Scraping Blue?

[Andrew TinsleyParticipant @andrewtinsley63637]

Hello,

I now have a good master surface plate and some old Eclipse scrapers. I am stuck for engineers blue! I used to have the paint on variety, but it seems this has been replaced by an aerosol type which dries very quickly.

When I first learned a little scraping some 35 years ago. I used some red material which I think was red lead and castor oil? This was excellent for doing the "rubbing in" and finding the high spots.

If anyone still does scraping what "marking" material do you use? Is the spray on stuff any good? It is fine for marking out, but I doubt it has the same power of moving around under the rubbing action.

I would like to use the red lead and whatever the organic liquid was, which I used to use. has anyone got the make up of that stuff?

Thanks,

Andrew.

[Andrew TinsleyParticipant @andrewtinsley63637]

[MWParticipant @mw27036]

Hi Andrew,

I believe the spray on stuff you're referring to is what's known as layout ink, it also comes in ink bottles, sometimes with a brush and it's precisely like you said, just for scribing lines.

The stuff you want is stuarts micrometer marking paste, which is used to find contact points and high spots on surfaces for scraping.

There's a link here to ARC, I bought a tin of it once but it seems they now sell in this tube instead. 

http://www.arceurotrade.co.uk/Catalogue/Protection-Grease-Adhesives/Engineers-Blue

Michael W

Edited By Michael-w on 15/05/2017 17:29:43

[Russ BParticipant @russb]

Andrew,

I would go with a mixture of cement pigment and an oil of your choice (I go with ISO 32 hydraulic oil as I have plenty)

This way you can go for whatever colour better contrasts the base metal, and also use the two colour method if you prefer, where you'd apply a bright colour like red to the part, and roll blue (or black for me) on the table and take a rub – this way, when you get a high spot that rubs through the blue, your high spot is clear, and your low spots are red, so it's easier to spot the highs – as with single colour method, highs and lows are clear!

If that makes sense………

I love hand scraping – I'd challenge any surface grinder to beat the finish, but I have arthritis, so I'm now only doing it when essential for myself as I need to make my wrist last as long as possible or I'll not be doing anything!

[SteveIParticipant @stevei]

Hi,

 

I am using this:**LINK**

 

It is water based. So easy to clean and keep the blue off of other things. I find it is different enough to the stuarts micrometer blue that you'll have to experiment a little bit at the beginning. I don't get on well with the stuart's too messy and harder to get a good print.

 

Having said that I have no idea where to buy that volkcorp product in the UK. I think it is not CE marked so I get it hand delivered from the USA. The other option for water based is the "dykem high spot". Again I got mine via the USA.

I have some yellow ink as well as the blue. This is used as a highlighter and it makes seeing what you are doing easier when you get towards the end of the work. These USA options are well referenced over on the PM forum.

 

Having tried the water based I wouldn't ever go back to the Stuarts. They don't last forever though after a few years the die seems to collect into tiny pellets and it spoils the prints.

 

It would be nice if some enterprising company started to import the water based solutions.

 

 

Steve

 

 

Edit – to add a picture of the water based spotting ink

Edited By SteveI on 15/05/2017 18:49:11

Edited By SteveI on 15/05/2017 18:50:06

[Brian HParticipant @brianh50089]

Quote"When I first learned a little scraping some 35 years ago. I used some red material which I think was red lead and castor oil? This was excellent for doing the "rubbing in" and finding the high spots."

As an apprentice some 60 years ago I can remember scraping in bearings using red lead. We used to scrape brass bearings between 6" and 16" using a dummy journal to get it close so that customers' would have little work to finish them to suit the engine that they were refurbishing. We then finished them with a criss-cross pattern that we were told was to retain a small amount of oil whilst running-in and if the pattern didn't look good to the foreman we had to carry on until he was happy!

