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actonern Super Member
Joined: 15 Aug 2007 Posts: 444
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Posted: Mon Nov 05, 2007 3:58 pm Post subject: bitumen and turpentine |
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Manfio, if you get this message, (or others)...
I put about 250 gms of bitumen into a small jar and covered it with turpentine. The mixture has been disolving over a few days, but it seems to have reached a point where the turpentine will disolve no more of the tar. It is a deep black color, but not the "honey" consistency that you wrote about in another post.
Did you increase the concentration over a water bath or does it just take a long time to disolve more tar?
Best regards |
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Andres Sender Super Member
Joined: 23 Mar 2007 Posts: 275 Location: N. CA
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Posted: Mon Nov 05, 2007 8:34 pm Post subject: |
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Different tars from different sources behave in different ways.
It may be that there are parts of your stuff which don’t want to dissolve in the turpentine, or conceivably the solution is saturated, i.e. won’t dissolve more than it has already (this seems unlikely though). You can test the latter by putting more asphalt in to see if you can make it thicker.
The only reason to worry about making it thicker is if you can’t get enough darkness in your varnish without ending up with too much turpentine in the mix.
So now’s the time to just start testing what you’ve got, in your varnish, on sample pieces until you are sure it’s working right in terms of color, brushing, and drying. |
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MANFIO Super Member
Joined: 11 Apr 2007 Posts: 458 Location: Sao Paulo
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jethro Member
Joined: 07 Apr 2007 Posts: 178
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Posted: Wed Nov 07, 2007 3:21 pm Post subject: same experiment --- ? |
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I have also just been disolving roof compound in turpentine. The product
I tried is called "blackjack" in a calking tube. It says it contains asphalt,
but I don't know how much -OR what else is in there. I disolved it on a
coffee cup warmer (160F) and since have left it open to the air to let the
excess evaporate and it is now all most honey like in thickness. I put
some into some cheap varnish and brushed some on sone scrap to see
the color. It was something like my honey-amber transtint except it had
a more brown color and the color had a bit of a "dirty" look that I didn't
like the looks of. Like an dingy looking honey amber- it did not have a
warm glow look. It may be that this Blackjack is really not the corect
stuff ! Where do yall get your asphalt ?
Tim |
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Andres Sender Super Member
Joined: 23 Mar 2007 Posts: 275 Location: N. CA
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Posted: Wed Nov 07, 2007 4:09 pm Post subject: |
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Different places. I think MD got his from some roofers or a construction site, so it's the hot stuff.
Some better artist-supply places carry it (make sure it's the real stuff though).
Others of us ordered it from specialized suppliers. I think I got mine from a place that was selling it on ebay in small quantities. |
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MANFIO Super Member
Joined: 11 Apr 2007 Posts: 458 Location: Sao Paulo
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Posted: Wed Nov 07, 2007 6:48 pm Post subject: |
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The final colour will depend on concentration, it can go from a light golden brown to black. Following Michael Darnton's advice I use it with Kremer's "Alizarin Crimson in oil" on my varnishes.
Yes, depending the way you use it it can give an antique look to the varnish. _________________ www.manfio.com
http://www.flickr.com/photos/7875988@N02/with/464604020/ |
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