Extensive Gelcoat cracking and grazing

[boatpoker]

Originally Posted by Aethelwulffe

#1 Don't use high-build primer...ever. It absorbs moisture, and then mold grows in the stuff. You can take a sander to a lot of boats and find out this is true.


#2 Paint does not get rid of the cracks. You will see them.


#3 Fixing this for real isn't that complex.


So...You have removed all the hardware, and given everything an 80 grid DA sanding down to fresh color. FOR THE FOLLOWING PROCESS do not bother doing anything to the non-skid areas. Use those as you working areas. We take care of that later.



You then mix up some 1:1 epoxy resin (laminiating resin, high adhesive strength. You now either spray or roll and tip (avoid bubbles) and squeegie it on the whole deck or hull. Lay it on the horizontals THICK, and work it in with a spreader on those areas. Do this in either big, slow curing batches of resin, and keep a wet edge. KEEP it out of the SUN or you will get a mass of bubbles.


You may notice that where you put the material on in sufficient thickness (1/16 inch, 2mm) that the epoxy has self-leveled when curing, and has given you a slick mirror like finish over the cracked old polyester gelcoat.



You now have a "candy-coated" boat. You may see some through-print of cracks on vertical areas. Wash the layer, or wipe (one direction, not waving a rag back and forth) down with alcohol, a scotchbright pad, and a rag to get the amine residue off the surface.


Test sand those print-through areas (which may not exist at all). If they are a problem, sand and re-coat with the straight resin.


Now sand the crap smooth, and handle anything else with epoxy and cabosil filler. Avoid the other "lightweight" fillers.


You can now sand to a smooth finish (220 - 320 grit).



Go to your paint store. Tell the salesperson you don't need no dang primer. Get Awlgrip or Sterling or some other good tough linear polyurethane two part paint (not Imron).


Spray or roll and tip with properly thinned and catalyzed (right kind of catalyst for the application method) in a thin-to-win painting scheme. Use small radius foam rollers, and *ultra-high density* 4 and 6" foam brushes. The brush tips or applies the paint while moving very very slowly and in one direction.


All painted now. Evaluate for a second or third coat if you can see through that very thin coat you applied directly on top of the epoxy resin. Prep with scotchbright pads on orbital sander to remove the gloss between coats.


By time you are done with the second coat, you will have learned how to run the foam brush slow and patient. Woohoo. You are now a real painter, and the stuff is at least as good a sprayup.


NONSKID.


Pull all your tape, fix any under-tape boo-boos where paint strayed onto your hatches or toe-rails etc...


Tape and paper off most of your fresh new paint, unless you are confident you won't goof up the next part.


Tape off the perimeters of your nonskid areas with nice radii on the corners and all that. Go an 1/8" larger then the original to establish a clean edge, or even change the shape if you want.


For the next step, you will want some sort of colorant to add to epoxy resin so that you can CLEARLY see to ensure you have an even coating, with no "holidays" or bare patches.



Roll out a very very even layer of this epoxy resin with a small radius foam roller over the taped off nonskid patches.


Taking 2 bags for a 30' boat, cast handfuls of 20/30 silica sand blasting media on top of that very very even layer of epoxy you rolled out. You are not sprinkling here. You are going to throw sand until the deck looks like a beach.


Let that cure. Don't mess with it. Don't try to patch it unless you must.


Vacuum off the masses of sand with your huge shop vac. Don't go grinding it into your fresh paint.


Sweep at the exposed sand stuck in the epoxy, and vacuum some more until very little loose material remains.


OK. What you now have is silica sand (essentially the same material as fiberglass cloth) poking out of a bed of epoxy. It is even and beautiful, but we still need to coat it.


You have two choices: Rolling more epoxy over the top, then painting the non-skid, or my preferred option, which is to paint it out with exterior (has paraffin wax added for a curing layer) polyester gelcoat.


Now Gelcoat is polyester, and polyesters (in any form) DO NOT STICK to epoxy for squat...BUT you have lots of exposed silica to bond to. So, you may now choose a light grey or tan (purple is not allowed I think) *cool* color to contrast your beautiful titanium white paint.


First, pull the tape you used to apply the sand.


Clean up (scraping any tape stuck under edges etc..) and re-tape a little bigger than the rough part, and over the edge of your pretty new paint job. This is a detail issue here, so get that tape stuck down CLEAN.


