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Tung oil vs Penetrol/Linseed oil?


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#1 GregC

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Posted 15 July 2010 - 06:44 PM

Hi,

I recently finished one of my first pieces with a copper sulphate (sulfate) on mild steel rust patina. Came out looking great and I had some left over automotive clear so I put a couple of coats of that on... but I failed to neutralize the copper sulphate (I only wiped down with acetone) and the rust continued under the clear. So I scraped all the clear off. Rinsed with water, applied a water/baking soda solution and scrubbed it in, then rinsed with lots of water. I gave up on the automotive clear as my thinking was if it continued to rust I wanted to go with a coating that I could easily reapply. So I did lots of reading on here about penetrol and linseed oil. Doing a bit more reading I found that linseed oil could promote mold and since I live where we see all four seasons I figured that was out, but that Tung oil was a good alternative and has been used before for sealing metal and stone.

So I got some Tung oil (described as: Circa 1850 Tung Oil is a ready to use finish made with raw tung oil, and does not contain any other oils, resins or varnish) and mixed it 1:1 with mineral spirits and applied it with an HPLV spray gun. I got a bit of white haze in places, but I think I know the problem, I applied the second coat before letting the first fully dry. Where it was dry before the second coat I do not see any of the haze. It was very hot when I applied it. I applied in the morning and it baked in the sun all day. By the afternoon it was dry to the touch and had a feel similar to the clear coat. Definitely darkens up the colour, but in a good way and not as glossy as a clear coat.

Anyway just wondering if anyone else has used it and if they had much success?
Here are some photos:
Completed piece
stoneinabox_024.jpg

Copper sulphate application
applyingcoppersulphate_004.jpg

Close up of the patina, no clear or tung oil at this point
applyingcoppersulphate_005.jpg

Bag O Rust, the scraped off clear coat (doh!)
applyingcoppersulphate_013.jpg

Close up after applying Tung oil (fully dry)
applyingcoppersulphate_011.jpg

Many more photos here.

#2 Chuck Girard

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Posted 15 July 2010 - 06:57 PM

Well Greg,
I to am still experimenting with Rust Patina.
My good friend here in the Valley turned me on to several versions of the Rust/ Penetrol metheods.
I had to be different than everyone else. I suppose anyway.
I Patina the material then I use Penetrol wiith Japan Dryer.
For my personal taste this seems to work best.
I have used penetrol with linseed oil. But again my personal preference in the look of the finish is what I have described.
Without trying to jack your thread I'll give you an example.


Heat Wave Top Finished.JPG
The piece in the fore ground without linseed oil
And the piece in the Background is slightly darker with linseed and Penetrol

Hopes this helps your cacuse.
[Peace]


Chuck Girard

A.K.A. CHUCK ROAST


"Simplicity is the Secret to Success!" (Someone Smarter than ME!!)[Worthy]



http://www.girardcustomcreations.com

#3 GregC

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Posted 15 July 2010 - 07:48 PM

Hi Chuck,

The foreground piece, is it still wet when the photo was taken, it appears glossy but perhaps that's just the lighting. Both look great.
Greg.

#4 Chuck Girard

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Posted 15 July 2010 - 08:48 PM

Hi Chuck,

The foreground piece, is it still wet when the photo was taken, it appears glossy but perhaps that's just the lighting. Both look great.
Greg.


Actually a day or two dry. I apply with a brush 3 coats min.
The Japan dryer does really help.
[Peace]


Chuck Girard

A.K.A. CHUCK ROAST


"Simplicity is the Secret to Success!" (Someone Smarter than ME!!)[Worthy]



http://www.girardcustomcreations.com

#5 PTsideshow

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Posted 16 July 2010 - 07:13 AM

Tung oil, is useful when it are applied on porous materials were it can get into seal the surface. It works well on stone as all stone is porous to differing degrees.

It is an oil from a nut tree, so people with nut allergies may be affected.

It is not considered to be good product for exterior work,when exposed. The life of the coating isn't long, and it will have to be reapplied at intervals. The length of time will depend on the atmospheric conditions the piece is displayed in. It is what is called a rapid dryer, and does have a tendency to bloom(frost). It has a medium yellow color, to a yellow orange. It also has a medium refractive index.

The two will alter the colors they are applied over.

The blended versions, generally contain a thinner Stoddards solvent, and have an additional dryer some version of a cobalt dryer. So using the blended formula's you would need to use less of a thinner.

The pure Tung oil does have a higher flash point temp/lower fire hazard

The hotter(stronger thinners) work better and the ratio is from 1:1 to 1:1½ oil to thinner. There is still a debate on whether a thick or thin coat is best.

Linseed oil is from the Flax plant, flax seed same thing linen is made from, along with the food supplements.

And to address the linseed oil molding. Depending on what type of linseed oil, Raw, Boiled, Blended,Heat Processed, Cold Pressed,Steam Pressed,Washed and Stand oil (heat processed linseed oil in the absence of oxygen. The rate of molding is generally not much of a problem other than with raw/old oils.

And finally Penetrol is According to the MSDS from the Flood company is a proprietary blend of heat polymerized linseed oil,naphtha solvent, Stoddard solvent and soya long oil alkyd resin.

In lay terms generally a synthetic soya bean-type drying oil. So adding Linseed oil to Penetrol seems a little point less since you wouldn't be improving the properties of Penetrol you would be hindering it. The addition of another thinner would be bringing it back to the original point, if you hit the right combination.

What you are doing is basically making a quart or gallon cover more. In addition you are changing the protection qualities of the product.

I can testify that sign painters, have tried over the years to improve the life span of the sign paints, and a quick workable color restorer for old signs. most doesn't work as well as when used according to the manufactures instructions!
glen

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All the usual and standard disclaimers apply. Do not try this at home, use only as directed, No warranties express or implied, for the intended use or suggested uses, Wear safety glasses, closed course, professionals only

#6 Chuck Girard

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Posted 16 July 2010 - 11:42 AM

Thanks Glen,
Damn, I did something Right!!!!!!
Miracles will never cease[Shock]
[Peace]


Chuck Girard

A.K.A. CHUCK ROAST


"Simplicity is the Secret to Success!" (Someone Smarter than ME!!)[Worthy]



http://www.girardcustomcreations.com

#7 Kirsten Skiles

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Posted 03 October 2010 - 08:42 AM

I use the pre-mixed tung oil varnish that is easy to open, maybe Formby's. (hate those push and twist caps) I only use it for jewelry and interior artwork. It has not been durable on steel when exposed to high humidity or straight water drops.
I keep a creative blog at http://www.kaskiles.com
and an online shop at http://www.leafylady.com (forwards to artfire shop)
My facebook fanpage is http://www.facebook.....Skiles.Jewelry . I post links to new blog entries and new metalwork/jewelry.




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