Topic: underlayment

[Fastback2013]

I have red all the posts concerning the underlayment of a 67 fastback.
I do have a question about the top finish of the craft paper.
When I look at my original underlayment, the craft paper is black.
Should it be black, or is it due to elements of time that it is worn black?
Or must it be brown and finished with fresh motor oil, like mentioned in the very nice tutorial off Jeff?
Thanks for your time and effort.
Regards,
Jeroen

[J_Speegle]

Guess you read the article in the library also


Depending on supplier it appears that one or both side could be black tar with a thin clear layer or craft paper. The craft paper takes on the "black" dark look after time - absorbing the tar from the next layer. We used motor oil over the paper once done to increase the migration of the tag from one layer to the other. Then laid it out in the 110 degree plus sun for a few days

Fresh oil was used though I wanted to try used for the darker color but there was a concern about the great chance of a not so pleasant smell

[Fastback2013]

Thanks Jeff!
Looking at my old underlayment, it has indeed 1 thin (top)layer of (craft?) paper.
I sure did read your article, but since it is for 69/70 I didn't know for sure that the top layer must be also 'brown' instead of black.
Now I know why it is getting black after the years.
Thanks for your help and explanation.
Kind regards,
Jeroen