Roll a coat of gelcoat (molding gelcoat, without wax), then follow up with a second coat after that starts to cure using Exterior (also called "tooling gelcoat" or "wax added") gelcoat.


Pull the tape when the gelcoat has reached the "orangepeel" stage, or it is soft-cured.


Pull all tape and crap off the boat. Rinse with water. Wash with soap and water. Go sailing. Six days well spent.

Wow !

[Tillsbury]

Originally Posted by boatpoker

Wow !

Or, buy a boat with a nice finish

[Sweetdreams2]

I had a friend with a Cape Dory about the same age and he was always trying to fix the deck cracks that seemed to be all over the deck. I have never seen that amount of deck cracks on another boat. He would try to fix the cracks but they came back all over the boat. Other boats the same age don't have the problem as bad. I had a 1975 Westsail 42 with no cracks on the deck and now have a 1982 Valiant 47 with the original deck with no cracks. Earlier Valiants had bad blister problems due to fire retardant added to the resin till 1981.

[Exile]

Rather than 2-part paint, you could also opt for applying new gelcoat. This is how I've been slowly dealing with the decks on my boat. I do have some cracks and a fair bit of crazing, but mostly just thinning from age to the point where the underlying laminate is printing through in places.

One of the upsides to using gelcoat vs. paint is that there's generally less surface prep involved, and it doesn't require a layer of epoxy primer. It also doesn't require as much care in its application. Downsides include color-matching (can be tricky), post-application wet sanding & polishing, and periodic compounding/polishing/waxing to keep it glossy and thus less porous against moisture & dirt. Gelcoat is also generally easier to repair than many 2-part paints. On the other hand, once you've gone through the trouble of properly preparing the surface & applying a good 2-part paint, you're probably good to go for 10 years or so without further need for maintenance.

[vonchris7]

I've got a 1981 Cape Dory 36. Bought it 4 years ago. The surveyor at the time said don't worry about it as the gel coat was put on thick. So it's mostly just a cosmetic "issue." I do have one area where it creaks when you walk on it but solid when tapped with a hammer. Need to most likely check that spot out from below and reinforce. I wouldn't walk away from a CD 36 just for that reason. They're excellent, well built bluewater cruisers. One of only a few boats prequalified to enter the Golden Globe Race. Enough said?

[Aethelwulffe]

Gelcoat is an awesome thing...INSIDE A MOLD. We use tooling gel as the final fairing pass on a plug (thing to build a mold). 22' boat plug...40K worth of finishing to get that gelcoat faired and polished.



-and you cannot get gelcoat to stick to a surface in a secondary bond anything like the original layup. And it goes on lumpy. And the wax in exterior gel makes recoating touchy...and...and...and -and there are lots of folks that can help you shoot a perfect coat of LP (20 years, not just ten really) and almost no one that really knows what they are about that will help you apply tooling gelcoat.

[Aethelwulffe]

Oh, btw...the Cape Dory cracks? First time I ever did this candy coat trick was on one of those 33's (is it a 32?). Straight 1:1 epoxy resin is really awesome in that it really sticks to stuff, has great tensile strength and elasticity, decent hardness, and the thicker you pour it on, the more it self-levels and makes rough surfaces fair. Bigtime prep saver. It even glues together the chinzier bits of cracked gelcoat underneath.

[Exile]

Originally Posted by Aethelwulffe

Gelcoat is an awesome thing...INSIDE A MOLD. We use tooling gel as the final fairing pass on a plug (thing to build a mold). 22' boat plug...40K worth of finishing to get that gelcoat faired and polished.



-and you cannot get gelcoat to stick to a surface in a secondary bond anything like the original layup. And it goes on lumpy. And the wax in exterior gel makes recoating touchy...and...and...and -and there are lots of folks that can help you shoot a perfect coat of LP (20 years, not just ten really) and almost no one that really knows what they are about that will help you apply tooling gelcoat.

Yes, some of the guys at the boatyard have been echoing some of these same concerns to me. And I've already noticed some adhesion problems with the new gelcoat. The yard/marina no longer allows spraying, and I've already resigned myself to hiring pros at an enclosed facility to respray my awlgripped topsides. (20+ years!). So I was hoping to deal with the decks on a DIY basis using brush & roller, and it seemed like gelcoat required less expertise. Perhaps not based on the method you described above and I should reevaluate.

