Blacking engraved lines

Rather than hijack a current thread about blacking aluminium dots on dice I thought I would start a new thread. I would like to know what people do to get very sharp clean black engraved lines on steel items such as machine dials. I have tried a few techniques in the past with varying degrees of success.

I look at some pictures of beautifully engraved and blackened lines and marvel at how good they look in comparison to my poor efforts. Is there a good way of achieving consistent results?

Doug

Clockmakers have traditionally used Wax [sealing wax], but there is a trend towards epoxy resin loaded with black filler [printer toner might do]. Scrupulous cleanliness is obviously essential.

MichaelG.

On tooling I would use a paint stick by Edding just write over the engraving and then wipe over the top with a paper towel damped with a solvent cleaner. They come in different colours Edding 10 mm broad tip paint marker pen for metal.

David

Douglas, I have made many engraved panels for equipment, my lathes, shaper, rotary table controller, etc,  and lots of radio ham equipment - I use single sided ( copper on one side only)FR4 Printed Circuit Board ( fibreglass type), with the copper side pre-painted and then engraved, as this gives a nice sharp edge to the lines. I then fill with plain black boot/shoe polish! I use an old credit card as a squeegee and squeeze the wax into the lines. Wipe the panel with a clean lint free cloth and let dry for an hour or so and then a brisk rub to clean up and the job is done!

The problem with resin fillers, or any paint with a solvent based filler is that the filler tends to adhere to the painted surface so you have to clean the excess  right away and that is not so easy - if the filled line/text is still wet, wiping over the line tends to drag more of the filler over the panel surface, and as that starts to dry or cure, it becomes more difficult to clean. Also,  the solvent base of non wax style fillers tends to attack and dissolve the painted panel surface as well, leaving fewer choices of paint to use on the panel, ie, epoxy based paints are about the only types impervious to turpentine or thinners based fillers.

I have panels around 11 years old made in this way, and they show no deterioration at all - some are panels on radio equipment in my 4X4, panels which have endured many, many months of hot African sun!

The panels on my lathe ( an Electronic leadscrew system), shaper, etc,  are  similarly made and after maybe 2 years of use, with the usual oily and grubby fingers , there is no sign of filler departing the panel, etc.

Joe

Edited By Joseph Noci 1 on 10/02/2019 19:17:14

The method used at Colchester Lathes was to black anodise the whole dial and then skim the dial surface, removing a small amount of material and leaving the blacked engravings.

Bob

Having worked for Xerox for a number of years I would advise anyone to steer clear of printer toner, extremely nasty stuff.

If the material is steel then I have had good results with "Curator Antiquing Fluid" this can be diluted and the parts immersed. Takes about 2 minutes with good results. Whilst intended for Brass it says it will work on steel and it does.

There are solutions available for blackening aluminium, but as yet I have not tried them, it is on my to do list with an up and coming project on the Emco Compact 5.

A couple of examples

Regards

Gray,

Edited By Graham Meek on 10/02/2019 20:22:46

.

Thanks for the warning, Gray

... duly noted.

MichaelG.

I was experimenting with this today. The graduations on my HLV cross slide are rather faint and I wanted to make them stand out. I rubbed some fine magnetite powder into the surface and it brought the marks up beautifully. Unfortunately I have not managed to find a way of fixing it into the engraved markings.

Some very interesting ideas there, I must try out some of them. Again some of these photos leave me green with envy, they are simply superb. Right, I have got my shopping list; boot polish, antiquing fluid,metal blacking, sealing wax etc.. I must try oil blacking then skimming the surface, that might work as well. Thanks for all the ideas.

Doug

Having filled many engraved markings the best is to clean in cellulose thinners and then fill with black celluluse paint. wipe off the excess and when hardened use a thinners dampened cloth to clean off the rest of the paint.

Clive

As a matter of interest is cellulose paint better than other types of paint for this task or will other types work just as well ? Also, which is best, gloss or matt ?

Doug

Doug,

If you haven't already done so ... I suggest you revisit the other thread

https://www.model-engineer.co.uk/forums/postings.asp?th=140690#2427699

Brian G has made an excellent suggestion

MichaelG.

Edited By Michael Gilligan on 11/02/2019 10:11:49

Made many drivers cab litter bins for BREL. The BR logo and the word "Litter" were engraved into the anodised aluminium outer wrapper and overfilled with Black cellulose. The surface was then subjected to a "Sharp card" dragged across the logos.

Technique is known in the engraving trade surprisingly enough as "Sharp Card Printing"

Regards Ian.

John Wilding used to recommend biddblack cement colouring in epoxy. Cementone is the current incarnation.

regards Martin

Carbon black works fine to colour epoxy resin, if you do not have you just crush some Norit tablets. Niko.

I've used Humbrol matt and/or gloss black enamel, the advantage of which is you can brush the paint into the grooves followed by a wipe with a white spirit dampened kitchen towel or cellulose thinners if the paint has dried for any length of time.

In my instrument making days.long ago,scales and verniers in brass or nickel silver were made on linear or circular dividing machine ,depth was approx 4 thou ,any slight burrs were removed with a water of Aire stone, the divisions were filled with black sealing wax applied hot, the excess scraped off with scrapers made from old hacksaw blades or when getting close to finishing ,aluminium scrapers then finishing up with extremely fine polishing grade emery paper,the finished scales were then sprayed with clear cellulose varnish, Engraving wax could not be used as the wax and varnish did not agree with each other. Items which required deeper marking ie nickel silver micrometer thimbles were filled with black engraving wax and just left polished.I aquired on of my old companies products a measuring microscope at least 55 years old and the engraving is still in good order.All sounds a bit laborious and rather trying,especially if a scale was scratched,it meant that the whole scale was machined to remove the markings and start again, batch quantities could be up to a hundred,with even more work on the circular scales of 100 batches of spectrometers.All a bit tedious and the reason why I moved on to get wider experience in other more interesting aspects of engineering .

I use engraving wax, which is applied cold. It works well for markings made with letter punches as well as engravings.

George

I use a Markal paint stick from MSC (was J&L). Same idea as the engraving wax and cellulose paint. Rub on, then wipe over with a non-fluffy rag.

Where I used to work, we made a lot of electronics boxes for the military. So it had to be robust and soldier/sailor/airman proof. There was a lot of engraving, one person used to do the infilling, he used Humbrol enamel, black, white, red whatever. After near obsessive cleaning the engraved characters were infilled with a small brush and the excess wiped off with a Humbrol thinners dampened cloth. Much like what has already been suggested.

cheers

Bill

Edited By Bill Pudney on 12/02/2019 02:20:33