Best glue for brass-to-brass or brass-to-plastic or brass-to-wood

[ITG]

For the new layout under construction, I’m planning on changing the way I construct remote uncoupling ramps (00). I have used servos to lift small plastic or wood ramps, and whilst they work reasonably well, I’ve found they need two tubes in line underneath the ramp, one linked to the servo and the other to stop any twist as it lifts - obviously any such twist causes derailments.

Instead of using round section plastic tube (sized to fit between sleepers), I now plan to use square section (3.96mm) brass tube that is fixed, with 3.2mm perfect fit brass tube inside it which the servo lifts. Being square, there should be no twist, and thus only a single tube per ramp.

The question is how I secure (glue) the rising hollow brass tube to the ramp, which in theory could be either brass, plastic or wood (lollipop stick). Probably wish to avoid brass ramp if possible as reluctant to have a conducting material sitting between the rails.

Being hollow (well, unless I can find right size solid tube for inner), there’s a limited surface area to bind to the ramp.

ideas please.

Ian

[ianLMS]

Brass to brass = solder if possible. Superglue works well

 

Brass to plastic. epoxy or superglue should work. I would drill a hole in the plastic and push the rod though to secure

 

Brass to wood. As with plastic. 

 

I am sure others may have better solutions but i have only used superglue, evo stick or epoxy in similar situations.  

[john new]

Could you solder an upside down copper clad sleeper to the top of the tube to form a T and then glue your slightly wider piece of plastic or lolly stick for the ramp to the uninsulated plastic/Paxolin side?  Reason for suggestion, a solid joint metal to metal for the weakest point and then a wider area for the glued surface to adhere too.

[MyRule1]

A left field option could you build a ramp out of epoxy filler and embed the tube in it?. The ramp could need reinforcing with some aluminium mesh.

Edited November 13, 2023 by MyRule1

[Izzy]

You can get square section plastic tube - plastruct - that slides one size inside the other. Some use it for under baseboard tie-bar units. Could you use that instead of brass?  Then of course just a plastic strip on top.

 

Bob

[Steadfast]

I'd go 2 part epoxy. With tube, you're potentially increasing your surface area, as the glue will secure both the inside and outside of the brass, whereas a solid rod would only have glue on the outside faces. Also epoxy isn't brittle like superglue so less likely to snap. 

 

A slight recess in the surface or a lip / peg on the surface the brass is being mounted to will help secure it too

 

Jo

Edited November 13, 2023 by Steadfast

[Hal Nail]

The suggestion of widening the surface area in brass is good but if I was sticking a brass tube to wood I'd use araldite personally.

 

Steadfast has just said exactly what I was laboriously typing!

Edited November 13, 2023 by Hal Nail

[Michael Hodgson]

If you're choosing brass to brass, then solder is by far the best adhesive. 

The plastics solutions above may be easier if you're not happy about soldering.

But if you're going to use square section tube to prevent rotation, don't forget you're going to need to get one of those special drills for drilling square holes!

[cypherman]

Hi all,

If soldering is not your thing. And I admit it is not mine a decent glue is the best way to go. This is the best superglue I have found. It sticks everything to any thing so far for me. including that horrible greasy plastic that you some times get. But I have never tried it on wood so cannot say about brass to wood.

https://www.hafixs.co.uk/products/profglue/index.html

[ColinK]

Been working on similar uncoupler with one of my friends.  We found the best solution was to use rectangular brass tube fixed in baseboard (either force it gently into round hole, or fix with epoxy.  Then use a rectangular piece of plastic inside the brass for the bit that goes up and down.  Then use polystyrene cement to stick the actual ramp on the top.  By using rectangular sections the actual uncoupler doesn’t twist round and by using plastic for the uncoupler plate it doesn’t short out the electrics.

 

This method came from suggestions on RMweb and construction of four different prototypes. All are raised and lowered by servos.  Megapoints make suitable servo control gear.  Heathcote Electronics sell a complete kit, including the ramp raising mechanism.

[Nearholmer]

 

Epoxy stick well to wood, because it “soaks in”, but sometimes forms only a weak bond with brass (which must be clean and roughened) due to lack of key (epoxy first expands, then shrinks as it sets), so try to give a mechanical key, rather than just a flat, face-to-face, contact area.

 

Overall though, I like the “mould the head in milliput” idea best!

[BachelorBoy]

12 hours ago, Nearholmer said:

(epoxy first expands, then shrinks as it sets),

I didn't know that. Makes sense. Thanks.

[woodyfox]

For a very strong bond in an awkward space with various materials I always use superglue with bicarbonate of soda either sprinkled on to the wet glue around the join or put on first before the glue. It sets very hard and can be sanded back. I've used this method to secure magnets on O Gauge vehicles to act as couplings without any failures. 

[stewartingram]

I've sometimes taken the "surface must be heavily scored" to an extreme, by actually drilling holes into either of the 2 surfaces, or both. Theory being theat the glue can't penetrate the flat surface, or have much to grab on to with a scored surface, but in passing through holes it actually sets through the surface/material..

[ITG]

Update… I tried simply driving a track pin through the centre of the ramp (I tried both plastic and wooden lollipop stick) and inserting this in the brass tube, along with a dollop of fairly standard superglue, both in the tube and around the underside of where the pin penetrates the ramp. Worked fine, it’s a solid join.

But, another couple of problems to iron out. Firstly, the inner brass tube and outer brass tube seem not be be sufficiently engineered to slide perfectly through; it slides through part way, but then sticks. This may not be a huge issue, as I’m testing with some 20cm lengths, whereas the actual length of the outer section embedded in the baseboard will only be maybe 2cm. So will just have to ensure I use the friction-free sections.

Secondly, I found the friction was made more so because the pressure in sawing the tube to the right length distorted it’s square section slightly.

Back to the drawing board…

Ian