Marking out fluid?

[mark costello 1Participant @markcostello1]

On the Internet there is a video of a (ship) large machine shop, large machinery and all that. They show a connecting rod with it's centers laid out with some white lay out fluid. Does Anyone know what They used and is it suitable for a home shop? It looked like it was applied with a house painting brush.

[mark costello 1Participant @markcostello1]

[Brian WoodParticipant @brianwood45127]

I don't know but would hazard a guess at lime wash.

I use a black spirit marker pen in my shop, have done for years.

​Brian

[KWILParticipant @kwil]

You could always search for it in the usual way. "Marking out fluid"

[Speedy Builder5Participant @speedybuilder5]

Brian, sounds like a "White Wash" to me !! In olden paint technology (before emulsion paint), what was distemper ?
BobH

[KWILParticipant @kwil]

A viral infection in dogs?

[Brian HParticipant @brianh50089]

From my (long ago) apprentice days, on castings we used French chalk mixed with water or, for a quicker drying time, French chalk mixed with cellulose thinners, both applied by paint brush.

Brian

[SillyOldDufferModerator @sillyoldduffer]

Used for marking out black steel (or anything else dark). Blue is better for shiny metals.

The old boys used acidified copper sulphate solution to lay down a copper coat, which should be good on both black and shiny steel. Possibly copper went out of fashion because it doesn't work on non-ferrous alloys. Does anyone know?

Dave

[not done it yetParticipant @notdoneityet]

Like another current thread, copper sulphate is reeelly dangerous. It is a poison. Probably not allowed to grow copper sulphate crystals in school science classes these days, even though we used to do it without any problem 50 years ago.

[JasonBModerator @jasonb]

On castings I sometimes give then a squirt of white or grey primer from a can, shows marked lines quite well as the darker CI shows through when scribed.

[mechman48Participant @mechman48]

I use a black marker pen for my marking out, cheap & readily available & doesn't flout elf 'n safety regs.

George.

[Martin ConnellyParticipant @martinconnelly55370]

Rocol have a white layout dye for use on dark materials.

Martin C

[Nick_GParticipant @nick_g]

Posted by mechman48 on 15/07/2017 19:04:01:

& doesn't flout elf 'n safety regs.

George.

.

Nick

[mechman48Participant @mechman48]

Oooops… go on…tell me it's a dummy ?…

George.

[SillyOldDufferModerator @sillyoldduffer]

Posted by not done it yet on 15/07/2017 18:03:49:

Like another current thread, copper sulphate is reeelly dangerous. It is a poison.

…

Only a poison if you manage to eat at least a teaspoonful of vile tasting blue crystals. True the solution irritates skin and eyes but I'd say it's not as dangerous as bleach.

Copper Sulphate might have been knocked on the head for H&S reasons but I doubt it. My modern bottle of Dykem Blue is plastered in scary warnings. Apparently it might damage my fertility. Good job I'm past it!

Dave

[Brian OldfordParticipant @brianoldford70365]

Posted by SillyOldDuffer on 15/07/2017 20:21:49:…. . . . . . . .

. . . . . . .. Good job I'm past it!

Dave

In my case the chance would be a fine thing.

[Jeff DaymanParticipant @jeffdayman43397]

On the Internet there is a video of a (ship) large machine shop, large machinery and all that. They show a connecting rod with it's centers laid out with some white lay out fluid. Does Anyone know what They used and is it suitable for a home shop? It looked like it was applied with a house painting brush.

In the machine shop I started in as a kid, they machined a lot of castings and forgings. The machinists used a mixture of chalk and methyl hydrate or wood alcohol for the marking out. It was brushed on and dried fast. That shop dated to the 1870s (as it seemed some of the machinists did too, but obviously not, in late 1970's). Lots of the practices used probably dated way back as well. Many of the machines were flat belt drive by modern electric motors. Originally it was all line shaft drive to all machines, but this was mothballed sometime in the 1950's for safety reasons, and the individual motors were fitted. One machine still had an original 50 HP DC motor and mercury pool rectifier in a glass vessel about the size of a bathtub. Scary to watch, but it worked.

Edited By JasonB on 16/07/2017 07:26:58

[Harry WilkesParticipant @harrywilkes58467]

Not wishing to 'highjack' the thread but I have some copper sulphate what's the best way to make it into a usable marking out solution ?

Cheers H

[SillyOldDufferModerator @sillyoldduffer]

Posted by Harry Wilkes on 15/07/2017 21:24:12:

…

I have some copper sulphate what's the best way to make it into a usable marking out solution ?

Cheers H

Newnes Complete Engineer says 'Add as much Copper Sulphate as will dissolve in a medicine bottle of water, preferably distilled. To this solution add 10 to 20 drops Sulphuric Acid. The surface of the work must be wiped free from oil and grease and the solution applied with a clean rag. A light coppered surface will be produced, which, when dry, provides a good base for marking out lines. If the surface is not very clean a light rub-over with emery cloth will provide better results. Great care must be taken to avoid getting the liquid into cuts and wounds, as the solution is very poisonous, and the hands should be washed after use."