[Aethelwulffe]

Well, I can only say this:
I would not be describing this process if I did it one time, and got results that satisfied myself, and had not explored every possible alternative. Over a decade since I shifted to medical software development from being a boatwright, I can still spit out the process description in detail because I have done it dozens of times, on all manner of substrates. Over a long period, I had the opportunity to witness the long term effects as well. There is a boat in Gulfport marina I see regularly (one of those old Rangers that were a total mess of crazing) that I renovated in the late 90's. There are a few wear spots on the coachroof where a boom tried to saw a hole in the deck, and there are some bangs in the cockpit, but when the owner actually goes out and shines it up, it looks *sellable*. That boat was probably brushed with Awlgrip with the #3 Awlcat brushing catalyst. The paint is tight, smooth, and is probably a better job than most anyone will get with their first roll and tip, and probably better than 90% of the folks that paint for a living...but others in boatyards have followed my instructions, and aside from some brush strokes here and there have at least DURABLE results. The non-skid texture intensity freaks out some folks that didn't spend time on a navy vessel, but it works very well to keep people on board. The paint parts also resist staining from bottom paint dust and mold much better than even new gelcoat.


I always loved a good gelcoat finish, especially when they come out of the mold and they are so instantly perfect. Love that smell...but once the gelcoat is chalked and dead...it is dead. "Repairing" it is a pursuit left to folks that don't understand the chemistry of the materials they are using. Polyester a glue does not make.

[Exile]

Originally Posted by Aethelwulffe

Well, I can only say this:
I would not be describing this process if I did it one time, and got results that satisfied myself, and had not explored every possible alternative. Over a decade since I shifted to medical software development from being a boatwright, I can still spit out the process description in detail because I have done it dozens of times, on all manner of substrates. Over a long period, I had the opportunity to witness the long term effects as well. There is a boat in Gulfport marina I see regularly (one of those old Rangers that were a total mess of crazing) that I renovated in the late 90's. There are a few wear spots on the coachroof where a boom tried to saw a hole in the deck, and there are some bangs in the cockpit, but when the owner actually goes out and shines it up, it looks *sellable*. That boat was probably brushed with Awlgrip with the #3 Awlcat brushing catalyst. The paint is tight, smooth, and is probably a better job than most anyone will get with their first roll and tip, and probably better than 90% of the folks that paint for a living...but others in boatyards have followed my instructions, and aside from some brush strokes here and there have at least DURABLE results. The non-skid texture intensity freaks out some folks that didn't spend time on a navy vessel, but it works very well to keep people on board. The paint parts also resist staining from bottom paint dust and mold much better than even new gelcoat.


I always loved a good gelcoat finish, especially when they come out of the mold and they are so instantly perfect. Love that smell...but once the gelcoat is chalked and dead...it is dead. "Repairing" it is a pursuit left to folks that don't understand the chemistry of the materials they are using. Polyester a glue does not make.

I appreciate these follow-up comments. Your process also sounds attractive since it negates much of the time-consuming prep work involved in de-waxing, etc. prior to applying primer. And I still get to use up my stash of gelcoat (for the nonskid). I re-read your excellent post detailing the process step-by-step and had a couple of questions if you're so inclined.

1. Re: the nonskid, if the sand silica turns out too abrasive for one's liking, wouldn't it be as easy as applying another layer of paint or gelcoat to make it less so?

2. I'm not familiar with "laminating" epoxy resin, only as applied to polyester/gelcoat. Does it refer to the epoxy resin's viscosity or, like gelcoat, does it mean it doesn't fully cure allowing for successive coats without sanding?

3. Why is a 1:1 resin/hardener formula preferred, as opposed to the more often seen 5:1, 4:1 and 2:1 ratios?

[Aethelwulffe]

You still should remove any wax you have applied to your hull. You gotta sand a bit to clean your surface up (scrub with alcohol, buzz it once with some 150 grit on a 6" Porter Cable electric DA (You can find at Lowes now, but get the rolls of "OEM" brand sticky back paper from FiberGlass Coatings Incorporated: My price was about 22 bucks a roll of 100). With the DA sander, that is less than a 200 buck investment that will save you time and money, and frankly you will use that sander all over the place.


1. Yes. Lay on the gel until it makes you smile. I recommend two passes for wusses. Three for break-dancers.



2. Laminating Epoxy is just regular Epoxy resin. Laminating resin can be painted/recoated without a whole lot of cleaning away of amine blush off the surface, and is full weight resin, unlike marketing ploys like "penetrating resin" that are just 50-50 thinned resin...and a ripoff. Get it from Fiberglass Coatings Inc. as well.



