Finishing Lead Keel?

[Snowpetrel]

Originally Posted by Dockhead

Would one use a belt sander for the rough sanding part of this, or better a big orbital sander?

Be very aware of the lead dust. Nasty stuff that is best hand sanded or done with a random orbital at a low speed.

A hand wire brush works very well and quickly on rough surfaces. Its probably all you need. Do the fairing on the epoxy bog, rather than the lead.

[Wotname]

Originally Posted by Snowpetrel

Be very aware of the lead dust. Nasty stuff that is best hand sanded or done with a random orbital at a low speed.

A hand wire brush works very well and quickly on rough surfaces. Its probably all you need. Do the fairing on the epoxy bog, rather than the lead.

Yes, any sanding brushing etc on the lead is only to clean it.

As for lead dust, I considered it in the way as antifoul dust - avoid at all costs. While it doesn't stay in the air for long, it does stay on/in the skin so keep your gloves on (along with the rest of your PPE - of course).

As an aside, back in the days of lead covered telecommunication cables, the lead was "hand wiped" when repairs were carried out. It was found that although linesman would wash their hands after "wiping" the lead, some lead remained on the skin which would be transferred to the mouth (lips) when they smoked. Wiping meant smoothing just molten lead with a piece of doeskin.

[wayne.b]

Originally Posted by Dockhead

OK, thanks. And what do I fair it with?

===

A mixture of epoxy thickened with colloidal silica and micro balloons. Apply with a notched trowel, sand it with a long board and then final fairing/filling with a smooth trowel. Rinse/repeat as needed, then coat with Interprotect.

[dfelsent]

Originally Posted by wayne.b

===

A mixture of epoxy thickened with colloidal silica and micro balloons. Apply with a notched trowel, sand it with a long board and then final fairing/filling with a smooth trowel. Rinse/repeat as needed, then coat with Interprotect.

And apply the filler mix over clean shiny lead. Use that wire brush to scrub a bit of the filler or straight epoxy into the shiny lead surface.

The colloidal silica keeps sagging to a minimum but is a bear to sand. The micro balloons help with the sanding.

[lifeofreilly57]

I'm a little late to the game, but while your at it you might want to check to see if the keel is symetrical in shape, and the correct shape.
I've seen some keels that were way off side to side, on one of my previous boats that had a custom keel I made patterns to mimic what the shape should have been and used them to guide my application of fairing compound and then while sanding and shaping. That keel was pretty close to start with but was off enough to make the boat point better on a port tack than on starboard. At first I thought it was the rig, so I went through the rig completely to ensure that the rake, centering and column were spot on (which improved tacking right off) but still had the issue of pointing higher on one tack than another.
Once I faired the keel and matched it side to side and to the centerline of the boat it pointed higher on both tacks, which gained a couple seconds a mile and also was fairly even port to starboard in pointing. If your going to do the work it's not much more to make sure its symetrical side to side, the templates will keep it simple.
Remember, it's a hydrodynamic wing, they have a particular shape for a reason.
The worst keel I've seen was way off on centerline and no where near symetrical side to side, I won't mention the maker, to avoid any blowback other than to say it was a "first", which surprised me since it is supposed to be a performance model. This was an early 2000's model.
When you sighted the boat when on the hard, looking from the rudder through the bow centerline it was easy to see, it wasn't aligned with the centerline of the hull, but had an apparent direction to port, about 2 degrees off. Don't know if it was from the original casting or from the mounting, when stripped the casting was quite rough, it looked as if it were cast while lying horizontally, but that's just my guess.
It took almost 2-1/2" of fairing on the starboard side leading edge to make it symetrical in shape and much grinding and sanding to get the correct shape, but once done and back in the water the improvement was immediately noticeable.
Something to consider if your going to the trouble of stripping the keel to coat it. Most aren't that far off and just need a little faring and shaping, it's not really much more work than what your already doing. The shaping on my older boat was about 10 hours of work, not counting the 2 hours it took to make the cardboard templates.

