Aluminium angle for cassettes - warnings!

andrewnummelin
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Aluminium angle for cassettes - warnings!

Postby andrewnummelin » Thu Mar 01, 2012 8:57 pm

I've just started track laying and decided to begin with a cassette "fiddle yard" that will temporarily fit where a bridge will eventually be located. After carefully aligning the thing with a tiny bit of plain track, and levelling it across some temporary bridge supports, the time came to connect it up and try a loco on it.... excitement turned to frustration when nothing happened - as the loco had not run for a few years I did the usual and pushed it along for a bit... and it derailed!

Out with the test equipment to see what was wrong and I discovered:
- the anodised(?) coating on the aluminium is non-conductive
- the aluminium angle was not straight .

I cannot remember having read of these problems in the model press (but my memory may be failing). So be warned and take precautions before building so you won't have my problems to cure!

By the way, does any one know of an easy way to remove the anodising? A quick rub with emery paper did not suffice - a lot of elbow grease was needed to clear just a patch for the electrical clips to function properly.
And how about widening the gauge once the aluminium has been glued down? I'd laid it using two track gauges, one at each end of a 90cm section and had not noticed that the angle strips were not straight - visually they look fine but measurement shows that they are slightly bowed. 0.2 to 0.3mm each - twice that results in serious gauge narrowing!
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Andrew Nummelin

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grovenor-2685
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Re: Aluminium angle for cassettes - warnings!

Postby grovenor-2685 » Thu Mar 01, 2012 10:45 pm

I believe the normal recommendation is to buy plain (Ie non-anodised) aluminium angle from B&Q et al. But I have not seen any warnings against bent pieces before so I would assume they are not common. Easy to check in the shop before buying, same as you have to do if you buy any timber in there.
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Keith
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DougN
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Re: Aluminium angle for cassettes - warnings!

Postby DougN » Fri Mar 02, 2012 2:49 am

Interesting. I find it hard to buy anodised when I want it here in Australia. I think it is a chemical process along the lines of "blackening" steel. I do know that it is available in a number of colours usually last seen in the 1970's Ie Bronze, gold.
Doug
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Terry Bendall
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Re: Aluminium angle for cassettes - warnings!

Postby Terry Bendall » Fri Mar 02, 2012 7:35 am

Doug is quite correct and anodising is a chemical process.

I have used aluminium angle from B&Q for cassetts without any problems. For Brighton Road Barry Luck obtained some via a web source and again no problems with conductivity. The only issue that we have had is mixed sizes. Some cassettes that I made used 5/8 inch angle and the stuff that Barry got was 16mm.

Terry Bendall

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jim s-w
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Re: Aluminium angle for cassettes - warnings!

Postby jim s-w » Fri Mar 02, 2012 8:17 am

Don't forget strips of electrical tape down the outsides if you are using dcc. Picking up a live cassette gives quite a kick.

Cheers

Jim
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Mark Tatlow
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Re: Aluminium angle for cassettes - warnings!

Postby Mark Tatlow » Fri Mar 02, 2012 1:18 pm

jim s-w wrote:Don't forget strips of electrical tape down the outsides if you are using dcc. Picking up a live cassette gives quite a kick.

Cheers

Jim


Now that is a worthy warning, DCC does indeed kick off quite high ampages at 16V.

I managed to leave one of my locos with a tyre across a crossing/rail joint thereby creating a short circuit. The said loco had gibson wheels that started getting hot, started to smell and then got a bit soft and mushy. The loco now has replacement wheels and the particular wheelset that caused the problem now looks like a gruyere cheese!

To add injury to the insult, I lifted the loco to my nose to see what the smell was and touched the offending wheel rim on the tip of my nose. It was hot and I burnt the end of my nose!

Doooh!
Mark Tatlow

Steve Carter
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Re: Aluminium angle for cassettes - warnings!

Postby Steve Carter » Fri Mar 02, 2012 1:32 pm

Mark Tatlow wrote:To add injury to the insult, I lifted the loco to my nose to see what the smell was and touched the offending wheel rim on the tip of my nose. It was hot and I burnt the end of my nose!

Doooh!


Now that's almost as funny as cleaning out the hopper on a static grass machine whilst it's still charged!!!

"je repose ma valise"

Bon weeked.

Steve
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grovenor-2685
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Re: Aluminium angle for cassettes - warnings!

Postby grovenor-2685 » Fri Mar 02, 2012 5:05 pm

But on a serious note, your DCC system cut out should really prevent that, worth checking out the sensitivity.
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Keith
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steve howe
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Re: Aluminium angle for cassettes - warnings!

Postby steve howe » Fri Mar 02, 2012 6:34 pm

Mark Tatlow wrote:
jim s-w wrote:Don't forget strips of electrical tape down the outsides if you are using dcc. Picking up a live cassette gives quite a kick.

