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

[ThisIsMyFirstRodeo]

MOD any chance we can make this a sticky?

There seems to be some solid data and observations gathered through scientific method, both supporting and debunking various anecdotal hypotheses/practices, and  I already see them being invaluable resources that I will continue to refer to. 
I know there were others contributing as well, but props to FredK. Have you by chance assembled a compendium of your research/experimentation?
 

I also want to add in that the historical practices also have much to learn from. Again, I know others contributing to the conversation, but thank you Aventurine. Any particular go-to sources that you pull from? I love learning about the history and foundations of my various hobbies. 

Edited September 8, 2024 by ThisIsMyFirstRodeo
Give credit where credit is due

[fredk]

Here we are; 1 year completed (more or less)

September 30 2024

Set #1, the car set - Pieces treated and kept on the top of the dash in the south facing  windscreen (windshield) of a car

1. Baby Oil; Both sides are very dark, More flexible than Control 1 (C1), No smell,  No sign of rot or fungus

2. Cooking Oil (rape seed);   Both sides very dark, Slightly more flexible than C1, No smell, No sign of rot or fungus

3. Lard (pork fats);  Light but darker than C2, Slightly more flexible than C1,  No smell, No sign of rot or fungus

4.  NFO Compound; Both sides very dark,  Flex is better than C1, No smell,  No sign of rot or fungus

5. Olive Oil ( Pure Extra Virgin); Both sides very dark, Flex is only slightly better than C1, Slight odd indistinct smell,  No sign of rot or fungus

6. 3 in 1 oil (benzine); Both sides very dark, but back less so, Flex is stiffer than C1, No smell,  No sign of rot or fungus

7. Vaseline; Very slightly darkened both sides, Flex is slightly stiffer than C1, No smell,  No sign of rot or fungus

 

Set #2 were hung outside on a wood frame. They got light and heavy rain with periods of sunshine,  warm overcast and wind, both light breezes and strong winds

The same oils were used in the same sequence . Control C1A was hung with the other pieces

1. Baby oil; Both sides are very dark, Flex is better than C1A, Slight smell of leather  No sign of rot or fungus

2. Cooking oil;  Both sides very dark, Flex is very slightly better than C1A, No smell, No sign of rot or fungus

3. Lard; Both sides slightly darker, Flex is about the same as C1A, No smell,  No smell, No sign of rot or fungus

4.  NFO Compound;  Missing, blown away

5. Olive oil;  Both sides and fairly dark, Flex is better than C1A,  No smell,  Grain surface feels oiled, No sign of rot or fungus

6. 3 in 1 oil;  Both sides are now a very dark brown, Flex is better than C1A, No smell, No sign of rot or fungus

7.  Vaseline;  Both sides very slightly darkened,  Flex is only very slightly better than C1A, No smell, No sign of rot or fungus

None of the pieces seem to require re-oiling

All but 1 test piece have a neutral smell, or none.  That 1 piece, #5 of Set 1, the slight odd smell is so very faint and its not a bad smell therefore I'm not worried about it.

#4 of Set 2 went AWOL just the day before  I brought the pieces in to record them

In conclusion; No rot or fungus. Just the loss of smell - either of leather or of the oil used. The darkening of the leather by some oils and greater flexibility by most

I think thats it for now

 

[SUP]

Thank you @fredk.

My one year update is long overdue. Strapped for time.

I am keeping watch and all leather appears unchanged from last time. The detailed descriptions, I will be able to get to it by late Oct or early Nov.,2024.

[fredk]

I was thinking no-one was interested in this anymore      

I look forward to your report, whenever you can make it  

[SUP]

Oh, I am interested. I am watching the leather pieces as well. 

A lot going on right now so I don't have the time to make the tables and give the careful descriptions that I like to do. Ergo the delay.

I will be interested as long as I live, I think. it is that sort of experiment.

[txcowboyforhire]

Please keep us informed I am sure I am not the only one who checks in on this thread!

[fredk]

I'll be doing an up-date report at the end of January

In the meantime; I brought all the outside pieces in over late December to now as we had gale force winds nearly constantly, 40 to 60 mph wind with gusts up to 90 mph. I reckoned they'd just be blown away. Now I need to find where I put the pieces. But . . . but . . . I found the missing piece #4! In the front 'garden' of all places

[SUP]

Working on my sets today. I have been very delayed this turn - health and other issues. But now I am able to get down to it. It's so cold here now, at least for those of us here who are more used to warm weather.  Waiting for it to get a bit warmer in the day before venturing out to get the leather that is placed outside.

Edited January 15 by SUP

[SUP]

I started working on my sets of leather pieces and then realized that today and next week, the temperatures are going to be unusually low for this area and the leathers have not been exposed to such low temps. So I postponed my updates until after the temperatures rise to a reasonable level (for this area) next week. Let's see how they react to such temperatures. I will check on them when the temperatures are low as well.

[fredk]

As the end of the month nears and my report looms, I never got the out-side pieces out again. We had a couple of very big storms, with winds blowing 75 -80 mph, gusting to 90 -95 mph. Only a couple of days between the storms which lasted about a week each.

However, the pieces inside the car are ok

see y'all later