3. 1:1 has the highest adhesive strength, and a higher modulus of elasticity than more rigid formulations. It also has the LEAST amine, which makes it better in joints. 5:1 in West System reformulators are actually making an aircraft resin...something you would use to build a thin skinned kayak or something like that. More rigid, higher tensile strength, but lower adhesive strength and not as high of elasticity. It also BLEEDS AMINE...which is like it generating a layer of sticky oil when it cures. 1:1 from FGI is also about (my cost) 35 bucks a mixed gallon. Way less than the inappropriate stuff they sell as boat stores. 1:1 makes a better "filled glue" sort of stuff for woodworking and the like as well. Just sticks harder to substrate, and does not have all that excess amine that can get trapped in a joint, causing a delamination later.


Why you see other ratios more often? They are cheaper to make, but marketing has served a purpose of making them more expensive. Better profit margins.

[Exile]

Originally Posted by Aethelwulffe

You still should remove any wax you have applied to your hull. You gotta sand a bit to clean your surface up (scrub with alcohol, buzz it once with some 150 grit on a 6" Porter Cable electric DA (You can find at Lowes now, but get the rolls of "OEM" brand sticky back paper from FiberGlass Coatings Incorporated: My price was about 22 bucks a roll of 100). With the DA sander, that is less than a 200 buck investment that will save you time and money, and frankly you will use that sander all over the place.


1. Yes. Lay on the gel until it makes you smile. I recommend two passes for wusses. Three for break-dancers.



2. Laminating Epoxy is just regular Epoxy resin. Laminating resin can be painted/recoated without a whole lot of cleaning away of amine blush off the surface, and is full weight resin, unlike marketing ploys like "penetrating resin" that are just 50-50 thinned resin...and a ripoff. Get it from Fiberglass Coatings Inc. as well.



3. 1:1 has the highest adhesive strength, and a higher modulus of elasticity than more rigid formulations. It also has the LEAST amine, which makes it better in joints. 5:1 in West System reformulators are actually making an aircraft resin...something you would use to build a thin skinned kayak or something like that. More rigid, higher tensile strength, but lower adhesive strength and not as high of elasticity. It also BLEEDS AMINE...which is like it generating a layer of sticky oil when it cures. 1:1 from FGI is also about (my cost) 35 bucks a mixed gallon. Way less than the inappropriate stuff they sell as boat stores. 1:1 makes a better "filled glue" sort of stuff for woodworking and the like as well. Just sticks harder to substrate, and does not have all that excess amine that can get trapped in a joint, causing a delamination later.


Why you see other ratios more often? They are cheaper to make, but marketing has served a purpose of making them more expensive. Better profit margins.

You mean the boaty world has produced yet another overpriced, rip-off product??

Another post filled with exceedingly helpful info -- thank you! And FGCI looks like a comprehensive & reasonably priced source (even at retail) for one-stop shopping.

I was under the impression that removing wax required more than just alcohol (or acetone?) plus sanding to remove, and one had to use special wax removal solvents. In any event, an additional step (but not all that cumbersome).

[MVDarlin]

Take it to Mexico. I had my entire 1982 52 ft power boat painted in Mazatlan for $12,000 three years ago. Beautiful.

[mvweebles]

Originally Posted by MVDarlin

Take it to Mexico. I had my entire 1982 52 ft power boat painted in Mazatlan for $12,000 three years ago. Beautiful.

Which yard did you work with? I was originally going to use Baja Naval in Ensenada to paint my Willard but they didn't work out (my opinion: bit of a bait and switch). I was thinking of headed to Mazatlan but found a decent team in Ensenada (Niza Marine) that I've been happy with. Rates I was getting via email in Mazatlan were higher than Ensenada.

To your point though, this boat is already in the Rio Dulce, a known area for inexpensive and fairly high quality repairs. I actually thought it a benefit that it was there versus US/UK/Other given the type of work it needed.

[Aethelwulffe]

You can absolutely get excellent work at a great price in Mexico. On the other hand, this bit of work does not need a great paint job, it needs a special remediation of the gel crazing. You could probably work with someone to do it as I suggested, but the trip to Mexico will cost a lot more than the time and materials to do this job on this small boat.
-Just hire your Mexicano (or other motivated individual) locally and take him/her to lunch every day and have a great time!