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Member postings for Graham Stoppani

Here is a list of all the postings Graham Stoppani has made in our forums. Click on a thread name to jump to the thread.

Thread: electrolytic derusting
11/05/2022 14:28:30
Posted by SillyOldDuffer on 08/05/2022 09:59:54:
Posted by Graham Stoppani on 08/05/2022 06:28:32:

In this process the electrolyte doesn't change. The paint loss is either due to the metal underneath it being eroded away on the sacrificial anode or possibly by the oxygen bubbles being formed.


Partly , but Washing Soda (Sodium Carbonate) is a junior paint-stripper in its own right. Washing Soda and Caustic Soda are both alkalis, which attack grease and oil.

As many paints are held together by a drying oil, they can be stripped by an alkali - it destroys the binding agent and the paint falls apart. Caustic Soda works faster because it's strongly alkaline, but Washing Soda would loosen paint even if the power wasn't turned on as well!

Might even be essential. I think what's happening is the paint surface is first penetrated by the Soda, allowing electrolytic effects to develop behind the paint and at edges, thus accelerating it's separation by removing the supporting metal and levering flakes off with microbubbles.

Probably best to start by removing paint first because it weakens the mix, slows down the main attack and is a bit messy, but I don't suppose it matters much!


Did I mention that I used to be Managing Director of Turco Products Ltd? Manufacturer and supplier of paint strippers to the aerospace industry? wink Not disagreeing with what you say, just keeping it simple for the OP.

Thread: Motorcycle General Discussion
11/05/2022 07:16:11

Talking of favourite motorcycle photos:

Ruben Xaus, knee down, sliding and spinning the back wheel - while giving a thumbs up.

This to me is the visual expression of Hunter S. Thompson's words,

“Life should not be a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside in a cloud of smoke, thoroughly used up, totally worn out, and loudly proclaiming "Wow! What a Ride!”


Thread: electrolytic derusting
08/05/2022 06:28:32

In this process the electrolyte doesn't change. The paint loss is either due to the metal underneath it being eroded away on the sacrificial anode or possibly by the oxygen bubbles being formed.

simple explanation Link

long winded explanation Link

Thread: Galvanic Corrosion
01/05/2022 05:59:07

Horses and barn doors, but this might help at re-assembly time. We used this or something similar on my father's yacht.


Following up on the Plusgas suggestions (I use it as well) looking at the SDS it is mainly kerosine. Other organic solvents worth a try if you have them to hand. Diesel, a bit stinky but I've seen stuff left to soak in this for a few days getting released eventually. I've also seen toluene and xylene suggested on line. Haven't tried these but you've probably got some around in the form of brake or carb cleaner or paint solvents.

In all cases thinks in days rather than hours for the stuff to do its work.

Thread: Central Heating Control
16/04/2022 06:39:05
Posted by John Doe 2 on 15/04/2022 09:28:36:

I hope to install a system working on similar principles to our next house - it needs an extensive make-over so I hope to be able to install suitable ducting as I go, along with a heat recovery system on the bathroom and kitchen extractors.

We have such a system installed. Mechanical Ventilation Heat Recovery (MVHR) The bedrooms and living rooms have outside air ducted into them through ceiling vents while the kitchen, toilets and bathrooms have similar vents extracting air. The two systems pass through a heat exchanger that recovers about 60% of the heat.

The benefit is that the in coming air is filtered, and living in a bungalow we have the added security of not needing to open any windows. The down side is that it makes it slightly more difficult to keep rooms at different temperatures.

Thread: Financial surnames
05/03/2022 11:10:39

As a teenager opening my first bank account in the 70's I was interviewed by the local branch manager of Barclays to see if I was worthy of their services... When the manager asked me why I'd chosen to bank with them, I confidently replied

"Because may father barks at Banklays!" doh!

Edited By Graham Stoppani on 05/03/2022 11:34:51

Thread: Railway station toilet signs
05/03/2022 11:05:38

Saw this sign on the toilet lid when travelling by train last year

toilet sign.jpg

Thread: Songs about Engineering
26/02/2022 07:39:28
Posted by Andy Stopford on 23/02/2022 20:09:25:

For a problematic interface between man and machine, how about "The Widowmaker" from "Captain Lockheed and the Starfighters"?

Come to think of it, "Death Trap" by Hawkwind describes mechanical failure

bloody radar crew.jpg

Edited By Graham Stoppani on 26/02/2022 07:45:55

Thread: Metal Cleaning Using Vinegar?
20/02/2022 11:38:47
Posted by noel shelley on 20/02/2022 11:24:39:

Graham, purely on a note of safety, they look like nyloc nuts and as such should not be reused ! Noel.

You're right Noel. They were destined for the bin anyway so I thought I'd just experiment on them on their way there.

Thread: Front door locks
20/02/2022 07:22:11


I have previously worked for an organisation providing pendants and associated services to the elderly as well as using the same organisation's services for my own father.

