Gun / engraving folk - Birchwood Casey 'Super Blue' etching ink?

[Ali]

I need to fill the lettering in a brass engraving, it's quite fine and shallow and my usual technique of blasting it with a bit of cellulose followed by wet and dry isn't working, the paint is tearing out.

I'm going to try a squeegee / wipe off technique next using a bit of thinners on blotting paper to polish off the excess. But I've been reading about Super Blue and wondering if it would work for this application.

 

[Ali]

 

[Agroshield]

As far as I can tell, super blue is for steel parts. I am not sure if it would work on brass. Please link to the product you have seen in case it is not the one of which I am thinking.

There are potions for blackening brass, so one of those might be an alternative.

Could you redo the engraving in a more 'fillable' manner? That would be deeper or more vertical sides (shallower angle v-bit) or both.

The 'A' of par and 'e' of French will be difficult whatever you use as they are not well defined in the picture.

Maybe an epoxy paint, properly cured, would be harder than cellulose. The way you are abrading it might also make a difference: a piece of wet and dry on a wooden block might be too springy so something more like a wetstone would be worth a try.

 

[Ian X]

I will find some brass and try it later. I blued a dovetail saw blade and got some on the brass reinforce back but I just think it stained it a little. It's for ferrous materials really.
Maybe as Agro' suggested try epoxy paint or dyed epoxy resin. I wonder if you could cleanly razor the resin off the faces then polish after, perhaps first wiping the pieces cleanly and flatly over a taught cloth or stiff card that has a whiff of silicone spray on it to deter adherance of the resin? Might be a stretch not to get any lube within the engraved portions but perhaps worth a try.

 

[mark roberts]

When doing machine tags I find find rattle can paint is the best because it is really thin, sometimes I've used masking fluid what artists use, which is liquid latex and just peels off the bits you dont want paint on.

 

[julianf]

Is this rotary / mechanical engraving?

When I do small stuff for infill work, I change the cutter geometry. I use quite "pointy" cutters anyway, but, for work that's to hold infill, the tip truncation is reduced, to get a slightly deeper cut for any given surface width.

This then doesn't look as good if the job isn't to be filled, hence the different cutters for different jobs.


I suspect, without the depth of cut, you won't get anything to hold, and you're on to chemical blackening agents only. Which I've had so little success with!

But, in theory, you apply in excess, and then polish the job on a flat surface.

The part in my "avatar" was pretty small. The coin was a penny. The infill would be a "solid marker" stick (the sort of thing car dealers write on the windscreens with) but, again, without the depth of cut, it's not going to stay in place.


This is all just ancillary information, as I've neither heard of, nor used, "super blue" - but if it's a chemical blackening agent, I recon that's your best chance of success at this point.

 

[julianf]

Ps. I don't think the large areas are ever going to hold with a shallow fill in an area that may suffer abrasion.

I realize you know about this stuff, but I always describe it to customers like the grime under your finger nails - if it were on the palm of your hand, it would just wipe away in no time, but it gains it's staying power by the protection of the edge.

Again I think chemical blackening is your only chance.

 

[northwest]

The Birchwood Casey stuff is totally unsuited to blacking Brass so won't work.

 

[Ian X]

Caseys gun blue is not for you, here is the result, just a brown stain.

 

[Ian X]

I looked through the promotional bumph that came with my gun cleaning kits, in the Casey pamphlet is a product called Brass Black. I don't know what the finish is like so perhaps google will help out. Here is the link to the product on the Casey website. https://www.birchwoodcasey.com/products/brass-black-touch-up-3-fl-oz-bottle.html

 

[Ali]

Thanks for the tips. As @julianf says I think this job is just too shallow and something chemical is probably my only choice. I will have one more go with the wipe off technique instead of wet & dry. I don’t want to be spending too much as it’s just a bit of fun.

Julian, yes it is rotary but just the finest 40deg tool I could find, nothing fancy.

 

[julianf]

Thanks for the tips. As @julianf says I think this job is just too shallow and something chemical is probably my only choice. I will have one more go with the wipe off technique instead of wet & dry. I don’t want to be spending too much as it’s just a bit of fun.

Julian, yes it is rotary but just the finest 40deg tool I could find, nothing fancy.

I cant do anything until next week, but, depending on what cutters your spindle takes, i may be able to grind you up one here to the geometry that i would use for the job, and send it over.

 

[julianf]

if you have a measuring microscope, it would be interesting to know what the truncation (the flat at the end) is on your cutters?

i would think about 0.15mm (6 thou) or possibly larger. i would use a 0.1mm truncation with an, umm, i forget until i look at the grider, angle (but pretty pointy!)

any less tuncation, and youll just loose the tip. ive used less in the past for specific jobs, but you then end up having to do multiple passes, stepping down each time, to try and maintain the tip, but 0.1 can go to the required depth on alloy without snapping off on the first plunge (obviously this is only relevant when the angle of the cutter is taken into account too - without that specified the strength of the tip can obviously vary hugely)

 

[Ali]

I cant do anything until next week, but, depending on what cutters your spindle takes, i may be able to grind you up one here to the geometry that i would use for the job, and send it over.

That’s kind of you, I’ve got collets for 1/8”, 11/64”, 2mm, 3mm, 6mm. However as mentioned it’s just a bit of fun so let me see how I get on with the wipe off technique first.

if you have a measuring microscope, it would be interesting to know what the truncation (the flat at the end) is on your cutters?

i would think about 0.15mm (6 thou) or possibly larger. i would use a 0.1mm truncation with an, umm, i forget until i look at the grider, angle (but pretty pointy!)

any less tuncation, and youll just loose the tip. ive used less in the past for specific jobs, but you then end up having to do multiple passes, stepping down each time, to try and maintain the tip, but 0.1 can go to the required depth on alloy without snapping off on the first plunge (obviously this is only relevant when the angle of the cutter is taken into account too - without that specified the strength of the tip can obviously vary hugely)

I don’t have the means to measure it but when I used to I think it was around 0.15-0.2.

 

[Agroshield]

I don’t have the means to measure it

More a question than a suggestion: if you had a piece of 1mm squared graph paper (like you used at school) could a very good photo of it with that paper as a background be used to determine the measurements?

 

[Ali]

More a question than a suggestion: if you had a piece of 1mm squared graph paper (like you used at school) could a very good photo of it with that paper as a background be used to determine the measurements?

Possibly, but I’m not sure it would come out much better than my informed guess!