How to make Mating Electrical Connectors

I make no guarantees, use at your own risk!

I recently got a set of retrofits with Toyota/Kioto ballasts. Unfortunately, they did not come with the power plugs, the previous owner was just using spade connectors which seemed why too prone to falling off.

I tried hitting up ebay and the usual haunts, but turned up empty, so I made my own. For all I know, someone may have them for sale, but it's snowing, I'm impatient and might prove useful for others.

So here goes...

Here's a pic of the ballast and connector. Female spade terminals fit, but worried about them staying put. So I'm making some out of Raycrete (a safe, non-toxic polyurethane, that cleans up easily (lemon juice) and has a nice slow transition from viscous to solid).

It's recommended as an electronics potting material, so no worries. I've used this for a lot of things, from mounting my LCD into my Double din, to making a shifter out of it. It can be colored with concrete colorant (though I don't know what that is composed off, so might effect conductivity), the only pain is painting it, some paints just won't stick. A flexible bumper primer like Transtar 2&1 works well though.

The ballast... Denso KDLT002 ballast

The rough fit, 10ga is overkill, but all I had that wasn't too small. ballast rough fit

Raycrete, love this stuff (also goes by the name EZ-Poly now) Raycrete, getting read to fab

I make a little dam of tape. If I had taken my time, I could have gotten a better looking part, like making a cardboard dam. Tape dam

For a release, I cover the spade terminals with two sacrifical ones (so I don't have to worry about cleaning the female contacts) and spray inside the dam with PAM non-stick cooking spray, buttery goodness! Release agent aka PAM

Make sure the terminals are upright and spaced correctly (mine were bent a little), otherwise, might be difficult to plug,unplug, OTOH, the insulated spades have some room for play, but not that much. Rough fit of ballast, terminals perpindicular

Hate wasting material, so I'll use the excess for a mount for my boost phone that I use with my CarPC. The reason I always save the packaging. Cell phone holder

Mix up the Raycrete, equal parts A&B at first it's a like runny pancake battery, carefully put some in and let it sink, try not to move the wires! Pouring the raycrete

After about 20 minutes, use a popsicle stick to remove whatever dripped, it's kind of like cookie dough at this point.

Why not? :) Molding the cell phone

After about 40 minutes, it's firm enough where it should have a skin, so carefully remove the tape. Not that pretty but the stuff is easy to sand, for a spur of the moment project, not bad. I'm more concerned with it working than being pretty.

Removing the tape dam

At this point, it's still soft, so trim any overhang that may cause problems, I just used a little screwdriver to trace out the edge of the connector.

Rough finish

About 1:20 after pouring, I demold, a little early, but if it's going to catch, I'll still have some play as it's not full strength yet.

Not too shabby! Due to the lazy tape job (glossy cardboard bent into the proper shape probably would have worked better) I got an air bubble or two, but it's done. They came off without too much effort, but not too easy like the plug should. The tab works on the one that's has it (the other was missing before starting it). The connectors after a little sanding

Oops, some air bubbles

Now for some finishing...

It's still not set to full hardness, so it's easy to sand and shape. A little flexing of the wire makes most of what's on it pop off. A few minutes with the handsanding and just about done.

Ballast connectors, polished up a bit

Not too bad, these things are not slipping out, perfect fit. If I had taken a little more time, probably could have made them pass for OEM. A little tape and it will look fine.

Now that they are cleaned up, going back in until tomorrow when they are fully hardened. Then I'll clean up any residue from the PAM with contact cleaner. A few hours on a snow day, not too bad. I spent more time trying to track the originals down :(

A perfect fit

Oh and why not, the phone cradle, this I should have waited until tomorrow to demold, almost cracked as it's only 1/4 to 3/8 thick.

The cell phone dock demolded

Scroll to top