Fixing a bronze bush in wood.

I want to fix a bronze bush in a hole in beech wood. It won't be under much axial stress, so maybe anything would do, but as I've no experience in gluing metal to wood I'd be interested to know if there are any adhesives which are particularly good of bad for this sort of thing.

Any experiences out there?

Regards, Robin.

If you must glue it, probably epoxy would be as good as anything. Could you put a wide flange on the insert and pass a couple of flathead wood screws through it into the wood? I really don't fully trust metal inserts glued into wood to carry any loads. I know IKEA does them by the millions daily, but if building something I try to make it more robust that that.

Knurl it and squeeze it in if it has very little pressure on it.

Will it get hot/warm and also will it get wet at all as both of these can effect some glues

JB weld , put a very light knurl on the outside of the bush or at least key it with coarse sandpaper or emery paper., degrease the bush with acetone or isopropyl alcohol then coat both parts with the JB and fit together . The join can only ever be as strong as the wood around it .

Through or blind bush? Cross or end grain? Details do help if you want the right advice.

Robin, as Clive says a straight knurl will probably do but if you want to glue it as well I would recommend Gorilla Glue, it expands while setting and is specifically made for dissimilar materials and gap filling. Epoxy does not bond well with wood but if you do want to use that type I would recommend a metal reinforced one, these do bond well to wood providing it is clean and oil free.

Blimey, that was quick! This is work (as a favour) for someone who has already had the bush machined (to a convenient 21.3mm OD!), so I'm not able to redesign, though it's not how I would have done it.

I'll go with JB weld / keying the bush then - I had thought of JB , but wasn't sure if it was OK for for a close fit as its quite viscous and I worried that it might be squeezed out.

Robin.

Edited By Robin Graham on 06/12/2018 23:03:31

Through, cross grain. Always difficult to know where to draw the line when one's in the dark and doesn't know what the relevant details are.

Robin.

As the wood expands and contracts any rigid glue will break away. Even if it has already been made I would pop it in the chuck and run a pointed tool down it in a course thread or a series of grooves and use a contact adhesive like evostick or uhu (not in contact mode) that is flexible. One problem is that bronze and brass are 'slippery' so need roughing up to get a grip.

If you want something a lttle bit thinner use araldite 24 hr . Not sure how cyanoacrylate would go on bronze and the stuff is also brittle . Ideally you want a drop in fit for epoxy so if the bush is a tight fit you may need to fettle the hole a little.

You could screw cut the outer surface and drive it into the wood

Just a thought

Quite a few comments on the metal part (as would be expected) but the timber component is also relevant.

I am not sure how much experience you have with these so I may be doing a little preaching here.

Epoxy is fine with wood although there are as many variants of epoxy as there are of metals. If fixing to a hard wood then a nice runny epoxy (as in 24 hour Araldite or one of the specialist woodworking/boat building epoxies) would be recommended. Softwood is less critical in this regard although you are still trying to achieve good penetration of the wood fibres. Depending on the type of finish required on the wood post-gluing the extent of penetration may be an issue as it may not be compatible with some surface finishes.

Also, beware of teak and some very oily timbers as these may pose issues with adhesion. A thorough degreasing with acetone or one of the more aggressive degreasers may be required. The area will appear to be bleached but this is mostly temporary although application of the degreaser should be confined to the gluing zone.

Hope this helps

Pero

Noting that Robin mentioned beech wood [which is typically fine-grained, quite dimensionally stable, and non-oily], I would use good old Loctite anærobic retainer ... probably 601.

MichaelG.

Edited By Michael Gilligan on 07/12/2018 08:38:22

Robin, I used the knurled method many years ago on bushes pressed into the rails on the swing gear of a rocking horse.

Straight splines, quite heavy, parallel with the bore of the bush. Worked a treat no adhesive needed.

Adrian.

If going the JB weld route be very patient with curing time at this time of year. Put somewhere warmer after 6 or 8 hours and leave for a day.

I made a pair of wheels with a 15 mm ply disc, the bush is welded to one square washer at one end, and on the other side is another square washer. All held in place by a screw in each corner of the washers, clearance on one side, tapped on the other, countersunk head, all nice and neat. The wheels have a rubber tires.

Ian S C

Hello Robin,

I have glued short ends of bar onto the end grain of softwood 3 x 2 inch battens as 'handles' using Gorilla Glue, a foaming polyurethane adhesive, which after 24 hrs of curing, allows you to saw off slices or whatever in the bandsaw

Gorilla Glue is widely available.

Because it foams you need to clamp the joint to maintain contact otherwise the joint can be forced apart by the foaming action. The strength is good and it will be more than adequate to hold your bush in place

Regards

Brian

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