How to Graphite Shield

[Smirnov-Arta]

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The nature and classification of graphite Crystalline graphite ore can be divided into scale-like and dense-like. The scaly graphite ore crystallizes better, the crystal size is larger than 1μm, generally 0.05~1.5mm, the largest can reach 5~10mm, mostly in aggregate).

[Daves]

The nature and classification of graphite Crystalline graphite ore can be divided into scale-like and dense-like. The scaly graphite ore crystallizes better, the crystal size is larger than 1μm, generally 0.05~1.5mm, the largest can reach 5~10mm, mostly in aggregate).

What is the graphite powder size you use?

[Smirnov-Arta]

".

Have you ever seen a woman's face powder? This is the same size of graphite.

[Smirnov-Arta]

?

In another way, the size of graphite can be described as a toner for a laser printer

[Daves]

I'm still doing the sensor. But so that you don't have to wait, I took the broken protection for the sensor. And applied 2 types of graphite. Everything is applied with a brush in 3 thin layers. The only difference is graphite, its France. In the center there is a larger fraction-powder (gray color), on top there is a very small fraction-powder (black color). The binder is a quick-drying varnish.

Hi again how its going can u send me new photos of your application?
I will buy graphite and try it, maybe I can ask questions

[Smirnov-Arta]

Hi again how its going...

Hello). I'm sorry, but I didn't take and don't take many photos). I don't need it). And I don't understand what else do you want to see? Everything will look the same. Or use graphite spray from a spray bottle or make yourself from graphite and a binder (varnish or glue). Spray from a spray bottle is a ready-made factory product with good quality. Everything you will do on your own will be a trial and error method. And this is normal and does not happen in any other way when self-made. Take pieces of plastic (neither wood, nor cardboard or paper, only on plastic) and prepare the mixture in different proportions by volume ... 1/1, 1/2, etc. Apply the prepared mixture in strips 10 cm long and 2 cm wide and dry for 1 day. This is the only way you can choose the proportions you need and practice applying to plastic. Everything will work out. Calmness and patience, take your time).

[Daves]

Hello). I'm sorry, but I didn't take and don't take many photos). I don't need it). And I don't understand what else do you want to see? Everything will look the same. Or use graphite spray from a spray bottle or make yourself from graphite and a binder (varnish or glue). Spray from a spray bottle is a ready-made factory product with good quality. Everything you will do on your own will be a trial and error method. And this is normal and does not happen in any other way when self-made. Take pieces of plastic (neither wood, nor cardboard or paper, only on plastic) and prepare the mixture in different proportions by volume ... 1/1, 1/2, etc. Apply the prepared mixture in strips 10 cm long and 2 cm wide and dry for 1 day. This is the only way you can choose the proportions you need and practice applying to plastic. Everything will work out. Calmness and patience, take your time).

I tried it with spray before, but when I measured it, the values were very high and looked very different.

I bought 99% pure graphite powder. I will try mixing this with sodium silicate.

As the second method, I bought transparent varnish and will mix it with graphite and try it.

I will prepare it as 1:1 or 1:2 and try it. If I see a value between 1k and 10k ohms when I measure at 1cm intervals, I think it is good, what do you think? If I see 30,40k I will try adding more sodium silicate or varnish to thin the shield. If I see around 500ohms I will experiment with adding more graphite.

If there is something different you suggest, I will try that too.

[Smirnov-Arta]

...

That's right). More binder, less resistance, more graphite, less resistance. Please note that the curtain should be in several layers. With drying between the layers. You need to finish off a uniform and continuous application, without gaps or holes. Smooth and solid coating. This is usually 2/3 of the layer. Accordingly, if you applied 1 layer and after drying you have 30 kOm, then you applied 2 layers to get 20/15 kOm, etc. On the general question, what kind of resistance should there be... There are answers from forum participants and administrators on this forum. Look at them and focus on these values. Plus/minus 1 kOm will not play a role. The main thing is not to make it low-resistance...300 Om or less. Sorry for my google translator language).

[pito]

try graphite dry lubricant spray, resistance not critical, about 2k.


Assembled coil should not react to water sprayed on it.

[Daves]

try graphite dry lubricant spray, resistance not critical, about 2k.


Assembled coil should not react to water sprayed on it.

