BIG disappointment

Submitted byRandy onMon, 05/06/2019 - 15:24

I completed a Guillemot Petrel late last fall so it never saw water, stored indoors all winter. I got it out this spring and something had happened to the finish. I am assuming I made a BIG mistake as I have built several kayaks and this is the first finish problem I have had. I thought I followed the same procedure as on previous boats but apparently not .  .  .  .

The build sequence - sand with 120 grit, apply stain using the same sandpaper, sand very lightly with 220 grit, apply another coat of stain with a rag, sand VERY lightly with 220 grit and apply epoxy sealer coat. Apply 4 oz. cloth then 3 filler coats and sand then 3 coats of varnish. All the epoxy coats were within 8 hrs. of each other and the epoxy dried a good 2 weeks before varnish.

When stored for the winter it looked excellent, just like Nick's mahogany stained boat with the light colored trim. When I brought it out into the light this spring it looked really bad. Full of spots, milky, the deck/hull seam looks especially bad. I did not see a single pin hole / white spot on the boat last fall, this spring :(  :(

I will enclose a before and after photo or two. What dumb mistake did I make ?? I won't be removing the glass and reglassing the boat, I will sell it and build anoither one :)

A little difficult to tell in the photo's but the glass is turning green ??

Sorry, 3rd photo is refusing to load

Thank you for your thoughts :)

The first photo is Nick's boat but mine was exactly the same - for awhile, the next two are mine


Rob Macks Laug…

Thu, 05/09/2019 - 09:38

The only thing I can imagine is the boat went through some extreme temperature swings to stress the glass out as seen.



Thu, 05/09/2019 - 16:58

Are you sure that's not a varnish problem? I know there's plenty of cases of stain going green but I would give the varnish a wet sanding with 240 or finer before you decide. From what I have heard, the stain going green usually happens fairly quickly and not over a full winter. Good luck.

Could it be the varnish interacting with the epoxy, how long did you allow the epoxy to cure before applying varnish?

As far as temp changes, it was finished in the shop last fall at 65 degrees - warmer when glassing - then through the Michigan winter which was close to zero a few times.

Varnished about two weeks after sanding the filler coats, pretty much what I have always done. Same brands of varnish I have always used. I also discovered today that last summer I built the instrument panel for my current aircraft build out of .040 aluminum, covered it with a coat of 3 oz. glass, another layer of carbon fibre then another coat of 3 oz. glass. I took it down from the wall today to install it and it is also turning green tint. Very similar to the kayak color :(

The inst. panel I will remove the glass and finish the bare aluminum, to much labor involved not to use it. 

I have become very leary of fiberglassing anything of value until I figure out what I am doing wrong ????

Is it possible you are using a new glass you have not used before and the finish on the glass is not made for epoxy resin.  I know some glasses do turn greenish when they cure.

I'm seeing clear damage to the glass/epoxy matrix. The white dots are classic stress marks where epoxy has ripped apart from glass fibers.

This happens when there is embedded stress in the construction, like when hull and deck are forced to mate and heat/cold
cycles release the stress and damage the layup. Extremes of temperature can also cause this as can impact. Kayaks should
be stored with hatch covers off so heat can't build up should the boat be subject to sun or other heat sources.

This is not a varnish issue. Yes, you can have varnish/epoxy compatibility issues but this would simply leave you with a soft
coating which never cures. If you try sanding with 220 and the sandpaper just clogs quickly the vanish has not cured.
Cured coatings sand to dust.

There are a great deal of variables in achieving a transparent fiberglass layup.
Sometimes you get lucky and sometimes you do not.

I eliminate luck by following these time tested procedures -

All the best,

Rob Macks

Laughing Loon Custom Canoes & Kayaks



“Persistent people begin their success where others end in failures.” - Edward Eggleston

"I'm seeing clear damage to the glass/epoxy matrix. The white dots are classic stress marks where epoxy has ripped apart from glass fibers. This happens when there is embedded stress in the construction, like when hull and deck are forced to mate and heat/cold
cycles release the stress and damage the layup."

It looks like "damage" to me too but there seems to be no seperation of glass from wood or epoxy from glass. I don't know how I would have stressed the boat during construction. I heat-form all strips so they pretty much lay in place before gluing and I use spacers to hold the shape of the deck and hull until assembly so there is no need to force anything

Rob, when I don't understand what happened I cannot rule anything out, I can just keep addressing suggestions and telling the construction history of the boat until I say something that gives someone a clue to what I did/didn't do so please keep the comments coming - - 

Etienne Muller

Mon, 05/13/2019 - 04:12

Hi Randy. Sorry about your woes.

the main question... Just how bad is it, from a couple of yards away? Am I willing to be seen in it? After a year of hard use you will care less.

