Author Topic: PRIMER
mariner
posted 03-14-2000 08:26 PM
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CAN ANYONE TELL ME THE BEST PRIMER AND FINISH PAINT TO USE OVER 68 YEAR OLD STRIPPED CEDAR PLANKS, WITH SOME IRON FASTENING BLEEDING.
AND IS EPOXYING THE BLEEDERS THE BEST WAY TO STOP THEM?

chemist
posted 03-14-2000 09:17 PM
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The discussion (the back-and-forth about a topic is here called a Thread) titled CPES, the one started by Jojo on 1/27, has near the end some discussion by me that may answer some of your question. I know what Bob Cleek will say but far be it from me to steal his thunder.
(There's your intro, Bob)
You can also find data by using the search feature of this forum. Click on SEARCH at the upper right of the topic page, and you can enter various words and the WB computer can search any thread for any mention of such things as fastener bleed, epoxy, electrolytic corrosion, or whatever.

Bob Cleek
posted 03-15-2000 12:07 AM
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Do go back and check out the past posts... but, I'll do it once again for old time's sake.
Sand her very fair, preferably to bare wood. Soak her in CPES. This product, by Smith and Company, is the only thing to use. DO NOT use thinned hard epoxy. Use CPES. (A little goes a LONG way. Ask Smiths how much. Check the posts on CPES in here... there's a million of them.) The same day, spray Interlux or Z Spar white undercoat. (If you paint over CPES within about 36 hours, you will get a molecular bond between the penetrating epoxy sealer and the paint and it will stick like nobody's business... this you want.) This stuff has talcum or whatever in it and it will fill some and also sand easily. Spray, because otherwise, you will have nothing but brush strokes with this stuff, or else, you will have to thin it so much that you will have to put fifty coats on to get where you need to go. Use a decent Binks spray rig, or the equivalent. Start working around the hull until you CAN'T SEE ANYTHING BUT SNOW WHITE. If you spray, it should dry by the time you work around to the start and you can just keep going without down time waiting for it to dry. (Wear sunglasses or you will go snow blind... no kidding!) Remember this... and repeat it like a mantra... "My enamel will NOT cover... My enamel will NOT cover..." Believe me, it will not. That's the base coat's job.

Now, when it's all white, go over the hull with Z Spar Dual Purpose Surfacing Putty or the equivalent, filling EVERY little bit of grain and divit. Then sand again with 120, working down to 220. Make sure the surfacing putty isn't standing proud anywhere. Repeat this mantra at this point..."Every imperfection WILL show... Every imperfection WILL show..." They will. When it is perfectly smooth and there are no dings or anything left to fill with the surfacing putty... and you now know how important that first sanding step was way back when... Spray it with more undercoat, repeating the "My enamel will NOT cover.." mantra. The previous sanding will likely have raised spots that show through, you see.

Now, sand carefully with 220, working down to 320. Use your compresson to blow off all the dust. Then tack thoroughly.

If you want a really decent job and you aren't an experienced painter, find one to help you on the next step... it's important. Mix your enamel. You have to consider the temperature, humidity and phase of the moon. Add Flood's Penetrol to promote leveling. Add the proprietary thinner for hot or cold weather (fast or slow drying). How much is where the experience comes in. If you are someplace like Kansas where they don't have boat painters, maybe you can ask a professional painter, or if all else fails, practice a bit on some scrap wood until you feel competent. (A BAD topside enamel job is a sad, sad, sight!) Your enamel should be about the consistency of light cream or half and half. Now tack again. Kill a chicken as an offering to the topsides gods. Use a good brush that's the right size... six inches at least... (forget that roller and tipping off BS)... keep a wet edge, work fast and let the paint level itself. Put as much on as you can without starting curtains. Work out of a big cardboard bucket. Your arm will love you for this and you won't get paint all over. (If you haven't learned to paint, get a book on the subject and "brush up" on it! No offense, but about one guy in ten who works on his own boat knows how to use a brush properly.) Let it dry. Brush off all the bugs that landed on it. (DO NOT try to remove them when the paint is wet! TRUST ME.)