I'm trying it out, I'll share it soon

[Daves]

That's right). More binder, less resistance, more graphite, less resistance. Please note that the curtain should be in several layers. With drying between the layers. You need to finish off a uniform and continuous application, without gaps or holes. Smooth and solid coating. This is usually 2/3 of the layer. Accordingly, if you applied 1 layer and after drying you have 30 kOm, then you applied 2 layers to get 20/15 kOm, etc. On the general question, what kind of resistance should there be... There are answers from forum participants and administrators on this forum. Look at them and focus on these values. Plus/minus 1 kOm will not play a role. The main thing is not to make it low-resistance...300 Om or less. Sorry for my google translator language).

I made the first layer of graphite shield and glued a wire to the shield at several points with glue. I placed the coils on it, made my adjustments, then poured the first layer of epoxy. I applied the second layer of shield and waited for it to dry a little, left the coil outside to dry quickly (the weather was hot) I measured the first layer and saw values like 80-90k. After 30 minutes, I applied the second layer of shield. After the second layer, I attached the coil to the device and made adjustments with the adjustment wire. As a result, the device works very noisy and the depth decreased because of this.

When I measure the first layer of shield, the values are different and high.
When I measure the second layer of shield, the values are different and high.

Note: I did not pour epoxy after the second layer of shield at the moment. I glued the adjustment wire. I glued the second layer shield connection cable to the graphite so that it would touch.

[Smirnov-Arta]

..

Clear. Or you didn't understand the translation of my words. Or you did not understand the manufacturing technology of the sensor as a whole. 1. The proportion of graphite with a binder is selected. The binder is either glue (not epoxy) or varnish (can be quick-drying). I'm sorry, but I do not know what kind of graphite you have and what kind of binder. You need labels/technical description of what you are using. Otherwise, it is difficult for you to answer accurately. Further. The proportion is selected in such a way that after application and drying of the composition, it gives a resistance of about 2kOm. The drying time depends on the binder you choose. For example, if it is a quick-drying varnish, then 1 day, but preferably 2 days. There are varnishes that dry for at least 3-5 days. And only after that, measure its resistance and if it is necessary, then continue working further. But!, if you did not wait for drying and began to pour epoxy resin, then when it solidifies, it deforms this non-dried composition. And as a result, a significant change in its resistance is possible.

[Daves]

Clear. Or you didn't understand the translation of my words. Or you did not understand the manufacturing technology of the sensor as a whole. 1. The proportion of graphite with a binder is selected. The binder is either glue (not epoxy) or varnish (can be quick-drying). I'm sorry, but I do not know what kind of graphite you have and what kind of binder. You need labels/technical description of what you are using. Otherwise, it is difficult for you to answer accurately. Further. The proportion is selected in such a way that after application and drying of the composition, it gives a resistance of about 2kOm. The drying time depends on the binder you choose. For example, if it is a quick-drying varnish, then 1 day, but preferably 2 days. There are varnishes that dry for at least 3-5 days. And only after that, measure its resistance and if it is necessary, then continue working further. But!, if you did not wait for drying and began to pour epoxy resin, then when it solidifies, it deforms this non-dried composition. And as a result, a significant change in its resistance is possible.

I only have the following information about the graphite I use;
Purities: 95%-99%
Size: < 44 Microns
Humidity: 1%

I used varnish as a binder. I applied 3:1 as a mixing ratio.(example 60gr varnish and 20gr graphite) Frankly, I did not wait 1-2 days after applying the shield, so could there be an error in the measurement values?

[Smirnov-Arta]

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Sorry, one more time. At first (!) try the composition simply on a piece of plastic, and not on the sensor housing! Of course, the drying time! Each varnish has its own time of complete(!), not partial drying. This is written in the instructions in the varnish. But, believe me, it's not minutes, it's a few days. Therefore, at least 3/5 variants of proportions are made, applied to a piece of plastic, dries until completely dry (several days). And only then will you get the right proportion, etc. They just rushed it. Alas, this is the most important mistake in this case. Remember, it takes at least 1 month for a good sensor. This is in order to comply with all procedures and time intervals of drying and polymerization.

[Daves]

Sorry, one more time. At first (!) try the composition simply on a piece of plastic, and not on the sensor housing! Of course, the drying time! Each varnish has its own time of complete(!), not partial drying. This is written in the instructions in the varnish. But, believe me, it's not minutes, it's a few days. Therefore, at least 3/5 variants of proportions are made, applied to a piece of plastic, dries until completely dry (several days). And only then will you get the right proportion, etc. They just rushed it. Alas, this is the most important mistake in this case. Remember, it takes at least 1 month for a good sensor. This is in order to comply with all procedures and time intervals of drying and polymerization.

ok i will try again and let you know