One of the local building suppliers locally is beginning to push the sale of a wood called Paulownia (I have seen different spellings…) used as a substitute for cedar for exterior wood trim. I’ve tried searching the web for some objective research but mostly anything I’ve found is from people trying to sell you either the lumber or the tree.
I was wondering things like:
Workability (machine, hand, breathing sawdust)
Durability (resist dings, weathering, etc.)
Finishing (sand, paint, staining…any tannin bleed?)
Anything else I should know?
Thanks,
Mark
Replies
I don't know anything about it's rot resistance, but it's a very light weight wood with strength to weight comparable to Balsa. Used alot to make surfboards.
I havn't used it myself, but I heard a few things about it. It seems to be a fairly rot resistent wood, in china they make coffins out of it. It's lighter in weight than cedar, almost like balsa wood. I also heard that the trees themselves grow really fast, so that should make it green too. That's all I know.
It machines well, hand tools easily, is fire resistant, is relatively decay resistant, has no tannin leachate, accepts paint and stain very well, and is fairly large open pored. Sanding tends to fuzz the grain up. It will ding easily. Very easily.
I love it, used it for guitar bodies for a run of 30 , and they all came out sweet. Lightweight as well as dense enough to be a tone wood.
Fast growing and often large clear boards.
Oh, it stinks something awful.
Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
You gonna play that thing?
http://www.youtube.com/watch?v=32Ln-SpJsy0
Thanks for the response guys.I know this is a longshot, has anyone had a project they installed it something like 5-10+ years ago?Thanks,
Mark
Pawlonia wood drawers
(Yeah, I know that this thread is 3 years old)
m04arch: "has anyone had a project they installed it something like 5-10+ years ago?"
I made a set of Pawlonia clothes drawers for an armoire back in 2002 or 03. I left the wood unfinished a la Japanese tansu style.
No shrinkage, splitting, warping, etc. since then. They seem to be holding up very well.
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paulownia wood as Trim board
General Characteristics
Paulownia is a soft hardwood native to China. The heartwood is light in color and the sapwood even lighter. Color differential between the two is not distinct. The wood is without odor or taste and is mostly free from knots. Planed or sanded, it has the feel of spun silk.
Wood Structure
The demarcation between heartwood and sapwood is not clear and the wood is straight grained and lustrous
Wood Properties
Paulownia is comparatively soft and light in weight for a hardwood. Physical weight is slightly less than kiln dried western red cedar. It is low in overall strength, but has a high strength to weight ratio. The shrinkage coefficient is smaller than most commercially harvested coniferous and broad leaf woods. The wood dries rapidly and does not easily warp, cup, end check, splinter or split. Movement in service is rated as small.
Paulownia has one of the lowest thermal conductivity values of any wood; therefore the wood has very high insulation properties. Low thermal conductivity contributes to the low shrinkage in use.
Compared to most woods, Paulownia has a high resistance to fire and flames and a higher ignition/flash point.
Paulownia is naturally decay resistant and any rot is generally superficial. The wood is also naturally resistant to insect attack.
Paulownia has no measurable pitch, resin or tannins so it is not subject to extractive bleeding
Working Properties
Paulownia is easy to work using hand or machine tools. It is easy to plane, sand, saw, rip, route, and carve, and even during quick processing there is no danger of splitting or chipping. It easily absorbs glue, paint and stains.
Ada Feng
Sales Manager
Heze Hengxiang Wood Co.,Ltd.
Add: Zhuangzhai town , Cao County , Heze City , Shandong province, China
Mobile: 0086 13365305711
Tel: 0086 530 5320099
Fax: 0086 530 6160078
skype: hezehengxiang
Ada
Here in NW Oh, paulownia is offered as an exterior board-comes primed and is finger jointed. Nice to work with, but there's been some talk on forums of it not holding up to the weather.
Can you comment on your experiences?
