etch an aluminium chassis.

[madball]

Hi,

I would like to know how long do you guys put the chassis into the Ferric chloride liquid to etch the chassis?
Also how "deep" can you etch into the metal?

I've done this last week, I put my chassis into the 'brown stuff" and immediately see some bubble getting out..
After a few minutes I exam the chassis and find that the "etch" is not deep enough. I expect it will be at least 1 mm in depth.
so I put it back, and waiting for another few minutes. Still the etch is very shallow. (I exam it with my eye only because I don't want to touch the "brown stuff"). Eventually the chassis was etched for a few hours, I still find the etch is not deep. I think I've done something wrong, so I wash the chassis and sand off the mask ( I use magazine paper with laser printer tone transfer). It turns out the etch is acceptable but not great, and the area which supposed to be mask have a little etch. i.e. small black dots..

so... what I've done wrong? any tips to make a perfect etched chassis?

I will upload a pic of the result when I back home. stay tuned.


laiben

[bean]

A few minutes should be plenty to get a decent depth.

Are you warming your FeCl before immersing the enclosure? That might help etch more quickly.

Also, you can take out the box periodically and soak it in water. This stops the reaction. If you gently wipe off the face with a paper towel it will help loosen the crud from your mask. Then just throw it back in the chemical to etch some more.

[madball]

Here are the pics. Any suggestion to improve the result?



seems like some metal is etched thru the toner mask and the etch is not deep!!

[madball]

A few minutes should be plenty to get a decent depth.

Are you warming your FeCl before immersing the enclosure? That might help etch more quickly.

Also, you can take out the box periodically and soak it in water. This stops the reaction. If you gently wipe off the face with a paper towel it will help loosen the crud from your mask. Then just throw it back in the chemical to etch some more.

I use hot water (not warm) to dissolve the Ferric.
Could you tell what do you mean by "reaction"? why I want to stop it if the reaction is the etch the metal if I want to etch it deeper?
what is the purpose to loosen the crud from the mask? what is crud?

Thanks a lot

[bean]

I use hot water (not warm) to dissolve the Ferric.
Could you tell what do you mean by "reaction"? why I want to stop it if the reaction is the etch the metal if I want to etch it deeper?
what is the purpose to loosen the crud from the mask? what is crud?

Thanks a lot

Are you diluting the FeCl? Is that what you mean by dissolve?

What I was asking is if you a heating up the chemical first before trying to etch. It will work more quickly that way.

The purpose of temporarily interrupting the process is to check the progress of the etch. Dousing it with water will help halt the process. You will probably find that your mask has a lot of junk on it from the etching. You can clean that off gently with a toothbrush to check the depth of the etch. If you need more just throw it back in...it will work well since you have cleaned the area around the mask.

[madball]

I use hot water (not warm) to dissolve the Ferric.
Could you tell what do you mean by "reaction"? why I want to stop it if the reaction is the etch the metal if I want to etch it deeper?
what is the purpose to loosen the crud from the mask? what is crud?

Thanks a lot

Are you diluting the FeCl? Is that what you mean by dissolve?

What I was asking is if you a heating up the chemical first before trying to etch. It will work more quickly that way.

The purpose of temporarily interrupting the process is to check the progress of the etch. Dousing it with water will help halt the process. You will probably find that your mask has a lot of junk on it from the etching. You can clean that off gently with a toothbrush to check the depth of the etch. If you need more just throw it back in...it will work well since you have cleaned the area around the mask.

Thanks for the tips bean.

The FeCl I used is solid powder, I put them into hot water to produce the brown liquid used for etching.
I think I know what you mean, I will try it next time.
Maybe the mask (toner transfer from magazine paper) is not dense enough so the area protected by the mask is not clean after etching..

Last question: the etched areas are turns black after some etching, can the black area to be etched more? or the black layer will protect the metal from further etching?

Thanks.