Old Schoolers

[rgranger]

Hey

I need some knowledge from those of you who have been around longer than I

I'm almost done resurfacing a swing keel from a Balboa 26'. And on the lead bulb I removed about 5 layers of bottom paint until I got to a very hard, mustard-yellow, coating. This stuff is hard. I wanted to remove it all so I could start with a smooth surface but I'm having a really tough time getting it off. I've used peel away, citrus strip and even the red tip on my pressure washer. Some of it came off but most of it is still stuck. The next step would be to grind but I'm a bit apprehensive about that.....

I started worrying what mustard yellow might mean. I think the old-school red paint might be a lead paint and the blue is copper....

What is yellow? Should I be worried about arsenic? This is a 1974 boat so .. ... I really don't know what they were using back then. I've been using an industrial respirator and eye protection but now I'm wondering if I should avoid grinding this stuff for fear of spreading arsenic dust around my yard. The chips I can pick up but dust would be a problem.

Here is a pic of what that mustard yellow looks like. I didn't get a pic of what I did today because it started raining. So this pic is older but you can still see the mustard yellow color in this pic.

Any of you old schoolers know what a yellow, hard, non-ablative paint might be?

 

[dscribner]

Haven't got a clue but this may give you a key word to search. We used a primer when I was in the military in the early 80's called zinc chromate. Probably still used, I don't know. It was a strawflower yellow when dry. Ours came from a spray can but it probably is available in cans too. Again, just something to help the search.

Don

 

[sailingandsuch]

No idea what the yellow stuff is but here is my opinion of your situation.

When your painting something basically you want the paint to be able to grip onto something so that it will not come off. So what we do is try to get off all the loose paint/rust from a keel to give us a good base for the paint to grab onto. So if you have gotten down to something that you can't get off then it sounds like you have found something that if the paint adheres to it then it's not going to come off under your paint.

I'd say paint over it, it's a good foundation....

 

[anchorclanker]

yes, looks like zinc chromate. Some moron pained the stainless siding on my Bus with it and nothing seems able to dissolve it. In your case you could grind it off, get it all down to bare metal as best you can, then sand blast it. I would probably give it several coats of zinc chromate again as its a good metal preservative and as you see, it does not readily come off.

Me? I dont know what im going to do. Its polished stainless so its not like I can sand the paint off very easily without messing up the original shiny metal finish, which is precisely what I am trying to restore.

 

[FourPoints]

soda blasting will remove zinc cremate from the stainless.

 

[rgranger]

No idea what the yellow stuff is but here is my opinion of your situation.

When your painting something basically you want the paint to be able to grip onto something so that it will not come off. So what we do is try to get off all the loose paint/rust from a keel to give us a good base for the paint to grab onto. So if you have gotten down to something that you can't get off then it sounds like you have found something that if the paint adheres to it then it's not going to come off under your paint.

I'd say paint over it, it's a good foundation....

I subscribe to that logic most of the time but this stuff is also thick. so the surface is "lumpy". I really want a smooth surface before I paint.

 

[rgranger]

Haven't got a clue but this may give you a key word to search. We used a primer when I was in the military in the early 80's called zinc chromate. Probably still used, I don't know. It was a strawflower yellow when dry. Ours came from a spray can but it probably is available in cans too. Again, just something to help the search.

Don

Zinc Chromate? Good clue.

Thanks! I'll look into that.

What ever this stuff is, it is really tough. Twice now I've covered it in citrus strip, covered the citrus strip in plastic sheeting and let it sit for 12 hours. Absolutely no effect. Dang. Hit it with the red tip of my pressure washer and still.... nothing.

 

[Kermit]

I've been following this thread for a while. It looks like rust to me.

 

[rgranger]

I've been following this thread for a while. It looks like rust to me.

Naw

I got all of the yellow off of the rusty keel portion in the middle (see pic #2). But I can't get it off of the lead bulb. Lead don't rust

 

[Eddie7045]

Zinc chromate was outlawed due to environmental

concerns. It was one of the best primers for corrosion protection but it was too toxic . I'd say that if you got down to it, leave it on and repaint over it.

 

[Ross]

Re: Zinc chromate was outlawed due to environmental

I googled lead compounds and got this hit: http://www.webelements.com/compounds/lead/lead_tetrachloride.html The best suspect is a chlorine compound of lead so check that out but also look at the others.

 

[tkanzler]

Perhaps you can knock the bumps off, and leave the rest, since it doesn't want to come off. Fair it smooth.

BUT, I would also sandblast, then prime immediately. Sandblasting digs an 'anchor profile' that the paint can hold onto.

 

[Charlie Jones s/v Tehani]

If Zinc Chromate has been banned, why can I buy spray cans of it in ACE Hardware? Just got some two weeks ago to redo my aluminum side plates on a rudder.

 

[wflowe2]

When in the Navy a long time ago, we used two types of primers on the ship. One was lead based, called Red Lead; you might be able to guess the color and the other was Zinc Chromate and it was yellow.

 

[rgranger]

Thanks Everyone....

I'm guessing it is Zinc Chromate. You can still buy it and Rustoleum even sells it by the can. Wikipedia lists it as a known carcinogen and it is also known to cause skin "ulcerations".

...sounds like some nice stuff.

So I'm going to smooth it as best I can with a wet grind to keep the dust down, keep my respirator on and just live with an imperfectly fair keel bulb.

 

[bffatcat]

rusty keel what to do

Ok you say you got the yellow stuff off which was a 60`s coating for cast iron keels. once you get it all off thats 90% of the battle. I just refinished my cast Iron keel last year
This is what I did. First my keel did not have zinc chromate on it What it had on it was a coating of fiberglass 38 years in salt water loosened the fiberglass coating so that most of it fell off. I hired someone to scrape and grind the rest off. At 75 and after having back surgery im too old for that kind of work. After the keel was clean I washed it with lacquer thinner. As soon as the keel was dry I applied 2 coat of Pettit rust inhibitor The 1 part silver stuff. It dries fast make sure its dry between coats And finally I put on two coats of west system epoxy. I did this last fall The boat was outside all winter No rust. I just painted the bottom Good luck