If you are experiencing problems with vape cartridges leaking, Please follow me to have a look：
Nobody likes an oil spill of any magnitude. Moreover, CBD or THC oil is so expensive.
Background: those cartridges we talked are all have the same structure: the airflow（intake) hole is on the bottom. And oil was leaking from the intake hole or bottom hole like the below pictures showing:

1. The material we prepared:
Normal e-liquid,not thick oil ( no THC or CBD oil can be sold in China), two pcs white papers, Pyrex CE3 Bud (1.0ml,0.7mm hole,)
M6T Cartridges with press fixed drip tips (0.5ml, 1.6mmhole), TH205 (We also called G5) with screwed drip tips (1.0ml or 0.5ml, 2.0mm)
2. subjects: bottom airflow hole

Procedure:
1. screwed off the mouthpieces and fill the oil in the cartridges, three samples without mouthpieces and 2pcs G5 have been screwed with mouthpieces immediately after filling with oil. Then no leaking, and the paper is still clean:

1.After 8mins, only G5 comes to leaking:

2.After 12 mins, the M6 comes to leaking:

3. Then screw the G5 with mouthpieces and pressed the M6’s mouthpieces into the tank also. Clean the rest of the bit oil which kept the bottom, no leaking at:

4. After 25mins, the pyrex CE3 also began to leak:

5. Screwed pyrex CE3, and it stops leaking more, the paper is still clean and dry:

6.serveral hours later, no one leaking more,even with this normal e-liquid (Tips:After several hours of the cartridges not leaking,it is best to turn them upside down and store them this way at least 12hours like picture shows. This will greatly reduce the chance of leaking. After 12 hours, pack them anyway you want. )

Results and Discussion
So we can learn the information clearly through the real pictures by steps:
1.all the tank will leak without mouthpieces finally
2. The biggest oil hole will leak firstly, then the smallest ones will leak latest.
3. If you screw with the mouthpieces immediately, then no leaking at all
4. If you screw with mouthpieces after they leaking, then it will be back to good and won’t leak more.
How to do:
1.If you have thicker oils you will experience fewer leak issues overall for big hole cartridges.
2.please screw the cartridges in mouthpieces and do not get off the silicon bottom caps at the same time which will secure it from any form of leaking.Come to witness the miracle.

Then why?
First, we need to know their own structure clearly:

The ceramic coil was wrapped around by a layer of cotton which can absorb oil . Then the coil was pressed in the metal tube and put in a glass tube, and screw with bottom base. So you can know there are no resistance to stop the oil from flowing out the bottom.it is empty like below picture shows, the whole tank is not hermetic space.

When you fill the oil in the tank, the oil will flow in the coil through the oil hole, (bigger oil hole would absorb the oil faster), then the coil cannot keep oil and oil will flow to the bottom directly. then leaking through the intake hole or bottom hole
As when the tank is open, the air coming to the tank and produce air pressure.which would press the oil to sink and flow. And coil cannot keep or absorb the coil. So leaking problem.

If you screw with the mouthpieces, then no air coming, the oil can be kept in vacuum space, there is no or less air pressure, the oil can be absorbed by coil well and won’t flow to bottom.

When you smoke it, then it can provide huge cloud vapor which is lighter than oil and prevent the oil from leaking also.

In Words, the good news is there is not anything wrong or faulty with the cartridges.all you need to do is to screw in the mouthpieces timely to reduce back pressure and keep them in a good way.

Other ways to prevent leaking :
1. The best manufacture can do is to expend the resist-leaking time. They can try to make the coil can absorb more oil or narrow the tolerances between the coil and metal components which can block the oils from flowing faster.
2. Consumers can choose other Leak-Proof structure cartridges .if you need a recommendation to visit us at www.vapes-wholesale.com and we will make sure to provide you perfect cartridge.
3. Different oil match different cartridges