TUTORIAL: Acid Etching

[KIT FISTO]

What keeps the acid bath from coating the inner wall of the piece and eating it away from the inside out?  Do you block/plug up the hole with something so no fluid gets inside the part?

[Goodman]

What keeps the acid bath from coating the inner wall of the piece and eating it away from the inside out?  Do you block/plug up the hole with something so no fluid gets inside the part?

Yes, plugging the ends of the tube is essential. If the part being etched is a 1" or 1.25" tube (for most of my inner G-Core chassis parts), I use the rubber cap that came with my pre-made blades to block the acid from leaking inside the inner wall. For MHS tubes, I need to find a rubber cap which is tight enough around the ~1.45" diameter. Until then, I use the clear packing tape with this method for a water tight seal:

1) Place a single piece of wide clear packing tape face down on the MHS's tube opening and press down firmly against a table top to set the tape.
 
2) Trim the excess all the way around leaving 1" of overhang.

3) Cut the overhang into strips every 30 degrees.

4) Fold those strips down against the outer wall of the part.

5) Wrap the outer wall with clear tape to double the seal of those strips.

6) Squeeze all air bubbles out with the rounded end of your hobby knife.

The benefit of the clear packing tape method to plug holes, though somewhat tedious, is that you can still see inside the tube. During etching, I'll check every few minutes to see if any acid has leaked in.

[Goodman]

I did have one question. Would I be able to use shelf contact paper instead of masking tape I personally find it easier to use for cutting and designing?

Using my tutorial's method, essentially you are creating a "one time use" stencil or sticker directly on the hilt by cutting out areas of the mask which you don't want. For the mask, you can use any material as long as it is adhesive enough to bond to the metal surface completely to resist the acid 100%, and obviously can also resist the acid itself.  I haven't used shelf contact paper, but try it and post back your results!

One development I've tried out which isn't pictured here is using tinted tape for the mask. The tape is mostly translucent, but has a slight shade of red, for example. This allows me to see the resulting mask much more clearly during the scribing process, because of the higher contrast between the red masked areas and the aluminum exposed areas. Obviously it provides a much higher contrast that clear tape vs aluminum! I get my tinted tape locally. If I can find an online source for a a cheap price, I'll post it here.

The clear tinted tape is also produced, among other formats, in a 12" wide film for certain applications like covering a large clear part, like a car headlamp. This is a useful size for us because we could conceivably mask an entire hilt with one mask ( = no seamlines). A 12" wide, 32 foot long roll is $40 shipped from China, but there are lots of stateside providers, too, in art stores or car accessory/upgrade stores. As mentioned I'm still researching a source for the cheapest, most easily available online source which fits our needs the best.

http://www.aliexpress.com/store/product/Free-shipping-Wholesale-Wram-Pink-Headlight-Tail-Light-Film-Protive-Sticker-Tint-Wrap-Lamp-Vinyl-Film/106960_624696040.html

[blackluc]

Could I dip some pieces for a really short time to achieve a light weathering effects?

[Yygdrasil]

I ve got a question on this:
I can get only 40% ferric chlorid here, would this also do some etching progress in longer time ?

[Goodman]

Could I dip some pieces for a really short time to achieve a light weathering effects?

Yes, a shorter exposure time would reduce the depth of the etch. For corroded corners, apply the acid to specific areas with an eye dropper. The surface tension of the liquid will allow it to collect in small puddles on the surface of the saber. Alternatively, allow the acid to collect in the recessed areas of the saber, to create a deeply weathered effect. Depending on your acid/water ratio and exposure time, a rusted effect can also be achieved.

Experimentation is key.

[Goodman]

I ve got a question on this:
I can get only 40% ferric chlorid here, would this also do some etching progress in longer time ?

What comprises the other 60%? Typically I mix an approximate 50/50 acid/water solution.

[Darkjedi]

Great tut! I can't wait to get started. I work with a lot of acid (batteries) I have all the gear(PPE).

Oh you Sabers are truly great too!

[Yygdrasil]

What comprises the other 60%? Typically I mix an approximate 50/50 acid/water solution.

I was refering to this:
http://www.conrad.de/ce/de/product/530736/Bungard-Eisen-III-Chlorid-Loesung-fluessig-73131-01
But u answered my question ! if u mix 100 % ferric chloride with water half an half, the product i am heading for will do the job