Glue for laminating (ie Making a tiller)

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mortehoe

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I'm at my wits end. All the glues that I have used have failed. Over the past 3 years I've made, re-made and re-made and re-made a spruce/mahagony as laminated M-S-M-S-M-S-M with each layer being originally 11mm thick with a sexy bend in the middle of the tiller. Each time the layers were compressed in a frame to about 40 psi continuous over the 1.6m length (cramps at 10" intervals) [Sorry about the mixture between Imperial and SI - but I still think inches and metres!]

The 'glues' that I have used are:

1) [Big mistake] Evostick Resin_W .... It failed after 2 months at sea. The tiller ended up being bound-up with string to hold it together to get back home.

2) Next disaster: Aerolite 306: Bloody stuff wouldn't mix properly so I put it in her ladyship's Kenwood .... It mixed and was duly spread on the taken to pieces/cleaned up/restored bare 7 bits of now re-pristined timber. The frame, timbers, glue and presses were used according to the manufacturers instructions ... and all looked good except her ladyships mixer_bowl (glass and spinner) which was well and truly fubar as the leftovers had set! .... /forums/images/graemlins/frown.gif The tiller lasted 1/2 a season before the now essential roll of string had to be brought into use again.

3rd failure: Cascamite/Extramite (Humbrol) .... Not even a month ....

4th failure: A proper marine adhesive guaranteed to be .... 1000% marineproof .... Balcotan One Component Marine Polyurethane Wood Adhesive .... A whole season plus 1/2 a ball of string.

The spruce that I'm using is 'Russian unsorted' clear; the mahagony is 'Ghananian 2nd' de-oiled.

What am I doing wrong???? The only thing that has remained the same is the original ball of string which makes me think that "How can I use string where 21st C glues fail fail fail ?????
 
The Reason Its Falling Apart Is Probally Because You Put Too Much Pressure On! Your Squezing All The Glue Out!
Try Epoxy Resin With A Filler In, They Stick Plywood Boats Together With It So It Should Be Good For A Tiller!
 
St Peter\'s pocket

I was always taught that if you joined two things together with the gluer being stronger than the background then the new mend would rip the original hole apart.

BTW I used in each case the original manufacturers pressures.
 
I used west epoxy. It worked really well

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Very difficult to understand what you are doing wrong, have used all the glues you mentioned, would have thought at very least Balcotan would do the job. The other one I would reccomend would be West System. Couple of points to consider. Was the timber abraded to form a key and was the temperature right, I have had failures in cold weather
 
Yes, the timbers were abraided so that they were 'roughed up' along the grain for glue absorbancy.

The glueing temperature in each case (measured) was min 12C to max 20C.
 
I have (amongst many other things) a rudder and a tiller that I laminated from iroko about 9 years ago and have had no problems. The best glue that I have found is cascophen, if you can find it. It is a purple syrup with a powder hardener; very easy to mix in small quantities and is spread like butter.

The most important thing to remember, as has already been pointed out, is not to apply too much pressure or the glue-line is bound to fail. In my opinion, however, this will be difficult to achieve with the thickness of your laminations. I think that anything over 6mm requires pre-bending. Also, do the laminating in stages, i.e., do not clamp all the laminations in one go.

Good luck.
 
I made a tiller with a double bend from Ash and Mahogany strips which were steamed and bent and then held for some days in the bent position on a former prior to glueing. I used epoxy glue and had no trouble.
 
Epoxy and a lightweight woven glass sheathing. Plus suitable varnish to protect the epsoxy from UV, you probably wont even see the glass sheathing with good varnish and plently of Epoxy wet on tacky, 3 to 4 coats, Plus several of good varnish. Stronger and the glass will stop the whole lot splitting.
 
I've now used West epoxy on two curved, laminated tillers, with 6mm laminates, with complete success and would recommend it, although I would expect Aerolite and Cascophen to be OK, though less tolerant of gaps. Your 10" spacing of clamps seems too wide, especially if the tiller has much curve, IMO. For a 1m tiller I used a dozen or more, ie about 3" spacing to get thin glue lines.
 
Unless the laminations have taken the set of the curves, make a former to the shape of the tiller and clamp to that. 11 mm is thick - normally would be 6-8 mm if there is significant curve. As others have noted Balcaton should have held, but best would be epoxy such as West. Make sure you clean all the residue of the earlier glues and clean with acetone. Coat with neat epoxy first to penetrate the wood then thicken the epoxy with silica and apply to faces while the first coat is still wet. Do not overtighten - just enough so that the mix squeezes out evenly. You might find it easier if the curve is severe to do them one at a time. Clean of the surplus before it is fully set as it will be very hard. Ideal to coat with a UV resistant varnish, but many people make a natty "condom" out of canvas to cover the tiller when not in use.

