Thread: spotted gum

spotted gum is lovely, strong & stays straight once seasoned.
I have heard tell that some like it for a keel.
Drop in on the woo boat forum & see what they recon.
Its not all that troublsome when seasoned.

Soundman is spot on... spotted gum makes excellent keels, many moons ago was involved in the cutting of an extremely long keel(s) for the replica of a very famous boat, amongst others & I figure if it was good enough for this big $$$ project, it should be ok. Word of warning though there are many sub-species, with different density & strenghts, not to mention hardness & resin/silica content. As a rule of thumb, the further north in NSW & into QLD it comes from, so the density increases, with some areas in the Casino/Richmond range area cutting like and possessing wood properties very similar to grey IBK.
Any of the Ironbarks are brilliant in most applications and are quite easily obtained, (if somewhat pricey)including quite large/long sections if you know who to talk to.

Bruce C.

Quite a few old ex trawler wooden boats I've worked on have had Spotted Gum boards and keels, don't know if it was the premium species for this application but it was certainly popular.

Mick

how does ironbark and spotted gum take glue like epoxy. would it alow sufficient absorbtion.

Yihang,
sorry, never glued it. If no one else here can help you you may need to do a few trials.

Mick

I glue up some spotted gum door panels about 12 months ago with weldbond. To date they have not moved, but then they are just in my bathroom not on the bottom of a boat.

Hi
I had a Williams built in 1929 it was Spotted Gum below waterline and Oregon above. To prepare the seams and the new deck for glueing I used Teak Preparation 101. It preps any oil based timbers by sealing it to allow the glue to bond. I replaced the forward deck with Spotted Gum over Marine ply. It worked a treat.

the trick to glueing spotted gum is to hit it with a coarse grinder and then wet it out within several minutes, works a treat.

I was talked into using spotted gum in my yacht.Internal and external -it rotted in both places over 10 years. It was from Northern NSW .

I have since pulled it out . It does not like damp conditions and is a durability Class 2.
Research DPI QLD forest service Timber Species notes no 14

Do some research and look for durability Class 1 timbers. I try to get Turpentine now from the Atherton Tablelands.Teaks of course , white beech , tallowwood , Crows ash , Black bean, White Cypress, White Mahogony ,Forest red gum , red bloodwood ,grey box , carbeen ( morton bay ash) , chengal , grey gum , narrow leafed red ironbark , Gympie messmate ,satinay.

Thats a quick run through the notes .
I think many people building boats follow like sheep and don't know what to use. People seem to want to appear knowledgeable even when they are'nt. Research it for yourself if you are going to do much of it .

Spotted gum was and is a popular timber for Trawlers and Yachts in Northern NSW as I have seen . I have also seen it rots easily especially along any gum lines in the timber . It is dense and very hard but moves a lot in use . It does not hold glued joints very well , they crack away and the timber cracks and breaks whatever sealer you put on.
http://www2.dpi.qld.gov.au/hardwoodsqld/7581.html

Here is a good list of timbers and properties

http://www2.dpi.qld.gov.au/hardwoodsqld/7680.html

It is difficult to see where Tytower is coming from. Spotted Gum has been used by commercial boats since Jesus played front row for Jerusalem. As a class 2 timber, it has a life expectancy of over 40 years! No timber will tolerate lack of circulation, so maybe that is his bitch, but that was not the question. As far as strength goes, I have been informed that one could drop a Spotted Gum hull onto some rocks, and the rocks would come off second best. We are talking seriously strong. That also means it is not very amenable to glueing. Ironbark is definitely worse. Basically, the better a timber is to glue, the weaker it is, and vice versa. It has to do with the permeability of the grain. No matter what American management gurus have to say, zero sum, win-win equations do not exist in the Real World. Figure out which advantage you want, and run with it.

Hmm

rots along gum lines.......boat building..... gum lines

framing large boats... spotted gum...... glue joints failing

I know it is real a living dead thread but there are some issues.

Adequate quality timber..... no splits, checks, gumlines, sapwood... and so on.
Construction methods consistent with materilas choice.....you wouldnt use a construction method that relied on a property that a materila didn't have....so would you use glued structrual joins in spotted gum like you would in.... o..... meranti.

moisture moisture moisture....... from what I understand the single most important thing in boat design is deciding what you are going to do about moisture.....

cheers

Sorry, I had not realised this thread had done a Frankenstein, and reanimated itself, but the subject matter is rather important, there being so many boats in Oz with large amounts of spotted gum keeping the briny out. Maybe it has morphed into a new post, but I got to it by Googling 'How to avoid rot in spotted gum', so with the Administrator's permission, can we allow it to stray off the original subject?
To summarise the collected wisdom- The stuff is hopeless for glueing, so don't even think about laminating it. This has major ramifications for recaulking carvel hulls. Other forums suggest hitting it with a grinder or wire brush, then water blasting before applying any adhesive.
Rots along gumlines- thankyou, I shall be looking very closely for them. This is not mentioned in any standard literature I have read, and one of the reasons these forums are so valuable.
The timber becomes more dense the further north it is grown. This is in defiance of conventional wisdom, but again, very valuable info.
Moisture- and air are the defining problems of wooden boat building. Maybe that is why I have never seen a commercial boat with a lined hull. But for the inevitable areas that do not have adequate ventilation, such as around the Icebox, has anyone some suggestions? I have a set of oars on my tender that were totally US when I bought it, but have responded to many coats of boiled linseed. The blades were reglued with epoxy before applying the oil, and no structural weakness has ensued, but they are open grained oregon, not spotted gum. Anyone have any experience with Linseed or maybe WEST as a moisture barrier/displacement for poorly ventilated areas inside the hull on spotted gum?
I am a new member, and apologise in advance if I have breached ettiquete, but would really appreciate any feedback.

Originally Posted by dylanthomas6

It is difficult to see where Tytower is coming from.

He was banned because he lied about who he was, lied about his experience, invented stuff to make himself sound good and to cause trouble and became aggressive to some who stood up to him. Ignore everything he's put on the forum - the moderators would serve us well to remove all his posts so we don't have to keep correcting the misinformation he spread.

Richard