Brian

[Chris Evans 6Participant @chrisevans6]

As stated you need Stuarts micrometre blue, the last few tins I have bought have been far to wet to use so I have resorted to the "Red Stuff" to which you refer. It is made up using jewellers rouge and a medium oil. It is a bit harder to clean off but better than wet blue.

[JasonBModerator @jasonb]

If your Stuarts is too oily put a bit onto some stiff card (business card) and leave for a few mins, the card will soak up the oil and you will have a better blue to use.

[Brian HParticipant @brianh50089]

Prussian blue oil paint in a tube from artists suppliers is suggested on some USA sites but it must be oil and not acrylic,

Chris Evans suggestion of Jewellers rouge and oil strikes a chord in my memory and shouldn't be too had to obtain in small quantities.

Brian

[Alan VosParticipant @alanvos39612]

Posted by Michael-w on 15/05/2017 17:27:31:

There's a link here to ARC, I bought a tin of it once but it seems they now sell in this tube instead.

I can see why. I bought the tin, for value. When it arrived, I wished I had bought the tube. Not ARC's fault, but the courier process almost inevitably means that a fair quantity of the blue transfers to the lid, which make an almighty mess when opened. To make it more manageable, I pulled some into a small syringe. That is *much* better.

[Andrew TinsleyParticipant @andrewtinsley63637]

That is a very interesting set of replies, seems the Stuart blue is a favourite . Not sure about going to the trouble and expense of importing it from the US though. I have a friend who has a house in the US and regularly commutes. Maybe I could get him to bring some back if I can find a retail outlet in the States!

I could have sworn that the stuff I used all those years ago was red lead, However I have some jewellers rouge and plenty of oil so I can make some up! Just a bit leary about the abrasive properties on my nice master plate!!!!

I have never heard of the two colour method before, it sounds intriguing. I can see the logic behind it and I am impressed by the simplicity. This seems to be requiring water based materials as you probably have to clean the plates down after scraping and repeating the process, or have I got this wrong?

Thanks for all your input, a simple thing like the colour for rubbing the plates together, turns up a wealth of unexpected information!

Thanks,

Andrew.

[Andrew TinsleyParticipant @andrewtinsley63637]

I am a little backwards in my artistic talents, can someone explain what "cement pigment" is. I am definitely not an artist!

Now that is a touch naughty, I should have the sense to Google "cement pigment". I am just being lazy!

Andrew.

[duncan webster 1Participant @duncanwebster1]

If all else fails use lipstick, it's not as good as the proper blue stuff, but it works. I nick it from SWMBO

[JasonBModerator @jasonb]

Posted by Andrew Tinsley on 15/05/2017 20:47:05:

I am a little backwards in my artistic talents, can someone explain what "cement pigment" is. I am definitely not an artist!

Its powdered pigment that you put in cement mortar to change the colour, eg if you want a black/dark grey joint on your brickwork you tip in some Cementone pigment. Available from all good builders merchants

[Peter KroghParticipant @peterkrogh76576]

I, for one, would certainly NOT use anything as coarse as cement pigment for spotting in surfaces. Lapping them in maybe……

Here in the USA there is a product called Permatex Prussian Blue that is available at almost every auto supply store and many hardware stores. It's what most fitters use and what I've used for almost 50 years…

Pete

Edited By Peter Krogh on 16/05/2017 07:43:27

[Chris Evans 6Participant @chrisevans6]

I have tried drying out the wet blue on newspaper and "Kimwipes" shop towel such a messy thing to do. I was using a tin a week at times bedding out large moulds and dies (Think chair size.) Now retired a tube will last my days out.

[Russ BParticipant @russb]

Pete, the pigment dissolves completely, it's not a grain of sand, or anything else abrasive or corrosive but I do sieve and mix carefully to make sure all the lumps have dissolved.

Andrew, yes wipe clean the part with some sort of spirit and debur with a stone. I use whatever I have to hand, usually white spirit or paraffin. I leave the black on the table for more than a few rubs, since it's black, smudging a bit of light colour into it has little effect.

