Old poster re-appears....

G'day Gentlefolk,
I bring you greetings from about 5 years ago, which may well be the last time I posted on this group.
I made the mistake of moving house in 2002 - getting the workshop back together wasn't a problem but finding the time to actually do any modelling has been (a side-trip into the wonderful world of vintage tractors didn't help).
I did build a Worden (<http://www.bobunitt.me.uk/worden/worden.htm ) a couple of years back, but I have to admit that it was so I could sharpen tools to mend bits of tractor... Come to think of it, I may have posted here then - I can't remember, and any such posting will have long since expired on my PC.
I went the show at the Fosse on Friday mainly to get some paints, but thoroughly enjoyed the whole day. There were many fine models as usual - I was particularly taken with the BSA sidecar Taxi. I managed to keep the moths safe in my wallet for most of the time, although one or two did escape towards John S (who recognised me, surprising as we only ever met once, and that was in the previous century...) and at the paint stand.
However, I'm now attempting to 'return to the fold'. I had 85% completed a 'Lady Stephanie' (<http://www.bobunitt.me.uk/steph/steph.htm ) before I moved, which has now receded to 80% (various bits didn't survive the journey), but which I've resurrected in a desperate attempt to get it finished before senility finally sets in.
In order to 'get my hand in' again before re-starting the Lady, I made a model of a 17th century mortar (<http://www.bobunitt.me.uk/mortar/mortar.htm ) .
I have two problems :-
1) A brown patina on the steel bits of the lady. It's definitely not rust, as it comes away leaving the original steel surface when attacked with 000 wire wool. I assume it's a residue of the oil (mainly 3-in-1) with which I coated it to prevent rust before moving. It's not an issue with the larger pieces, but some parts (e.g. governor linkage, valve levers) are just too fragile to clean mechanically. Can anyone suggest a suitable liquid which will remove it without damaging the steel and brass ?
2) It was my intention to leave the mortar unpainted, coating it with varnish or lacquer for protection. When I went to the 'Precision Paints' stand at the show on Friday, I was told that EU regulations now forbid the production of the relevant lacquers, and they had not yet found a viable alternative. Can anyone either point me to a supplier of a suitable product, or provide a recipe so I can make my own ?
If anyone is undecided whether to go to the show by the way, I would heartily recommend it - and you might even got a bit of sunshine thrown in !
--
Bob Unitt (UK)

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On Sat, 18 Oct 2008 16:24:28 +0100, Bob Unitt

Congratulations on your work, it all looks good, and not a thin slot screw in sight <G>
Problem 1 I cannot help you with though I would at least try a soak in todays equivalent of "Trike"
Problem 2 I thought that "Rustins" Clear Metal Laquer was still available. I have 1/2 a bottle if you cannot find it. I am in Cheltenham.
Going to the show tomorrow.
Richard
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Richard,
>On Sat, 18 Oct 2008 16:24:28 +0100, Bob Unitt
>>I have two problems :- >> >>1) A brown patina on the steel bits of the lady. --- Can anyone >>suggest a suitable liquid which will remove it without damaging >>the steel and brass ? >> >>2) It was my intention to leave the mortar unpainted, coating it with >>varnish or lacquer for protection. -- -Can anyone either point me to >>a supplier of a suitable product, or provide a recipe so I can make >>my own ? >

Can't abide them, they engender nothing but discord. :-)

I don't know what constitutes the modern equivalent of "Trike". My initial encounter with Triclorethylene was at my first job as a pale and callow youth in the 60's. The factory I worked in had a big hot-tank of trike accessed from a set of wooden steps (no hand-rail). Nobody had bothered to tell me that breathing trike fumes through a burning cigarette was a bad idea (phosgene ?) - fortunately, when I passed out, I fell backwards off the steps rather than forward into the tank...
My wife has subsequently suggested Coca-Cola or HP Brown Sauce - I'll report back in due course.

I don't know how I managed to miss this when I google'd - must have got the search-terms wrong. It would appear to be readily available from any number of mail-order places, but I'll try the local hardware shops first.
It's advertised as being suitable for copper, brass, stainless steel etc., do you happen to know if it works on mild steel as well ?

Thank you for your kind offer, but it looks as if I'll be able to get it fairly easily.
>I am in Cheltenham.
I'm not very far away - Hereford.

I hope you enjoy it as much as I did.
--
Bob Unitt (UK)

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On Sun, 19 Oct 2008 14:12:56 +0100, Bob Unitt

You could try 'brake cleaner' or 'carb cleaner' from a motor factors.
Tim
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Tim L wrote:

ordinary brake fluid will dissolve some surprising things .. or maybe try cellulose thinners, or xylene (all available on eBay)
-- Peter Fairbrother
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On Sun, 19 Oct 2008 16:59:33 +0100, Peter Fairbrother
....especially large areas of paintwork on the body and bonnet of a brand new car......if some prat leaves the reservoir cap off - DAMHIK. :(
--
Chris Edwards (in deepest Dorset) "....there *must* be an easier way!"

