Painting FAQ

[veets]

Work is proceeding on my Redmond Bluegill project, thanks in large part to the kind of assistance of many forum members. I have successfully attached the bottom and am well along in the initial fairing.



The next thing I plan to do is fiberglass the bottom up to the waterline with 6 oz fabric. In preparation for this step, I have done a lot of reading from various sources on the topic of applying fiberglass but also on painting, since I know that any decision I make while fairing and fiberglassing will impact the quality of my final paint job. So here is the question:

Are any of you -- especially those who developed projects out of plywood and fiberglass -- willing to share your major steps to a fine paint finish? It would certainly help me and it might form the basis of a painting FAQ that might prove useful to the other novices like me.

Here are the steps I am contemplating; your comments are welcome, as well:

* fill all holes and fair using West 407 filler
* apply 6 oz fiberglass fabric to the waterline using West's 207 hardener
* coat the entire bottom with West using 207
* sand
* apply several coats Tru-Kote primer
* sand progressively down to 220 grit
* apply several coats of Brightsides, color TBD, sanding lightly between coats

I have been through the forum and many other sites and books and it seems there are an infinite number of approaches. (I have read folks on this forum say the primer is unnecessary because epoxy is the primer. Others say never apply Brightsides directly over epoxy.) But I haven't found anything resembling a collection of best practices.

[mike hanyi]

you can pratice your painting skills on that drywall!
do you really need to epoxy and glass everything? would it not do just fine in doing the bottom and just tape the seams?

then 2 componant paint.

[veets]

I don't have time to paint drywall. I have a boat to build.

I suppose I could just tape the seams. It seems like that gives me two edges to feather all the way round instead of one, which is more work. More work than coating and sanding the entire bottom? Maybe not. (Plus I already bought the fabric.)

[George Ray]

I assume Tru-Coat is a 2 part epoxy. I have been using Interlux Epoxy Prime Kote 404/414. It is a multi-purpose two-part epoxy primer for use above and below the waterline and it makes a great sanding surfacer. Sprays and brushes very well. Alternate color of primer surfacer to help pick up low spots/scratches. Epoxy primer can be easily tinted with resin colorant.

One suggestion on safety. I recently found that I have a respiratory epoxy allergy and had to upgrade my breathing protection. Epoxy is fairly inert when fully cured, however it is not fully cured for many days or weeks and can cause allergic reaction. My symptoms are pretty subtle, there is No rash, no coughing or gasping. I just get lethargic. Hardly can get out of bed and I try to think and nothing happens, not obviously sick but fairly useless. UCK! A standard 95% dust mask was letting enough epoxy dust through that after an hour of sanding one day old epoxy I had a case of the SLOWS for about three days.

Most 'good' hardware store dust masks are 'N95' or 'P95' which filter 95% of airborne particles. While I realize that particle size plays a big part that is how they are usually referenced. You can find (e.g. McMaster Carr ) N99 (99%) and P100 (99.97%) and they make a big difference. Best is a fresh air hood and I have one now but it is expensive and the compressor (clean oil free air) setup is difficult. The bulky cartridge painting masks from Lowes or Home Depot are often N99 rated but some are only N95 so you have to check. It took me 50+ years of breathing dust/fumes/junk before it bothered me and some folks never seem to have a problem. Good Luck....

I have had good luck with Brightside in years past. I used a foam roller and a very good badger hair brush on fancy jobs. Need to move fast and keep the wet edge. Experiment with thinner to help it flow and keep wet edge. I rolled vertical and brushed horizontal and except for one spot where I lost the wet edge, people thought it was a spray job. I did have an expert at my elbow helping with thinning and urging me on 'hurry hurry you'll lose the wet edge'. You might consider finishing with 320 if your looking for high gloss other wise 220 is great.

I have recently started painting with US Paint 'AwlCraft2000' a cousin to AwlGrip and it is wonderful stuff. Flows outs wonderfully, dries to touch (rainproof) in couple of hours and over spray is almost non existent. (Poison! => Isocyanates can cause asthma and other lung problems, even with very low exposure levels. Allergic people have died from using this stuff!!) I was around it a few years ago and had better mask (but not fresh air) than anyone else and I was laid up/tired/useless for a couple months and no one else was affected. CAREFUL!!

[kc8pql]

I apply fairing compound after glassing and a light sanding. It bonds better to a glassed surface than to bare wood, fills any areas in the cloth weave you missed, fairs in cloth overlaps, is a lot easier and faster to sand that unfilled resin and reduces the chances of sanding into or through the cloth.