Hope this helps
 
Use epoxy and dont clamp it so tight, wet the join first with unthickened epoxy, then mix some binder, in the epoxy and glue it all together, do not clamp too hard, use slow hardener, should be fine, my masts are held (Scarphed) together like that.
 
Perhaps you may have very large gaps between the laminations.

All of the glues you have used are not good at 'gap filling'. They require a very well matched joints between the strips.

It may have appeared that when you clamped the tiller together that you were filling the gaps with the glue but, especially with Balcotan when it tries to fill a gap there is no structural strength. The stuff foams up into something with the strength of builders foam.

When I laminate tillers I never make the strips thicker than 6mm. This helps the ease of forming the curve and the gaps between the slats will be minimised.

I would always use epoxy for this task and, as has been posted by more than one formite, use a layer of neat mixed epoxy on all joining surfaces prior to assembling with a thickened mix.

By doing this any suspect gaps between slats will still have adequate structural integrity.

It is also essential that the finished assembly (once sanded) is coated with a UV resistant varnish.

Cheers

Iain
 
It is very easy to sqeeze too much out when you use epoxy. You also have a very short open time.

Try some Aerodux style glue from Severn Valley Sailplanes. If that won't hold it you have another problem like incompatibilty with residue of previous glues.
 
Tiller construction:

If more than one bend, slats should be no more than 6mm (quarter of an inch).
Support points should be not more than 75mm (3 inches apart) at bend areas.

Preparation:
Surfaces to be joined should be sanded and cleaned, then wiped with Acetone to remove any surface oils contained in the timber and allowed to dry for a few minutes, not too long or the oil will return to the surface.

Add a coat of epoxy resin mixed with hardener and 30% Methylated Spirits, this will thin the epoxy and improve penetration, apply at least 2 coats.

You can let this cure and re sand, ready for construction later, or, you can apply glue and continue provided the resin is still soft.

The Glue: Mix a small batch of epoxy resin and hardener and add some Micro-Fibres (Not Balloons), mix to get a toothpaste consistency and apply to both surfaces, place in your jig and build up the layers, look for any areas that the glue may be getting squeezed out due to bend pressure. Stop adding layers and let it cure before continuing. It is important that the glue is not too thin between slats as this lead to failure of the joint.

Finishing: any item coated with an epoxy should be given extra coverage when completed, this can be applied wet on tacky to avoid sanding between coats.

Epoxy resin will leave a wax like coating on it's surface after curing, this should be removed BEFORE sanding or coating, sanding will only spread the contamination and coating may delaminate if the residue is not removed. Removal is easy and no chemicals needed, just a running hose, start at the top and work down rub with a plastic scotch-brite and run the water over it till the water no longer forms beads.

Temperature and Humidity are critical when using an Epoxy resin so ensure the temperature remains above 20*C and the humidity below 74% for the duration of the curing.

Epoxy resin will degrade if exposed to UV light and MUST me protected, a simple coat of paint or varnish will achieve this.

I hope this helps

Avagoodweekend......
 
I used epoxy for the whole boat. Keel, stem, gunnel, tiller laminations. Iroko and maranti/iroko. Excellent. Resoltec resins (sold by Connexion in UK) I especially like their water based coating resin, 50/50 mix, goes on like milk, looks like varnish after 3 coats.
Cascophen is a rescorcenol resin and requires HIGH clamping pressures, around 125/140 p.s.i. with thin glue lines (.007") No gap filling.
Epoxy needs just enough to hold the pieces in the curve, any more and you risk dry joints (as mentioned)
Try fresh wood and epoxy.
Andrew
 
Pardon my asking but, if you are using freshly cut 6mm strips that are presumably uniform in thickness, and you are using sufficient clamps against a proper former, why would you need gap-filling? There ought to be no gaps at all if the operation is being done properly! IMHO.
 
Thanks Oldsaltoz. I wasn't questioning a proper glue-line but the term 'gap-filling' in the sense that when faced with that expression I have visions of trying to bridge intermittent gaps of 2 or three millimetres, such as one may get when not offering clamps up properly. Must be some form of language barrier on my part /forums/images/graemlins/wink.gif

Perhaps I still prefer recorcinol type glues because the glueline is easier for me to see! I also find them more tolerant to mixing proportions. Just a personal opinion of someone who does not work on boats for a living.

I must say, I always read your contributions with great interest and I find them very instructive and with a no-frills, down-to-earth approach.

Thanks and have a good day! although I understand that the weather has not been too kind lately.
 
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