Glue in place of welding

[silverfox]

Watching a programme about buidling a London Cab. They are using a glue that is stronger than a weld after heating

Is this available 'over the counter' and could it be used, for example, in building up tenders, cabwork etc where it could well act a a sealant as well and there is not a significant amount of stress.

Ron

They are also using a cold cure glue as well!!

[dscott]

I am now using Super Steel to stick and seal things like angle in place.
You can get it square, hold it in place, sets in 5 minutes, can scrape excess off and then drill or spot through holes without anything moving. Or in fact warping or twisting if you are soft soldering.

I feel it is worth the expense as a rusty rear to your angle weeping all down your paintwork is a terrible sight.
Not to mention far more expensive than having to strip down your locomotive to rectify later.

David and Lily.

[ettingtonliam]

I'm a bit suspicious of anything like glue claiming to be 'stronger than steel'. Remember carbon fibre? The wonder material of the late 60s and early 70s, stronger than steel, far lighter, you can do anything with it including making the fan blades for Rolls Royce RB211 jet engines. Until it came to the bird strike test which involves firing a 4 lb supermarket chicken into the engine intake when its running. Result - fan shatters, Rolls Royce collapses.

[springcrocus]

May 15, 2020 2:39:44 GMT ettingtonliam said:

I'm a bit suspicious of anything like glue claiming to be 'stronger than steel'. Remember carbon fibre? The wonder material of the late 60s and early 70s, stronger than steel, far lighter, you can do anything with it including making the fan blades for Rolls Royce RB211 jet engines. Until it came to the bird strike test which involves firing a 4 lb supermarket chicken into the engine intake when its running. Result - fan shatters, Rolls Royce collapses.

Yes, but they forgot to thaw the damn thing first.

Regards, Steve

[92220]

The greatest problem with using one of these new super-strong adhesives to fit structural parts is that, as yet nobody knows for sure, if the adhesion will degrade over time. I have some of the adhesive they use for attaching supercar bodies to the chassis. It is quite expensive, as you would expect! Interestingly though it is a 2-part mix, you don't have to mix it manually like you do 2-part Araldite. It comes in a 2-part syringe and has a detachable convoluted nozzle, that mixes the 2 parts together, in the correct proportions, as it is dispensing it.

The nozzles vary in price dramatically, depending on where you buy them from. I have seen them advertised for £13.00 a dozen, and have bought them from somewhere else, for £3.00 a dozen. As well as buying mixing/dispensing nozzles, you have to initially, buy a hand held unit for operating the syringe. I can't remember how much that one was but I seem to remember it was something over £20.00. I 'bit the bullet' and spent the money, to see just how good the adhesive was, and how easy to apply, after I had seen a TV program, last year, about how Pagani supercar bodies were assembled. It is certainly easy to use. I still have quite a bit left and will be interested to see if it has solidified over time, in the applicator, so that it is no longer usable. I did try to use it 6 months after the first trial, and I was still able to clean up the dried glue on the end of the nozzle, and start applying new glue. I would still be very wary about using it to hold anything structural on a loco though. The only time I have used superglue is to hold something in place, that I can't clamp, to drill and tap for the proper fixings.

Bob.

[barlowworks]

There was a TV program on a couple of weeks ago about Aston Martin. Their latest model is totally glued together so they must be pretty confident it can cope with the stresses of a 200mph supercar.

Mike

[mr swarf]

The Lotus Elise used an adhesive on the chassis and they've been around for over 20 years now.
Paul

[uuu]

I suppose there's a need to provide sufficient mating area in the design. So you couldn't just use glue on a butt joint which you might previously have welded - you'd need to add flanges.

Wilf

[silverfox]

I was thinking about using it for the tender The brass angle will still be used for attaching sides/bases etc, but i look at it, the less holes i drill, the less holes to leak!!

[simplyloco]

All you need to know is in this 'ere book. 
John

books.google.co.uk/books?id=9XFD8ZsZzAsC&pg=PA301&lpg=PA301&dq=Concorde+and+Araldite&source=bl&ots=-pPqRPQHBn&sig=ACfU3U1sRhhKSM0sb4cT2VbPQ8_keNBsuQ&hl=en&sa=X&ved=2ahUKEwjIiPX_xrXpAhWWUxUIHTB4BUAQ6AEwEHoECAoQAQ#v=onepage&q=Concorde%20and%20Araldite&f=false

[silverfox]

John

Thanks

The visit is still in the to do book!!!#

Ron

[Roger]

I think there's a lot of misunderstanding when it comes to adhesives. Most of the claims involve Aluminium, not Steel when it comes to strength. Even this has to be taken in context of the whole joint. Using Rivets or Welds concentrates the stresses in local areas, whereas Adhesives spread the load over a larger area. The joint may end up stronger when glued, but if you used it in local areas like you do when using rivets or welds, it most certainly wouldn't be stronger as a joint.

There's a world of difference between amateurs performing processes compared to those used by industry. You may be able to create a welded or riveted joint that's close to the strength of one done in industry, and with some confidence. The same can't be said of Adhesives. Preparation is key (pun intended), as is the housekeeping of the Adhesive, whether it's appropriate for the material, how it's mixed and applied and then cured. In industry, they make samples that go through the same process and are tested to destruction to give confidence that the joints you're creating are sound. This is the sort of thing that we need to be doing if we want to know if our joints are any good or are just cosmetic.

