Vented Cubie Caps

By Rick Da Tech


vented cap

Draining the glycerin can expose you to high levels of methanol fumes. These can be virtually eliminated with a vented oil jug cap. The cap will let you drain your glycerin into the oil jugs you pick up your oil in. There have been a number of vented cap designs on the Internet. This one draws from and simplifies those designs. This very simple easy to replicate design does not call for any special skills to assemble. All of the parts are available at the hardware store except for the Camlocks and those are available at hydraulic supply stores.

Bill of Materials

Qty Description Price
1 3/4" Type E camlock $2.60
1 3/4" Type B camlock $6.96
1 3/4" Type F camlock $2.60
1 1/2" Camlock set with one Type F, one Type B, and one Dustplug $12.21
8" 1/2" hard copper tubing $3.85
1 PVC Schedule 80 TEE $3.47
1 3/4" hose barb $0.37
1 1/2" x 3/4" hose barb $0.84
3 ft 3/4" clear PVC tubing $2.00
10 ft 1/2" clear PVC tubing $5.20
1 3/4" x 3/4" x 1/2" Black Malleable TEE $1.20
1 3/4" x 4" Black Pipe Nipple $1.09
4 Hose clamps $4.00
1 3/4" Conduit Lock Nut $0.25
1 Silicone Sealant $3.65


Required Tools

  • Tubing Cuttertube cutter
  • Inexpensive tubing cutters can be found at the hardware store, you will need a set that can handle 5/8" OD type L (hard) tubing.
  • Pipe Wrench
  • Your standard Pipe Wrench
  • Hammer
  • The common framing hammer will work great
  • Needle Nose Pliers
  • These will be used to tighten the conduit lock nut
  • Hacksaw
  • Sharp Knife

hose barb

Use a hacksaw to cut the hose barbs off the threaded portion on the 3/4" hose barb. You want to use one of the extra hose barbs from the kit.

cut barb

Put the threaded portion over the end of the tubing. Notice the hose hole is slightly smaller than the tubing. Using a light tapping, hammer the threaded portion of the hose barb onto the end of the pipe. If you stop every so often and trim away the shavings it will go easier. You will want to use a scrap piece of tubing for this, since it will most likely damage the tubing in the process. This step is why you must use the hard tubing. The soft tubing would not cut the plastic.

type b camlock

With the copper tubing inserted into the modified hose barb, assemble to the TEE and then to the type B camlock.

cut hole in jug lid

Cut a hole in a WVO jug lid big enough to be able to pass all the threads of the type F camlock. I used a knife and a file to slowly whittled out the hole.

Put a bead of silicone on the shoulder of the type F camlock and slide into the cap. Screw the conduit locknut on to secure the cap to the camlock. Allow the silicone to cure for 24 hours

top of tank

Remove the vent and add the 3/4" x 4" nipple and the 3/4" x 3/4" x 1/2" TEE in the resulting hole. Then put the vent back into the TEE on top. Screw the 1/2" type B camlock into the side of the TEE.

This is where you will hook up the vent from the cap using the 1/2" Type F camlock. The dust plug is to be used when the vented cap is not in use.

vent on jugcross connections

Just screw the camlock cap onto the cubbie and slide the TEE assembly down onto it and fasten. The vent hose is attached to the side with the hose barb. The tubing on top is a mismatch. The copper tubing is 5/8" OD and the PVC tubing is 3/4" ID. I used two hose clamps here and had a bit of leaking until I laid the connection in the sun to let the PVC tubing soften and then retightened the hose clamps.

The 3/4" PVC tubing is attached to the lower manifold via the drain port. I have installed camlocks in the drain port and used a Type F Camlock to terminate the end of the hose.

Copper Camlock Cubbie Cap

cubie camlock in copper

For the DIY person with soldering skills, here is the camlock cubbie cap in copper. The copper parts cost under $10.

It's all standard copper parts with two exceptions. The 3/4" elbow on top is a street ell which lets you clamp your 3/4" tubing directly to the ell. The 3/4" end of the 3/4" x 1/2" reducer is the same size as the tubing and will slip inside a coupling. The 1/2" end is normal and 1/2" hard tubing will slip inside the reducer.

There is no need to file any bumps or ridges off since the 1/2" tubing does not need to go all the way through the reducer. The short 3/4" tubing is to slide down into the TEE to act as a spacer for the reducer to rest against. Of course, some of the reducer is sticking out of the TEE. That part cubie camlock in copper sticking out is what you solder the ELL onto.

The Type F camlock is mounted to the cubbie screw cap the same way as shown with the plastic version.



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