What price blacking?
QAre Intertuf or Keelblack hull blacking products worth the price, or is a cheaper paint like Black Jack just as good?
JEFFRICE, from the CB website
ATONY REPLIES… Blacking covers a lot of products. Traditional blacking falls into one of two types: tar-based or bitumen-based. If you put tar-based over existing bitumen, the bitumen is likely to dissolve and shed the new blacking. To test it, rub the hull with a rag soaked in white spirit. If the blacking starts to come off on the rag, it’s bitumen and you should only reapply bitumen-based blacking (unless you blast the whole hull back to bare steel). Bitumen will often cover well-weathered tar based blacking.
Black jack is a simple bitumen paint, but for a little more you can get modified bitumen like Premium that has more body and is a little better suited to hull work. Intertuf ( International’s blacking lines) has a number suffix eg Intertuf 16 or Intertuf 203 to identify the product, so without the numbers, I cannot comment. Keelblack, bitumen in a water-based body, is a new product. It’s too new for much user feedback but the claims made for it seem good.
Probably the most long-lasting blacking is one of the two-part epoxy products, but they should be applied to bare steel so blasting is required. Although much tougher than ordinary blacking, the coat is still likely to be damaged by abrasion on lock walls etc.
In summary, find out what type of blacking you have, check out products using the same base, and evaluate claims made for it against price.