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-   -   Soldering, waterproofing question (http://www.bikeforums.net/electronics-lighting-gadgets/363081-soldering-waterproofing-question.html)

cerewa 11-17-07 10:58 AM

Soldering, waterproofing question
 
I figure the best place to ask about this kind of thing is in this forum, although my question is an electric bike question.

I'm putting together an electric motor system for my bike, and the battery pack I bought doesn't come with a connector so I have to set up matching connectors on battery and on the motor wires. I want to make the connection waterproof.

I've heard there are tube shaped pieces of "shrink wrap" that one can use on a connection like this. (maybe with some grease or glue to help prevent water intrusion.

What sort of store would I look in to find these shrink tubes? I didn't notice any in Radio Shack or Home Depot... I'd prefer not to buy online and wait for shipping although I will if I have to.

I've also heard there's some type of glue which can be used to seal connections such as where insulated wiring comes through the hole in my electric motor's casing (or my light's casing). Anybody know what product I need, and where I can get it?

reiffert 11-17-07 01:02 PM

I'm pretty sure I've seen it at Home Depot type stores or maybe in Sears. For sure in electronics / computer stores. Ask for heat-activated shrink tubing.

for the second question - maybe silicone caulking / aquarium glue?

n4zou 11-17-07 01:20 PM

www.mouser.com is an online electronics supply store where you can purchase just about anything and everything electrical. They have a huge selection of connectors, heat shrink, and sealing compounds you'll need for your project. There are no minimum order requirements and they're happy to take small orders form hobbyists.

Something to think about is the need for waterproof connectors. Your dealing with low voltage DC so a little water getting into the connectors is not going to cause any "shocking" problems. All you really need is automotive type spade connectors with the plastic shields to prevent accidental short circuits when in close proximity to other wires or conductive parts and Vaseline jelly. Just pack the connectors with Vaseline jelly, connect them together, and wrap with spiral wrap to protect them from damage. The Vaseline jelly will prevent oxidation of the wires and connectors.

twobikes 11-17-07 04:07 PM

Radio Shack does have what you want. Go to one of their stores and ask to see catalog item numbers 278-1627, 278-1610, and 278-1611. They call it "Heat Shrink." You can look at these items on-line at www.radioshack.com. The path is: Cables, Parts & Connectors > Wire & cable management > Heat shrink.

Doug5150 11-17-07 06:52 PM

Quote:

Originally Posted by cerewa (Post 5649886)
...I'm putting together an electric motor system for my bike, and the battery pack I bought doesn't come with a connector so I have to set up matching connectors on battery and on the motor wires. I want to make the connection waterproof.

Heat-shring tube won't be waterproof. It will be water-resistant, but it'll also be a permanent join, as once it's shrunk it won't un-shrink at all.

You can also use clear silicone sealant for electrical waterproofing as well, on anything low-powered. But it too is permanent. Either the "aquarium" stuff of the "utility" stuff sold at hardware stores will work. The clear silicone is nice because you can see inside it, if the wire has overheated and started to burn the silicone it's easy to tell.

Digi-Key sells electronic components online; page 358 has some waterproof automotive connectors:
http://dkc3.digikey.com/PDF/T073/0358.pdf
....before ordering you could also go around to some automotive-parts stores locally and see if they have anything on hand. Even Wal-Mart has trailer hitch wiring kits that include a multi-pin plug+receptacle for that purpose.
~

Road_Biker 11-18-07 07:04 AM

Radio Shack aint what it used to be. Finding much more than a soldering iron and one or two types of wire is tough. Going to a 'bigger city' Radio Shack helps.

Also, since you seem intent on this whole electric bicycle task, look in the phone book yellow pages under electrical suppliers. These stores are generally found in larger cities and carry everything needed for such a task. They keep regular industry hours (8am-5pm) and are sometimes open Saturday mornings. Stores such as Mouser.com (which I also recommend) have all the names and descriptions for the parts needed.

There is a product called liquid tape which can be used instead of heat shrink tubing. It's a rubber dissolved in acetone that can be painted onto connections. Heat shrink tubing is more durable. Good Luck!

Edit: Auto parts stores carry some electrical wire and heat shrink tubing. Check in the electrical section.

n4zou 11-18-07 08:46 AM

Quote:

Originally Posted by Road_Biker (Post 5653605)
Radio Shack aint what it used to be. Finding much more than a soldering iron and one or two types of wire is tough. Going to a 'bigger city' Radio Shack helps.

That’s the truth! Before Radio Shack became Cellphone Shack I worked out of there parts bins repairing older electronic equipment. I didn't need to stock parts at home so that offset the additional costs involved in purchasing parts from Radio Shack. Then they stopped stocking there parts bins and hired employees and paid them commission based on Cellphone sales and service. Even in large Radio Shack stores with parts bins the sales people ignore them as there not making any money on that stuff. The bins stay empty as no one wants to take time and money out of their pocket to inventory and order parts to fill them. I can't blame them! I gave up and made a huge order from mouser.com and keep my on stocked parts bin for common repair items like power transistors and audio amplifier chips. I don’t know how Radio Shack even stays in business; all the X-mart retailers now service the Cellphone consumer industry at a lower cost than Radio Shack. I never bother to walk into one anymore.

ovrrdrive 11-18-07 09:56 AM

Quote:

Originally Posted by n4zou (Post 5653854)
Thatís the truth! Before Radio Shack became Cellphone Shack I worked out of there parts bins repairing older electronic equipment. I didn't need to stock parts at home so that offset the additional costs involved in purchasing parts from Radio Shack. Then they stopped stocking there parts bins and hired employees and paid them commission based on Cellphone sales and service. Even in large Radio Shack stores with parts bins the sales people ignore them as there not making any money on that stuff. The bins stay empty as no one wants to take time and money out of their pocket to inventory and order parts to fill them. I can't blame them! I gave up and made a huge order from mouser.com and keep my on stocked parts bin for common repair items like power transistors and audio amplifier chips. I donít know how Radio Shack even stays in business; all the X-mart retailers now service the Cellphone consumer industry at a lower cost than Radio Shack. I never bother to walk into one anymore.