Now, sand lightly with 320. Put on more surfacing putty on the spots you missed if you have to. (There always seem to be one or two.. it's that snow blindness thing.) If you do this, lay a light coat of basecoat on the putty spot. Sand it smooth and put a light coat of enamel on the patched spot. Sand that along with the enameled hull. (If you just put another coat of enamel on top of the putty, you will get a dull spot there.) Blow and tack and so on. Put on another coat of enamel. Pray that that one looks okay. If not... go for another. At some point, you will either be satisfied or get tired and consider it done. If all else fails, tell yourself you will do better next haul out! LOL OH... and have fun doing it. This is one of the most satisfying parts of the game. Nothing makes me feel better than having my boat in the yard with a brand new topside job and watching the plastic boaters come up and ask me what kind of gelcoat polish I use! LOL


Ian Wright
posted 03-15-2000 04:56 AM
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,,,,,,,,,or,if like me you think that traditional ways are still valid replace the CPES with metalic primer for wood, fill imperfections, sand, re-prime, undercoat,sand, undercoat, re-check and fill, sand, undercoat50/50 gloss, sand, finish coat gloss,remove masking tape, go to pub, drink beer.
Ian.


Scott Rosen
posted 03-15-2000 06:02 AM
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Wow. Bob that was the one of the best painting lessons I've read. Your advice is right on the money. But for those of us without spray equipment, brushing the primer works, it just takes more sanding to get the brush marks out. And you need to lay the primer on thick when using a brush.
We still have to deal with the bleeding fasteners. I don't know if this is the best way, but after applying the CPES and before applying the primer, I'd hit the offending fastener heads with a very light shot of unthickened, fast-cure epoxy, being careful not to create a proud spot.

As far as picking the best paint . . . well that's really a matter of personal preference. There are lots of good marine enamels, and each seems to have its own unique qualities. I like Rivale for a polyurethane enamel, and Kirby Paints for traditional alkyd resin enamel. You also need to decide whether you want gloss or a flatter finish. Gloss, especially with dark colors, will show every tiny imperfection. A semi-gloss, especially white or other light colors, will hide well, at least when you're looking at it from about ten feet away.

[This message has been edited by Scott Rosen (edited 03-15-2000).]


mariner
posted 03-15-2000 05:02 PM
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thanks a million. regarding cpes- will this allow the planks to breath and not become a water trap? Also ( a question i have pondered) will darker colors do any damage to planks, like heating in the sun, shrinking and then allowing fresh water in.
The boat is down to bare wood and i do have a good deal of experience painting and varnishing, but always willing to learn.(wb owner for 23 years)

dasboat
posted 03-15-2000 05:25 PM
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As a doityerselfer I will add just three things.Perhaps it is a function of my years,but I have to have someone help when I paint.Their job is to keep me on my toes by checking for holidays and tacking just ahead of me.Second,my boat is planked and has routed seams,so I tape off about a 3 plank portion and brush completely around within this boundry
in order to keep a wet edge.
Third I always keep a set of bright lights handy.It is impossible to clearly see the edge in certain light conditions and the artificial light really helps.
Regards,Darryl


mariner
posted 03-15-2000 05:49 PM
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unfortunately i will be painting,not spraying. The phone number for Smith and Co. is ????

Jorma Salomaa
posted 03-15-2000 07:33 PM
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I think I heard "at next haul-out"? It must mean you paint the topsides every year! Could it be because the paint cracks. And could that be because there is so much primer (read: filler) and hard paint?
I used to get a little nervous every spring waiting for the cracks to appear at the topside seams, because it meant sanding, filling and painting a hull that didīnt really otherwise need any painting at all. Then I quit using enamel paint and fell in love with good old oil paint and have lived happily ever after...


chemist
posted 03-15-2000 09:50 PM
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Some paint companies hire idiots who do not know the meanings of words but call a product whatever impressive words they think will stun the consumer into buying the product for reasons they will not know when the trance wears off.
Easypoxy sounds like some sort of easy-to-apply epoxy, right?? Well, it is a silicone-modified oil-base enamel paint! Never came witnin a country mile of an epoxy structure.

