Paint problems

[Chick Ludwig]

I've tried a new paint and think the problem has to do with a reaction to the epoxy it is applied over. I know that there can be problems with some varnish.

 

I rolled and tipped the paint. The rep said that it would be a good way to apply the paint. It was applied directly over the B and B epoxy coating that was sanded prior to application. Actually, here were three problems. 

   1. The paint didn't flow out and level. Every brush mark showed. The brush "dragged", even after reducing the paint.

   2. The paint was dull-not gloss.

   3. It remained tacky (I pressed my finger against the surface and fingerprint remained. It felt slightly tacky.) ---even after three days. It should have been tack free in about 4 hours.

 

I reduced the paint with mineral spirits per instructions.

 

The paint is Sherwin Williams Pro Industrial Urethane Alkyd Enamel.

 

After the weekend I applied another coat reducing with Flood Penetrol. That seemed to work right, but it was over the previous surface that was full of brush marks, so it was hard to tell how well it leveled, but it did dry hard and with gloss.

 

Any thoughts?

[Hirilonde]

Primer after epoxy and before paint?

[Chick Ludwig]

No, I have never used primer on any of my small boats. I always just fill and fair using epoxy resin and Q-cell, finishing with 2 coats of epoxy over the Q-cell fairing. I've not had this problem with other oil based single part paints before.

 

I'm just about to call the Sherwin Williams rep and have him look into it.

[Hirilonde]

I use Awlgrip 545 primer for all applications over epoxy and under all paints for this application. 

[Phil Garland]

From what I have read, use epoxy primer like Awlgrip 545 or Interlux Epoxy Primecoat over the B & B or West System epoxy before applying the finish coat of polyurethane.  I have also seen Alan's CS15 build videos in which he applies the Devoe two-part polyurethane directly over the sanded and cleaned epoxy.  The one part polyurethanes like Brightside need the epoxy primer.

[PAR]

This is a problem with some alkyds and you can't tell which ones it will occur on, so the general recommendation with oil based paints is to prime, preferably with an epoxy. It seems counter intuitive that you'd prime with the same stuff (epoxy) as what causes the problem, but there's a difference between epoxy primer and straight epoxy used as a coating.

 

Something with the alkyd vehicle compatibility with the glycol groups in the epoxy causes this. Sometimes you can wait and it will eventually cure, but other times it just never does or does so pretty soft and again, you can never tell which brand might react. I've seen enough of this over the years, that maybe a list of the known alkyds should be drawn up, so folks can avoid using them or know to use primer. I see less of this with acrylic urethanes and have never seen it with LPU's or acrylics, but it's not uncommon with alkyds.

[Chick Ludwig]

Thanks Par. I guess this is one to start the list with. Luckyme! Trying to save a few bucks by not buying primer.

[PAR]

I use lots of primer. I use it to complete the fairing and smoothing process, so I don't run into this problem any more. It's a lot easier to sand primer then filler or straight epoxy, so I apply usually 4 coats of primer. The first two coats are simply to bulk up film thickness and offer something to sand. It fills much of the low spots and any slight imperfections in the surface. As I fine tune the surface, I'll apply more coats of primer, so I'm not wearing through what's there. It also permits paint to go down neater and more uniformly, so I'll spray 10 - 12 mils of primer, before it's all said and done. I also change colors in the process so I can keep track of what's been removed and where I might need more. A few tea spoons of regular paint (the same type as the primer) will add enough color to make a noticeable difference. I like to start dark and work to a lighter color. This way if I see some dark base cost showing through I know to stop and apply more primer, before I burn through into the epoxy or raw wood below.

 

Lastly it also helps to find a "paint system" that you're comfortable with. I'm using an acrylic urethane system, which is like what they use on cars. Eventually you'll find what the paint you're using likes and doesn't, so just stick with it, once you find success. The only place you can "save" anything on with paint is the prep, because this is the vast bulk of the work (80% prep or more) in any paint job. The actual paint in hand, on brush, roller or spray gun is insignificant in terms of time, so this leaves just the products (sand paper, solvents, cleaning agents, shop supplies, reducers, wetting agents and the paint). There might be some savings in paint cost, but how much do you need on solvents, cleaning stuff and other paint related gear or supplies, plus are these really adding up to a savings? Unless using an straight acrylic (latex), like house paint, where clean up is water and paper towels, the saving on solvent based paints isn't as much as you might think, once all is said and done.

[LennieG]

Chick

i had some of the same issues with Interlux Premium Yacht Enamel, a similar sounding oil based paint. I found that the lack of leveling out and getting brush stroke marks was due to the paint setting up too quickly, and was resolved by thinning to the max, using a foam brush, doing smaller areas and applying at the lowest possible temps, which for me was early am.

Ironically, I did use a primer And it was the first coat of it which took like a week to dry and harden. I am not suggesting you don't use primer as the pros are saying but it may just be that that first coat over epoxy gets dicey.

[Chick Ludwig]

Par. I can't spray primer where I am now, so roller and brush are my only options. Also, no local source for marine products, so I have to order on line. I may only build one small boat (canoe, birder, Spindrift 12) a year and don't want to have to buy a gallon kit of paint and throw away a bunch of it. Also hate to order something with freight and Hasmat charges. So, what would be the best system to go with? Labor "cost" is not the consideration, limited financial budget is.

 

Lennie. I did thin and do small areas, and it was cool, but did not use a foam brush. I think that if I'd used the Penetrol on the first coat, but maybe I would have. 

