Ring flashes are alright is you are but, make for a flat shot without a supporting light, reflector or some such, Most wouldn't notice the flatness unless it was pointed out to them.
Experiment with flash positions and play around with the flash on your phone, bounce it, reflect it, just learn what it can do. Some phones have various flash settings. Worst that can happen is you'll delete a file, it's not like film and developing costs and time. All you are wasting is time and it'll be time well wasted.
It's wise to learn the limitations of any and all equipment so you will recognize when you are stretching capabilities.
You get the award for artful use of a bath towel! Nice job!
I did purchase a $5 Ebay light box with LED light strip, I use my old point and shoot still that is 20 years old. Wife has a DSLR with teleophoto lens but the field of vision is always wrong We also have a $600 point and shoot, but it has the same issue as with the DSLR. Woodsroad tried to help me (a professional photographer), but to no avail.
Shooting good pipe pictures is a lot harder than it would first appear.
You can also just use a north-facing window, a neutral background and white foamcore or mirrors. For more punch, you can cover the foamcore with aluminium foil.
In a simple, uncomplicated nutshell: the main point is that you just don't want the main light to come from the front, on the same axis as the camera. All the more so if the pipe is rusticated/sandblasted, because frontal lighting will wash out the texture (which is why we use frontal lighting to take portraits of old people: it hides the wrinkles); for textured surfaces you want the light to come from the side (raking) so as to emphasise said texture. Ditto for pipes that sport plateaux rims, such as the ones the OP's showcasing here.
Even for smooth pipes or surfaces (i.e. stems) you don't want frontal light because of the ugly glare.
You don't have to read all the epistle, but I reckon the pictures' footnotes would help. Feel free to read the whole thing, if you so want, though:
Again, thank you all for the information and lots to digest. Olko, I read that article all the way through and bookmarked the page. I will have to re-read it several times to digest and understand the information. I've cut and pasted and printed several of the comments and they are now hanging on my shop wall where I can refer to them as necessary.