Introduction: Plastic Bottle Funnel

About: I like making things out of items that would have otherwise been discarded. Check out my other projects!
I had been putting off changing my vehicle's oil for too long. As a DIYer, that's one of the projects i will take on when maintaining my ride. It was cold out so i was kind of in a rush. On top of that, someone just called me and needed to meet me at work. I said i could be there in 20 minutes. After all, changing the oil takes no time! I pulled onto the tire ramps and quickly scrambled under and drained the -- oh wait - why is that fluid red?

My car was bleeding some other essential fluid. I called the only person i could think of that wouldn't judge me as an idiot and might know what i could do to fix it. My brother.

With him on the phone and the manual for my car out and my head under the hood he was able to tell me that i probably drained the transmission fluid. I learned that there is another dipstick under the hood (three including me when i'm monkeying around in there) - i checked it and sure enough - it was dry. But i couldn't figure out where to refill the fluid. He suggested that i just pour it down the dipstick tube.

Of course. When i was at the store buying new oil i looked at their collection of funnels and thought to myself that i really could use a set of a variety of sizes some day. Turns out that day was way closer than i anticipated. Time to get all Mavericky -- er i mean, MacGyvery.

I'm sure you see where this goes. No? Here's how to make a funnel out of a water bottle.

Step 1: Tools and Equipment

  • Bottle
  • Bottle cap that fits the bottle
  • Pen that fits inside the liquid's destination
  • Utility knife
  • Drill
  • Drill bits
  • Hand saw
  • Sealant

Step 2: Prep the Cap

Carefully determine the proper drill bit diameter to use. If you have calipers or another accurate way to measure then use it. But I don't. I tend to rely on the rack that my drill bits came in to approximate the right size bit. Of you can hold them up to each other and eyeball it. Or put the drill bit and pen on a level surface (check with your level first) and with them close to each other - perhaps an inch or two apart. Then put the level on and make sure it is still close to level. In all cases you actually want the drill bit slightly smaller than the pen.

If you have a vice you can try putting the bottle cap in it. Or adjust a set of locking pliers (Vice-Grip type) so that they will hold but not crush the cap. Or screw it onto the bottle and bravely drill the cap while holding the outside of the bottle. I, of course, would prefer that you find some safer way to do this though.

Step 3: Prep the Bottle

Use the utility knife to cut off the bottom of the bottle. If you'll be using the funnel at an angle you can get fancy and cut the funnel at an angle that would keep the opening horizontal. I'd also suggest rinsing and drying the inside of the bottle.

Note - in some cases this is the only step you need. If the bottle opening will fit inside whatever you are pouring into then you don't need to mess with the cap or pen.

Step 4: Prep the Pen

Disassemble as much of the pen as possible. Use the saw to cut a length of a few inches. Clean up the opening with the utility knife.

Step 5: Assemble

With the cap on the bottle see how close the pen fits the opening in the cap. If it is too tight slowly whittle a small amount away from the cap opening until you can jam the pen in tightly. If you would like you can apply a sealant inside the funnel and around the pen to ensure there are no leaks and to make more of the liquid flow into the pen and not get trapped in the well formed around it.

Step 6: Alternate Materials and Thoughts

This Instructable was a dramatization. Any similarity to actual events is...

Just kidding. I really did need to whip up a funnel But i ended up using part of a floor lamp. I recognize that most people probably don't have a bin of lap parts ready to become funnels though so the pen idea filled in as a bit more universal solution.

But if you ever are throwing a lamp away (please sell it, give it away, donate it, or at least recycling as much as possible) save some parts like these threaded but hollow pieces. One came in handy for me!

The fit was so tight that i had to use pliers to put the "spout" on the bottle cap.

Be sure to recycle any scraps you cut off of your bottle. And try to only kill a pen if it is dead or doesn't work well.

If you make a few of these with slightly different sized bottles they could nest. The best part is that the bottle caps are probably the same size so you can swap a small diameter pen for a larger piece of a lamp spout to your funnel to suit your need.
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