I see you claim it is naturally insect unfriendly and not susceptible to decay. That seems to be in direct contradiction.
thanks.
hello
Dear Sir,
I just see your reply this moment , I do not often come to visit this forum .... so if you have questions, can you pls write email directly to me ? so I can answer to you very soon : [email protected]
thanks !
Ada Feng
Besta
Keep the discussion on this board-so we all can learn or take part.
And, please answer the question I directed to you, since you found your way back to this forum
thanks.
reply on paulownia Trim boards
Hi , pls see my replys as follows :
Here in NW Oh, paulownia is offered as an exterior board-comes primed and is finger jointed. Nice to work with, but there's been some talk on forums of it not holding up to the weather. Can you comment on your experiences?
I understand why you have this question, paulownia wood is seen as a kind of soft wood lumber , however people usually see their physical weight but ignoring the natural super characteristics , in fact :
First: Tests by the University of Southern Queensland of Western Red Cedar and Paulownia showed that Paulownia had better compression and shear qualities. When this is coupled with the comparative density at 11% moisture of 275Kg/m3 for Paulownia and 450Kg/m3 for Western Red Cedar: Paulownia lighter but stronger, so the result is when put into the weather , paulownia is much more durable!
Second: we need to see the paulownia wood’s cell structure , when the paulownia wood is dried , the wood cell becomes totally closed structure , just like some crowd of people are hands with hands together to fight their enemy (water, strength …) , thus paulownia is much more dimentionally stable in structure ---this results the paulownia is better when presenting into the weather ! no warping , no splitting …
Third, about the paulownia’s working properties: Gluing of paulownia wood :Gluing - Paulownia has been tested with five different brands of PVA, Cross-linked PVA and Urea Formaldehyde adhesives. Samples were prepared with each type of adhesive and Standard Separation tests conducted. Manufacturers recommendations were observed for each adhesive. 100% of the tested samples passed i.e. they did not separate along the glue line. AlI gave excellent results with minimal clamping time. Comparative tests between Paulownia and other hardwoods all showed the superiority of Paulownia timber with respect to fast cure time and uniform glue time. In all cases, using PVA adhesives on Paulownia halved the average time required for clamping. The time and cost saving in a board jointing production run is obvious.
---that is to say , paulownia’s gluing working property is super !
Fourth : I noted your address in OHIO , we are selling a lot there ! probably what you seen the paulownia trim boards are made from our company :D ! we are using bi-component exterior water-proof glue ! to be used in the exterior environment has none problem !
Fifth: it is same important if the manufacturer is using water-proof painting for the trim boards also ! we are making with exterior water-proof painting , with good adhesiving to the paulownia wood , which makes the paulownia trim boards very much suitable to the weather !
All in all, paulownia trim boards are very much good when they are holding up to weather !
I see you claim it is naturally insect unfriendly and not susceptible to decay. That seems to be in direct contradiction.
I need to be clear : paulownia is naturally friendly to the Nature ! and the reason why we say paulownia is naturally insects-unfriendly is because : experiments statistics from USA, Australia and China paulownia or forestry research centers shows: Paulownia wood has a lot of tanin Acid in it , the Tanin Acid is very much bitter in tastes , that is why the insects does not like to bite paulownia ! so if paulownia wood is put together with other kinds of wood species, the insects prefers to eat other wood than paulownia wood because the paulownia wood is too bitter for them !
however , if only put paulownia with paulownia wood together , the insects will not choose to starve to death if they have a bad “food” , so they will also bite paulownia .
For the question why paulownia wood is resistant to decay – again back to the wood cell’s structure : when the wood is dry , the wood cells become totally closed structure , that will have direct protection to themselves from decaying J
Hope I am understood by you , if any questions, pls don’t hestiate to contact with me at any time !
AdaFeng
Manufacturer for Paulownia wood Trim boards/Mouldings from China since the year 1988 .
Sales Manager
Heze Hengxiang Wood Co.,Ltd.