[veets]

Thanks for the caution on epoxy sensitization. To be honest, there were three concerns that nearly prevented me from ever tackling a boat building project: would I be able to find the right materials, would I be able to develop all of the bevels with a plane, is epoxy too risky to work with. Good so far on the first two. Still being careful on the third. I plan on moving the entire hull outside when it's time to sand down the epoxy on the fiberglass in addition to suiting up.

[George Ray]

Most people do not seem to be bothered by epoxy or polyester in a respiratory way, skin dermatitis seems the most common complaint.

For years I washed resins/paints off my skin with solvents and to date there seems to be no ill effects, but now I only clean up with hand cleaner/soap-water. The use of vinegar to clean up epoxy gets very mixed safety reviews but it does seem to work well. I use disposable paper suit, painters head sock, dustmask and barrier cream (or just skin lotion) with gloves. When sanding/grinding I use soft leather driving gloves to keep the dust/glass fibers out of my skin. When mixing and applying resin/paint I use disposable nitrile gloves. Try to have compressed air to blow the dust off your work and yourself at the end of a session.

[Todd Bradshaw]

"Most people do not seem to be bothered by epoxy or polyester in a respiratory way...."

Epoxy no, but polyester fumes can severely damage several organs that you might want later.

You're bound to get lots of different opinions here as there can be more than one way to accomplish the goal. Why WEST 207, since it's really formulated for clear finishes and you're goint to paint it? It will work, but the others would work just as well and probably at a lower price.

I apply filler coats of resin with a foam roller and if needed, tip out any bubbles with a "brush" made from a chunk of roller hot-glued to a stick. I apply thin coats and usually do about six of them, doing all the glassing and filling in one day, most of which is spent waiting for resin to harden (105/205 works great for filling and shortens the waiting time). You simply add filler coats until the weave of the cloth is completely gone and then add one more and quit. This ensures that you have enough filler that you won't cut into the glass fibers when you sand it smooth (which would defeat the purpose of fiberglassing it in the first place). I use plain resin for filling, not mixtures like 407 or 410. It gives you a more abrasion-resistant surface by far on small boats that get beached compared to resin stuffed full of fluff.

If you will be using Brightside on WEST epoxy, primer doesn't add anything unless your filling/sanding job isn't very good and you have a lot of small irregularities to hide. The paint goes on and sticks just as well to properly sanded epoxy as it will to primed epoxy. If you did properly fill and sand the surface, it should be just as smooth in the epoxy state as it would be with multiple coats of sanded primer. You also don't need or want a 220 grit surface. Read the can directions on the paint. Once you get beyond 100-150 grit at most (depending on your sander and what sort of marks it leaves) all you're doing by polishing the surface with 220 is reducing the quality of your paint bond. You can prime if you really enjoy more sanding and like to watch your sandpaper fill up, but is isn't going to do anything to improve the paint jobs texture or adhesion.

WEST 105/205/barrier coat additive, topcoated with plain 105/205 then sanded to 120 on a random orbit with no primer and Brightside rolled and tipped over it. Work done outside in the summer, no thinner added.

[donald branscom]

I assume Tru-Coat is a 2 part epoxy. I have been using Interlux Epoxy Prime Kote 404/414. It is a multi-purpose two-part epoxy primer for use above and below the waterline and it makes a great sanding surfacer. Sprays and brushes very well. Alternate color of primer surfacer to help pick up low spots/scratches. Epoxy primer can be easily tinted with resin colorant.

One suggestion on safety. I recently found that I have a respiratory epoxy allergy and had to upgrade my breathing protection. Epoxy is fairly inert when fully cured, however it is not fully cured for many days or weeks and can cause allergic reaction. My symptoms are pretty subtle, there is No rash, no coughing or gasping. I just get lethargic. Hardly can get out of bed and I try to think and nothing happens, not obviously sick but fairly useless. UCK! A standard 95% dust mask was letting enough epoxy dust through that after an hour of sanding one day old epoxy I had a case of the SLOWS for about three days.

Most 'good' hardware store dust masks are 'N95' or 'P95' which filter 95% of airborne particles. While I realize that particle size plays a big part that is how they are usually referenced. You can find (e.g. McMaster Carr ) N99 (99%) and P100 (99.97%) and they make a big difference. Best is a fresh air hood and I have one now but it is expensive and the compressor (clean oil free air) setup is difficult. The bulky cartridge painting masks from Lowes or Home Depot are often N99 rated but some are only N95 so you have to check. It took me 50+ years of breathing dust/fumes/junk before it bothered me and some folks never seem to have a problem. Good Luck....

