years old, what you are looking at may smell rich with resin, but in fact it is sapwood full of sugar that will rot while you watch. For stripper construction, you are better off using heartwood from a non-durable species than using sapwood from a durable species.

Slash is harder and heavier than most of the rest, and commercially used to be intermixed with Longleaf. If your 60-year-old logs have enough useable heartwood to highgrade out, you may have something suitable for boat framing. I can't get exited about whether your sun-grown logs have four, six, or eight rings per inch. RPI doesn't seriously affect strength, but probably does durability...however the differences here are minute compared to shade-grown old-growth.

Mike Fonville has one in the shop now for repair that's only two years old, yet its entire SYP frame is rotten and requires replacement. It looked and smelled good on the racks, but it was all sap:

http://pic20.picturetrail.com/VOL12/1104763/24098621/402268650.jpg

PeterSibley
04-26-2012, 01:29 AM
Not much shade grown old growth slash here Bob, are you saying yes or no? I own this trees and frankly would love to be able to use them.There's no / zero market for slash here so strip planking is certainly a good use... as long as it won't rot on me.

Bruce used DF and keeps his boat in the Caribbean, similar temperature to here.

RFNK
04-26-2012, 03:05 AM
With all that flooded gum up there Peter, why not just use that? It's not too heavy, very durable and very stable.

Rick

PeterSibley
04-26-2012, 03:18 AM
I've got 3 or 4 good gums Rick, not really enough for my needs .They not that big, perhaps 400 diameter although one is bigger. My pine plantation would build as small town and quite frankly I'd love to find a use for it ! Commercial millers don't want it although I could probably sell it to pallet maker or something. With that option I'd let it stand ...if it was good for a boat I'd really consider it.

It's also considerably cheaper to have the pine sawn with a mobile rig rather than shipping it to a mill and paying .The gum needs a mill with a bench, it's much smaller than Duncan's and would spring appallingly on a mobile rig.

Yes, I suppose the gum would be better, in fact there is little doubt. It was just reading Bruce's thread about his Venus ketch build and realising that the whole project was based on a timber identical to my plantation! His boat is 30 years old and going strong ... all douglas fir and vast amounts of epoxy!

RFNK
04-26-2012, 03:47 AM
I can certainly see the sense in using wood that you already have - I'd want to too. When are you planning to start this build?

Rick

PeterSibley
04-26-2012, 04:45 AM
I have no specific plans Rick, more a desire ! I have always wanted to build a big boat and as you know had started my own design... then things changed. As the dust settles and it is settling, it has become possible to think of such things again. Bruce's build was / is inspirational and inspiration is a very good thing!

The 18 footer is first .

RFNK
04-26-2012, 05:19 AM
Good to hear it - get into it!

Rick

Bob Smalser
04-26-2012, 08:04 AM
... are you saying yes or no?

Yes to any heartwood you can find:

http://pic20.picturetrail.com/VOL12/1104763/24098621/402276020.jpg

No to all the sapwood. Use it for something else.

http://pic20.picturetrail.com/VOL12/1104763/24098621/402276021.jpg

wizbang 13
04-26-2012, 08:29 AM
sapwood = boat shed, lofting floor/sail loft joists, keel molds, station molds, ribbands , woohoo!

PeterSibley
04-26-2012, 05:53 PM
I'm going to have to look carefully, is p.ellioti / slash pine sapwood obvious? I haven't dropped one of those pines for 25 years... since I built my house and used a log's worth for fitout. Most of my local timbers are quite obvious in the difference ... is p.ellioti?

Bob, can you help? The net isn't rich with photos of pine cross sections The page has one http://web.me.com/conceptscreated/ConceptsCreated/hartpine.html but will my slash pine be as obvious?

Duncan Gibbs
04-27-2012, 08:47 AM
Peter, you have a surfeit of the damn things growing down the back of your place. I would have thought at least 70 or 80 of them. I'll bring my chainsaw around and we'll drop one of them and see what it looks like for a lark! We could use the resultant stick to get this pine tar manufacturing experiment going as well.

Bootles indicates that it is a stronger timber than DF any day of the week on all counts. Rob would hate milling it up - "It gums up me blades!... Awful stuff!" - but he'd still mill it up.

Bob Smalser
04-27-2012, 08:52 AM
A Yellow Pine log should be obvious compared to any white or sugar pine log based on the color and resin in the heartwood and stump, but differentiating between the different species pines is extremely difficult and isn't done in the field. I would have to send them to the Forest Products Lab.

wizbang 13
04-27-2012, 08:57 AM
If it is gummy, that is a strike against gluing and a game ender for grinding/ sanding.
Fir has the occasional pitch pocket, but is takes the epoxy well.
30% of the time building Woodwind was grinding. Not romantic, but true.

Duncan Gibbs
04-27-2012, 09:04 AM
It's all either Slash or Radiata here Bob. The only other pines are the local species such as Hoop or Bunya and they're all from the Araucareae family and very obviously different. DF is grown in New Zealand and a little bit down in the cooler parts of Southern Australia.

Bob Smalser
04-27-2012, 09:08 AM
Bootles indicates that it is a stronger timber than DF any day of the week on all counts.

