CS17 #370 Peggy-O

[LennieG]

Thanks Dale!

 I ordered the System Three WR-LPU today for cabin

appreciate everyone's help.

[LennieG]

Back in the shop and making progress. I have 4 weeks before a vacation and hoping to make a serious dent in the build. Enjoying the System Three WR-LPU very much.  The fact that one can put on two coats in a day speeds things up. I have three primer coats down on the aft cockpit and the underside of the seats. Plan on three topcoats today and tomorrow and also install the fore seats. Should be receiving the Honda 2.3 today or tomorrow and then will go to work on a motor well.

 

The bad news and a question: seems I once again made the enamel mistake ( I can't believe it), this time on the masts. A bunch of sanding, cleaning, primer coat, sanding, and a couple finish coats with rustoleum professional enamel . It is already chipping and scratching in the shop from a little movement. I believe I will strip it and repaint with better paint. I have been told that with an etching primer, primer, then topcoats by the System Three tech folks that their paint (WR-LPU ) would work well. Do you agree?

what have you had success with on masts?

thanks

[Howard]

Lennie:

 

I think the masts depend on the appearance you are going for. Although they don't look very good, one way is to leave masts unpainted or untreated at all. An aluminum oxide layer will form on the surface, which protects it from further corrosion, and if scratched, will heal itself by forming a new oxide layer on top of the wound. But it won't look all that pretty.

 

When I was looking to paint my Spindrift mast sections (the aluminum one), the paint guys I talked to started talking about acid etch primers (to get rid of the AO, which forms almost immediately after you take the old layer off), then epoxy primers, LPU paints, etc.

 

On my existing sailboat, the builder (accomplished boat industry expert) advises if one wants to paint their mast,  to sand the mast, apply an automotive epoxy primer, then automotive LPU paints, which in our case, will also need a flex additive. All this gets sprayed on, so not only will you need a good HVLP gun, you will need to know how to use it, as well as know your paint chemistry and application techniques. Most of the guys who do this for a living have gone to trade school to learn all that.

 

So after looking at all the angles, in the end, I took mine to an automotive paint shop and had them painted there. I simply left them and they got around to it when they got around to it. But they came out pretty good and the paint is tough. That is also what I intend to do with the Princess masts.

[PAR]

To do a good job on raw aluminum, you need to get the primer down as soon as it's cleaned. I literally clean with one hand and as the cleaner flashes off, I'm applying epoxy primer with the other. Once the primer is one, you can use any paint you want. I'm not a big fan of the System Three WR-LPU's, mostly because they're difficult to work with professionally (can't spray it), but a roll and tip job with real solvent based LPU will work very well. I too have switched to acrylic urethane automotive paints. These are very durable, easier to apply, much more vivid color choices and dry fast. This is the paint systems used on cars now and it's tough stuff, costly, but flexible (with additives) and very good gloss retention and finish workability.

[LennieG]

Thanks Howard and Paul. I have about 10" of glass.,goo etc at each joint (3 per mast) so leaving it bare wouldn't look good at all.

Paul- just to be clear with what you are saying......I'm going to strip the old paint first obviously. When you say "clean" are you saying like an acetone wipe? I guess I am a little confused as to the order......is it ok to strip it bare, sand it if necessary and then leave it.....then at some point like next day clean it with a solvent like acetone and at that point quickly apply the primer?

thank you

[PAR]

Aluminum oxidizes pretty much immediately after you remove whatever you have that's cleaning it. By cleaning, I mean removing surface oxidation, which usually means sanding. West System recommends you sand the aluminum, wipe with a tack rag, then as you're applying epoxy, use a Scotch Brite pad, wire brush (whatever) and continue scuffing the surface in the goo itself, to insure you've toothed the aluminum and placed any residual oxidation in suspension, within the epoxy. I've done this and it does work well, but what a mess.

With the presanded aluminum tube on some saw horses, I'd quickly sand again, tack, then apply the epoxy primer, all in one continuous motion. It does help to have an assistant sand and tack, while you apply the paint. With me, I'd be spraying the primer, so I'd do an area, tack it off, then shoot it, leaving enough room to continue sanding and tacking without contaminating the paint (about 3'). If doing everything by hand, I'd be tempted to try the West System approach and scuff the aluminum through the wet paint, then tip it off as best as you can. Epoxy primers have some working time, unless you're in the tropics like us. Start very early in the morning (3 - 4 am) so it's as cool as it'll get and you'll have more working time.