I have had good luck with Brightside in years past. I used a foam roller and a very good badger hair brush on fancy jobs. Need to move fast and keep the wet edge. Experiment with thinner to help it flow and keep wet edge. I rolled vertical and brushed horizontal and except for one spot where I lost the wet edge, people thought it was a spray job. I did have an expert at my elbow helping with thinning and urging me on 'hurry hurry you'll lose the wet edge'. You might consider finishing with 320 if your looking for high gloss other wise 220 is great.,,,,,,(clipped)

Nice work George very professional.WOW

[donald branscom]

"Most people do not seem to be bothered by epoxy or polyester in a respiratory way...."

Epoxy no, but polyester fumes can severely damage several organs that you might want later.

You're bound to get lots of different opinions here as there can be more than one way to accomplish the goal. Why WEST 207, since it's really formulated for clear finishes and you're goint to paint it? It will work, but the others would work just as well and probably at a lower price.

I apply filler coats of resin with a foam roller and if needed, tip out any bubbles with a "brush" made from a chunk of roller hot-glued to a stick. I apply thin coats and usually do about six of them, doing all the glassing and filling in one day, most of which is spent waiting for resin to harden (105/205 works great for filling and shortens the waiting time). You simply add filler coats until the weave of the cloth is completely gone and then add one more and quit. This ensures that you have enough filler that you won't cut into the glass fibers when you sand it smooth (which would defeat the purpose of fiberglassing it in the first place). I use plain resin for filling, not mixtures like 407 or 410. It gives you a more abrasion-resistant surface by far on small boats that get beached compared to resin stuffed full of fluff.

If you will be using Brightside on WEST epoxy, primer doesn't add anything unless your filling/sanding job isn't very good and you have a lot of small irregularities to hide. The paint goes on and sticks just as well to properly sanded epoxy as it will to primed epoxy. If you did properly fill and sand the surface, it should be just as smooth in the epoxy state as it would be with multiple coats of sanded primer. You also don't need or want a 220 grit surface. Read the can directions on the paint. Once you get beyond 100-150 grit at most (depending on your sander and what sort of marks it leaves) all you're doing by polishing the surface with 220 is reducing the quality of your paint bond. You can prime if you really enjoy more sanding and like to watch your sandpaper fill up, but is isn't going to do anything to improve the paint jobs texture or adhesion.

WEST 105/205/barrier coat additive, topcoated with plain 105/205 then sanded to 120 on a random orbit with no primer and Brightside rolled and tipped over it. Work done outside in the summer, no thinner added.

I would be really proud of that. Looks great.

[boatbear]

Very informative thread. Thanks. Should save me some future blundering. :-)
Charlie

[RodB]

Lots of good advice here. I don't understand why you didn't just glass the bottom and side panels on the outside surface before putting the hull together...its much easier glassing on the horizontal. Also, now...why not just glass the entire bottom and sides.... you get such a tough barrier and lots of protecton with very little added weight. Once the glassed surface is sanded and faired its quite straight forward to apply a decent paint finish....and the surface is so uniform...and easy to fair.

If you prep the plywood properly by just plain sanding...there is usually no need to fill much of anything. Just apply the glass, fill the weave well to a level that allows for sanding to a satin finish without touching the glass fibers. Then, as suggested above, you can fill any areas that need it.

After the epoxy cures when glassing, sand to a nice satin finish with 80 grit on a good ROS. As a final step in sanding, I also hit the surface of my 18 foot skiff with a quick once over with 100 grit on a PC 333 sander....and the finish was great with Kirbys Alkyd enamel. My designer/builder did not recommend anything finer than 120 grit...and he has built over 60 boats, large and small...and many were painted with Brightsides. He does not use the Interlux epoxy primer, but a tough alkyd base coat that uses a hot solvent (Xylol) and is a high build white primer that sands beautifully and fills in all small imperfections.

