Copper Mod - New Twist

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COPPER TUBE mod:
The best material to build a mod is Copper. Copper is an excellent conductor of electricity. Not like those thin walled tin, alloy, cast or aluminum mods which are very poor conductors.
Also, the claim that some PV builders use are NO SOLDERED connection. This leads to poor connections and amperage loss if not properly aligned to the adjoining parts. I have experienced this with a mod I bought.

I have just built a copper pipe tube mod. I cut down the length of both end caps to half their original length for a better look. I soldered the atty base to the copper cap. Still waiting on a switch to arrive. The atty positive will be soldered directly to the switch. The switch will be a 3 amp switch. The other end of the switch will be soldered to the positive copper head screw, filed flat to fit flush against the head of the battery post with the entire diameter of the screw covering the entire battery post.

All wire used is 20 gauged for less loss, not that thin 24-26 gauge telephone wire. The negative spring is a thick diameter gauged steel. I would have used copper but the copper springs that I have seen are thin diameter and loose there spring tension eventually.

To hold the battery bottom end cap I drilled a small hole in the cap and soldered in a ball bearing. In the bottom of the tube I cut an "L" shape to lock the cap in place. Worked great. Perhaps I will post some photos once I find the right switch. I ordered a couple but I need to see what they look like.

I've seen several Copper Tube Modders use the plunger instead of a switch. My view on that is that the contact point would have to fit squarely flush for best contact. It seems impossible if there is any side to side play/movement.

Here is a drawing:

 

[Rocketman]

Great ideas there.
If you can get the total path resistance (from atty connector, through all wiring, mod body, the switch, the spring) down to less than 60 to 70 milliohms then you will have a high conductance mod. From my experience, that seems to be the minimum for a flashlight mod using aluminum.

 

[Java_Az]

The best material to build a MOD is Copper. Copper is an excellent conductor of electricity. Not like those thin walled tin, alloy, cast or aluminum mods which are very poor conductors.

Not to disagree with you but copper is not the best metal conductor. Silver is the best. Tin is pretty bad steel is bad , brass is getting better but not great. Aluminum is actually not that bad of a conductor. It is used for Wire for AC units in houses And also any long runs that require high amps. Although Aluminum not as good as copper it is still up towards the top of the list. I hate to see aluminum get a bad rap it is considered a good conductor of electricity, not poor or very poor.

All wire used is 20 gauged for less loss, not that thin 24-26 gauge telephone wire. The negative spring is a thick diameter gauged steel.

Everything your working for is lost with that steel spring being a weak link. I would look for a silver plated beryllium-copper spring for the ground.the breryllium should keep it from loosing it's spring. Steel for sure is not a good conductor.

I hope you dont take this the wrong way. I have studied this subject quite a bit for the mod i am working on and for sure agree with you on some of the materials used in mods as conductors. I am incorporating something similar into my mod so it has top notch conductivity top to bottom. Here is a list of metal and there resistance lower the number the better. Steel is pretty high.

 

[breaktru]

Hey Java, thank you for your wonderful technical details. It is truly much appreciated.
About aluminum. It was used in house wiring in the mid 60's and was a cause of house fires because of high resistance between the aluminum wire and the contact point which was the circuit breaker. (High resistance because of oxidation). Aluminum mods are great because of the availability in a flashlight conversion, but I'd rather go copper. You know what they say? Once you go copper, there's none to top-her.

Oxidation

Oxidation on aluminum forms a barrier on the surface that is impervious to additional oxygen and thus prevents further oxidation. It is this property that makes aluminum such a desirable material in outdoor settings. Unfortunately, the electrical resistance of this oxide layer creates problems in electrical distribution applications. The electrical resistance of aluminum oxide (or alumina) is so high that in some high temperature testing environments, alumina is actually used as an electrical insulator.

The problems with oxidation can be made worse by a microscopic metallurgical phenomenon know as fretting corrosion. This is a very complicated issue resulting from compounds that form with the interaction of aluminum and various other metals. These compounds create erosion and corrosion problems from the micromotions experienced during vibration and expansion/contraction cycles. Fretting corrosion can create a build-up of oxidation between components within a connection, resulting in high electrical resistance.

About the Spring, It is plated but like I said it's a thick diameter so the thickness of the gauge makes up some what to it's poorer conductivity properties. But as you wisely stated, silver plated beryllium-copper spring would be much better.

Java shows the poor conductivity of solder in his chart so............
Important note to new or inexperienced solderer's: I have extensive experience in soldering. back in the 70's I worked in an electrical shop wiring and soldering 8 hours a day. The wire should make contact with the object it is being soldered to by wrapping it through and around, then cinched before soldering (when possible). Ideal for everything but the atty connection. Both objects should be heated first before the solder is applied. DO NOT melt the solder over the contact points. Let the contact points melt the solder. Care should be used on atty connectors, to much heat will soften the insulator that holds the center positive pin. Soldering would have to be done quickly and a heat sink would help. Use an old atty in the base that is being soldered. Sounds good on paper right. But sometimes you will have to improvise.
Always keep the connections from moving when allowing the soldered connections to cool. With one hand keep it still and with the other, touch your long-nose pliers or scew driver to it to quickly absorb the heat for a solid connection. This will avoid a cold solder connection which is a high resistance point.

