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silver epoxy, maximum voltage for motor and its RPM

PG1995

Active Member
Hi,

Q1:
I was looking for something so that soldering could be avoided. Is silver epoxy a good alternative? I think solder paste still requires soldering.

1: https://www.amazon.com/MG-Chemicals-Silver-Epoxy-Adhesive/dp/B003BDMJSY/
2: https://www.amazon.com/Clean-Temperature-Solder-Paste-Grams/dp/B017RSGPI8/

Q2:
Is there any way to figure out the maximum voltage for the motor shown and maximum possible RPM?I tried to run it at 10 V for 2 minutes, it didn't break. Such motors could be found in robot kits like this one: https://www.amazon.com/Smart-Chassis-Motors-Encoder-Battery/dp/B01LXY7CM3

Thank you for the help!

20200925_215929.jpg
 

Diver300

Well-Known Member
Most Helpful Member
Silver epoxy will work fine and doesn't need heat, but takes a long time to set and can't be easily taken off, and is expensive.

You are correct that solder paste needs soldering. Like solder wire, solder paste is solder + flux. When it is heated, the flux helps to clean the oxide from the surface of what you are soldering, and the molten solder then bonds with what is being soldered, forming a solid join as it cools.

All I know about Q2 is that brush wear will go up as the motor is run faster. At some point the armature will be going too fast and centrifugal forces will make it fail, and it will burst.
 

PG1995

Active Member
Thank you.

Re Q1:
Does something similar to silver epoxy also exist which can be used? I mean less expensive and which takes not that long to set. BTW, is that "takes a long time to set" in hours?

Re Q2:
Note sure if the description below is correct but this is what I found on Amazon. I still cannot find the RPM value around 9V.

Product description
Style:Smart Car Motor x4
100% brand new and high quality
Operating voltage: 3V~12VDC (recommended operating voltage of about 6 to 8V)
Maximum torque: 800gf cm min (3V)
No-load speed: 1:48 (3V time)
The load current: 70mA (250mA MAX) (3V)
This motor with EMC, anti-interference ability. The microcontroller without interference.
Size: 7x2.2x1.8cm(approx)
Source: https://www.amazon.com/AutoEC-4pcs-Motor-Smart-Robot/dp/B00U4HP0SQ
 

JimB

Super Moderator
Most Helpful Member
But why do you want to avoid soldering?

The connection tags on the motor are intended to be...
soldered.

JimB
 

Diver300

Well-Known Member
Most Helpful Member
Re Q1:
Does something similar to silver epoxy also exist which can be used? I mean less expensive and which takes not that long to set. BTW, is that "takes a long time to set" in hours?
You could probably connect with a crimp like this:-https://uk.farnell.com/te-connectivity/160625-2/crimp-receptacle/dp/1822075

That would be more suitable for testing than either epoxy resin or soldering.

The setting time for epoxy resins varies. The ones that I used needed 45 mins at 125 deg C to set, and it seems like the Amazon one is similar. The epoxy resin itself doesn't conduct, and I think the silver epoxy only starts to conduct when set. I don't know if fast-setting conductive resins exist.
 

gophert

Well-Known Member
Most Helpful Member
soldering irons are cheap. and there are many videos online to teach you how to do it. You can practice with bare wires. I've been soldering since I was 11-years old with a used, $3 soldering iron from a garage sale.

if you really want to use Ag Epoxy, then it will work. Conductive adhesives don't care how much voltage you put through,they are only bothered by temperature. It is unlikely that little motor will draw enough current to soften the adhesive (assuming you have a reasonable a 0.5 to 1mm cone of adhesive around your connection). Not that temperature will increase as current is passed through a resistance as (I * I * R = Power). The R, in this case is resistance through your adhesive or solder joint. The more intimate copper-to-copper contact you have before applying adhesive, the better (lower resistance) your connection.

And, to answer your question about non-silver adhesives. Silver is a magical metal because, it is the only metal that rusts (oxidizes) and still conducts electricity. Ok, Rhenium, Ruthenium and Iridium and several others but none cheaper than silver).

copper and aluminum flake have been used but the corrosive matrix used to keep the metal free Of oxides makes it difficult to find acceptable applications (substrates) and environmental conditions to make them useful. Most copper and aluminum-containing adhesives are used for thermal conduction.
 
Last edited:

PG1995

Active Member
But why do you want to avoid soldering?
Laziness! I did do soldering once with the help of someone. Honestly, I'm not even going to solder anything. I asked it out of interest.

The setting time for epoxy resins varies. The ones that I used needed 45 mins at 125 deg C to set,
Thanks. 125 deg C is too high.

Silver is a magical metal because, it is the only metal that rusts (oxidizes) and still conducts electricity. Ok, Rhenium, Ruthenium and Iridium and several others but none cheaper than silver).
I didn't know that. Thanks.
 

gophert

Well-Known Member
Most Helpful Member

JimB

Super Moderator
Most Helpful Member
But why do you want to avoid soldering?
Laziness!
Shame upon you.

I did do soldering once with the help of someone.
Hmmm...

I'm not even going to solder anything.
But why?

You obviously have a good understanding of electrical/electronic things, having been a member here for a number of years, and ask good insightful questions.

But by avoiding the practical aspects of the electrical world, you are only seeing half the picture.

JimB
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Yes, crazy idea not learning to solder - I taught my daughter to solder at Primary School (and bought her a number of small LED style kits to build). It stood her in good stead when they did a soldering project at Secondary School, where she could solder much better than the teacher, and again at University where they built a simple electronic project in Chemistry, and again she could solder better than the professors and the techs.

It's not as if I'd even rate her soldering abilities as 'good', but they were better than most out there.

It only takes ten minutes or so to learn to solder, it's a valuable skill to have, and comes in useful in all kinds of applications.

Does anyone watch Wheeler Dealers?, where they buy, restore, and sell old cars - often they solder wired connections (quite poorly), and then seal them with heat shrink (using the heat from a soldering iron to shrink the heat shrink - horrible).
 

JimB

Super Moderator
Most Helpful Member
Does anyone watch Wheeler Dealers?, where they buy, restore, and sell old cars - often they solder wired connections (quite poorly), and then seal them with heat shrink (using the heat from a soldering iron to shrink the heat shrink - horrible).
Or even worse, many of the American Chopper Bike/Hot Rod/Old Car Fixit TV programmes where they solder and heat shrink with a propane flame torch.

JimB
 

PG1995

Active Member
Why would this matter....


if, as you say,...
You have a point but if I ever decide to do it, I might need a mini flamethrower. :)

Shame upon you.
I cannot take the burden of this shame! :) So, I've decided that I'd rather do soldering if any such need arises.

You obviously have a good understanding of electrical/electronic things, having been a member here for a number of years, and ask good insightful questions.

But by avoiding the practical aspects of the electrical world, you are only seeing half the picture.

JimB
Yes, I'm indebted to electro-tech-online for being a source of so much help in the past. I cannot thank some members enough because without their help it wouldn't have been possible.

I tend to forget things quickly but it's still there somewhere in my mind. Trying to get myself back on track.
 

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