And that brings me to the subject of what is oil paint or enamel, as you can see in the post just above. In Finland the terms mean something different from what American marketing types use them to mean, or what they used to mean. It used to be that there was paint, which was enamel, which dried and chemically cured and could not be redissolved in its solvents. The paint was called oil paint because it was made from certain oils extracted from oilseed vegetation such as walnut, tung berries, sunflower seeds and many others. We have linseed oil as another of them. As a general class they are called drying oils because they "dry" by a chemical polymerization reaction. Varnish originally was basically as above and to make paint the manufacturer dispersed some pigment in it. Very crudely, that is what those terms meant and should mean. These materials, once dried and cured, will NOT redissolve in their original solvent.

Lacquer, by definition. should mean a resin dissolved in a solvent which, spread upon a surface such that the solvent can evaporate, forms a hard dry film BUT IF THAT SOLVENT IS APPLIED TO THE DRY FILM IT GOES BACK INTO SOLUTION. THE DRYING AND REDISSOLVING REACTION IS A COMPLETELY REVESIBLE ONE AND DOES NOT CHANGE THE CHEMICAL STRUCTURE OF THE LACQUER.

Enamel, you see, is not lacquer and lacquer is not enamel. The term "catalyzed lacquer" seen on some polyurethane or other two-component paints is a corruption, but at least can be recognized as such. When idiots sell latex (waterborne ) paints as enamel they destroy our ability to communicate with each other and be understood.

If you look on the side panel of the can that should have data that will help. Oil-base enamel paints will say they contain petroleum distillate, mineral spirits, aromatic hydrocarbons, aliphatic hydrocarbons, something like that, and that they may be cleaned up with those things. The Material Safety Data Sheet should also say these things in the ingredients section. Waterborne/latex paints will say they clean up with water. There are water-emulsion two-component epoxy paints in existence and under development, but I would hope they do not steal the nomenclature of historically successful products to wrap themselves in the cloak of someone else's success.

I reckon the best guarantee of knowing what the product is, is to keep asking your supplier "What, exactly, is that?" and "How is that similar to/different from (other products with which you are familiar)" until you get answers you can understand.

[This message has been edited by chemist (edited 03-15-2000).]


Bob Cleek
posted 03-16-2000 01:12 AM
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Mariner, sorry, but it's too late to hike out to the shop and check the can again for Smith's phone number. But, they are in the 510 area code in Richmond, CA, and are officially "Smith and Co. Industrial Coatings" (or close to that) on Channel Ave (Blvd?). That should get you the number out of information.
PLEASE, read what I wrote about spraying the undercoat. I really wouldn't attempt to brush the undercoat. It leaves brushstrokes like crazy, or you have to put on dozens of coats really thin. Spraying it is very easy and you can just walk round and round the hull spraying until you get full coverage. No waiting for multiple coats to dry, either. Spraying also leaves little sanding to be done on the undercoat. Even if you have to rent a compressor and gun, it is really worth it. This is an important step and a major labor saver.


Jon Agne
posted 03-16-2000 09:28 PM
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"My enamel will not cover, my enamel will not cover,......"
OK, got that part, BUT 320 grit paper???? I might do that for a Herroeshoff (genuine), or Crocker, or Lawley.......but I have a Crosby catboat. I use 120, if I'm feeling ambitious, maybe I'll use the next more fine.

Anyway, thanks again for the paint sequence. I have it printed out in my paper files and pull it out every spring.

Think LAUNCH!