 

Guess I'll give up and buy primer next time, but hopefully I can find one to roll and tip and buy locally. Now, for a varnish to use over epoxy. I've always used Captain's varnish, but can't get it locally. Sherwin Williams has a spar varnish, but now i'm afraid to try it. Has anyone used it? Other local suggestions?

[makenmend]

Chick I have used the Sherwin Williams 440 spar varnish with no problems.

 

MM

[Chick Ludwig]

Thanks, MM.

[Designer]

I just do not use one part paint on epoxy. I understand the various reasons for doing so. As has been mentioned, uncured amines on the epoxy surface will prevent one part paints from curing properly. 

 

Here is what you should. After proper prep, paint a small section of the boat that will be easy to remove if there is an issue, a square foot is plenty. Paint a square foot on a nice clean surface that has no epoxy. This is your control. If both cure at the same rate, then you should be okay. If the control has cured and your painted epoxy is still soft, then you get to clean off a small area instead of big miserable job. Do not be fooled, the paint surface may have skinned over but under the skin is still soft.

 

As has been said, priming first is best for a good finish. If you use a one part primer, do the test, it may save you a lot of work.

[Chick Ludwig]

Well Graham, as you can see, I'm still learning the hard way. In the past, I've painted with Easy-poxy or Rustoleum with no problems. I was trying something new that I thought would give a harder surface, but would be available for a good price locally, never realizing the problem with one part paints. My bad! I'm going to flip the boat and finish it so I can have it for the mess-about. If, in fact, the paint doesn't cure all the way through, I'll just have to worry about it later. If it does cure, I'll still have to sand it to remove the ripples and brush marks, and recoat. But this will be later. Got my little fingers crossed! ...and toes...

 

Thanks to all of you for the advice---too bad I didn't ask first, and paint second!

[LennieG]

Let me ask a question on same point please. I also painted with one part paint (Interlux premium yacht paint) on hull despite some advice here and I did so for a number of reasons that made sense to me at the time.  I then painted with a two part on cockpit (system three LPU ) and liked it and got over my health concerns regarding LPU.

Rather than compounding my mistake and using enamel on deck, which really doesn't match the cockpit paint all that well I am thinking about biting the bullet and removing hull enamel and re painting it and the deck with the LPU. It will be easier now for me with shop set up than later.

A few questions:

1. Ideally I would like to strip the paint down to epoxy on the plywood joints only, re smooth them which wasn't done well first go around, sand the rest of the hull and then re paint. Is that possible or do I need to strip all the paint down to epoxy everywhere on hull? In other words can I get away with not doing a complete strip? ( the enamel did pass the scratch test originally)

2. Assuming I need to strip the entire hull is that an impossible job? How big is it?

3. What is process? Sand with 60 or 80 grit, chemical stripper, then sand and scrape until paint is gone? Is a new layer of epoxy prior to epoxy primer recommended?

thanks

[Chick Ludwig]

Lennie, guess I'm in the same boat. (Ha, a little pun...) In my case, if the paint isn't hard, i guess I'll need chemical stripper. What a mess! Will it attack the epoxy?

[PAR]

Epoxy is pretty tough, though the chemical stripper should say "safe for fiberglass" on the label to be on the safe side. Yes, ideally you'll want to get back down to the coated substrate (epoxy). If you have a well stuck base coat (paint) then it can stay there, just feather the edges and apply primer. Once the primer is smoothed up, you can put any topcoat of choice, without worries.

 

Lennie, considering the difficulty you've had with painting, maybe you should enjoy what you have and do the strip an redo, when you need to do a wholesale job on your deck (some years from now). I mean, man you're killing yourself. It's not a piano, just a boat. Finish 'er up, have fun, cuss about the paint issues and you can get to it eventually.

[LennieG]

Paul-

Thanks. As always you are offering great advice and I appreciate it. As I balance the issues I keep coming back to a few conclusions:

- I really care a lot about how the boat looks when I am done.

- I love working on the boat, sweating, grinding it out, learning....this is the fun for me.

- I worry about never getting back to it later, and I have momentum now.

i figure I lose a couple weeks is all if I redo the hull, and gain years of personal satisfaction, so I probably will take the hit and do it.

thanks

Lennie

[PAR]

 

. . . I worry about never getting back to it later, and I have momentum now . . .

 

Oh please, you'll never be done and will always have time. Home builts have a few commonalities about them, the usual things are they are constantly evolving for the first few years after they launch. As these "upgrades" take place, paint gets touched up and usually about 3 to 5 years into it, a wholesale new paint job, if only to cover the scars of learning to sail and the puttied over fastener holes of moved hardware. It's like a child, you can repaint their bedroom when you finally get them in collage, just to find they hate the color when they return home jobless. Trust me, she's going to look great when you roll her out into the sunlight and splash her for the first time. You'll feel guilty when you bash into your first dock, which will cause you to think about bigger rub rails or maybe a rubber abrasion strip along their length. This is the normal course and you'll doing fine.

[Chick Ludwig]

I tend to agree with par. After turning Turtler over, my resolve to strip and repaint is fading away. She don't look too bad from a few feet away, and she'll get plenty of abuse out on the lake. Speaking of adding an abrasion strip---where is a good source for hollow back, 3/8" and 1/2" keel strip. (It has to be that narrow to fit.) The vinyl abrasion strip won't work here.