Cheers

Jim


Now that is a worthy warning, DCC does indeed kick off quite high ampages at 16V.

I managed to leave one of my locos with a tyre across a crossing/rail joint thereby creating a short circuit. The said loco had gibson wheels that started getting hot, started to smell and then got a bit soft and mushy. The loco now has replacement wheels and the particular wheelset that caused the problem now looks like a gruyere cheese!

To add injury to the insult, I lifted the loco to my nose to see what the smell was and touched the offending wheel rim on the tip of my nose. It was hot and I burnt the end of my nose!

Doooh!


Its true! he showed me the fried remains (the wheel not the nose) over breakfast at Watford...quite put me off me bacon & eggs!

Steve

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Tim V
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Re: Aluminium angle for cassettes - warnings!

Postby Tim V » Fri Mar 02, 2012 7:25 pm

jim s-w wrote:Don't forget strips of electrical tape down the outsides if you are using dcc. Picking up a live cassette gives quite a kick.

Cheers

Jim

Only one side needed, if you don't turn your cassettes round. I used masking tape, coz that was all we had one hot summer day at an exhibition.
Tim V
(Not all railways in Somerset went to Dorset)

allanferguson
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Re: Aluminium angle for cassettes - warnings!

Postby allanferguson » Fri Mar 02, 2012 9:48 pm

Its Amps wot kill you, but they need volts to push them through. I understood that DCC works on approx 16V AC. Is that enough to go through you? (I've never felt anything off the track)

Allan F

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jim s-w
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Re: Aluminium angle for cassettes - warnings!

Postby jim s-w » Fri Mar 02, 2012 11:03 pm

its not so much that Allan. Its more that the jolt makes you want to drop the cassette which is usually full of train.

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Jim
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allanferguson
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Re: Aluminium angle for cassettes - warnings!

Postby allanferguson » Fri Mar 02, 2012 11:23 pm

Ah well -- I wouldn't have thought you'd feel anything from 16V ac (but I respect the fact that people on here are speaking from experience, and I've never used cassettes). Wouldn't the power be disconnected if you were lifting the cassette? Maybe the two lengths of aluminium form a capacitor :?

Allan F

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Re: Aluminium angle for cassettes - warnings!

Postby Terry Bendall » Sat Mar 03, 2012 8:11 am

allanferguson wrote:Maybe the two lengths of aluminium form a capacitor


If it did, it would be something new in the history of electronics1 :)

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shipbadger
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Re: Aluminium angle for cassettes - warnings!

Postby shipbadger » Sat Mar 03, 2012 9:37 am

Only just read this thread but as a user of cassettes for 20 years or more perhaps some of the things we took for granted in the early days have been lost in the mists of time. Never assume any extruded aluminium is straight. There are a couple of extruders not far from where I used to work. When the section comes out of the die it runs onto roller tables. At the start of the run especially it tends to wobble it's way along in a series of S shapes. Just like buying timber you need to hold one end up to your eye. For this reason I wouldn't buy aluminium for cassettes by mail order if it could be avoided. Cleaning with a glass fibre scratch brush is required before every show and sometimes during. It's not just ordinary layout 'crud' but if unused for a period the aluminium oxidises on the surface and reduces the ability of loco wheels to pick up. Using a track rubber just adds another cleaning process to get rid of all the rubber bits afterwards. One other point, when Chris Pendelenton first described his cassetes in MRJ they were on softwood battens as were all my early ones. These have proved troublesome over the years as the wood expands and contracts accross the grain. On one particularly bad day we had to throw them into a bucket of water in the middle of a show as they had shrunk so much. I know use good quality ply with several coats of polyurethene varnish.

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Paul Townsend
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Re: Aluminium angle for cassettes - warnings!

Postby Paul Townsend » Sat Mar 03, 2012 10:02 am

Over the years there have been various reports of aluminium oxide troubles with cassettes so when I made mine I used NS rail as the running surface. In effect the rail lines the inside edge of the ally angle. Thus wheels never touch the ally but all usual advatages of cassettes achieved at cost of widening the cassette by 2 or 3mm.

I built these by screwing down one length of ally and its rail, second rail is gauged to this and held by little strips of paxolin cut to 18.83 wide and glued down. Second ally angle is then screwed down while pressed against the rails while glue is still soft.

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Re: Aluminium angle for cassettes - warnings!

Postby grovenor-2685 » Sat Mar 03, 2012 10:31 am

If it did, it would be something new in the history of electronics1

Not really, a capacitor is usually made of two sheets of aluminium separated by a dielectric, which can be air.
But the capacitance of your average cassette will be very very low, you need lots of surface area with the two sheets very close together to hold a significant charge.
Keith
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Mark Tatlow
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Re: Aluminium angle for cassettes - warnings!