I use red and black because they're common and contrast quite well – no link to the red lead. I guess you could use any strong pigment but as cement pigment is required in quite large quantities for its purpose, a few hundred grams is cheap and goes a long way.

[SillyOldDufferModerator @sillyoldduffer]

Posted by Andrew Tinsley on 15/05/2017 20:40:15:

… seems the Stuart blue is a favourite . Not sure about going to the trouble and expense of importing it from the US though.

…

Andrew.

Hi Andrew,

You may have your wires crossed slightly. No need to get it from the USA – my tin of Stuart Micrometer Blue says it was made in Wales! My local metal stockist keeps it, I've seen it at shows, and there are several UK suppliers on ebay. Perhaps you were thinking of trying the US water based product someone mentioned.

Dave

[CirclipParticipant @circlip]

Can always tell when someone has been "Blueing" by the stains in every direction on clothes, woodwork and metal surfaces anywhere but on the job in question.

 And yes, "Micrometer Blue"? a little goes a loooooooooooooooooong way.

 

Regards Ian.

Edited By Circlip on 16/05/2017 09:46:47

[David ColwillParticipant @davidcolwill19261]

Stuarts do a red version **LINK**

David

[David ColwillParticipant @davidcolwill19261]

I do have some but haven't used it.

David.

[roy entwistleParticipant @royentwistle24699]

Jewellers rouge is an abrasive and I doubt whether you could get Red Lead today. At one time any paint manufacturer sold it

Roy

[HopperParticipant @hopper]

I use "bearing blue" purchased from my local car parts store.

Most important thing is not the specific brand etc etc but to remember the golden rule of not to put too much on the job. Wipe it on with one finger, then wipe it off with another. What's left is about the right amount.

Having a light source behind the job, whether a window or a lamp, and getting the right angle of sight and light is important too.

[SteveIParticipant @stevei]

Andrew,

You use the yellow high lighter by putting it on the part you are scraping. Wipe on a very thin coat. It should be dry to the touch. I.e. not transfer over much if you touch it. I use an old cotton rag to wipe off any excess. In fact most of the time there is enough yellow on the cotton rag that I use that to apply it and wipe off excess. Plus I use my hand to wipe over to make sure it is nice and evenly applied. Your hand is very sensitive to feel for any contamination as well. So I always rub my hand over the yellow or blue. That is another reason why it is nice to have a water based ink. Having said that I seem to have some blue stain on my hands most days.

Then when you present the part to your plate and blue it up, the blue is much easier to see. I use this when the blue is starting to get to very small dots (i.e. when going from 30 PPI and getting close to ~40 or greater PPI). I also use it if I have a high spot problem that I can't easily see.. I.e. I put the yellow on the part. Then I present it to a clean granite plate and "polish" the part. The high spots are polished such that all the yellow ink is rubbed off the high spots. This makes it very easy to see the offending spots. Again when you are getting close to finished on a high PPI job a couple of rogue high spots can make it look like your going backwards. It makes all the difference to spot them easily and this way you can identify them and bump scrape them off, and then re-print the part.

Of course it is enough to do that with no ink as the high spots get polished by the granite anyhow. All the yellow does is simply make it easier to see what you are looking for.

I have found that everyone I've met or discussed the use of the water based inks with, that have tried it, prefer it to the the stuart's. Of course it is not essential, it just makes the job easier and also easier to clean up afterwards. DAPRA amongst others sell it in retail in the USA. Recently I have been told that the BIAX dealers around Europe are starting to sell it. I've not asked **LINK** who are the UK BIAX dealers.

Regards,

Steve

Again it would be great if an enteprising company in the UK started to sell.

[Peter KroghParticipant @peterkrogh76576]

Russ, thanks for the clarification on the cement tint. I had visions of some horrible grit!! Obviously I've never used the stuff…

Pete

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