Full Chisel Blog

May 12, 2010

Cooking Pine Resin

Filed under: Finishing,Historical Material,Of Interest,Uncategorized — Stephen Shepherd @ 12:47 pm

Or pine sap or tree squeezings, it is the sticky stuff that exudes from the conifers Pinus spp.   I have a quantity of pine pitch so I am doing some experiments.

First of all, it is soluble in alcohol, almost completely, so it can be made into a spirit varnish.  It is also soluble in spirits of turpentine, so it can also be made into a spirit varnish.  But in this form [dissolved in turps] it can be easily mixed with linseed oil to form varnish.

It can also be cooked and this process will darken and harden the resin.  How dark will it go, I am not sure but the darker one has been heated about a half a dozen times to the point that it was giving off visible fumes and a delightful fragrance.  As for the temperature, I am not sure but it is at least 300 degrees F [I need to get a good thermometer].  Don’t try this at home, unless you do the cooking out doors or have adequate ventilation, the fumes are flammable.  The sample on the right has been just heated once and melted.

I will cook this sample until it becomes very dark and then test its properties.  There are opinions as to how long things need to be cooked.  Running, fusing or cooking the resins is done to make them soluble in oil, also to harden the resins and to add color.  This particular experiment is to determine how dark I can make the resin and if the excess cooking effects the properties of the resin.

The stuff is not as hard as the Spruce Resin that I cooked up.  I am currently powdering up the cooked spruce resin I made and am dissolving it into spirits of turpentine, to which I will add some kettle boiled raw linseed oil, which I will be boiling up soon, to make oil varnish.

Stephen

6 Comments »

  1. I want to go through this process for the sheer olfactory experience.

    Comment by Tico Vogt — May 13, 2010 @ 9:07 pm

  2. Tico,

    That is one of the benefits of cooking pine sap.

    I also borrowed a thermometer and tested the sample. It melted and became liquid at 140 degrees [F], started giving off smoke at 250 degrees and boiled at 300 degrees.

    Stephen

    Comment by Stephen Shepherd — May 14, 2010 @ 8:06 am

  3. I have been looking for pine resin(rosin) to “bake” potatoes in. Melting hard resin to liquid(300) then in go the potatoes, great food

    Comment by Bob — March 11, 2011 @ 1:25 pm

  4. Bob,

    Welcome and you can buy pine resin [brewer’s pitch] from James Townsend and Sons in Indiana, just do a search, they are 18th and 19th century re-enactor’s suppliers.

    Stephen

    Comment by Stephen Shepherd — March 12, 2011 @ 7:55 am

  5. you can buy pine rosin from ebay I sell it sometimes. Just look up seanhknife.

    Comment by Sean — August 15, 2012 @ 6:37 pm

  6. We are now commercially distilling pine gum rosin and gum spirits of turpentine in south ga

    Comment by chip — October 3, 2012 @ 8:07 pm

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