Marine glues

[davidej]

I am about to start resurrecting a derelict Oppy and convert it into a pram rowing dinghy. This will involve repairing a number of the joints which have split and adding some ply buoyancy tanks which will double as seats.

I was brought up using Aerolite 306 which seems to fallen out of favour. I am also familiar with West type thickened epoxy as a glue altho this is expensive and seems overkill for something which is only going to be used on a largish garden pond.

I am thinking of using polyurethane Gorilla type glue. Is seems to be waterproof and quick setting and I am aware of the need to clamp properly.

Has anyone got any observations on this choice?

 

[sailorman]

The issue i have with epoxy is the wood srinks / moves & the epoxy doesnt, it can leave a protruding glue line

 

[Tranona]

Polyurethane glues like Gorilla are good general purpose glues. Aerolite is cheap and easy to use, but is not long term waterproof and goes brittle with age. Epoxy is a superior adhesive and much more versatile than any other adhesive, particularly as with suitable additives it is structural with good gap filling properties. Although it seems expensive you get very little waste if you plan jobs properly. filleting is a technique that makes jobs like adding buoyancy tanks much easier as there is less need for framing. suggest you get the Wessex Resins publications on using epoxy from their website.

 

[srp]

I would also go with epoxy, along with a suitable filler such as microfibres. A digital scale helps avoid waste as it ensures every mix is going to cure properly. Having carried out tensile testing of epoxy samples on a Hounsfield tensometer in a past life, I can tell you that epoxy is flexible and has quite a large elastic range - easily enough to accommodate any movement of plywood (unlike the casein glues such as cascamite or whatever they call it these days).
Polyurethane glues are good, but if you want to form a glue fillet or fill a gap then it is no use, you need epoxy. A box construction with fillet joints is very strong as Tranona suggests - and it can be assembled with masking tape to hold it together while the epoxy cures, you don't need cramps or mechanical fastenings.
A split joint between two panels can be repaired by cleaning out the split with a router or a handsaw, priming the area with an unthickened epoxy mix, and then filling with a microfibre-thickened mix. A bit of masking tape over the top will stop the mix slumping while it cures, and if you want to reinforce it then a layer of woven glass cloth on on or both sides can be added.

 

[dur]

See also Nick Gates Getting Afloat video series for use of the polyurethene glues on his Sharpie restoration. So much easier than epoxy if you can close cramp the work.

http://www.ybw.com/forums/showthread.php?473846-Getting-Afloat-series-now-on-YouTube

 

[Poignard]

I use polyurethane glue when I can, and epoxy when I can't.

 

[PCUK]

Still using Cascamite!