On the plus side, I have never heard of a key being stolen from a properly installed key safe. It is also useful to place the key safe in a less obvious place that right next to the front door.

On the down side, in our experience basic pendants are not very useful for clients with advancing dementia. Unfortunately, they forget to use them in case of emergencies or falls. More advanced systems are available that purport to be able to identify if the wearer has fallen or not moved for a time. I have no practical experience of the latter type.



Thread: Metal Cleaning Using Vinegar?
20/02/2022 07:09:37

While restoring a bike I had five identical rusty nuts taken off a sprocket carrier so decided to do a little experiment. Keeping one nut back as a control item I tried 4 different acid solutions overnight in an unheated garage to see what the comparative results where.

The picture below shows the control item at the front and from left to right:

  • 14% sulphuric acid solution;
  • Gateros acid salts made to recommended solution strength;
  • White vinegar (5% acetic acid); and
  • Citric acid crystals made up to 3 heap teaspoons in 200ml aprox water.


The results show that the vinegar was the least effective with the sulphuric not much better. (As a side note sulphuric acid tends to be more reactive with organic materials than metals compared to hydrochloric acid. Harpic toilet cleaner contains hydrochloric acid and can be used as a mild metal cleaner.) The Gateros product left a dark tarnish.

The clear winner was citric acid. It was also the cheapest, costing £5.39 for a kilo from eBay.

As all four products reduced the rust there were no losers and leaving the nuts to soak for longer or in a warmer environment would also have improved the results.


Thread: Calculator App
17/01/2022 10:12:23

If you have MS Excel either on your phone or PC it easily converts fractions to decimals and back.

For example, format cell A1 as a fraction and enter 15/16. Put =A1 in cell B1 and voila it gives you the decimal equivalent, 0.9375 (rounded to 4 decimals places - more if you want).

You can work the other way by formatting A2 as a fraction and entering the formula =B2. Any decimal you then enter in B2 is converted to a fraction. You can also specify how the spreadsheet will convert decimals that are not an exact equivalent to a fraction to the nearest 1/4, 1/10, 1/16, etc up to 3 digits 1/999.

Thread: The Bistella motorcycle
25/12/2021 08:19:35

Most of the time "custom" bike builders are just adding someone else's prefabricated parts to a bike. More project manager than engineer. But this guy gives Alan Millyard a run for his money. Thanks for sharing.

Thread: 2021 Christmas Cracker-ish humour
20/12/2021 06:20:33

Q: What's round and sounds like a trumpet?

A: A crumpet!

Thread: Motorcycle General Discussion
10/10/2021 09:31:10
Posted by Mike Poole on 08/10/2021 09:24:33:

Keith Code wrote some interesting books on motorcycle handling and riding, I loaned mine to someone and I don’t think I will see them again.


Had the pleasure of Meeting Keith Code when doing the California Superbike School at Silverstone in 2011



And this is me trying to put it all into practice!


Thread: Steel Prices
13/08/2021 07:27:09

My neighbour's mum works in sales for British Steel and she mentioned that stuff she used to sell for £700 a tonne is now going for £2,000 a tonne.

I asked her if she ever had off-cuts for sale. She said yes but to her an 'off cut' is a 6 metre length!

Thread: Moving machines
21/06/2021 07:53:36

I used an hired engine hoist when putting my Warco Minor mill/drill on its stand. I also purchased a lifting strap from Machine Mart rather than risk using ratchet straps or such like.

Thread: Appropriate grease for milling Spindle
19/06/2021 08:26:34

When I bought my round column milling machine I found that the top of the two taper bearings was running bone dry and the lower bearing was nicely lubricated with the grease that had melted and dripped down from the top bearing! So I would recommend a grease that has a higher melting point. I'm currently using a Castrol LM grease and haven't seen any evidence of it melting so far.

Thread: Etching Aluminium
14/06/2021 05:43:52

In a previous life I was Managing Director of Turco Products Ltd. manufacturers of etchants and maskants for the aerospace industry. A process we called 'chemical milling'.

Googling Turco and Chemical Milling will bring up a fair bit of information for you Neil.

The etchants had a basic ingredient of caustic soda with a number of additives. (In a similar way a plating bath has additives to modify the basic chemistry for a better finish). The maskants were made from a mixture of toluene, rubber and chalk.

Can I second the warning to keep well clear of hydrofluoric acid. The pills referred to are to replace the calcium that this leached from your bones and we instructed staff to start taking them straight away if they came into contact with the acid. Nasty stuff. The rare times we used this in our manufacturing process the operatives had to wear full haz mat protection.

Thread: Lack of material and prices
11/06/2021 06:46:00

I was talking to our heating engineer yesterday and he said that he was working on a building site when word went around that some wood had arrived at the local stockist. To a man, all the chippies downed tools and jumped in their vans.

Seems that wood may not grow on trees after all. cheeky

Friends of mine that own a small manufacturing company have seen the price of MDF jump by 40%

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