Jon


Bob Cleek
posted 03-17-2000 12:35 AM
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No, actually, I'd urge you to use a finer grit than 120 for the last go round. I'll grant you that 320 may be more than you want, although I use it between coats of enamel. At least take your base coat down to 220. Here's why... even though you have a perfectly smooth surface, if you look really closely, with a magnifying glass, if you want, you will see that the surface is scored with all sorts of scratches and swirls. If you paint gloss over it, all that will be there staring at you when the gloss dries! Actually, think of sandpaper grades as approximations. In your 120 sandpaper, maybe 10% of the grit grain will be as small as 220 and... maybe 10% will be as large as 80 grit! It's those odd large grains that leave the scratches. Similarly, on a sheet of 220, maybe 10% of the grit will be 120... you can cover those with paint pretty well. This is what makes the difference between a respectable job and a GREAT job!

mariner
posted 03-17-2000 09:08 AM
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Does the cpes affect the breathability of the wood?

chemist
posted 03-17-2000 11:21 AM
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There is a paper Smith published on-line at www.woodrestoration.com which answers that question. He tested deteriorated wood and found that it absorbed some water but not as much as before the epoxy treatment. This shows that wood soaked with CPES does "breathe". The paper is quite an interesting one, with lots of color pictures of sound wood and deteriorated wood absorbing CPES or water in time-lapse photography. He also shows by these pictures that deteriorated wood preferentially absorbs CPES and sound wood preferentially absorbs water. Go look and see for yourself.

chemist
posted 03-18-2000 02:10 PM
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The Committee Chairman promised me that PHYSICIST would be given the mechanical ones and I would only have to deal with chemistry, but they still haven't issued that persona so I have to handle it all.
There is a phenomenon that happens when sanding, which is that little pieces of the material being removed pile up and glue onto each other due to the heat generated at the microscopic sites where cutting action is happening. This has the result of excessive roughness in the piece being sanded, sometimes. It depends on the nature of the paint or resin being sanded.

The way to get the best sanding result with the fastest material removal consistent with a given finish quality is to wet sand. However, the little resin or paint particles do not usually wet with water, and so still ball up and the result is "better, but still not great."

The way to get the best wet sanding results is to add a bit of any liquid dishwashing detergent to the water and then use THAT water with the paper when wet sanding. I invite you to try this with any grade of grit on any material. What I personally observed was that 120 grit wet sanding with soapy water gave the same finish quality as 200 grit dry sanding on clear acrylic plastic.


Jorma Salomaa
posted 03-18-2000 02:30 PM
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I remember reading in some Ovatrol (DeksOlje) brochure that they advised to wet sand with Ovatrol 1 (which is the thin variety for impregnating and priming purposes). Any comment to this?

Scott Rosen
posted 03-19-2000 07:49 AM
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Chemist, you're good, but I've got to disagree with you on this one.
Wet sanding has its limitations. My experience is that there is no need to wet sand for any wooden boat related job. For obvious reasons, wet sanding bare wood is out of the question. My personal experience is that wet sanding paint and varnish makes a terrible mess, and the resin-filled drips get into everything. It slows your work down considerably, because you have to wash down with water and let dry before you can apply any finish or fairing compounds. Most important, though, is the result. When using oil-based yacht finishes, dry sanding with the right grit will get you a finish that is as good or better than a wet sanded finish.

There my $0.02.


mariner
posted 03-19-2000 11:14 AM
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Of interlux,z-spar,petit..... What would be the best product to go over a cpes sealer as a primer and finish coat?

chemist
posted 03-19-2000 12:18 PM
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Mariner:
The word primer has lost much of its meaning because it now has so many different meanings. There are

Adhesion-enhancing primers

Sanding-and-surfacing/filler primers

Sealer primers (in the old days when there was enanel paint and varnish and linseed oil and tung and walnut oil and life was simple, one applied a thinned coat of paint, oil or varnish to soak in and seal the irregular wood porosity at the surface. This prevented the grain pattern from telegraphing to the surface and gave a nice gloss finish)

Corrosion-inhibiting primers (for metal)

Moisture-diffusion barrier primers (used with the corrosion-inhibiting metal primers, also to prevent gel-coat blisters on fiberglass /polyester boats

Similar barrier primers for ferrocement hulls;

and so your purpose for specifying "primer " in your question needs to be asked. If it is force of habit, then all you may need is something to help your topcoat stick better. In that case,the CPES will likely glue down anything, by majority vote if for no other reason. If your topcoat is something specified by the manufacturer as compatible with whatever you used as the undercoat, then you have a chain of responsibility for the coating system. Enamel (oil-base) topcoats usually stick by chemical reaction to the same-chemistry undercoat, but test a patch to be certain.