Only at the expense of weight. Slash Pine is 25% heavier.

Bob Smalser
04-27-2012, 09:12 AM
It's all either Slash or Radiata here Bob.

Except I have no idea what Radiata looks like. Plus the seedlings planted there have been hybridized to the point they may be unrecognizeable to those in their native range.

If the differences aren't obvious after falling a couple, find a local guy who mills both and obtain some samples for comparison.

Duncan Gibbs
04-27-2012, 09:14 AM
Bruce, I think it's mainly the sap that has the higher resin content, along with phenolic compounds that make it pretty termite resistant. It needs to be milled and stickered very quickly as it is highly prone to bluestain which will do nothing to it structurally, but will make it look rather ugly.

I'm sure the heartwood would glue up nicely and wedges of the sap will pyrolise down to make some really good gum turps and then lovely and proper pine tar.

Duncan Gibbs
04-27-2012, 09:20 AM
Except I have no idea what Radiata looks like.

Radiata, whilst grown around here, isn't as common in the sub-tropics and has a highly ridged and creviced bark, which is dark grey, along with bigger cones. The Slash we have here has fairly uniformly scalloped bark with a pronounce reddish tinge and red margins to the scallops, smaller cones and finer needles. Once again they fairly easily discernible from one-another. Unlike North America we have very few monocot' trees growing here, and half of them are imports.

Sayla
04-29-2012, 01:40 AM
This website lists Slash Pine as being used in boatbuilding, as well as other useful information

http://www.woodworkerssource.com/online_show_wood.php?wood=Pinus%20elliottii

And this Australian site has useful information on Slash Pine

http://www.woodsolutions.com.au/Wood-Species/slash-pine

------------------------------------------------------

The following is Australian Data

Pinus elliottii var. elliottii
Pinus elliottii var. densa

Durability Class Inground 4
Durability Class Above ground 4
Marine Borer Resistance of Heartwood 4
Joint Group Unseasoned S5
Strength Group Seasoned SD5
Joint Group Unseasoned J4
Joint Group Seasoned JD3
Density Unseasoned 850 kg/m3
Density Seasoned 650 kg/m3
Hardness (seasoned) 3.4
Toughness Unseasoned L
Toughness Seasoned L
Tangential Shrinkage 4.2
% Unit Tangential Movement 0.3
Lyctine susceptibility Not Susceptible
Termite resistance Resistant

cheers,
sayla

PeterSibley
04-29-2012, 03:58 AM
Botanical Name:

Pinus elliottii






Other Common Names:
Slash pine, Yellow slash pine, Swamp pine







Common Uses:

Beams, Boat building, Boxes and crates, Bridge beams, Bridge construction, Bridge joists, Construction, Excelsior, Hardboards, Heavy construction, Joists, Millwork, Mine timbers, Novelties, Pallets, Particleboard, Piling, Plywood, Pulpwood, Rafters, Railroad cars, Railroad ties, Rough construction, Rustic furniture, Shipbuilding, Silos, Stringers, Structural plywood, Structural work, Veneer, Warehouse construction, Woodenware

From Sayla's site.http://www.woodworkerssource.com/online_show_wood.php?wood=Pinus%20elliottii

My trees are certainly heavy and the timber, especially the ones on the inside of the patch are very resinous and dense.

Bruce's comments re gluing and sanding are not encouraging though .

Sayla
04-29-2012, 04:42 PM
Bootles indicates that it is a stronger timber than DF any day of the week on all counts. Rob would hate milling it up - "It gums up me blades!... Awful stuff!" - but he'd still mill it up.

I used a lot in roof truss manufacture, back in the eighties - it would often stress grade at F11 (or better), but you had to select it. The resin can deposit in fissures along the grain, which, especially when running off at an angle, makes for a weak member, particularly when loaded in simple bending stress. Felling some sounds like a plan. You'd need to check the gluability yourself I reckon. It has the same durability ratings as Douglas Fir, on paper, though D.Fir isn't resistant to termites.

From "Wood Solutions"
Workability
Only the sapwood of Slash Pine can be treated with preservatives. When dressing, sharp planer blades are needed to avoid compressing the softer earlywood and the ridged surfaces produced.
Because of deflection by latewood bands, nails tend to follow the growth rings and care is needed when using fittings and fastenings. Good results can be obtained with nail guns.
Due to the high resin content of some material and the ridge of early and latewood in dressed timber, care is required when timber is selected for finishing applications and when surfaces are prepared for painting and varnishing. Earlywood and latewood can absorb glue differently but this rarely causes problems.


A Further reference for you Peter

http://forum.woodenboat.com/showthread.php?18396-slash-pine-and-epoxi&


sayla

cybuilder
04-30-2012, 01:30 PM
is p.ellioti / slash pine sapwood obvious?

It should be pretty obvious, Peter. The heartwood will usually show darker resin staining. Smooth cut or planed heartwood can appear "varnished" due to all that resin. Also, the stump should ooze sap from the sapwood, but not the heartwood.

PeterSibley
04-30-2012, 05:23 PM
Well, it will certainly make good masts but I'll have to see how it glues. I would really expect no problems, it's not that full of resin.