Author Topic: Q - Does petroleum jelly (vaseline) melt silicone?  (Read 20880 times)

Offline Ninja_Butler

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Q - Does petroleum jelly (vaseline) melt silicone?
« on: August 15, 2012, 12:53:26 PM BST GMT »
I've noticed that the tips of my clay-shaper tools seem to be dissolving away! I lubricate them with petroleum jelly but is it the PJ or the Greenstuff that's doing it?

Offline moonmin82

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Re: Q - Does petroleum jelly (vaseline) melt silicone?
« Reply #1 on: August 15, 2012, 01:54:57 PM BST GMT »
In time any amount of oil based lube will cause clay shapers to perish.

Offline Thrasym

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Re: Q - Does petroleum jelly (vaseline) melt silicone?
« Reply #2 on: August 15, 2012, 07:03:32 PM BST GMT »
Silicone is weird, it is weakened by oils and most soaps and all sorts of things but resistant to lots of stuff too. Specifics depend on its exact formulation of course.

Offline Ninja_Butler

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Re: Q - Does petroleum jelly (vaseline) melt silicone?
« Reply #3 on: August 15, 2012, 10:53:18 PM BST GMT »
Thanks Moonmin and Thrasym. I don't know how long clay shapers are supposed to last but I might try using olive oil instead of vaseline to make them last longer.

Offline moonmin82

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Re: Q - Does petroleum jelly (vaseline) melt silicone?
« Reply #4 on: August 16, 2012, 05:18:54 PM BST GMT »
I'd have thought you'd have the same problem with other oils too. Perhaps more so, as olive oil being more liquid than a grease such as Vaseline it would dissolve the silicone easier.

Silicone is a polymer and over time the interactions between the polymer strands weaken. Over time a rubber will go from being firm to being soft and more mobile (as the polymer strands / chains weaken and 'flow' more freely). Heat energy speeds up the process breaking apart the strands quicker. Dissolution in similar polarity solvents (i.e. oils and greases) aids the process further.

Do you wipe off all excess lubricant when you've finished sculpting?

PS Apologies for the impromptu chemistry lesson :-S

Offline moonmin82

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Re: Q - Does petroleum jelly (vaseline) melt silicone?
« Reply #5 on: August 16, 2012, 05:28:08 PM BST GMT »
Hmm... my bad:

"Silicone is a material of choice... due to its non-degradation by petroleum-based lubricants"

Thanks to Wikipedia :-P

Maybe it is the GS? Perhaps slight amounts of cured GS cause it to peel slightly?

Offline Ninja_Butler

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Re: Q - Does petroleum jelly (vaseline) melt silicone?
« Reply #6 on: August 16, 2012, 11:00:34 PM BST GMT »
Ha.. back to square one. Maybe they just don't last very long on Greenstuff? I guess they're designed more for polymer clay than epoxy putty, polymer clay being softer there must be less friction.

Offline moonmin82

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Re: Q - Does petroleum jelly (vaseline) melt silicone?
« Reply #7 on: August 17, 2012, 11:09:29 AM BST GMT »
Must admit one of mine looks like it's perishing a little. It's never had an vaseline etc on it (and rarely even water - I tend to use it dry...) so it must the GS / Procreate.

Offline Icy

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Re: Q - Does petroleum jelly (vaseline) melt silicone?
« Reply #8 on: August 18, 2012, 08:06:20 AM BST GMT »
I've always thought this was simply due to abrasion.

Offline Badsmile

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Re: Q - Does petroleum jelly (vaseline) melt silicone?
« Reply #9 on: August 18, 2012, 10:38:34 AM BST GMT »
I think clayshapers were first designed and thought to be used as some kind of brush for painting. Not sure though. Mine are used very little so I can't say anything apart that mine look like new but I have only used them on polymer clay so far and as I said only very very little.
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Offline aly.r

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Re: Q - Does petroleum jelly (vaseline) melt silicone?
« Reply #10 on: August 18, 2012, 06:13:09 PM BST GMT »
I remember Andrew Rea saying that his have been worn down from use with poly clay, cause the graininess of it acts a bit like sandpaper.

Offline Ninja_Butler

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Re: Q - Does petroleum jelly (vaseline) melt silicone?
« Reply #11 on: August 18, 2012, 06:26:20 PM BST GMT »
Sounds to be like "abrasion" is the definitive cause. It doesn't really make any difference but it does make me feel better that I haven't worn out my clay-shapers due to my own carelessness! :-)

BTW, I've noticed that most people seem to use size #0 clayshapers for miniatures but I bought a size #2 flat chisel and it's proven to be more useful than my size #0 flat chisel.

Offline Andrew May

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Re: Q - Does petroleum jelly (vaseline) melt silicone?
« Reply #12 on: August 24, 2012, 12:20:49 AM BST GMT »
Yep they're literally being worn away. At the rate I'm working ATM I'm going to have to replace mine every few months.

Offline mondria

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Re: Q - Does petroleum jelly (vaseline) melt silicone?
« Reply #13 on: September 02, 2012, 08:03:05 PM BST GMT »
you do you guys abuse them, I have mine for over 3years and in daily use not a mark on them, the metal part that holds the tip is worn but tip it self is still perfect. I dont use GS only PC and MS.

I use the back tipped ones, they are indeed also used as brushes to blend colors on the canvas