Etching front sight elements and alternatives.

[ovenpaa]

It looks like I have a rifle with a front sight that accepts non standard front elements and I need some. I was thinking about etching my own using brass sheet and ferric chloride. Now assuming I can actually print the correctly dimensioned elements and transfer the masks to the brass would it work?

As an alternative I can easily make perspex inserts as I can cut over sized discs, drill a variety of sized holed through them, add chamfers to the hole and then stack them on a mandrel and turn the outer diameter to size however I would prefer solid metal inserts in keeping with the originals.

Has anyone tried such a thing or have any suggestions for the manufacture of elements?

[1066]

I'm sure that's perfectly doable Dave. I've etched printed circuit boards and name plates but never etched a design out of a sheet.

Thin brass or copper shim, design your element on the computer then you need a way to transfer it onto the brass sheet. I'm sure I watched a youtube vid when I did it a couple of years ago.

Print out your design with a laser copier onto glossy paper from a magazine and iron it onto the brass shim, cover the back of the shim with tape so it only etches from one side and stick it in a batch of ferric chloride for about 1/2 hour.

This is not quite how I did it but it will show you how it works.

https://www.youtube.com/watch?v=NntLi4KcLlI&t=334s

Better way
https://www.youtube.com/watch?v=7Op6H0C18tM

[Doz]

I'm no expert but I experimented with etching brass a few years ago, producing small nameplates. It sounds obvious but I didn't consider it until it bit me - once the ferric chloride has started to do its thing, it will 'undercut' the mask and effectively blur the edges. Obviously this isn't a problem with PCBs etc as the copper layer is so thin, but the thicker the material the more it eats into the newly exposed edges and becomes a problem.

[WelshShooter]

I'm no expert but I experimented with etching brass a few years ago, producing small nameplates. It sounds obvious but I didn't consider it until it bit me - once the ferric chloride has started to do its thing, it will 'undercut' the mask and effectively blur the edges. Obviously this isn't a problem with PCBs etc as the copper layer is so thin, but the thicker the material the more it eats into the newly exposed edges and becomes a problem.

That reminds me of the time I spent in the semiconductor industry. We called that "isotropic etching" where a chemical etches equally in all directions during the process, including the undercutting of the masking material.

You can't really prevent this, unless in Ovenpaa's case he purposely makes the mask larger in dimensions than required, allow the ferric chloride to do its job, then finish the work piece up with fine files to define the edges a bit better. Difficult to do this neatly on the round parts of the sight element!

[1066]

How about two back to back elements. They only need to be a few thou thick and you could print a mirror image so you get two clean faces.
Would it matter anyway if the face was sharp, you only see a silhouette.

[ovenpaa]

I was hoping the front edge would stay sharp and the blurring/undercutting not be so apparent when viewed front the front, possibly this may not be the case with thicker material. I will have to experiment. I did think about laser cutting however that is not exactly a low cost option and 3D printing may be and option if it stands up to the recoil and is fine enough.

The perspex disk option is always going to be my fall back option if all else fails :)

[1066]

I'm getting some pretty fair results with the 3D printing but not usually as fine as that. Design is not a problem, you could have any arrangement you like, post, pip etc. so I'll run off a couple of trial prints to see if it will work. Certainly be the easiest way if the results are expectable.

This one is 17mm od and 1.5mm thick. Recoil won't be a problem as there's almost no mass and it's well protected from physical damage.

Some shooting specs I've printed.

[1066]

I think that might work ok Dave - This is first try 2.2mm hole in centre.

[ovenpaa]

Wow, it looks like 3D printing could be the way forward, what is the cycle time for a single item like this and what is the material?

[1066]

This is made from a tough plastic called PLA, it's a vegetable based stuff made from corn starch and sugar cane. Once it's set up this took me 11 minutes to print at my finest setting.

Have you got any elements for your foresight?