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

[MikeRock]

Fred,

Do you use Castrol in your Austin?  Sure loved the smell when I was racing bikes...  I wonder if the castor oil addition makes a difference on your leather auto straps?

[fredk]

I do use Castrol in my Austin engine. But it doesn't get any where the straps on the outside. Its getting hard to get now though

@SUP 60 -70 mph winds and weak hempen twine

[SUP]

@fredk, like during the monsoons in Bombay, now Mumbai. 'Curl up with a good book and a cup of hot tea and biscuits' weather, we called it, while the wind rattled the windows and palm fronds lashed violently.

[fredk]

They would be very strong but as ex-postie I enjoy being out in the wind and rain

[SUP]

I understand that! In my teens, my friends and I used to walk along the shore in that rain and wind. Rocky shore, so not much sand to contend with. Else that would not have been possible. But great marine specimens to be found post- storm!

[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

[Beehive]

I've been thinking that's what Fiebing uses in their oil dye. Mineral oil. When you rinse out a dobber in the sink. You can see drops of thin clear oil. If it's not mineral, I'd be extra curious to know what they use. Interested in your results too. 

[SUP]

Firstly, I am 4 months late with this report and I apologize. 

Secondly, I also apologize because I seem to have lost one of the pieces of leather, the control kept in the car. I will make a new one but it will affect the results. I searched for a couple of days but it probably fell out somewhere. I will make a new one but it will affect my results, unfortunately.

These are my results for 29th Jan., 2025

The leather pieces showed some differences from my earlier report.

Smoothness indicates the surface feel – silky smooth or rough.

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

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

Smoothness: Across the boat, the leather pieces treated with mineral oil continue to be the most smooth. Neatsfoot oil is next, followed closely  by coconut oil. The leather treated with coconut oil and kept outside exposed to the elements is as smooth as the mineral oil leather and both are smoother than the controls The pieces treated with mink oil continue to be the roughest in each of the areas where the leather pieces are kept.

Color: The leather pieces treated with coconut oil have been gradually decreasing in darkness. The coconut oil pieces are, in fact, comparable to the mineral oil one kept inside. The darkest, across the board, are the leather pieces kept outside.

With the exception of the pieces kept outside, most of the pieces have a more or less similar color, regardless of the location and oil treatment..

Shape: The mineral oil pieces continue to be the least warped in each location, now followed by the Neatsfoot oil ones and then the coconut oil leathers.  The mink oil pieces continue to be the most warped in each location

The control pieces show quite a bit of warping as well.

Stiffness: The stiffness differs according to location, with the pieces kept outside being the most stiff. The mineral oil pieces have softened and are now comparable to the coconut oil pieces in all but the outside locations. Surprisingly, the mineral oil pieces kept inside and in the car are stiffer and comparable to the mink oil ones.

The stiffest, across the board, are the leather pieces kept outside.

The coconut oil pieces have gradually lightened in color until they now are approaching the colors of the pieces treated with all the other oils.  They show the least stiffness across the different locations although mineral oil is comparable in the garage sample and the other two oils in the car samples. The exception is the piece kept outside which is still the least stiff in its location.

The mineral oil pieces are uniformly colored except for the piece kept outside. They are all a bit softer than they were in the previous report. They are slightly less flat but not enough to have curled edges.

The neatsfoot oil pieces continue to be moderate in everything – color, smoothness, dryness but they are a little stiffer, approaching that of the mink oil treated pieces.

The mink oil treated leather pieces are the driest, roughest of all the leather across the different locations and they continue to be the stiffest as well – but not as much as the pieces kept outside. The mink oil treated one kept outside is the stiffest of that location though.

The pieces treated with all the different oils and kept outside exposed to the elements are the darkest, driest, stiffest and most warped of all the pieces. So, keeping leather outside in the heat and cold and rain and snow causes significant damage, regardless of the oils with which it is treated. Of course, this is one and a half years after treatment. Next winter, I will treat a new set of leather pieces with all these oils and check whether treatment just before winter sets in, protects the leathers better.

At this point, the leathers treated with mineral oil, coconut oil and neatsfoot oil all  seem to be reaching similar characteristics – in color, stiffness and smoothness. The mink oil treated ones though, are rough, stiff and changing shape, sufficient to wonder whether it is worth using on leather.

I will repeat the experiment with a different source of mink oil because it is has a long history as a leather conditioner and I would not like to say otherwise without confirming the results.

Of the other oils, up to now, I find mineral il to be the most useful. It smoothens the leather, does not cause warping or dryness and it is virtually inert. Coconut oil is next – it surprisingly does not leave a rancid smell, softens without turning the leather to mush and smoothens as well. Neatsfoot oil in small quantities should work, as it has been doing for centuries now.

I will put up the results of the other oils within the next couple of days.

 

 

 

 

 

 

 

 

 

 

[fredk]

[SUP]

Thank you.

[jrdunn]

16 hours ago, SUP said:

Secondly, I also apologize because I seem to have lost one of the pieces of leather, the control kept in the car. I will make a new one but it will affect the results. I searched for a couple of days but it probably fell out somewhere. I will make a new one but it will affect my results, unfortunately.

Maybe it's in @fredk's front garden.  Just kidding.  I wanted to thank all the contributors to this endeavor.  It's very interesting.  Frankly, I don't have the attention span for this kind of research.  JM2C, Jim

[SUP]

Flew across the Atlantic?