A few points:

• Take care, wear gloves, it looks like NDIY was quite right to say it's poisonous.
• A medicine bottle is probably about 100ml
• One type of DIY Store / Plumber liquid drain unblocker is mostly strong sulphuric acid. Nasty stuff, not to be spilled, or got on flesh. Use a pipette to transfer the 20 drops rather than tipping the whole bottle to get a small quantity out. Unwanted acid can be disposed of down a drain but see the instructions. Whenever I use drain cleaner I open the bottle in a sink and have a large bucket of cold water handy just in case.

Dave

[Harry WilkesParticipant @harrywilkes58467]

Thanks for the info Dave

H

[Russell EberhardtParticipant @russelleberhardt48058]

Posted by SillyOldDuffer on 15/07/2017 20:21:49:

Only a poison if you manage to eat at least a teaspoonful of vile tasting blue crystals. True the solution irritates skin and eyes but I'd say it's not as dangerous as bleach.

Agreed, if you drink wine the vines have probably been sprayed with Bordeaux Mixture. That's a mixture of slaked lime and copper sulphate and is used to prevent milldue.

Anything is poisonous if consumed in sufficient quantity.

Russell

[MuzzerParticipant @muzzer]

Check out the LD50 for copper sulphate (300mg/kg) and sodium chloride (3000mg/kg). Perhaps you wouldn't sprinkle copper sulphate on your corn flakes but it's hardly going to make you drop dead at first touch.

There is no simple definition of "toxicity" and there are many forms. Some are due to the cumulative effects of heavy metals etc interfering with nervous system, some like salt can cause overloads of "normal" intake, some (ionising radiation and carcinogens) can cause insidious mutagenic damage, some (carbon monoxide etc) can interfere with intake of oxygen etc. And many "toxic" substances are essential for life – in small quantities.

Sodium hydroxide (oven and drain cleaning) would be just as unpleasant as acid if used as a weapon and is readily available.

Murray

[not done it yetParticipant @notdoneityet]

Plumber liquid drain unblocker is mostly strong sulphuric acid. Nasty stuff, not to be spilled, or got on flesh

 

As is often the case, some (possibly most) people don't know the difference between strong and concentrated with reference to these chemicals (acids or bases). Strong means well dissociated into ions when in solution (usually aqueous). Weak means the opposite (pH is a measure of acidity or alkalinity), while concentrated (or dilute) refers to the percentage of the compound (usually mixed with water, if less than 100%) in the substance/mixture.

 

Sulphuric acid as used for drain cleaning is concentrated. Pure acids are not necessarily ' strong' acids until water is present. Concentrated sulphuric acid has a very strong affinity for water, so removes water from anything it contacts – your skin suffers from both aggressive water removal and then strong acid reaction. Concentrated sulphuric acid will reduce sawdust to a morass of black carbon, whereas nitric acid will set sawdust on fire (as it is an oxidising agent as well as an acid.

Know your chemistry.

Oh, and btw, copper sulphate can kill you but it also can affect the nervous system in far smaller quantities.  A bit like lead poisoning, except that high blood concentrations of lead are more easily dealt with, by medics, than copper poisoning.

Edited By not done it yet on 16/07/2017 12:22:43

[SillyOldDufferModerator @sillyoldduffer]

Posted by not done it yet on 16/07/2017 12:10:44:

Plumber liquid drain unblocker is mostly strong sulphuric acid. Nasty stuff, not to be spilled, or got on flesh

…

Sulphuric acid as used for drain cleaning is concentrated. Pure acids are not necessarily ' strong' acids until water is present.

…

Concentrated sulphuric acid will reduce sawdust to a morass of black carbon,

…

Edited By not done it yet on 16/07/2017 12:22:43

Ah but I don't believe that drain cleaner is concentrated Sulphuric Acid in the 'know your chemistry' sense. Compared with the real thing acid drain cleaner only has a mild charring action on paper.

The label on 'One Shot Instant Drain Cleaner' says it 'contains' 91% w/w Sulphuric Acid, not that it 'is' 91% w/w Sulphuric Acid. It has an unusual purple colour and I'm pretty sure it's not full strength.

My guess is that it's mostly Sulphuric Acid, but is somewhat diluted plus dye and possibly some other chemicals to help clean the drain.

Challenge for Home Scientists: determine how strong the acid really is in drain cleaner. If I've got any washing soda and a beetroot I might have a go. (I'm supposed to be painting a gate but it's soooo boring.)

Dave

[mechman48Participant @mechman48]

Posted by Brian Oldford on 15/07/2017 21:00:43:

Posted by SillyOldDuffer on 15/07/2017 20:21:49:…. . . . . . . .

. . . . . . .. Good job I'm past it!

Dave

In my case the chance would be a fine thing.

​… what you guys talking about… what I used to do all night … then took me all night to do… now…

Geo.

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