Suggestion one... Is it possible that, perhaps in a quest for light weight, you did not add enough fill coats before you sanded the epoxy, and you sanded into the glass. Could you be getting some print through? I can see glass in the feathering at the stem and the joins. Perhaps they needed another epoxy coat after feathering and then another sanding?

Second thought... When I see a situation like this I immediately think of amine blush. Do everything the same as the last job that turned out fine, but if the atmospheric conditions are wrong, amine blush can strike. I used to have problems with blush using WEST 105 if I recall correctly, and with MAS using fast hardener. MAS low viscosity with slow hardener has, so far, never blushed on me, and Ireland has a terrible climate for blush.

Selling the boat is not going to net you much of a profit if it is cosmetically compromised... If it were my boat I would chalk it down to experience, remove the varnish, and have some fun giving it a radical paint job.



Good Morning ET,

It is bad - - from 10 yards away :(  (I meant meters :) As far a 'light weight' quest, I try to be reasonable but not psychotic about it. My procedure is to apply the glass in the evening then it is ready for fill the next morning. One fill at 7am, another at 1pm and the final at 7pm. Let cure for 8-10 days then sand. I almost always have to add another coat of fill in specific areas. I apply fill with an 1/8" roller as thick as possible without running and pop the bubbles with a foam brush. I do all the glassing / fill coats within  24 hrs. just to stay away from blush. Atmospheric conditions could have been a problem, I don't know. I work in a heated shop, usually 65-70 degrees and I keep the epoxy in a heated, insulated box at 80 degrees.

Yes, the glass is visible in some areas but not sanded through. Yes, I do use West Systems epoxy with both fast and slow  hardener's depending on what I am doing.

You are correct about selling the boat but I do not build boats or planes for profit, mostly because that is not realistic in either hobby. I build for my enjoyment, if I sell for enough to cover my material expenses and maybe enough to buy more material I am happy - - (this attitude really irritates my sweetie. We decided a few months ago she would take over the "selling" part of this hobby :)

You are correct again, after thinking about it for a couple weeks I have decided to use the boat this summer then strip the varnish and paint it next winter. I just painted the hull of my latest build and I really like it, much betteer than the standard all varnish look.

What is really puzzling to me is that A) the boat seems to keep looking worse, new spots turning green as the original stain is disappearing and B) the instrument panel I glassed using carbon cloth is also turning green ??? Done at totally different times with totally different cloth - same epoxy though ??

Thank you for your thoughts :)

Just my 2 cents ...

A green hue is commonly mentioned when there has been a compatibility problem between the epoxy and the "finish" applied to the fiberglass cloth by the manufacturer.

Per Sweet Composites ... " We do not recommend the use of Volan finishes because of the chromium content. Chromium is a toxic heavy metal that is considered a strategic material by the military and much of it is imported from Africa. Potential problems are evident! It also imparts a green cast to the fiberglass and the resulting laminate is generally rather grey and dirty looking. Silane finishes produce a clearer laminate and avoid the chrome problems. "

More here:

Ken Blanton




Ken, this makes sense and sounds reasonable and could possibly be my problem but I have 3 questions concerning your theory - - 

1) I buy all my cloth through reputable, volume dealers so it should be fresh and treated correctly ?

2) I have used cloth from this same roll on other boats with no problems ?

3) If this is the problem why is the carbon cloth turning green too ?

I have a feeling I may never know what happened. I will paint the boat, build another and cross my fingers

I appreciate everyone's thoughts so far but I haven't gotten that, "thats it" feeling yet

I started a thread a few days ago looking for information concerning the painting of boats, paint types used, preparation, application techniques,  tricks and tips etc. Only one comment so far, would be nice to see more participation . . . . . . 


I see several things. Since this is just based on the one photo, take this with a grain of salt.

 Over on the right is the white speckles Rob was referring to. I would agree that this looks like some kind of stress.

The discoloration at the upper left looks like some form of delamination: essentially a layer of air or something between the glass and the wood.

In between is a dark stripe that kind of looks like moisture in the wood making it darker.

Several things could cause these. A bad mix of epoxy (wrong ratio or incomplete mixing) could cause delamination. Changes in temperature over the winter may have caused the soft resin to fail. 

