Which epoxy to use? Mahogany lamination

stuhaynes

stuhaynes

Well-Known Member
Joined
25 Dec 2009
Messages
707
Location
Yorkshire
www.best-camping-stoves.com
I'm winding myself up to laminate a piece of mahogany 16 feet long 14 inches wide and 3/4 inch thick.

It's got a curve in it so I'm considering using 3 by 1/4 inch pieces for the thickness and doing the length in 2 halves, all epoxied together to give the finished length, width and thickness.

I've never done this before so would appreciate advice on a practical epoxy to use to provide a strong and completely water proof lamination.

If you've done something similar to this I'd appreciate your input. Cheers :)
 
As a lad I helped in steaming planks, and a few years ago me and a mate steamed a plank for a big clinker built boat.

If you want to do it the easy way by lamination, presumably you will make a jig, and then apply the planks one by one.


I am not sure why you would use epoxy glue, personally I would use resourcinol, because that is what I have used in the past.

Whatever glue you use it is important that the glue penetrates into the wood fibres. The only epoxy which might fit the bill is the West system which is extremely thin. You may be able to thin it with a solvent.. i would ask West
 
pappaecho said:
The only epoxy which might fit the bill is the West system which is extremely thin. You may be able to thin it with a solvent.. i would ask West
Click to expand...
I think that's a typo - should read 'extremely thick'.

And it's far from being the only epoxy - there are several others far more suitable, and which don't require thinning.
 
Re epoxy

I have laminated quite complex shapes and tend to use West Systems as I am familiar with it though there are cheaper alternatives. You don't say what the wood is for and what it might be subject too in the future. You could look at using Titebond 3 which is waterproof and much much easier to use than epoxy with far less cleaning up afterwards.

I recommend you assemble dry in your jig before the proper job to ensure all your clamping is OK
 
Collano Semparoc 60

I have recently started using Collano Semparoc 60 (used to be called Balcotan) - it is a single component polyurethane adhesive (no mixing or measuring) that is waterproof and has an element of gap filling as well. I joined a 6" (150mm for the French readers) mahogany board an inch and a quarter thick lengthwise to a 3" mahogany board with a half inch oak strip between them. It produced a fantastic bond without any fancy joints or dowelling and now looks like a single board with a stripe in it. Very pleased with the product. Supplier was Marine Store from Maldon down in Essex - great service.
 
Depends on the radius of the curve and what you are going to attach it to. That section should take quite a curve without laminating (or even steaming) if it is fastened to som ething solid. I have bent dry similar length/thickness, but not width for rubbing strakes with use of good fastenings and a Spanish Windlass.

If, however you want a curve that is freestanding then 3*1/4" laminations will work around a really substantial former. West neat on both sides then thickened with silica and well clamped will do the job. With the right sort of former and working quickly with lots of clamps you could do it in one hit.
 
I've had good success with West and SP (now gurit).

I favour West only because I have a reasonably priced supplier.

The key to success is less about the manufactuere and more about the user, invest in some decent digital scales and get your mix by weight absolutely spot on.
 
Agree with BurgundyBen's advice - West or SP, doesn't matter as they are both good. You'll also need some microfibres to thicken the epoxy, otherwise it will all soak into the wood and leave you with nothing in the joint.

What is it that you're laminating? And why 3 x 1/4"? How much of a curve? Are you building a former? You'll need a massive number of clamps if you haven't got a vacuum bagging setup.

The West website has got a number of videos showing various epoxy techniques which you might find useful. Apart from the digital scales mentioned above, get a box of nitrile gloves, a big polythene sheet to cover your workbench, a load of mixing sticks, some glue spreaders, a bottle of meths for cleaning up, and a helper to speed up the clamping.

I wouldn't use Titebond as the open time will be much too short on such a large glue area.
 
That's a big bit of wood!
Quite expensive on material, so needs to be right first time.
I would say West or Gurit as per their instructions will do a fine job.
The key will be jigging and clamping.
I would look at making sure the jig is foolproof and the clamps are easy to get on quickly.

Try it with a dry run as suggested, but bearing in mind that the bits will slide around a lot more with epoxy between them!

Get a mate around to help, and ask him to bring his clamps too!
There are diy ways of making simple clamps in various books, ideally you will need lots!
 
From experience any good quality epoxy resin will work.I like to thicken the epoxy a bit with something like talcum or microfibers when gluing.I usually paint the surfaces with unthickend resin first and then apply the thickened mix.
 
tillergirl said:
How much of a curve?
Click to expand...

