Glue 4 Mahogany?

[Seagreen]

Can anyone recommend a very strong glue for mahogany? I'm building a cabin table out of reclaimed mahogany so I'd like a fine finish to the joins, but it also has to be very very strong. My first choice is epoxy with sawdust filler, but I'm open to suggestions.
Many thanks.

 

[sailorman]

Extramite
will not show any glue line

http://www.tool-net.co.uk/p-320781/...mite-1-5k-g-cascamite-extramite-adhesive.html

 

[Blue5]

I always use Extramite with mahogany, never had any problems to date. If you are gluing up a table well worth taking extra time to shoot and match the joints, avoid any filler in the glue as it keeps the joint open. When clamping up also use cauls to keep flat.

 

[srp]

The thickness of the glue line you get depends almost entirely on how accurate you make the joint. Epoxy is certainly suitable, but I'd use microfibres rather than sawdust, and mix it to a runny consistency (think of single cream). Next choice would be a polyurethane adhesive, but there are many different types - I use one called Balcotan, which has a fairly long open time compared to many. Third choice would be a water resistant PVA - not totally impervious to damp conditions but may be suitable in your cabin, and has the advantage of being easy to use and to clean up.
I have to say that in my personal experience Extramite (or Cascamite in its' previous incarnations) doesn't cut the mustard - when cured it is brittle and hard, and doesn't move with the timber, leading to joints which open after time unless they are reinforced with mechanical fastenings. All the interior woodwork (galley, sink etc) on my Corribee has been glued with Cascamite and it just falls apart when I take the screws out (not done by me I hasten to add).

 

[OGITD]

Gorilla Glue

Not used Extramite… but the lads who know a thing or two highly recommend Gorilla Glue.

 

[Tranona]

Balcaton or other similar polyurethane would be fine, but if it is decorative you might want to mask the joint as the foaming can stain the surface. Epoxy is overkill from the strength point of view, but use it if you have it. Would not use sawdust if joints are close but a dash of silica and microfibres to give it a bit of bulk and brown microballoons to colour it and give that nice controllable consistency! Bit like icing a cake.

 

[Boo2]

Not used Extramite… but the lads who know a thing or two highly recommend Gorilla Glue.

I've found that using polyurethane glues like GG gives a very strong joint but at the expense of a visible glue line or trouble cleaning up or both. Is that just me doing something wrong or a general experience ?

Boo2

 

[Seagreen]

Thanks all. I do have a ready supply of epoxy and have previously enjoyed Balcotan. I may invest in some cascamite, but I remember an old mirror dinghy in my youth suffering from cascamite failure. Gorilla Glue? Maybe I'll just stick with the epoxy.

 

[Seagreen]

So what, in essence, is the difference between Balcotan and Gorilla Glue? They both seem to be foaming polyurethane glues to me.

 

[Danny Jo]

So what, in essence, is the difference between Balcotan and Gorilla Glue? They both seem to be foaming polyurethane glues to me.

They are both foaming polyurethane glues. Good, waterproof, easy to use, but nothing like as good as epoxy.

 

[Poignard]

Correct me if I'm wrong but I always understood that close-fitting joints are not what you want when using epoxy.

 

[CET1]

My choice would be any gluefrom the titebond range joints are nearly invisable and if you require water proof then use Titebond III Ultimate Wood Glue. For joining large boards we normally reinforce the joint with beech biscuits. Have a look at

http://www.axminster.co.uk/woodworking-adhesives-dept812854_pg1/

 

[Danny Jo]

Correct me if I'm wrong but I always understood that close-fitting joints are not what you want when using epoxy.

Yes and no. You can make joints with epoxy that are close fitting externally but allow space internally.

When making a scarf joint, for example, first make the fit perfect, then cut a little material away from one surface to make a shallow depression along the middle of the joint. I would join boards for a table top with epoxy and a fairly loose-fitting hidden wooden fillet.

 

[capt_courageous]

Hi
Aerolite glue ( not Araldite ) is very good for this sort of job and is used in light aircraft and boat building. It is not messy and makes it easier to get a tidy job.

 

[Poignard]

Yes and no. You can make joints with epoxy that are close fitting externally but allow space internally.

When making a scarf joint, for example, first make the fit perfect, then cut a little material away from one surface to make a shallow depression along the middle of the joint. I would join boards for a table top with epoxy and a fairly loose-fitting hidden wooden fillet.

That seems to be a very sensible solution.

 

[Seagreen]

I was going to hire a bisuit jointer for the day joining the boards on top with ends channel jointed(? like tongue and groove) for extra support. I've got enough router kit and clampery. Just hope the design works. I'm also going to use piano hinge for the table leaves and supports. I may even post pics of the results up here.

 

[capt_courageous]

Hi Danny
That is the way I was taught to do this sort of job, then use sash clamps to hold it all together till the glue sets.

 

[sailorman]

I was going to hire a bisuit jointer for the day joining the boards on top with ends channel jointed(? like tongue and groove) for extra support. I've got enough router kit and clampery. Just hope the design works. I'm also going to use piano hinge for the table leaves and supports. I may even post pics of the results up here.

a good "true" butt joint will be as strong as the wood with xtramite

 

[Amulet]

Extramite (was Cascamite if I'm correct), does not claim to be completely waterproof and isn't.

Aerolite claimed to be waterproof and was proven wrong (on the 30 year time scale)

Poxy would be my choice probably, but it does duff over your plane smoothing it off afterwards.

Might be tempted to use Balcotan to be kind to my tools.

I would have suggested biscuiting it as you indicate, but I have a biscuit jointer. Before I had it I used loose tongues for this task - cut a 6mm slot in the side of each part and insert a strip of plywood as the tongue. (Obviously you wouldn't take the slot all the way to the end.)

I think you can make your joint fit well and use no filler in poxy if you are using biscuits. My dining table at home was done that way and has survived much abuse.

When clamping you have the problem of keeping the panel flat as well a squeezing it together. I use these Axminster panel clamp heads on lumps of softwood, which seems to work well. (Tip, cover the lengths of softwood with shiny packing tape to stop them sticking to the glue.)

I think you piano hinge will be a bit of a pain, I'd be inclined to just use some proper brass hinges. My saloon table's leaf folds over on top of the table rather than hanging down when not in use, so I used these backflap hinges, but cutting the recess for them is fiddly and nerve racking.

 

[Seagreen]

Cheers Amulet. I'm going to stick with the Piano hinge, mainly as I want the top to be very smooth shiny wood and the flaps will just fold down, and be held folded by cabin hooks. I may swap the hinges for some solid butt hinges. Still thinking about that. The most expensive bit of the excercise so far has been the table bolts from Classic marine. I was also toying with the idea of a bit of marquetry in the middle of the table but I've no idea on how to do this, but the idea won't go away.