Postby Mark Tatlow » Sat Mar 03, 2012 12:11 pm

Waterloo wrote:
Now that's almost as funny as cleaning out the hopper on a static grass machine whilst it's still charged!!!



Its alright Jo, we won't tell them it was you........
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Re: Aluminium angle for cassettes - warnings!

Postby Terry Bendall » Sun Mar 04, 2012 5:58 pm

shipbadger wrote:I know use good quality ply with several coats of polyurethene varnish.


The cassettes I use are described briefly on page 5 of Scalefour News 176. Although in the Beseboard sereies I have cautioned against the use of MDF, this material has worked well for these cassetts, but to be fair they are only 300mm long. On Brighton Road we use 5 foot long cassettes which are also on MDF and they have prooved to by satisfactory so far.

On making them, the important thing in my view is the pilot hole for the fixing screws. On one or two of those that I have made, the hole went off course and really the only solution is to drill a new hole in the aluminium and a new pilot hole in the MDF. I used the Roger Sanders "MINT" gauge to set the gauge of the aluminium.

Terry Bendall

andrewnummelin
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Re: Aluminium angle for cassettes - warnings!

Postby andrewnummelin » Sun Mar 04, 2012 6:30 pm

Thanks to you all for the interesting, useful and fun discussion. I've certainly learned some things to apply when I construct the next cassettes.
I've spent the afternoon with a mini-drill: steel brush to remove anodising and burr to widen the gauge - very slow and tedious but at least I have a functional cassette. Now to get on with the bit of track linked to it that I started a long time ago at Great Missenden.

I bought the aluminium angle at Homebase. I'll check other suppliers next time to get uncoated material.
The bow in the angle was certainly not visible (to my eye) when I looked along it, even with a 1m steel rule placed about 1cm away. It was only when the rule was placed tight up against the angle that one could detect a gap of a couple of tenths of a mm at one end. I had intended to post a photo but my camera has just failed!
Regards,

Andrew Nummelin

HowardGWR

Re: Aluminium angle for cassettes - warnings!

Postby HowardGWR » Sun Mar 04, 2012 8:56 pm

What's wrong with laying down a length of flexi track on a wooden cassette ('like this one I made earlier')?

I've missed a point here, I know I have but do tell me.

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Tim V
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Re: Aluminium angle for cassettes - warnings!

Postby Tim V » Sun Mar 04, 2012 9:12 pm

How do you align the end of the track to the rest of the layout?

How do you ensure the stock stays on when you lift the cassette onto its perch?

You'd better read MRJ25 :!:
Tim V
(Not all railways in Somerset went to Dorset)

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Re: Aluminium angle for cassettes - warnings!

Postby HowardGWR » Sun Mar 04, 2012 9:31 pm

Well I did, but why not just have the wood bit come up alongside the stock so it can't tip off? Connecting up, just have usual connectors.

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Re: Aluminium angle for cassettes - warnings!

Postby Terry Bendall » Mon Mar 05, 2012 7:58 am

HowardGWR wrote:What's wrong with laying down a length of flexi track on a wooden cassette ('like this one I made earlier')?


Nothing at all - just another way of doing the job. Using aluminium angle helps to stop things falling off although strips of wood along the sides woiuld do the same thing.

Tim V wrote:How do you align the end of the track to the rest of the layout?


One way is shown in the current issue of the News and that would work from a cassette to the layout. Other ways include making a "translator section" with a short length of plain track to join to the layouts and then a short length of aluminium angle, both on a separate base, and use folded over brass slipped over the fixed piece of aluminiuum and the cassette.

Tim V wrote:How do you ensure the stock stays on when you lift the cassette onto its perch?


By taking care. Having used the 5 foot cassettes on Brighton Road last weekend, things do stay on when you lift the cassestte but if it gets jogged that is another problem. I would not use cassettes to lift trains onto a sheff, nor would I use them to turn a train round. On Brighton Road, and on Ravenscroft Sidings before we changed to traversers, there are separate cassettes for the locos. This means the loco can be uncoupled, picked up still in its cassette and moved to the front of the train and recoupled to the stock. The only think that needs handling are brake vans.

Tim V wrote:You'd better read MRJ25
Well I had a look but could not see a reference. Must need new glasses. ;)

Terry Bendall

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Tim V
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Re: Aluminium angle for cassettes - warnings!

Postby Tim V » Mon Mar 05, 2012 8:07 am

I was asking Howard, not you Terry!

I only use cassettes for transport, putting the stock in a box. Here the superb advantage of aluminium over travk realy shows, by putting a strip of thick plastic down the gap, stock can be easily retailed. You wouldn't be able to do that with plain track.
Tim V
(Not all railways in Somerset went to Dorset)


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