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

[fredk]

Might. But I'll stick with the vaseline on these. They had about a week for the vase to 'soak' in. Next time I'll put them straight out

[SUP]

Okay. 

[fredk]

Its been raining today. Not very heavy. I put vaseline on the pieces again and put them out

One piece after about 1 hour. Seems the rain is soaking in at the edges. The water is being repelled on the surface

Another piece after 1 1/2 hours. The rain has soaked in but its also being repelled on the surface

On its own and in one coat its not good at waterproofing but I think multiple coats, each allowed to soak in and be absorbed before the next coat is put on may be a decent waterproofer

I don't think I have anything to try out my thoughts. It would need a leather hat or a shoulder bag and I don't have anything like that made

[SUP]

I'll maybe make a small coin purse with veg tan ad try Vaseline on that. Let's see.

[fredk]

Excellento

[SUP]

I kept several pieces of veg-tanned leather with petroleum jelly , which I shall now call PJ, in the rain. These results are after a night long, heavy exposure. It rained heavily overnight and I could check the leathers only in the morning..: 

I used 6 pieces of leather as follows:

	Petroleum Jelly	Mineral oil
Control.	N/A	N/A
CM	N/A	Yes
PJ1	Yes	No
PJ2	Yes	No
PJM1	Yes	Yes
PJM2	Yes	Yes

 

Observations and conclusions follow.

Edited May 27, 2024 by SUP

[fredk]

PJM1 is looking promising

What oil?

[SUP]

OBSERVATIONS:

	FRONT	BACK	EDGE
CONTROL	S, WD0, TN; FD	S,TN, FD	S
CM	S, WD0, TS, FD	S, TS, FD	S
PJ1	S-, WD, TN, FDRY	S0, TN. FDRY	S50, TN, FDRY
PJ2	S-, WD, TN, FDRY	S0, TN, FDRY	S50, TN, FDRY
PJM1	S, WD+, TS, FD+	S, TS, FD+	S
PJM2	S, WD+, TS,FD+	S, TS,FD+	S

The key: 

Soaking:		S = heavily soaked.
		SL= lightly soaked
		S- = surface water absorption
		S0 = no water absorption.
		S50= half absorption
Water droplets		WD=water drops present
		WD0= no droplets
		WD+ = Many water droplets
Feel of leather:		FD = damp
		FDRY = dry
Texture:		TN  Normal
		TS = soft

 

Control: Soaked through no water drops on surface, not softened. Sides clearly soaked through as is the back.

Control plus mineral oil: Darkened due to the oil, no water drops on surface, soaked through, sides and back are soaked as well. Noticeably softer.

PJ1: Darkened due to PJ, Water drops on surface, surface water absorption, sides show water absorption on surface, back dry, texture unchanged.

PJ2: Darkened due to PJ, Water drops on surface, surface water absorption, sides show water absorption on surface, back dry, texture unchanged.

PJM1: Darkened due to PJ and MO, plenty of water drops on surface, complete water absorption, sides show complete water absorption, back show water absorption, texture soft, leather feels damp.

PJM2: As for PJM1.

CONCLUSIONS:

It is clear that PJ does inhibit water absorption by leather, this inhibition being affected by other factors. Here, the mineral oil clearly decreased this water repellent effect.  Petroleum Jelly is not absorbed by the leather. It remained on the surface. When applied on plain clean leather, it stays in place and is an effective repellent. When applied on top of mineral oil however, the 2 greasy materials slide against each other and the petroleum jelly being on the surface, probably did not spread well and possibly got drained away by heavy water drops and left the leather vulnerable.

With a night of being exposed to heavy rain, the leather pieces with only PJ are still not soaked through. For short exposures, petroleum jelly appears to be a good water repellent.  

When and with what to use it and how to ensure it remains in place are the next questions.

I will next try to see if warming the leather after petroleum jelly application helps.

Unfortunately, although PJM1 and PJM2 both had plenty of water drops on the surface, they absorbed a lot of water as well.  Need to see how to avoid that, other than not leave the leather out in torrential rain all night!

[fredk]

Your PJ is different to my vaseline. The leather absorbed the vaseline

I'll do some more tests later

[SUP]

I'll go get the Vaseline brand of PJ and see what happens.