Cao County Hengda Wood Products Co.,Ltd.
Add: Zhuangzhai town , Cao County , Heze City , Shandong province, China
Mobile: 0086 15865892712
Tel: 0086 530 5320099
Fax: 0086 530 6160078
skype: hezehengxiang
Web: http://www.hengxiangwood.com http://www.hengdawood.com
besta
I'm not so sure that you can assume because of good compression and shear tests, that the wood is better suited to exterior applications.
Could you provide a link to any tests done regarding decay and/or resistance to rot?
thanks.
hi, Calvin ,
thank you for your message, I think the American Paulownia Association professors will give you great help , you can contact with them : http://www.paulowniatrees.org/ and you can also see the website to understand more .
as I have mentioned the paulownia research are located in not only China , but also Australia , USA , and also some other countries , you can also visit this website : http://www.silvatree.com/paulownia.html
in this website, there written :
Timber Properties and Value
Known in the industry as the “Aluminium of timbers”, Paulownia is 30% lighter than any comparable hardwood, it is twist, shrink and warp resistant and virtually rot free. Its fine grained properties make Paulownia wood exceptionally suited for making wooden surfboards, boats, pallets and household furniture as well as plywood, prefabricated houses, moldings and internal construction panels. Paulownia is also being grown as a sustainable, Carbon neutral source of bio-fuel, a crucial step towards solving the global energy crisis.
also, I think it will be good to show you some statistics , hopefully will be great help :
Properties of Paulownia Timber
1. Weight - Paulownia is a very light timber. At a dry density of around 280 kg/m³ Paulownia is lighter than most common timbers. Density comparisons are Western Red Cedar (340), Meranti (580), Pine (500), Teak (750), Robinia (750).
2. Strength - With a modulus of elasticity (stiffness) of 5.6 GPa and a modulus of rupture (bending strength) of 28 MPa, Paulownia is not classified as a structural timber in its natural state. However because of its light weight, Paulownia has a high strength to weight ratio, an important feature in the various uses of the timber.
3. Deformation & Warping - The shrinkage co-efficient of Paulownia is very low compared to most timbers being 0.094 radially, 0.268 tangentially and 0.362 in volume giving the dried timber a high level of dimensional stability.
4. Hardness - The Janka hardness rating for Paulownia is low at 1.3 kN. Western Red Cedar is rated at 1.5 and Meranti 2.6. While modern treatments can substantially harden up a finished surface, Paulownia is not suitable for flooring or areas where physical damage is likely.
5. Durability - The in-ground durability rating for Paulownia is 4 and the timber should not be used for that purpose. Paulownia used for other external uses out of ground has a similar durability to western red cedar.
6. Resistance to Decay - Paulownia is highly resistant to insect attack and rot. Research carried out by Queensland Forestry Research Institute in Australia indicates the timber to be unattractive to termites. Rot showing on neglected timber tends to be surface deep only.
7. Thermal Insulation - With one of the lowest thermal conductivities for wood of just 0.07 Kcal/m/hr/Cdeg, Paulownia has an excellent heat insulation capability being one of the best heat insulating timbers and far superior to brick, concrete or steel.
8. Fire Resistance - With an auto ignition temperature of around 400 deg C (most hardwoods around 220 deg C) Paulownia is reported to have a flame spreading rate considerably below most building codes.
9. Finishing - The sap of Paulownia is not gum or resinous based, thus the application of finishing products with various solvents as carriers does not risk any interaction with the timber, contributing to the very good finishing properties of Paulownia products. The timber readily takes stains, estapols and paints with excellent finished surfaces.
10. Workability - A major feature of Paulownia timber is its ease of working. All aspects of carpentry such as machining, nailing, screwing, gluing, sanding, sawing and handling are very user friendly with no splinters, cracking or splitting and excellent take-up of glues and finishes.
Thank you very much for your interest in Paulownia ! if you need any kinds of paulownia products , or have any questions on paulownia , I will be alwasy glad to be here !