It's probably only about 50mm across the length but because of the width of the board I'm concerned that any curve may 'flare', as the main fastening point is at the bottom of the board and there are 2 more boards to join above this base plank.

lw395 said:
That's a big bit of wood!
Quite expensive on material, so needs to be right first time.
I would say West or Gurit as per their instructions will do a fine job.
The key will be jigging and clamping.
I would look at making sure the jig is foolproof and the clamps are easy to get on quickly.

Try it with a dry run as suggested, but bearing in mind that the bits will slide around a lot more with epoxy between them!

Get a mate around to help, and ask him to bring his clamps too!
There are diy ways of making simple clamps in various books, ideally you will need lots!
Click to expand...

As far as the cost is concerned I've had a couple of quotes:-

Timberline quoted me £915.00 (this is for ONE side of the main cabin / galley / wheelhouse) straight from the saw (unplaned) :eek:

Trevor (who I've used before) at Gibson Craftwood £390.00 and this is planed! He actually suggested that because the middle ply won't be seen I could use sizes other than quoted and he would reduce his price to £320.00. :D:D

I've got no doubt at all that Timberline material is first rate, but a £600 difference in price speaks for itself. As I mentioned I used Trevor in 2007 and 2010, he's helpful, reliable and good to deal with. (I have no connection other than as a happy customer) He's based in Normanton on Trent. I don't have his number to hand right now but you're welcome to PM me if you want it.

Not sure if I said but the wood is mahogany.
 
50mm over a length of 16 ft seems tiny, I'd have thought solid 3/4" plank would be fine for that, and would avoid a great deal of trouble and expense in laminating.
 
Will you be offended if I suggest a foam/epoxy/glass sandwich and some veneer?
You could also use plywood for the main area with a hardwood edging.

I would be concerned that a solid bit of wood might crack in hot sun or something.
If laminating, I would be concerned about getting the curve in the right plane with no twist in it.
 
stuhaynes said:
It's probably only about 50mm across the length but because of the width of the board I'm concerned that any curve may 'flare', as the main fastening point is at the bottom of the board and there are 2 more boards to join above this base plank.



As far as the cost is concerned I've had a couple of quotes:-

Timberline quoted me £915.00 (this is for ONE side of the main cabin / galley / wheelhouse) straight from the saw (unplaned) :eek:

Trevor (who I've used before) at Gibson Craftwood £390.00 and this is planed! He actually suggested that because the middle ply won't be seen I could use sizes other than quoted and he would reduce his price to £320.00. :D:D

I've got no doubt at all that Timberline material is first rate, but a £600 difference in price speaks for itself. As I mentioned I used Trevor in 2007 and 2010, he's helpful, reliable and good to deal with. (I have no connection other than as a happy customer) He's based in Normanton on Trent. I don't have his number to hand right now but you're welcome to PM me if you want it.

Not sure if I said but the wood is mahogany.
Click to expand...

While solid mahogany looks nice for that sort of job, it is not ideal, particularly if you are then going to cut holes in it for windows etc. Very susceptible to longitudinal splts as the board expands and contracts across the grain. Highly unlikely to fail through bending that small amount provided it is properly supported at the bottom and top with carlins.

Veneered ply would be far superior as the construction of the boards results in much more stability. Even with the high price of ply, it would be substantially cheaper and suspect that Robbins might make a veneered board of the right size to order - or at least a board that could be scarfed to get your length.
 
Yes, it is thin. Used without any thickening agent it will soak straight into any reasonably porous wood such as mahogany and leave very little at the meeting faces of the joint. Maybe the reply to your first post was referring to something like the small tubes of Araldite, who knows, but it doesn't apply to the sort of epoxy we're talking about for this job, ie SP 106 and similar.
 
What are you making, if the panel knows what you are making then there may be a better way, because to get 14" wide you are going to need a lot of laminations at 1/4"

Thought I might add that if you are building a cabin side, strip planking may be a better alternative, instructions are in Fred Binghams book
 
Last edited:
I'm also in the dark about what exactly is being made, and also which way the 50mm bend is going - the reason being that a 50mm bend in a 3/4" plank does not need laminating, and a 50mm bend across the width of a 14" plank will be very difficult (and almost impossible with an individual 1/4" thick laminate). In fact, why is laminating even being considered as an option?

So, are we talking about something like a cabin side (as has been suggested), or maybe a side thwart running alongside the curve of the hull?
 
You must log in or register to reply here.

Share this page

Top