A simple circuit for driving an LED strobe synced with audio signal was posted over in the subwoofer forum.
Analog Servo Sub: strobe circuit
Analog Servo Sub: strobe pics/details
So I have got these 100% NaOH white grits (Kaustiksoda). How do I get a 0.1N (molar?) solution, please?
//
do you have 4 um aluminium ? or you are gone etch that huge piece ? rather have stock 4 um then using the etch method
i ask because i am looking for some to :0
Yes, where can we find 4-5 um alu?
I managed to etch 15->5u successfully. I'm thinking about how to control the current concentration (less on the sides, more in the middle) to compensate for the non linear field in the gap. Possible? Worth the trouble? By doing different stints of etching one could make different thickness?
//
I managed to etch 15->5u successfully. I'm thinking about how to control the current concentration (less on the sides, more in the middle) to compensate for the non linear field in the gap. Possible? Worth the trouble? By doing different stints of etching one could make different thickness?
//
Great idea, TNT!
One obvious suggestion is to have the middle area painted with some etch resistant stuff; it doesn't need to be perfect though.
Then etch the desired difference, remove the paint and then etch again.
Trouble is to find the etch resistance paint and then find out how to remove it without ripping the foil apart. Some kind of solvent?
Perhaps it is easier the other way around; first etch the whole and then apply paint to the middle? That way it should be easier to have several stints and perhaps you don't need to remove the paint?
You'll have to calculate the resistance for each step though, but that should be only to add several fictive aluminium layers width individual thickness in order to get the resistance for each step.
And if you are treating a longer foil strip than needed (to be cut into several when done) you could have resistance values that are easier to measure during etching.
But if you are using four point measuring during etching that might not be needed?
Sorry for the lecture, but just to be crystal clear:
No paint, etch until X ohm,
Paint in a small middle section, etch until Y ohm,
Paint in the wider middle section, etch until Z ohm.
Spot on solhaga! Thats the way to do it. Some solvent is needed to remove "paint" (wonder what it could be?) as any mechanical treatment is out of question.
I will try this in three steps as you describe above. Where are my magnets
Don't know if it possible to measure resistance. I think it will be about measuring thickness rather?
//
I will try this in three steps as you describe above. Where are my magnets
Don't know if it possible to measure resistance. I think it will be about measuring thickness rather?
//
Glad to be of any help.
I think it would be better to measure resistance while etching, then you can stop on the dot.
Otherwise you'll have to take the foil out of the basin, dry it and then measure.
To measure time could be tricky as the concentrations of the etching fluid can be different, also the "strength" varies with temperature, both ambient and due to self heating.
I think it would be better to measure resistance while etching, then you can stop on the dot.
Otherwise you'll have to take the foil out of the basin, dry it and then measure.
To measure time could be tricky as the concentrations of the etching fluid can be different, also the "strength" varies with temperature, both ambient and due to self heating.
Perhaps a Wheatstone bridge could be used.
Make a couple of reference foils as R2 by simply cutting away enough material to simulate the aluminium that have been removed by the etching steps.
The "foil in the bath" is of course Rx and then use the different R2s for each corresponding step in the process.
You could also have a fixed R2, but then you'll have to do some circuit calculations.
Make a couple of reference foils as R2 by simply cutting away enough material to simulate the aluminium that have been removed by the etching steps.
The "foil in the bath" is of course Rx and then use the different R2s for each corresponding step in the process.
You could also have a fixed R2, but then you'll have to do some circuit calculations.
electrolyte etching maybe gives more controll? in just copper sulfate and common salt?
at least the bath should not decay in strength in this method. its not taking anything from the bath (or it actually is but gets replaced)
i thought about stiffening the foil, start out with a thicker alum foil and etch sort of horizontal bars witch should be able to minimize the lagging behind of the middle part. ?
might as well to a honeycomb while where at it
so you get a sort of ribbed foil, like a belt for a pulley. looks a bit like corrugation offcourse but its not exactly the same.
at least the bath should not decay in strength in this method. its not taking anything from the bath (or it actually is but gets replaced)
i thought about stiffening the foil, start out with a thicker alum foil and etch sort of horizontal bars witch should be able to minimize the lagging behind of the middle part. ?
might as well to a honeycomb while where at it
so you get a sort of ribbed foil, like a belt for a pulley. looks a bit like corrugation offcourse but its not exactly the same.
Last edited:
do you have 4 um aluminium ? or you are gone etch that huge piece ? rather have stock 4 um then using the etch method
No, I don't have 4 uM Alu, and yes, one meter membranes aren't easy to etch!
(but it's possible)
So I have been thinking on how to build a cold rolling apparatus(?) for making thinner alu strips out of 10uM household foil.
I've done some experiments, seems that such a machine will become too big and expensive...
Yeah big metal rollers withouten inperfections are expensive and big I can imagine. There are sources easy to find but it all comes down to quantity . Group buys are the way to go to get virgin materials like al 2,3,4 micron or any other type likemylar backed etc it all comes down to quantity. I already tried to get people to gather but I can't seem to convince people to group up an get what we want