The trick is to avoid any epoxy curing solvents ruining your paint adhering to the epoxy. So, you have two choices... let the epoxy cure very very well, wash the surfaces with a 10% solution of ammonia and water, then get it very clean with plain warm water...then sand it...and if the epoxy is completely cured..you should have no paint adherence problems without a primer. The second method (the method used by purists) is to apply an appropriate primer to act as a barrier between the epoxy and the paint...and this is what my designer advised but he did say he has done it both ways with success. You still need to clean the epoxy first before sanding...(without a good cleaning with water/scotchbright scrubbing or ammonia/water then water scrubbing...you just sand in any blush that might be around on the surface). You really can use an good high build primer that uses a hot solvent...because you are really only applying a alkyd paint with some polyurathane resins in it. Interlux's own recommended primer for epoxy is probably a great way to go...just not cheap. The name and mfg of the high build Alkyd base coat is below on the photo of the primed hull...I love the stuff and keep it around for any painting on epoxy...its about $25/gal.

Heres a bottom ready for glassing...now I had to fill screw holes/staple holes because I coldmolded a layer of 1/4" merranti on the bottom....scarffed in place. Now, I didn't paint the bottom of my hull...cause I wanted to avoid paint rubbing off on the trailer bunks...but I primed and painted everything else...and the primer I mentioned above is quite tuff.



Bottom sheathed with Xynole polyester fabric and buried with System III epoxy, two final coats of graphite and epoxy applied....and to provide a tough slick surface for the bottom of the boat.


All surfaces here are glassed with 6oz cloth and sanded to a satin finish... The sides and bottom panels were glassed before the hull was assembled.


Heres the high build primer applied...its great cause you just SLATHER it on with a brush...TWO coats... it dries very fast...then it sands beautifully...to a really nice smooth finish. It is amazing how smooth and fair this primers gets with just a bit of sanding with some 120 grit. The primer is a fast drying base coat: #1640 Overlay from Parker Paint by Great Northwest Paint (interior/exterior Alkyd flat primer finish). . . it is thinned with Xylol (Xylene) and adheres very well to clean sanded epoxy and is a very tuff barrier.


Heres a look at the finished boat...FYI




http://www.woodenboatvb.com/vbulleti...ght=flats+boat

Good luck.

RB

[pipefitter]

On such a small boat,it really does no benefit to stop with the glass at the waterline. Economically,there isn't that much difference and saves from blending where the glass stops unless you cut a perfect line with the glass atthe waterline. If you don't mind seeing the transition or fairing it out,then it's really no matter but I would find it more work to fair in the illusion of a fair,homogenous surface than to just bring it up to level. Paint lasts alot longer over FG than on primed wood. Primer surfacers shrink for a long time and at different rates than the top coats. If a primer/surfacer is used,it should be so thin that it is nearly transparent and only used to fill small scratches and stand alone imperfections. To put brightsides over epoxy it just needs to be VERY clean. Worked very well for me.

[RodB]

Hey Pipefitter,

Its amazing...you and I both have built at least one long project with epoxy and ply...and we usually agree about 99% on the approach to to any task...

As usual you are right on the mark...

Rod

[veets]

Thanks to all for the thoughtful advice.

I chose to glass to the waterline since that is what is recommended by the designer (for those who choose to glass and I do.) I will consider glassing the whole bottom, though. Your correct that it is not much additional cost or effort. I will definite avoid a primer coat. I'm confident that I can prepare the epoxy surface based upon all of the cautions and advice in this thread and elsewhere.

I now plan to prepare and maintain a test board as I move forward, applying fiberglass and epoxy to it, so I will be able to test the paint on a like sample before applying it to the boat.

Thanks again.

[pipefitter]

Rod,I worked on some older work boats and noticed that everywhere there was glass over wood ,even polyester over wood,the paint was always in much better shape. Almost as if someone had more recently touched up a spot on the boat. or painted a stripe over the old finish. One of the first enemies of a paint finish in my experience has been checking wood underneath that exposes the film at many more points.Wood checking and then swelling the cracks shut again breaking the edges of the paint film further which also seems to cause premature flaking,especially with the more brittle alkyds.

Sandable primers, as what was told to me were only to be used for minor surface imperfections and microfairing and were thus sanded semi transparent as to not shrink and move at different rates than their compatible top coats and was in no way to make up for fairing work of the substrate "if" it could be avoided within reason and allowing for reasonable shrink/cure times(sometimes up to a month, ideally). The thought being from the veterans to the apprentice was to not get the future journeyman used to the notion that you could fix it with the primer and skimp on the fairing. I remember many times on paint day, figuring to recheck and end up spending an additional 3-4 hrs with the long board. On my own boat,I used primer as a blocker for the epoxy but sanded all the primer off. I was surprised how lazy I had been in fairing the epoxy.