Mineral oil bad for leather? Or good? Or neutral?

[fredk]

I'll be doing my next proper check this coming weekend

[SUP]

@fredk, I'm afraid I'm going to be later than that.

I'm going to Jim Linnell's classes! 2 of them over the week-end - Friday - to refine swivel knife techniques and Saturday to learn how to make leather jewelry - specifically how to make stones like Turquoise realistically. On Sunday he is teaching figure carving.  I might not be able to go for it. But 2 classes itself will be a great learning experience.

 

Edited February 28, 2024 by SUP

[fredk]

I forgot to do an update

The test pieces in the car - no change

At the start of this month I made up a second batch of 8 pieces and hung them up on a specially made rail. They'll get full sun on them as well as wind and rain. I'll check them tomorrow

[SUP]

 I've been lax. I need to pull up my socks and get to work. I will do a detailed update next week. 

Had a sudden cold  and rainy spell but warmer now, so it is time to see how winter affected the leather outside.

 

 

[SUP]

Report for 22nd March, 2024.

The leather pieces showed some differences from 3 months ago.

Firstly, an explanation of what the descriptions mean.

Smoothness indicates the surface feel – silky smooth or rough.

Shape indicates how the pieces hold their shape – whether the corners curl or the edges curve or even curve in a wavy manner.

Stiffness indicates how easy it is to bend or fold the leather.

Color: Indicates the extent of darkening.

Smoothness: The leather pieces treated with Mineral oil were all the smoothest, having a silky feel. The next were the leather pieces treated with Neatsfoot oil and Coconut oil, which were similar - relatively silky. The Mink oil treated leather pieces felt a little rough, even more so than the control pieces.

Color: Coconut oil darkened all the pieces the most, although all the pieces in all the locations except directly outside, are lighter now, than 3 months ago. in fact, they are almost as light as the leathers treated with the other oils. The least darkened are the leathers treated with Mink oil. Pieces treated with Mineral oil all have remarkably similar color except for the one outside. They also have remarkably uniform color - actually beautiful.

Shape: The most warping was seen in the control leather pieces at every location.  The Mink oil treated leathers were also relatively warped, the Coconut oil treated ones, less so. The leather pieces treated with Mineral oil were the least warped and held their flat shapes very well.

Stiffness: Here, the stiffness differed more according to location. The leathers kept outside were the stiffest in their treatment categories. The least stiff were the ones treated with Coconut oil and then the ones with Neatsfoot oil. Most stiff were the leathers treated with Mineral oil. The leathers treated with Coconut oil are actually very soft.

All the pieces treated with Coconut oil are the softest and smoothness is second only to Mineral oil treated leathers. This is surprising as, initially they had appeared a bit dry in Dec., 2023. They darkened earlier but over time, all except the leather placed outside are close in color to the leather pieces treated with the other oils.

The leather pieces treated with Mineral oil are the flattest with least warping, the smoothest and all darkened uniformly and to the same extent in all locations except outside where the piece darkened significantly more, as expected.  The darkening is also remarkably uniform over each piece.  They are all however, also the stiffest.in their location categories.

The leather pieces treated with Neatsfoot oil are moderate in every way. Moderately smooth, moderately stiff,  moderately dark and moderately but not too warped.

Mink oil continues to surprise me. The leather pieces in all locations feel least smooth, in fact a little rough. In all the locations- they feel like the controls – untreated. They are the most stiff and dry across all locations, including inside. They are however, the least darkened.

Smell: they all smell like leather to me. There is no mold on any of the pieces.

Seeing the results at this 6 month point (more or less), I can see why more than one ingredient is used to condition leather. Depending on the use of the leather goods, specific ingredients that complement each other can be selected to get the best results. This is still premature and I have added tallow, cod liver oil  and lanolin to the line-up. I just added them a couple of days ago, so have not included them here. I will list them separately next week and from next time, list them all together, along with any other ingredient that I might add.

If colors in the photograph appear different from my description, it could be the play of light.

 

Edited March 22, 2024 by SUP

[SUP]

CORRECTION: Leather pieces treated with Mink oil are not the stiffest. They are second to the pieces treated with Mineral oil.

[GeKl]

Interesting experiment! I ended up here when Googling for more information about whether or not vaseline would be bad as a component of a specific leather balm I had my eye on (Urban Forest Premium Leather Balsam, which I wanted to get as alternative to Obenauf Heavy Duty LP which isn't available here). I had already looked for what were 'good' products vs 'bad', with anything petroleum based (including vaseline) most often being chucked into the 'bad' pile. But that balm also has beeswax, avocado oil and other natural oils in it, besides vaseline. Reviews on it are excellent, as is 'picture proof', but still I was concerned.
 
While not conclusive/100% scientific yet, the rational debate and testing in this thread has at least given me a bit more peace of mind about potentially using that product; since it's not pure vaseline and contains natural oils and beeswax as well, there's a good chance it's a 'healthy' balance between them all and it might not long term deteriorate the leather (at least that's what I'm telling myself, since I couldn't find another product here that guaranteed only mixes only natural oils and beeswax, and making my own is not an option). It's also not like I'm planning to treat heirloom pieces with it, just some knife sheaths and revive/condition a few leather belt satchels. But when there's doubt, my mind tends to go down rabbit holes.

So thanks for your efforts, adding actual valuable info to the interwebs rather than just echoing/parroting (unfounded) hearsay.

Edited April 5, 2024 by GeKl

[fredk]

I'm due to make a report but in the interim my test pieces with vaseline are still slick with it on the surface. I would say it would make a good water repellent top finish

[GeKl]

For my use case, it's partially about water proofing knife sheaths, but also about conditioning/nourishing the leather, as some sheaths and pouches are a bit dry. But given that the product I'm looking at seems like a soft wax/oil mix, I think/hope it might have enough conditioning potential to not have to bother with really liquid oils first. I'd like to avoid having to get multiple products. Not sure if linking is allowed/frowned upon, so just sharing a picture of how it looks, makes me think it's the typical soft waxy conditioner that could even be applied without adding heat:
 
("Avocado and other high quality plant based oils, high quality vaseline, natural beeswax, subtle fragrance")

[SUP]

@GeKl, Thank you. 

I am, in fact, in the process of making a set with mineral oil + a very small quantity of coconut oil - I am using 10% - hopefully that will decrease the stiffness that mineral oil allows. 

@fredk waterproofing with Vaseline is a good idea - a small quantity should work, or maybe mixed with beeswax. 

@GeKl, I think I was typing as your response got posted. That product has oils as well as beeswax and Vaseline. Seeing how ubiquitous such ingredients are in almost every product, I wonder whether they are the ones mainly dong all the work and the plant based oils are added to satisfy customers who still have an issue with petroleum based ingredients. The plant-based ingredients seem to change in different products but the petroleum based ones are more or less the same ones.

Edited April 5, 2024 by SUP