[Dockhead]

Thanks to everyone for the excellent guidance! I hope it helps others besides just me.

We are well into it now and will finish the stripping today. At the end of every day we have been painting with thinned epoxy the bare metal after light sanding and degreasing just before painting. The paint job doesn't look very good but we will sand it and put another coat on after we get the whole keel that far. Then to fairing! It's remarkably labor intensive.

I will check the shape -- excellent suggestion -- but this boat was built by a high quality builder and this kind of thing is extremely well executed, so I seriously doubt there is any problem, but it is certainly worth checking. Doverit' a proverit' as the Russians say -- trust but verify

[Wotname]

Originally Posted by Dockhead

.........

We are well into it now and will finish the stripping today. At the end of every day we have been painting with thinned epoxy the bare metal after light sanding and degreasing just before painting. The paint job doesn't look very good but we will sand it and put another coat on after we get the whole keel that far. Then to fairing! It's remarkably labor intensive.

............

Curious - why thinned?

[Dockhead]

Originally Posted by Wotname

Curious - why thinned?

It was in the instructions. I guess to be sure it gets in every crevice.

[Wotname]

Originally Posted by Dockhead

It was in the instructions. I guess to be sure it gets in every crevice.

Pretty hard to argue against that - fancy reading the manual though

[De.windhoos]

Originally Posted by Dockhead

It was in the instructions. I guess to be sure it gets in every crevice.

Hi Dockhead, I'm planning to do the same next year, so Im interested in what instructions your read?

[Souzag818]

Originally Posted by lifeofreilly57

I'm a little late to the game, but while your at it you might want to check to see if the keel is symetrical in shape, and the correct shape.
I've seen some keels that were way off side to side, on one of my previous boats that had a custom keel I made patterns to mimic what the shape should have been and used them to guide my application of fairing compound and then while sanding and shaping. That keel was pretty close to start with but was off enough to make the boat point better on a port tack than on starboard. At first I thought it was the rig, so I went through the rig completely to ensure that the rake, centering and column were spot on (which improved tacking right off) but still had the issue of pointing higher on one tack than another.
Once I faired the keel and matched it side to side and to the centerline of the boat it pointed higher on both tacks, which gained a couple seconds a mile and also was fairly even port to starboard in pointing. If your going to do the work it's not much more to make sure its symetrical side to side, the templates will keep it simple.
Remember, it's a hydrodynamic wing, they have a particular shape for a reason.
The worst keel I've seen was way off on centerline and no where near symetrical side to side, I won't mention the maker, to avoid any blowback other than to say it was a "first", which surprised me since it is supposed to be a performance model. This was an early 2000's model.
When you sighted the boat when on the hard, looking from the rudder through the bow centerline it was easy to see, it wasn't aligned with the centerline of the hull, but had an apparent direction to port, about 2 degrees off. Don't know if it was from the original casting or from the mounting, when stripped the casting was quite rough, it looked as if it were cast while lying horizontally, but that's just my guess.
It took almost 2-1/2" of fairing on the starboard side leading edge to make it symetrical in shape and much grinding and sanding to get the correct shape, but once done and back in the water the improvement was immediately noticeable.
Something to consider if your going to the trouble of stripping the keel to coat it. Most aren't that far off and just need a little faring and shaping, it's not really much more work than what your already doing. The shaping on my older boat was about 10 hours of work, not counting the 2 hours it took to make the cardboard templates.

Years ago I bought a 23' boat that always had a list and sailed better/higher on one tack than the other . I checked the rig to make sure the mast was centered and plumb athwart ship, and moved things around on the inside, but nothing helped. After many years, I decided to drop the keel, have it sandblasted and epoxied (cast iron) and replace the keel bolts. When I was re-installing the keel, I noticed that when the keel was dry fitted it had a slight angle to one side. Making the hull level on the hard, and dropping a plumb line down the bow it was really obvious. End result is I had to laminate one side 5/16" at the keel stump in order to make the keel plumb! That made all the difference in the world. The list was gone, and now the boat sailed evenly on both tacks. It was a lot of work...