simple painting qestion

[ian webb]

hello all,

an easy question for a change

when antifouling and brightsiding a hull does it work better to mask the waterline over the brightside or antifoul, ie masking tape on which paint?

i'd prefer not to have a bootstripe.

Cheers, Ian.

[uncas]

ian...what kind of antifouling paint and topside paints are ya usin'.
This only matters as some antifouling paints rub off...Can't remember the specific brand...and it is supposed to do that...others create a hard finish.
The bottom line is how well you sand and prime above and below the line...Well sanded and well primed, should let you tape either side..
Also depends on the tape being used...3M Blue...works well. Staes that it is good for up to two weeks I think but don't trust it for that long.

[ 12-05-2005, 07:22 AM: Message edited by: uncas ]

[ian webb]

i'll be using an ablative antifoul, and have been told that i should just pressure wash the old, but not sure if this is going to be adequate. Going back to wood above the waterline though, and of course following through the primer, precoat, topcoat routine.

thanks for the quick response, Ian.

[uncas]

Ian...what condition is the old stuff...I mean is it flaking off...? If not, perhaps power washing is the only necessary approach ya gotta take...
I power washed Uncas last spring...no flaking...and put on two coats...hauled him in August for a look see...Standing up well.

[Zimmer]

You will get a cleaner paint line if you tape over the topside enamel and apply your bottom paint beneath. For a very crisp paint line use the fine line tape.

http://www.boatersworld.com/graphics/boatersworld/products/377870308.jpg

[uncas]

I think Zimmer is right...on the taped side...Don't know about agreeing with the choice of tape though.

Then again...Uncas has a boot stripe.

http://www.imagestation.com/picture/sraid161/p8e799d351774613b62145bdbbd448011/f4c8d991.jpg

[ 12-05-2005, 07:46 AM: Message edited by: uncas ]

[ian webb]

thanks, looks like blue 3m on top of the brightsides then.

i wont really know the condition of the old antifoul until she comes out but the waterline will get totally sanded out anyway.

cheers for the help, ian.

[uncas]

Just don't forget where the watrerline is....
Had a heck of a time with Uncas...put in a lighter...new engine...and took off..I bet 300 pounds or 15 coats of old paint...Waterline changed... :eek:

[Bruce Hooke]

Nothing, neither paint nor tape, sticks very well to ablative bottom paints. In addition, at least the final coat of bottom paint is best applied within a day or two of when the boat goes back in the water. Leaving it exposed to air for long periods of time is supposed to reduce its effectiveness. So, I would definitely do the topsides first. Make sure you let the topsides dry for a few days before you apply tape to it, and be careful when peeling off the tape so that you don't lift the paint.

Here's a good picture I found (on this web page (http://www.goshen.edu/~marvinpb/arted/tape.html) ) on the proper way to remove tape:

http://www.goshen.edu/~marvinpb/arted/taperemoval.jpg

Like Zimmer, I'm a big fan of green 3M "Fine Line tape." However, you are not supposed to leave it on for more than a day, so for extended use you need to use the blue tape. However, I am a big believer in removing the tape as soon as I finish applying the coat of paint -- while the paint is still wet -- so leaving the paint on for a long time is not an issue for me.

In general, on bottom paint in particular, I would not go back to wood unless you need to get to the wood for some reason (e.g., to see the bungs because you need to pull a plank) or unless the existing paint is just not sticking. When it comes to bottom paint more is almost always better...

[uncas]

Bruce...have not had that much luck with the green...A day is tops and even then....
I guess I now play it a bit safer...blue...

[Bruce Hooke]

When I use green fine line tape it rarely stays on for more than a couple of hours. It goes on just before the paint and comes off right after (or even before) I clean the paintbrush. You are probably right that for even 24 hour use the blue tape would be better. I've also found that the green tape does not have a good shelf life -- the adhesive dries out and it will no longer stick.

BUT, if it is not kept on the shelf for too long and if it is not left on the boat for too long, it does a great job of creating a sharp, crisp line.

I should note that when I worked as a painter in a boatyard (I only did this for one year while I was in college) we were encouraged to freehand lines whenever we could. The tape mostly came out for areas on deck where a very precise line was vital and for places where the painted surface and the surface to be masked came together at an inside corner.

[uncas]

Varnish work...think I'll stick to blue...no pun intended.

[Gary E]

Before you loose the waterline, score it into the wood with a knife, deep enuf so you know where it is after sanding..

[Wild Wassa]

The tape is only as good as the cleanliness of the tape's edges. Don't put the roll of new tape down on dusty or dirty surfaces and store the tape in a ziplock glad bag ... because once the edges of the tape get dirty, you will no longer have a hard edge.

I use blue tape for everything to do with epoxy but for painting hard edges, I use white paper tape and clean any glue resides from the surface with acetone, after the paint has hardened.

The white paper tape sits flatter than the blue tape, so your edges are harder and sharper. The white is about the same price as the blue and is found on the same stand.

Warren.

[ 12-05-2005, 05:33 PM: Message edited by: Wild Wassa ]

[ian webb]

many thanks to the forumites

i'll try to remember to score the waterline into the timber

and she's an old American H28 enjoying semi retirement in Aus so i'm not really striving for a perfect glasslike finish or razor sharp line, just a decent paintjob and get her straight back in.

(if no unpleasant surprises that is)

[Jay Greer]

Us old geezers are used to painting painting water lines and boot stripes free hand by cutting into a scribed line that has been cut with a fine back saw turned backwards and dragged along a fair tacked on batten. The batten should be set plumb with a bubble level so as to not cause the saw to ride up out of fair. If you want a real fine line, a Japanese Azibiki saw will do the trick. This should allow you to paint a clean line for many many seasons until the scribe line fills in and needs re-cutting.
JG

[Stiletto]

That is a good old time tip Jay, I wonder what one can do with a hull that is glassed on the outside.

[John B]

You paint your topsides first and you antifoul second.

[Stiletto]

Yes John, I've done it that way, I was actually referring to the idea of leaving a permanent mark.

[Bruce Hooke]

Originally posted by Stiletto:
That is a good old time tip Jay, I wonder what one can do with a hull that is glassed on the outside.I would NOT do this on a glassed surface. It would create a perfect spot for cracks to form in the glass...

[Jay Greer]

I recently cut a water line on a plywood boat that is glassed over. I tacked on the batten in the traditional way, using as few brads as possible without piercing the hull through. Then, with the aid of a new Azibiki I , carefully scribed the water line on the pull stroke. This was only in the resin and not into the glass itself. Holes were filled with red micros and epoxy. Once cut, unless the painter is drunk or dyslexic, it is easy to cut in the bottom paint to the line free hand. A good Hamilton brush or the equivalant is a must!
JG

[John B]

I was just answering the original question stiletto.
You paint your topsides first ,antifoul second . Therefore you mask the topsides paint.
I've seen people do it the other way and I just don't get it.
Virtually all of the old boats have scribed in w/l's. Its a great source of history.

[ 12-08-2005, 10:22 PM: Message edited by: John B ]