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Oops...
--
Bob Unitt (UK)

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Bob Unitt wrote:

I heard a similar suggestion at rec.crafts.metalworking. Someone said that automatic transmission fluid works as a paint stripper. What is in it which causes this effect, because plain oil doesn't normally dissolve paint, does it?
Best wishes,
Chris
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On Sat, 25 Oct 2008 16:48:34 +0000, Christopher Tidy

    I can't answer your question directly, but I know we have chemists about who probably can. The car was a one-day old Austin Healey Sprite......my pride and joy, and the brake or clutch fluid reservoir cap was left off during pre-delivery checks. It was a long time ago and I forget which.....but the car needed an engine-out complete respray.
    Of course, I should have spotted the problem myself....but I was young and it was a Sprite....!!
--
Chris Edwards (in deepest Dorset) "....there *must* be an easier way!"

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On or around Sat, 25 Oct 2008 16:48:34 +0000, Christopher Tidy

I thought it was brake fluid that did that. Certainly has on anything I've seen it leak onto.
--
Austin Shackles. www.ddol-las.net my opinions are just that
Travel The Galaxy! Meet Fascinating Life Forms...
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Reporting back after a few simple experiments...
I tried Coca-Cola, table salt dissolved in distilled vinegar and HP sauce.
The Coca-Cola did nothing.
The salt dissolved in vinegar slowly attacked the brown discolouration so it could then be removed by wiping gently with a paper towel.
The brown sauce behaved similarly, but to a lesser degree.
Adding a little brown sauce to the salt-and-vinegar mix seemed to speed things up. This mixture also cleaned up brass components without visible damage.
Problem solved, and the solution(*) is even organic !
(* - deliberate pun)
--
Bob Unitt (UK)

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Hi Bob,
Yes, I remember you. You've been here more recently than 5 years ago, because I didn't come to the group back then. Anyway, welcome back!
You very kindly offered to help me make a left-handed BA screw for an air raid siren I was restoring. I'm afraid that, like you, I haven't made a lot of progress with projects recently. I couldn't find a company that would make a replacement rotor for the siren at a good price, so the project has stalled for the moment. However, hopefully it will be resumed when I have more cash.

I would try white spirit, and if that doesn't work try paint stripper. I don't believe either will harm the metal.
Best wishes,
Chris
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Thanks.
I remember now - do you still need the left-hand screw ?
>> 1) A brown patina on the steel bits of the lady. <SNIP>

A mixture of salt and vinegar worked in the end - but I now have a rather smelly workshop...
--
Bob Unitt (UK)

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Bob Unitt wrote:

Yes, although not urgently. The project is on hold until I can find a company that will make a rotor fairly cheaply, or until I make enough money to pay for an expensive one!
I don't want to put you to any trouble until I've formed a plan for getting a new rotor.
Best wishes,
Chris
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Be careful with paint stripper and brass. If it's the 'Nitromorse' (methylene chloride?) type it will probably discolour the surface by whipping the zinc out and leaving it noticably copper coloured. It's not 'mechanical damage' s it's only a couple of microns deep, but you will see the colour change. DAHIKT
Rgds Richard
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It's not the methylene chloride that damages brass, it's the caustic soda (sodium hydroxide).
Cliff Coggin.
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On Thu, 23 Oct 2008 12:24:57 +0100, "Cliff Coggin"

I haddn't realised there was causic soda in Nitromorse, makes more sense now.
Cheers Richard
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Richard Shute wrote:

There isn't.
There are now two types of Nitromors, Superstrip and Surestrip -- and neither contains caustic soda. The formula(e) for Nitromors has changed many times over the years, but I don't think it has ever contained caustic soda.
Caustic soda is of course a superior paint remover, far better than Nitromors if the base material is compatible :)
A formula I once developed for stripping wooden furniture:
1lb caustic soda 3lb cheapest flour
mix, add water with stirring, to medium paint consistency.
Paint furniture with mixture, wrap in wet newspaper, cover with clingfilm. wait 2 hours - then remove everything, including old paint.
Wear rubber gloves, apron, eye protection, and so on - caustic soda is .. well, caustic. It'll burn holes in you if you let it.
-- Peter Fairbrother
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Richard Shute wrote:

There isn't.
There are now two types of Nitromors, Superstrip and Surestrip -- and neither contains caustic soda. The formula(e) for Nitromors has changed many times over the years, but I don't think it has ever contained caustic soda.
Caustic soda is of course a superior paint remover, far better than Nitromors if the base material is compatible :)
A formula I once developed for stripping wooden furniture:
1lb caustic soda 3lb cheapest flour
mix, add water with stirring, to medium paint consistency.
Paint furniture with mixture, wrap in wet newspaper, cover with clingfilm. wait 2 hours - then remove everything, including old paint.
Rinse, or preferably hose down with water.
The wood may have turned a grey/black colour, but it will regain it's natural colour in about three days if left in air and roomlight.
Wear rubber gloves, apron, eye protection, and so on - caustic soda is ... well, caustic. It'll burn holes in you if you let it.
-- Peter Fairbrother
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Those apostrophes are gone for ever though. If only we could collect the redundant ones and cash them in for air miles or summat.
--
Dave Baker



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