Alternately, moisture trapped inside the end combined with some pin holes allowing it to migrate from the inside into the wood. This could come from the boat being stored upside-down or on end and somehow (condensation, animal pee, water trapped in an end pour) moisture accumulating in the end. Again, over the winter, freeze-thaw cycles can cause the moisture to swell and force apart the lamination. This could account for the dark stripe at the edge if there were still some moisture in there.

Temperature cycling could also cause  the stress specks.

As far as a solution: Sand off the glass, re-stain, re-glass, refinish. With a few days of work you should be able to make it so nobody can tell.


Thank you for the reply Mr. Admin,

Your assessment pretty much matches everyone else's. I think it was more a technique error rather than a materials problem. 

I just got my latest issue of "Epoxyworks" and am thinking about contacting then for any possible information.

My problem now is what to do - - I am going to strip and recover the instrument panel today just so it can start "aging" and see what happens to it. As far as the kayak, my first thought was to paint it but I am also considering removing the glass and do-again. I guess my question at this point is what is this stained kayak going to look like sanded down and recovered ?? It can't be restained because the wood is sealed and I can't sand all the stain off to the point of having new wood to work with. I am thinking it would end up looking just as bad as it does now and I will repaint anyway. I have refinished several pieces of furniture and after removal of stain/varnish/paint they never refinish very well.

Anyone have any experience in removing the glass from a stained boat and what did the recover look like ?
Thank you,

I had the sun strike through my large side window one winter while my wetout coat was going off. Just the outside of the hull at that stage, thankfully. I got thousands of tiny bubbles at just the wrong time. I discovered the situation roo late and I had to strip the glass. It had set up fairly well, and required the heat gun.

I had intended to sand the left over epoxy right off, but it was still fairly new, so I hit it with the heat gun and scraper to thin it down and scrape it off at the same time. The result was easy to brush up with sandpaper once it had set up for a day or two. I didn't try to sand it all off, I just smoothed it and keyed it. It looked a bit patchy, but after glassing one would never have known there had been an issue. A perfect result really.

In your case though, not knowing what is causing the colour cast, you may want to get it all off, and then your stain is going to suffer. A bit of a quandry.

In your shoes I think I would get creative with some paint. Actually, I would probably get my sister to paint it. With nothing to lose I'd go really crazy.


I'd ask her to do something like this, perhaps...




Sun, 05/19/2019 - 06:54

At this point, its not going to cost more than 15 minutes of time to do a few test trials on some scrap wood with your epoxy and glass. One possibility that has not been mentioned is your epoxy mix ratio. You might have made a mistake with the epoxy/hardener ratio? Also the problem is at the bow of the boat and not the entire boat correct? And only on one side? You did a beautiful building job. Either live with it for a year and if it bugs you, sand it off and re-glass from cockpit forward. Any difference in tone will not show as much from the cockpit area. Meanwhile some experiments will give you confidence about all the glass / epoxy questions.

Actually, you can sand the glassed wood and re-stain. The stain and epoxy does not really penetrate that deeply into the wood. After removing the glassing most of the epoxy and stain will be gone. You can then re-stain. The problematic area will be the transitions from fully sanded to un-sanded where you will get a double layer of stain which may produce a dark perimeter. With care this won't be too noticeable.


Sorry for the delayed reply - just returned from visiting the National WW11 museum in New Orleans. If you have any interest in WW11 history this is a truly amazing museum, spent two days there and just barely saw it all. Visiting Burbon St. in the French Quarter after 9 pm is also an "eye opening" experience :)

OK, catch up on kayaks - -

Etienne, does your sister make 5000 mile house calls and work for board and room ? Painting is still high on my 'options' list.

Jay, the problem is the whole boat, both sides, deck and hull. it has horizontal streaks of good then bad then good, etc. I usually use 4 epoxy mixes for a deck or hull so a bad mix would be in a localized area not the whole length of the boat. The deck and hull were glassed about a month apart yet both look just as bad ? Thank you for the compliment about the building job, I wanted a boat that looked as good as the one Nick built and I had it - - - for about 4 months :(

Mr. "Admin." I am about to reglass the instrument panel. I think I will stain and glass two 1' square sections of Cedar and let set for the summer then remove the glass from one and sand, restain and glass and compare. This will also give me some time to think about it. Painting is the easy way out and I would much rather be building a new boat than 'remodeling' this one. Like I mentioned before, I may never know what I did, I just hope I never do it again !!

Thank you to all for your comments and interest :)

Not sure I understand your question Jared but the color differences are due to grain density of the wood, some strips soak up more stain than others. Pretreating the wood helps reduce this effect but does not eliminate it.