 

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Not to disagree with you but copper is not the best metal conductor. Silver is the best.

Yes Java Silver is better, but the statement was the best material to build a MOD. Silver would be to expensive to use. Copper is cheap and used in most wiring.

 

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I posted some photos. I have not as yet installed the switch:
Copper Tube Mod

 

[FreakyStylie]

Silver is the best.

I never realized this. Not that I do a lot of electrical stuff, but I'm glad silver is good for something. I buy Mexican silver jewelry from thrift stores all the time because it's so cheap. Now I have something to use it on.

 

[capecodjim]

About the Spring, It is plated but like I said it's a thick diameter so the thickness of the gauge makes up some what to it's poorer conductivity properties. But as you wisely stated, silver plated beryllium-copper spring would be much better.

You could put the 20 guage wire on top of the spring so it's making contact or make a little copper plate to go there and solder the other end of the wire to the copper wall.

That mod looks really sweet in the pics!!! Nice work!!

 

[Rocketman]

For those that are interested in the lowest possible mod resistance it might be helpful to reduce those paths and contacts that have the best potential for improvement. If you have a 1 milliohm contact resistance between two 30 milliohm components it would be obvious where the conductance gain should come from. Measuring low resistance can be done with even a cheap DMM but not on the ohms range, use the lowest mv range.

Put a large wattage 2 ohm resistor (10 to 20 watts for stability) and measure voltage drops from point to point. THe 2 ohm resistor should allow about 1.85 amps to flow through the circuit from an 18650 cell. Each mv of voltage drop in the circuit represents about half a milliohm of resistance.

I have a meter that can measure milliohms, so I made a copper plug the same size as an 18650 cell, put it in the mod and measure from the center post of the connector through the mod and back to the connector shell, total path resistance. This also includes the two connection points between the test setup and the connector.

It would be interesting to see what you end up with.

Rocky

 

[Java_Az]

Aluminum wire is still used in wiring i have pulled enough miles of it when i worked as a electrician to know. When they first started using it they didnt know about the oxidation problems. They use a dielectric compound on the exposed ends now days that keeps them from oxidizing. chemfilm and anodizing also keeps the oxidation problems in check. Chemfilm being a better one for using the aluminum as a conductor.

 

[WillyB]

.... I buy Mexican silver jewelry from thrift stores all the time because it's so cheap. Now I have something to use it on.

There is a good chance your 'Mexican Silver' has no actual silver in it. There are many things with Silver in the name, often they are an alloy of copper, nickel and zinc like nickel silver, German Silver, Indian Silver etc.

 

[breaktru]

I know Java, my house has aluminum feeders to the meter panel but copper through out the house. I used the compound on the aluminum over 20 years ago and tightened up the connections.

 

[FreakyStylie]

There is a good chance your 'Mexican Silver' has no actual silver in it. There are many things with Silver in the name, often they are an alloy of copper, nickel and zinc like nickel silver, German Silver, Indian Silver etc.

Sorry, should have been more clear. I buy 925 silver. Mexico is the only place that uses that mark for their silver to designate .925 purity. It is produced quickly and cheaply, so the purity is a little low, but it is authentically silver.

 

[jerry2111]

Thanks for the pic's, I think I'll try this one. It looks very good. Are you going to polish and clear coat.

 

[breaktru]

Thanks for the pic's, I think I'll try this one. It looks very good. Are you going to polish and clear coat.

Looks good polished with fine steel wool. I'll leave it like it is until I get tired of buffing and may eventually clear coat it.

It really performs well. The first 15 minutes of vaping on it, my ears were buzzing. Must be getting the full effect of the nicotine that I wasn't getting using the Indulgence V2 and my eGo. It's a real cloud maker. This thing is PURE delight, Even at 3.7v - 4.2volts. No loses due to poor connections.

By the way, I'm using a Joye 306LR atty. Fantastic.

 

[WillyB]

Looks good polished with fine steel wool. I'll leave it like it is until I get tired of buffing and may eventually clear coat it.

Getting a clear coat to actually stick over the long haul is not a trivial job. And when it's shiny your hand will get green.

BTW you never did say what the actual switch was you used. Did you actually use a DC rated one?

 

[5cardstud]

Aluminum wire is still used in wiring i have pulled enough miles of it when i worked as a electrician to know. When they first started using it they didnt know about the oxidation problems. They use a dielectric compound on the exposed ends now days that keeps them from oxidizing. chemfilm and anodizing also keeps the oxidation problems in check. Chemfilm being a better one for using the aluminum as a conductor.

Yes it is and they still have it in the electricians shack on the job sites. It's just not good for 220volt like stoves and dryers.

 

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I finally put the switch in. It's a C&K component 3 amp shown in the photos with the part number. See post #6 on first page of this thread for the link.

 

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I would like to build another mod with the left over copper pipe. I would make it longer to fit a switching regulator with a variable potentiometer. But need to decide on either 2, 3v CR123's for 6v or 2, 3.7v 18650's for 7.4v. I am assuming that the max voltage of the regulator will be 5 volts. My question is does it make sense to go with 7.4v if only outputting 5v max?
Any advise would greatly be appreciated.

 

[Rocketman]

copper pipe mod with 2 18650s is definitely the way to go. If you use a linear regulator, about 1/3 of your battery power will be consumed in the regulator. 2/3 will go to the atty.