Possible boat woodwork repair method

[roger]

I learnt from a friend a useful repair method for antique wooden chairs. Bear with me; it might be useful for boat furniture.
Antique dining chairs can get wobbly when the mortice joints get loose. Taking the chair apart is dodgy and can easily brek parts. The alternative he suggested was to use a hypodermic syringe and inject water based glue through a small hole specially drilled int the joint.
A 1/16" hole is certainly big enough to take the hypodermic needle. Warming and slightly diluting the glue makes pumping it in pretty easy. The small hole is pretty inconspicuous and can be filled. Even so best drilled where it's not obvious.
For on board use you do need a low viscosity glue. Perhaps low viscosity epoxy, perhaps Cascamite or even PVA.
What particularly surprised me was that a useful glue could be pumped effectively through a needle with a bore of less than a millimetre.

 

[DavidTav]

Your post is interesting because I have wondered if it would be possible to repair a cabin roof with a soggy balsa core in a similiar way with Cascamite, drilling small holes every few inches and squirting the Cascamite in. It sounds too easy, I wonder if anyone has tried it?

 

[castaway]

If you start by assuming that your repair is never going to be a 'proper repair' ie you cant be bothered or it is'nt really worth the time or expense to cut away the interior laminate and re build the deck head. ( all quite understandable in many circumstances).

I would rather use epoxy so long as you can get the balsa core dry enough...I you drill a small hole in the outer surface and then clear away some of the core material and then fill the void with epoxy it will certainly stiffen it up.

A good way to clear away the core material around the drill hole is to stick bent piece of stiff wire into a drill chuck then feed it in to the hole then whizz it round a bit. Another way is to use a hole cutter from the inside being careful not to cut a disc out of the outside as you go thro and then clear away the core material. You can tape over the inside and fill with epoxy from the outside. Repeat as many as you need to cover the area.

All sort of bodges but nothing to bad about that in the correct circumstances!

I don't think cascomite would work :-(

Re the original post and separating joints on old furniture I have seen this done using a small hole and feeding steam thro a little pipe into the joint......should think that would be quicker.

Regards Nick

 

[damo]

PVA is not a gap-filling adhesive and requires a compressed wood-wood surface in order to bond, so I very much doubt if your method would work with this glue.

Regarding antique joints - has your friend got it right? The syringe method is often used to inject meths to dissolve the remaining glue so the joint can be eased apart.
Traditional hide glues are applied after being heated and going runny, and they bind after cooling and crystallising, so I imagine they could be injected into a joint.

It is almost always better to dismantle and re-glue a joint, since bodges usually fail.

 

[damo]

The core would need to be thoroughly dried first so you don't trap moisture. Even if you can scrape out the rotten balsa I don't think an epoxy or cascamite would be sensible, since both are rigid and brittle. You could end up with flexing along the hard edges.

What about injecting foam? (not too much at a time /forums/images/graemlins/smile.gif )

 

[Poignard]

I've seen something advertised for loose joints in furniture, I think it's called "Chair Doctor" or something like that. I should think the same result might be obtained with "Captain Tollie's Creeping Crack Cure".

The technique for stabilsing/repairing balsa wood cores is well described in WEST publications. No idea if it's effective,

 

[Gunfleet]

Fox the mitres, is what I say. That keeps them in.

 

[roger]

I agree that PVA and Cascamite aare not very good for marine use. I was thinking of cbin furniture where this may not be so important. It is a question of finding a glue thin enough to go through a syringe needle. Obviously a gap filler would be better. I dont know if you can get epoxy glues with a low enough viscosity. The problem would be eased by using a bigger needle of course.
For the furniture I actually used a fish skin glue from France, provided by my expert friend - no, probably not much use for boats. It has worked well on the chair though.

 

[Slow_boat]

Why is cascamite no longer considered good for marine use? When my friends and I were building boats in the early '70s (Moths and Cherubs mainly) it was the glue of choice. Okay, epoxies were not widely known then but cascamite worked perfectly well.

 

[NickiCrutchfield]

Horrible idea.
Nicki Crutchfield

 

[roly_voya]

No idea what to do about rotten deck cores except replace the deck but the Glue injection techneque is exellent for all sorts of stuff from rebonding areas of loose teak to sealing shackes in wodden cabin trunks. You can use warmed epoxy, make sure its slow set or it will harden before you get it in, quite stiff to get in and does spread to far but good for local areas and voids. Also used polyurathanes very efectively particularly on decks or leacking joints. Because the glue 'foams' and expands as it sets this forces it alon any cracks and I have seen it come out 2ft away! I find a 10mm syringe without the needle and plugged into a 6mm hole works best. I have used large bore needels for small local areas but most glues wont go through them and you cant normally get enough in to do the job. If you are going to try you need needels for taking blood not giving injections!

 

[justdrifting]

cascamite is still the glue of choise for wood.Epoxy dose not like humidity

 

[damo]

Cascamite is quite brittle so shouldn't be chosen for applications where the components can flex. For "outdoor" furniture, teak etc, resorcinol is more commonly used - this is a 2 pack mix, is quite runny and stays workable for long periods.