The "etching" primers do the same thing chemically. They have solvents that physically attack the aluminum, leaving the surface clean and microscopically pitted, so paint can stick. I've only used these from rattle cans and not a lot, so I can't speak to their durability, compared to a real epoxy primer. All the pros I know, both marine and automotive are using nothing but epoxy primers. I know one guy that does custom gates and railings. He usually powder coats, but also does repairs and color matching, where he paints. He cleans the aluminum in a deep freeze locker, like that seen in a restaurant. It's a 8'x12' box and the primer goes on in a moisture free environment. Once it's coated, he pulls it out to dry at room temperature. Pretty slick, but the overhead on a big freezer paint booth has to be a killer.

For a home job, all by hand, scuff it up good, with a grit you can live with, tack right away and get the paint on as soon as you can, you'll likely be fine. Yeah, there'll be some residual oxidation starting to form, but do you own a freezer big enough to house your mast? Me neither . . .

[LennieG]

Thanks Paul 

[PAR]

What primer will you use Lennie?

[LennieG]

Paul- I am not sure. I spoke to a guy yesterday that has a storage room near me and he renovates old cars. He gave me the names of two auto body /painters nearby that he trusts and one powder coater. The powder coater apparently does all the local awning frames and poles etc. it would seem to me that that type of business would be able to do masts without much custom set-up etc. so I will speak to a few folks this week and hopefully farm this piece out, if not will check out some marine epoxy primers/ LPU 's and perhaps  an etching product. Maybe by the time I make a decision I will find that my current masts are cured, tough, and chip free, but I doubt it

[PAR]

If you can get them powder coated, this is the way to go. I now have a small powder coat setup, I can use on small parts. I use a regular oven to cook stuff (was my other half's, until she caught me drying some oak) for the cure, so he'll need an oven long enough to accept your mast parts. Also, I'm not sure what might happen to the epoxy bushing at the temperatures the oven will generate. You might have to sand them again for a good fit, possibly redo all or portions of them.

[mattp]

My masts are powder coated and I avoided epoxy for the reason PAR states. I can't remember the numbers, but the it seemed certain that the epoxy wouldn't stand up to the oven temps, so we welded instead.

[LennieG]

Graham and Alan -

what do you recommend for CS17 masts?

what do you do?

sometimes I feel like I am the second crew to headed to the moon and we are all figuring it out....there has to be some simple, proven technique that works.....tell me what to do, what to use and I will do that.

thanks

[PAR]

Regular powder coating requires close to 400 F (200 C) to fully cure. They do have "low temperature" cure powder coating, but they still require 280 F (138 C) to harden. You can cook the part in an oven or use an IR lamp, which is something I haven't tried yet, but would seem like a logical thing for a mast. A gun with it's transformer and powder cup will run you about a buck and a half for a reasonable one. I'll bet Harbor Freight has one cheaper, but we all know what they sell, though for a one shot kind of deal, maybe worth it. You'll also want some powder, which can be mixed and matched to make many colors.

 

I epoxy primed my CS-17 sticks and used a single stage urethane topcoat, mostly because my 2 piece assemblies had wooden tops that powder coat wouldn't stick to.

[LennieG]

So no etching primer?

[mattp]

Option overload!

[PAR]

No, I didn't use an etching primer, just a good quality epoxy. I had previously sanded the aluminum lower section with 180 grit and let is sit, until I built the upper birdsmouth section. As I previously mentioned, I made a custom set of sticks, of a single aluminum lower and wooden upper section. Yeah I like to change stuff, though usually to make things simpler or more to my liking/style. Once I was ready to paint, the upper section was epoxied in place on the top of the lower tube and a final 220 sand on the aluminum. Within 10 minutes I was applying primer and I got lucky with the day and weather, as it was winter and very low humidity. If it wasn't, I would have sanded in an A/C'd environment (back then the family room, when the other half was at work), to control oxidation as best as practical. Once the primer was on, the oxidation issue was gone, so I painted at my leisure.

 

Yes Matt, lots of choices (now), but this wasn't always the case. I'm old enough to remember there was only one kind of paint you used on a boat. You didn't have any choices, except for the stuff they used in art class in grade school, which was water soluble. You used oil and liked it, because that was it. In the last 20 years, huge advances have been made, naturally leading to a bunch of choices, which is why I try to cover most of the "usual suspects" on this topic. It can be confusing, but it's really pretty specialized now, with paints for all sorts of specific applications and having widely varying physical properties.