Best Regards !
Ada Feng
Manufacturer for Paulownia wood Trim boards/Mouldings from China since the year 1988 .
Sales Manager
Heze Hengxiang Wood Co.,Ltd.
Cao County Hengda Wood Products Co.,Ltd.
Add: Zhuangzhai town , Cao County , Heze City , Shandong province, China
Mobile: 0086 15865892712
Tel: 0086 530 5320099
Fax: 0086 530 6160078
skype: hezehengxiang
Web: http://www.hengxiangwood.com http://www.hengdawood.com
There's a difference between providing information and posting ads, and I think you've crossed that line.
No offense ada
but, industry associations are not the sole authority nor the most reliable information providers on the critical issues of a product.
Please present a link to independent testing associations as to the decay resistance and probability to rot when used in exterior applications of your product.
Do you add any chemicals to your exterior product to prevent the above?
thanks.
paulownia dry wood is rot-resistant naturally
hi, Calvin
I am sorry ,I do not know if there has some links to show to you to prove the paulownia's rot-resistance .
however Today I checked this with Chinese Paulownia Authority ( Chinese Academy of Forestry ), and his words as follows:
1. the paulownia wood , after they are dried , we tested compared with poplar wood, pine wood, fir wood, etc , without water , the microorganism will be very hard to live , that is why paulownia dry wood is rot-resistant .
2. paulownia wet wood ( green sawn wood ) the Moisture content is very big , easy for the microorganism to live , so not rot-resistant .
3. paulownia has very special characteristic : when they are dried, their wood cell becomes totally closed structure, very hard to absorb water , very hard to get the dry paulownia to be wet . from this level , we say paulownia wood is naturally rot-resistant .
experiments results: paulownia wood does not easily abosorb water and sink , the floating time is 3-4 times longer than other wood materials !
and we do not do the special treatments to the paulownia , only do the kiln-dry to make sure the paulownia wood is below 12% Moisture content , mostly will be 6--10% MC .
hope this can explains well for you :)
Best Regards !
Ada Feng
(Why, when I read that description, do I suspect you're describing balsa wood?)
(In fact, compare: http://www.matbase.com/material/wood/class4-5-10-years/balsa/properties . The properties are virtually identical.)
Paulownia wood VS Balsa Wood
Paulownia Wood... the Cheaper, Stronger Alternative to Balsa Wood
Balsa has been incorrectly considered to have the highest strength to weight ratios of any wood in the world.
Paulownia has been thoroughly tested and found to have a higher strength to weight ratio than Balsa!
Auburn University tested the strength of 18 lb p/cubic ft. Paulownia against Balsa, with an average weight of 10 lbs p/cubic foot.
Strength modus of rupture mor (psi)
Balsa - 2800
Paulownia - 5740
- Source: Dr. R.C. Tang, Auburn University
Some Balsa core material is sliced at 3/8 inch with end-grained material. Paulownia can be cut at 3/16 and offer approximately the same strength and weight. Paulownia offers a space saving benefit, being cut half as thick. There is also a significant cost savings because half as much material is needed.
Lighter grades of Paulownia weigh only 14lbs per cubic foot. This is lighter than many Balsa grades.
When considering the large amount of epoxy that Balsa soaks up, Paulownia gains an even larger weight advantage.
Paulownia is easily carved and can hold nails and screws without splitting. It also provides greater stability and flexibility for making molds and models.
How strong is Paulownia hardwood lumber really? See more: https://www.linkedin.com/pulse/paulownia-wood-vs-balsa-victor-garlington/
These values are strength and stiffness in bending... so if you are going to compare them, compare them to other values derived from bending. In the wood industry they refer to these as "modulus of elasticity" (bending stiffness) and "modulus of rupture" (bending strength).
Paulownia wood for sale learn more at: https://bioeconomysolutions.com/paulownia-lumber/