There is a 1min advert before the video, so be patient.
https://v.qq.com/x/page/i03493rjjqi.html
I think I have posted some of this here already , so apologies if duplicated information.
Briefly the intro to video:
1) clay is from any areas / mines around or even further places and in various qualities
2) coloring of the clay with many varieties of shades
3) lab test pointing on toxic substances and dangerous for health
4) fake certificates for teapots
5) duplicate of stamps ( those at bottom teapot ) , multi production of one identical stamp
apart of the chem. used on video , there are other chem.substances used . Like one for preventing / reducing contraction of the clay during the firing, so rises up the production efficiency ( less pots will break ) . Some teapots are machine made , the clay is being stretched and rolled between rotating drums like a tape magnetophone ( that requires clay being stretchable, so it doesn't tore apart ).
There are also made in forms like liquid clay being mold there ( to keep viscosity right, some chem. is also used ) , those teapots are not even fired sometimes, the have some chem. adhesive so they turn hard after while.
no point judging a teapot based on price or vendor's reputation. The vendor doesn't go to the mine get the material and doesn't keep an eye of clay production till teapot is made. Some vendors can go to the place of production and check the environment , learn something about tricks they do there in certain time.
Teapot makers just buy already made clay in tubs or bricks of 20-30kg , then make something out of it. Sure that experienced maker can feel if clay is very bad.
Many successful vendors follow the demand and reflect the market, which increases the possibility of fakes on demanded stuff. You need to understand , that if you are looking for something very old and rare ( and whole marketing is built on that factor ) , you are in competition with some million of Chinese tea enthusiasts who also many of them are tea vendors who might have an access to the real , but also fake stuff.
If you buy a teapot because easy to use and it's within your affordable / comfortable price range , you will be happy.
If you buy an expensive teapot because it is rare stuff , you will be upset each time you learn the possibility you have bought a fake ( unless you blindly believe that your is real because this vendor is recommended by everybody and this vendor is famous..etc. )
It is good to understand Chinese economy in this way. If there is a demand but not in stock, they will make it no matter what. That's the make money. They have in culture thing called 面子 (mianzi) - face . Loosing the face means get into the awkward, not comfortable situation, being disrespected ..or something like that (depends on situation ) . When I asked some guys if they are not afraid to loose their face when selling fake Bingdao or LBZ , they told me that these days for the bowl of rice ( means make some money ) , you shouldn't be afraid of anything.
I have noticed that even some foreign vendors ...more reputation - more trying the luck . I wouldn't dare to claim that it's intentionally but I believe the " give up on authentic search " , which is the most time ( and so the money ) consuming part of the business, plays the role as well.
Same stuff applies to tea.