 

A quick search on this site will reveal many previous threads on painting and clear coating (same thing). You'll quickly find you have three basic choices: alkyd (traditional oil base), acrylic (water based or borne) and polyurethanes. The oils are pretty much all the same, with various modifiers and additives to improve some aspect of their performance as a coating. They're getting harder to find now, because of VOC issues, but they'll still available and now the weakest among the usual suspects. Acrylics (latex) and water borne (not the same as latex) are now superior in most regards to the traditional alkyds, being harder, having better gloss, more durable, etc. The polyurethanes can be divided into two sub categories, single stage and catalyzed two part. These out perform the others in most regards and especially in price (they're not cheap). Some of the alkyd and acrylic formulations can also be divided into subcategories, but for the most part, they turn into single or multi part polys, once they really fool with the formulations much.

 

Because of this specialization, you can get products that stick to some things like no body's business, but not so well on other substrates. For example, you can powder coat stuff, but it has to be electrically conductive, which cancels wood out of the mix. There once was a time when you could only chrome plate metal, but amazingly enough you can chrome plate pretty much anything now and it's real chrome plating too, not paint that looks like chrome. This is the level of advance we've seen in recent decades in plastics and why we have so many choices in coatings. In the old days, you could stop a lower leg on an outdrive or outboard from rotting away. The factory paint would fall off, because of the oxidized aluminum under it. Now, with these specialized paints, you can buy a specialty rattle can, spray the outboard and it'll still look pretty good 5 years down the road.

 

For the most part the novice should just stick with a single part paint and follow the recommendations on the can. This typically means the same brand primer and solvents, but with a little research (sites like this for one), you can get better products, choices and techniques, often for less effort and money.

[Howard]

Lennie:

 

I should modify my previous post, in that I mentioned an etching "primer". There is such a thing, but from what I can tell, is an inferior process and not what you want.  What I meant to say was "acid etch" wash, which removes the aluminum oxide layer, followed by a zinc chromium wash, which gets in front of the aluminum oxide to chemically bond to the aluminum, and is something the epoxy primer can adhere to.

 

So the process was mild acid wash to remove the AO layer, zinc chromium wash, epoxy primer, LPU paint. When I heard all that is when I went looking for an auto shop to paint it for me.

[LennieG]

Thanks all. Hope I don't get a speeding ticket today as I rush to auto body shops.

I very much appreciate all the patience you have with me, and taking the time. It is a confusing topic for me, further confused by conflicting info from various experts, particularly the paint technical "chemistry" majors ( System Three) who tell me I can use their LPU marine paint, with their epoxy primer but must use etching primer first. This all follows deliberate and not casual research on the first go around painting the masks.

 

I've had more " do overs " on this boat than a first time lady golfer.

thanks

[Howard]

Lennie:

 

One way to short circuit the search process for a good paint shop is to call or visit your local auto parts stores that sell painting supplies and equipment. They will know must of the shops in the area and know the guys running them and working there. They can probably give you a very short list of the right folks to talk to.

 

I did that to find a local welder for my rudder hardware by asking around at the shop that sells steel and welding supplies. The guy they recommended wasn't even listed in the phone book. I'd driven by his shop 100 times and didn't even know it was there.  When he found out I needed help with boat hardware, he got interested in a hurry. Turns out his new found hobby is building RC speedboats out of baltic birch plywood and epoxy, so we had lots to talk about.  Not something I expected to find around these parts. Sometimes you get lucky.

[LennieG]

I am working towards painting the cockpit which I hope to complete in next week. I am taking it a little slower than hull and hoping to  minimize visible "seams" which has involved daily applications of fairing compound. Slow but hope it is worth it in the end. Each day I spread more epoxy/micro light mixture thinking I am done and next day see spots I missed.

 

i hope to be doing the coaming in a month and getting ready to order the lumber. I have a good supplier of mahogany and other hardwoods who mills on site at a fairly reasonable price. Can anyone point me to resources for learning about doing coaming? I understand this very little at this point.....There must be a prior thread here but I can't find one and can't find thorough explanation in any of four Boat building books I own.

i have a thousand questions-

- what is the reasonable minimum # of seams on a cs17?

- is 3/16 " mahogany a good choice?

- do you laminate off the boat and then install or laminate and glue on the boat?

- do you install and then shape or visa versa?

- do you need to steam bend?

- do you dye the epoxy so the seams don't show up like plywood? Shame to use a nice wood like mahogany and then have white glue lines.

 

i know it's a vast topic and don't expect all the answers here......appreciate being pointed to a good resource....

thanks