Don't get me wrong, I'm very much in favour of using Adhesives in Engineering. You just have to be aware that the lofty claims are by no means guaranteed when we try to emulate them. Do you really want to scrap and make the part again because your test sample proved to be hopelessly weak? These risks are minimised in industry so it doesn't happen that often. They have time to perfect and verify the process.

[rrmrd66]

May 15, 2020 6:22:01 GMT springcrocus said:

May 15, 2020 2:39:44 GMT ettingtonliam said:

I'm a bit suspicious of anything like glue claiming to be 'stronger than steel'. Remember carbon fibre? The wonder material of the late 60s and early 70s, stronger than steel, far lighter, you can do anything with it including making the fan blades for Rolls Royce RB211 jet engines. Until it came to the bird strike test which involves firing a 4 lb supermarket chicken into the engine intake when its running. Result - fan shatters, Rolls Royce collapses.

Yes, but they forgot to thaw the damn thing first.

Regards, Steve

Yes I was there! This blade test rig was part of RR Bristol Engine Division's Mechanical Research Department. The chicken was fresh from  a farm up the road. i think the farmer supplied us with pigeons and starlings for the multi barrel gun (but that's another story).If I recall correctly the "bird gun" had a 6" dia barrel. Compressed air was the medium (200psi I think) The trigger was a sheet of perspex ruptured by a .22 bullet . The thawed chicken was encased in  expanded polystyrene and all held by a steel "can"and sabot.  The polystyrene had previously been cast around the bird and then halved. At the end of this long barrel was a sprung can catcher which ensured that the can did not hit the blade. The lightweight polystyrene fell away form the speeding bird which continued into the blade. High speed cameras captured all of this. This testing for all engine compressor blades was a regular thing. The multi barrelled starling guns could also be used for hailstones - 2" diameter!The carbon fibre was as strong as steel in tension, It was the shear load of the chicken hitting the blade  that was the weakness.All this though was not as exciting though as explosively blowing a compressor or turbine blade of its disk whilst running at 110% overspeed and seeing if any metal punctured the containment shield around the engine.
CheersMalcolm

[ettingtonliam]

May 15, 2020 8:44:55 GMT barlowworks said:

There was a TV program on a couple of weeks ago about Aston Martin. Their latest model is totally glued together so they must be pretty confident it can cope with the stresses of a 200mph supercar.

Mike

Rolls Royce were pretty confident about their carbon fibre fan blades too.
Presumably the new Aston Martin will have to be crash tested before its let loose in the customers.

[chrisb]

I believe the Mz Skorpion motorcycle from the 90s used adhesive bonded tube and socket joints in the frame construction

[mattb]

There are loads of good engineering adhesives now and are common in the automotive industry. For example the BMW I3 is a carbon bonded chassis.

youtu.be/htuVoxuMQFQ?t=59

[nonort]

Hi guys I once built a water tank for a Clayton Steam Wagon I glued the corners with angle on the inside to strengthen the joint. The glue used back then was a toughened acrylic. Must say it worked very well stood on it, pumped it up with water to 50psi all ok. Finished the lorry steamed it up all honky dory. The Clayton had a feed water heater fitted so the tank rapidly got warm, by no means hot. You could place your hand in the water and keep the skin on it. Thing is the tank literally fell apart. The glue experts who sold me the adhesive said we sell this to a Hovercraft company we better tell them about this? I don't know what happened after this incident. What's that caveat empor thingy.

[kipford]

insert quote here

Rolls Royce were pretty confident about their carbon fibre fan blades too.

Presumably the new Aston Martin will have to be crash tested before its let loose in the customers.


The RB211 failure was 49 years ago now, technology and knowledge has changed significantly since then. In 49 years Aviation evolved from a stringbag at Kittyhawk to the genesis of supersonic passenger flight and space travel, so to the use of glues and composites. As mentioned Lotus have been using glued joints on the Elise chassis since its introduction in 1996 nearly 25 years without any known major joint delamination failures. F1 cars have used fully composite carbon fibre chassis since John Barnard pioneered it on the Maclaren MP4 in 1981 and these have saved countless lives since then. If you are still worried then don't fly in a commercial airliner because substantial parts of the critical structures in most airliners now flying are of composite construction. As Roger says the industrial use of glues and composites are well understand by engineers, how to design with them and the conditions and processes required too manufacture repeatable safe products. I spent all my working life in the aerospace industry and good proportion of it using composites and the biggest problem we faced is people not understanding glues only work in shear and that carbon fibre or indeed any composites is not black metal.
Dave

PS They do not use chickens these days, they use ducks for the large bird strike requirements. Chickens do not fly high around airports so are not representative. We used to use Aylesbury ducks as they had a medium bone density in the duck world.

Dave

[jackrae]

May 15, 2020 13:06:23 GMT kipford said:

insert quote here

the biggest problem we faced is people not understanding glues only work in shear

Totally irrelevant to the main subject matter but when I started uni in 1966 we were all fascinated by the new-fangled PVA glue sticks we bought from the college stationery shop. Lots of experiments done over pints of beer to establish the strength of a very narrow lap joint between two sheets of paper. When stressed in shear the joint would support major forces yet would simply peel apart under tension.