As a result of an unwise storage choice, one of my hulls has a good deal of hardened tree sap on it. I'm in the process of getting my H-17 ready for the water again (after more than four years on land) and I'd like to figure out how to get rid of the sap. The greatest accumulation is on the side of the hull below the waterline.



Choices that come to mind are:

* Buff sanding and then repairing the gelcoat

* Chipping/chiseling and then repairing the gelcoat

* Some sort of chemical/enzyme solution



Any suggestions? I'm already going to be doing some work to repair delamination and various chips and scrapes from over the years, so I'm prepared to spend a good deal of time in the garage over the next couple of weeks in any event.

Did you tried aceton?

If Acetone doesn't work try MEK (Methyl Ethel Keytone). It's available at large hardware stores. Wear gloves when you use it. MEK can dissolve a lot of stuff but not your hull.



Mike Hill

H20 #791

Tree sap is hardened non-polar resin most like turpentine. It will dissolve in a similar substance- like turpentine- that will not hurt polyester resin/gel coat. But turpentine (distilled from pine tree stumps) is now very scarce except in an art supply store. Use mineral spirits (or charcoal fire starter) to soften and dissolve it the sap. This takes a while for hard sap, even using a pad full of solvent sitting on it. Do NOT use lacquer thinner, acetone or MEK.

SIgned, Ph.D. Organic Chemist

Thanks for the info. This is just the sort of thing I was looking for. What are the dangers with something like lacquer thinner, acetone or MEK?



-C

Acetone did the trick. I tried mineral spirits, but it

took much too long. Acetone, with a little scrubbing

got rid of the sap and the hard water stains. Very nice.



I stayed away from MEK. It scares me - not too sure what

it would do to my lawn in the process.