Black Stains

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Postby Guest » Sun Mar 11, 2001 10:14 pm

This topic was on the old forum before I took delivery of my new boat. I did not think it was important at the time (as in how big of a problem could this be!) but now I know better.

I tried using Fiberglass stain remover today but it still leaves a shadow of the stain. I've heard Joy soap, comet, and acetone are possible other remedies.

Anybody have the secrets to get rid of these stains?

What was consensus on the cause? My other boats have done this, but not nearly as bad as the J80. I've cleaned the lifelines-I don't believe its residue in the wire. Your advice is appreciated.

Postby Guest » Fri Mar 16, 2001 1:13 am

If it is the result of ferrous metals (rust) Ospho is the treatment of choice. You can get it at the hardware store. (ospholic acid).
I just compounded the hull to get rid of stains running down from the deck which are caused by the effects of unburned jet fuel jettesoned by the military aircraft landing at Carswell NAS. 3m professional rubbing compound is great stuff. It removes severe oxidation, surface stains and polishes to a nice finish that can be protected with teflon polish.
See you in Ft. Worth tomorrow.

Postby Guest » Mon Apr 02, 2001 9:06 am

I was the one who asked about black streaks on the old forum. (Does anyone else miss the old forum as much as I do?)

Someone referred me to Fiberglass Stain Remover but I could not find it where I live (Toronto).

I was able to find another product referred to me, something called MaryKate On & Off Hull & Bottom Cleaner - the label says it contains Hydrochloric, Phosphoric and Oxalic acids. It comes as a liquid, no spray pump.

I also found a product called Starbrite Instant Black Streak Remover. It comes in a spray pump plastic bottle and the label says it contains Sodium Metasilicate and Sodium Tripolyphosphate.

I tried both products and both removed the black streaks on the sides of my boat (hull #267). In certain bright light and at some angles I still see the vague shadow of black stains. I have not tried to compound polish the hull.

I have a slight preference for the Starbrite product. I think it works a bit better and it is less expensive than On & Off and easier to use with the supplied spray bottle.

I concluded that the cause of the black streaks on my hull was industrial pollutants either settling on the deck or airborne in the rain. When it rains, I think this stuff washes off the deck and drains down the sides of the boat, causing the black streaks.

Postby Guest » Mon Apr 02, 2001 9:47 am

If you use dish soap or even a little bleach to wash the topsides, it will reduce the protection of the wax and then run off shows ( i.e. black streaks ). I just rubbed out my hull #33 with some Finese buffing compound.....does a beautiful grit, but really leave the glass shining with the "wet" look. You will need to put wax over when you are done. Try in a small area first to see if you get the results you want.

Postby Guest » Sun Jul 15, 2001 12:12 pm

The black streaks are air pollution and so the longer they sit on the deck and then the hull, the deeper they are. They will eat into the gelcoat to the point a light buffing is necessary. I find the Starbright Black Streak is a good remover if the streaks are not more than a week old, older streaks seem to need buffing and waxing.
Compounds remove gelcoat, of which there is a finite amount, be cautious in using them too much.
On-Off demands waxing after each use , and removes more than streaks if dribbled.

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