MYSTERY WOOD (mahogony questions)

[viking north]

I apologise for re posting this under another heading but I'm worried my Thread on this under MATERIALS heading below might have gotten lost after the great help i got on identifyint the wood. On post #13 of that thread i had a couple of questions on suitability, laminating and what adhesive (glue) and prep work ; I.E. If this wood can be used for my purpose. Is there a wood Guru out there that might be able to help me? , Thanks Geo.

[PAR]

I don't know of any of the mahogany sub species that are difficult to glue, machine or finish, though I'm not convinced you have a mahogany.

The usual adhesive choices for laminating should be debated, with the usual considerations of temperature, clamping pressure, precision of joint fit, water proofness, etc., as prerequisites for the desired result. The typical back yard builder would be well advised to skip all that and just use epoxy.

[viking north]

Par, I agree with you it's not a true mahogony but what is now called African Mahogony which comes from two different family of trees. Khaya from the Meliaceau family and Afzelia from the Fabaceau family. I'm 99% sure it's Khyaya of the Meliaceau family. Both are listed as good to excellent for boatbuilding with Khaya being superior.I have worked alot with mahogony over the years but only as trim or furnitue making, never used it for boat framing or planking and never laminating. Par i also have to qualify here in terms of my experience as a fabricator,(not boasting but so as to give a better idea to what level i can be advised on) I have a big well insulated heated shop(38x40x16ft) good fume and dust system.Front and rear 16x 14 ft.doors.Overhead travelling crane.Fully equipped for anything in heavy and light woodworking.Fully equipped for all welding, stick, mig.,tig, plazma cutter, (alum. stainless, steel) Pipe bender up to 3in. sandblasting, spray painting. I am a licenced journeyman carpenter woodworked/ cabinetmaker and a compitent welder in all three metals, My origional field was electrical/electronics engineering teck. I have a good background boatbuilding experience in FRP & Metal hulls but less in bigger wooden hulls. I have built only a couple of hulls and prefer to take it from a bare hull to reduce hired labour. At this point in my life i am supposidly retired and my one time employment shop is now my hobby shop. My weakness is in the engineering part of boat design although i do have a good library on such but have spent too much time working with my hands and not enough with my head. However i'm feeling much more confident in this now and getting a good grasp of the magic numbers so to say. Glad you recommended epoxy as i was leaning in that direction, it's a product i have used many times in laminating and feel comfortable using. Is there any special prep. work on mahogony like an alachol or acetone wipe? Assuming it's african mahogony, whats your take on me using it for deck and cabim beams and framing? My fear if it unknowingly gets damp does it go to powder fast like red oak. Thanks, Geo.

[PAR]

I'm not as familiar with that particular sub species, but the usual suspects of mahogany make excellent framing and structural elements. A lot depends on the focus of the build, for example I wouldn't use this as deck or cabin beams, on boats much under 30' on deck, as weight considerations would generally force me to consider other species, but if you can afford the density, you'll have little to worry about with this stuff. The only prep you need is 15% or less moisture content with 12% being ideal and if making laminate stacks for heavy timbers or curved beams, no more then 1" thick layers, preferably less to control the captive internal stresses common in hardwoods. I'm supposed to be retired too, now get over it . . .

[viking north]

Great stuff Par, thanks, will start gang sawing 1/2 in. thick strips tomorrow, three blades on one arbour, works slick. I'll be ok on the weight, allowed for white oak, this stuff is not as dense. Almost 1am. here old retired guy going to sleep now.---Geo.