[This message has been edited by chemist (edited 03-19-2000).]


chemist
posted 03-19-2000 12:31 PM
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Scott
I acknowledge your disagreement.

I would, however, point out that you did not do the experiment.

I never said that wet sanding might not be more messy.
It certainly requires a person to exercise greater control of their environment. Dry sanding has the advantage that the wind carries your sanding debris downwind to be (possibly) someone else's problem.
A coarser grade of grit nevertheless cuts faster and provides a finer finish with wet soapy water. That is a fact. I invite you to test it. Not on bare wood, naturally....that would raise the grain and produce all sorts of nonreproducible phenomena.
Take a wood or other surface with lots of coats of epoxy paint or a goodly thick layer of some epoxy resin on it. Take some 120 grit paper and sand away over a square foot area. Use vigor. Then, with the hose running, sand another square foot with a new 120 grit sheet. Use vigor. Then, with a small dish of soapy water and a sponge to convey it to the work area, use another 120 grit sheet and sand similarly a third square foot. Wipe and dry all and examine the finish qualities. Report your results.


steve sparhawk
posted 03-19-2000 12:51 PM
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'Got to go with Bob on the spray vs brush technique. I recently refinished a cedar strip runabout and sanded, filled, primed with the thinned Kirby enamel. One side was brushed and I discovered the brush marks were a b**** to sand out. The other side I sprayed the undercoat. It came out sooooo nice. Just a touch sanding to get off the bugs. There is a considerable economy factor as well. On the brushed side, I had to apply more coats to cover because so much was removed in sanding. The rest of the story is that the brush marks STILL show. Bummer!
And, Bob, thanks a lot for the great coaching job. Some of us may be aware of the correct techniques but are emminantly lazy and still need that cattle prod in the backside at times.


mariner
posted 03-19-2000 04:24 PM
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to chemist,
I do plan on using cpes. I have read bobs' notes on z-spar and spraying. I plan to do that even though i have to cover half the boat yard and pick my days carefully. I have used z spar products and been satisfied. just looking for more input.


Scott Rosen
posted 03-19-2000 05:00 PM
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Two things.
Chemist, everything you say is true. Wet sanding with soapy water cuts the fastest. One benefit no one's mentioned is that the sandpaper lasts much longer when wet sanding, I assume because the soapy water carries the resin away and stops it from clogging the grit. I guess at this point, we're talking about personal preferences. When I need to remove a lot of material, or get a fast cut, I use my random orbital. It makes very fast work of most sanding jobs, and I find it's easier to deal with the dust than the liquid runoff. But if wet sanding floats your boat, I'm not the one to argue against it.

If I wanted to rent spray equipment, what should I look for?

[This message has been edited by Scott Rosen (edited 03-19-2000).]


chemist
posted 03-19-2000 05:41 PM
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HVLP spray equipment (High Volume Low Pressure) has excellent transfer efficiency and pattern edge control. The transfer efficiency is important both when spraying something expensive, such as the modern high-class 2-component polyurethanes, and when you do not want to clean the downwind spray mist off of everyone else's stuff.

Bob Cleek
posted 03-19-2000 06:07 PM
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Scott, I'm still using an old Binks gun, but as Chemist says, the HVLP stuff is supposedly very good. Moves a lot of paint with very little overspray. (Incidentally, it's one eco-maniac idea that actually works better than the old gear.) HOWEVER, one point Chemist overlooked, although I'm sure he is well aware, DO NOT SPRAY TWO PART POLYURETHANES OR EPOXIES WITHOUT A SUPPLEMENTAL BREATHING AIR SYSTEM!!! This is really important and everybody ought to be super aware of it. You can spray oil based enamels downwind with a paper mask, but if you are working indoors, use a good filter respirator. If you are using the new hot two part stuff... you MUST use a supplemental breathing system. Most locations have outlawed shooting that stuff outdoors and require a specially filtered and vented booth. You inhale those fumes and you die.