It could be argued that because they don't keep the bins full and their people trained, that people are buying their electronic needs elsewhere...

I can't tell you how many times I've gone into the store and asked for help with a resitor or potentiometer and gotten a blank look and a giggle out of the kid behind the counter. If I'm going to have to figure it out myself, and make my own order, I'll do it at home and on the internet and save a few bucks...

tippy 11-18-07 10:58 AM

Quote:

Originally Posted by cerewa (Post 5649886)
I figure the best place to ask about this kind of thing is in this forum, although my question is an electric bike question.

I'm putting together an electric motor system for my bike, and the battery pack I bought doesn't come with a connector so I have to set up matching connectors on battery and on the motor wires. I want to make the connection waterproof.

I've heard there are tube shaped pieces of "shrink wrap" that one can use on a connection like this. (maybe with some grease or glue to help prevent water intrusion.

What sort of store would I look in to find these shrink tubes? I didn't notice any in Radio Shack or Home Depot... I'd prefer not to buy online and wait for shipping although I will if I have to.

I've also heard there's some type of glue which can be used to seal connections such as where insulated wiring comes through the hole in my electric motor's casing (or my light's casing). Anybody know what product I need, and where I can get it?

This will not meet your anti-online or water proof requirements but for simplicity ... try the Anderson Power Pole connectors. They are down right easy to build and use. They are great for battery connectors.
And if you want to connect two battery packs together (ie two 7.2v packs in series to produce 14.4v), it's a very easy connection:
http://dtipton.home.att.net/img/series_app.jpg

There is a limit to how water-proof you need to be. As long as the connector contacts are isolated enough to not provide a alternate current path when wet ... then it is not a big deal to get the individual connections wet.

Things that "assist" in current taking an alternate current path are:
Conductivity of the water ... fresh/rain water as opposed to saltwater
Distance and isolator between conductive paths.
Amount of power in a circuit ... low voltage/current vs high voltage/current.

cerewa 11-18-07 12:16 PM

Turns out my local radio shack has heat shrink tubing and the guys that work there know what it is as where to find it in the store.

It was in the back corner. I had looked at stuff within 1 or 2 feet of it and never noticed it was there.

The bike is now good to go with the electric motor and all, although I haven't waterproofed it.

jeff-o 11-19-07 09:08 AM

Another trick you can do with heat shrink to waterproof the connection is to put a ring of glue around the cable underneath where the heatshrink will be. Then, shrink the heatshrink tubing onto the glue. It'll squidge out a bit, but the seam will be sealed from the elements. Make sure you choose a glue that adheres well to both the plastic of the cable and that of the heatshrink.

derath 11-19-07 09:20 AM

If you didn't see it at Home Depot or Radio Shack you weren't looking too hard.

I bought some from Home Depot over the weekend. Huge seletion. I have bought it at Radio shack, but not recently

-D

Halloween 11-24-07 12:32 AM

Quote:

Originally Posted by ovrrdrive (Post 5654084)
It could be argued that because they don't keep the bins full and their people trained, that people are buying their electronic needs elsewhere...

I can't tell you how many times I've gone into the store and asked for help with a resitor or potentiometer and gotten a blank look and a giggle out of the kid behind the counter.

Last time I went to Radio Shack, I was just two steps inside when the perky college kid jumped out at me cheerfully barking,

:):)"And what can we do for YOU today, sir?!":):)

"I'm looking for a 110VAC to 12VDC adapter."

:):)
"And what'll THAT do for you, sir?!":):)

"It'll convert 110 volts, AC into 12 volts, DC."

:o"Oh.":o

She didn't follow me as I went past her without breaking stride, straight over to the rack on the wall, picked up the adapter I wanted, and took it over to the register for her to ring up. "Buh-bye!"

bmclaughlin807 11-24-07 01:38 AM

Radio Shack is very much a mixed-bag... some stores have very knowledgeable staff, some have well-stocked parts bins... a few rare stores even have BOTH! :eek:

Of the three that I get to occasionally, two have knowledgeable staff and not much in the way of parts, and one has a couple of very knowledgeable people and a good selection of parts. Of course it's a crapshoot as to whether the knowledgeable people are working when I go in. Ah, well... I know my way around well enough. ;)

bmclaughlin807 11-24-07 01:42 AM

Quote:

Originally Posted by Halloween (Post 5683535)
Last time I went to Radio Shack, I was just two steps inside when the perky college kid jumped out at me cheerfully barking,

-- Stuff deleted because the stupid forum thinks you put in too many smilies --

She didn't follow me as I went past her without breaking stride, straight over to the rack on the wall, picked up the adapter I wanted, and took it over to the register for her to ring up. "Buh-bye!"

My response is generally 'Oh, I'm just looking, thanks'... They assume I'm not going to spend any money and leave me alone. ;) Then, if I don't find what I'm looking for, I ask whoever looks most knowledgeable and see whether I get a blank stare or not. :D

bikingbrit 11-24-07 08:08 AM

Before going to Radio Shack I try to have the part number(s) ready; you can look them up on line at:

http://www.radioshack.com/home/index.jsp

Then if/when the clerk asks if (s)he can be of assistance I simply ask for the part numbers. THAT they can understand!


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