Gel coat again…

[Herschel]

Hi Herschel!

Wow!
A boathouse AND a boat port!
You treat your O’Day pretty nicely!

It will make it that much nicer to work on for sure!!!

I’ll follow your lead and get our pop up out to work on the boat trailer refurbishments….I’ll have to move it around but it beats gettting rained on and scorched when the sun comes out! It that time of year in the south! (Beats the cold rain and cold breezes up north ).
Gotta enjoy what ya got!

Best Regards,
Over Easy

One word of caution. The first night I had my cute little blue topped "porch" rigged up, we got a heavy rain. Went out the next morning to find three of the four legs doubled over and bent at 45 degree angles as water had pooled in the top in two places and overloaded the aluminum legs. Apparently these little shelters are mainly for sun and kids sporting events or the beach. I bent back the legs and reinforced them with...yes, duct tape and PVC pipes, plus support ropes to a nearby tree. The project has then resumed. All gunwhale fittings (e.g., padeyes, oar locks, jam cleats) have been removed. I'll do some sanding and cleaning next. Sometimes you gotta wonder if there is a "King Neptune" of the deep just looking for ways to foil hardworking mariners.

[OverEasy]

Hi Herschel!

Whoa! Thanks for the heads up about the rain pooling! Didn’t expect that!!!
I’m sorry to hear about your damage… but love your fix!

I’ll have to keep an eye on the weather… I was concerned with wind issues so I tied it to the trailer overnight to keep it in place…not rain.
Good to know! Thanks!

I hope to get back at it tomorrow to start replacing the frame through bolts… hoping maybe my neighbor can help with those as they are a two man job to drive the nuts back over the rusted bolt threads. Some of the nuts look ‘good enough’ to still hold a wrench… the others are gonna need a plumbers pipe wrench. None would be any fun to attempt using a cut off wheel on.

If the weather holds nice we might just set aside the tools and get out on the water instead!

Best Regards
Over Easy

[Herschel]

Well, my repainting of the interior and gunwhales of my O'Day Sprite continues. As to be expected there is some mission creep. I discovered that the stern seat void was seeping some water, so I have decided to recalk the seems, but since they are both King Starboard, I had to do some research on the best caulk to use. Life Caulk was recommend by a Starboard dealer. Although he did state that Starboard is a challenge to caulk, glue or paint as it is a very dense polymer surface. Hence he wished me luck, but stated not to get my expectations too high. But my old calk seemed to have done a decent job over the past few years. I will proceed. Removing old calk is no fun. The stern seat void is filled largely with spray foam flotation, so the calk is not critical to the flotation function of the boat. I think! I hope! I have found some peeling of the interior paint in the bottom of the boat, so it is a total interior repaint at this point.

[Herschel]

I know this is only tangentially related to Mac mods and repairs, but to complete the story of my "practice" work with a repaint on portions of my 1959 O'Day Sprite, here is a pic of the spray flotation foam applied to the stern void/seat when the boat was rehabbed for the second or third time back in 2008-ish. I plan to add some Styrofoam of some form to fill the portion that has shrunk. Otherwise it looks entirely serviceable as flotation/void filler. Clearly I need another tube of life calk. Does anyone see a problem with adding Styrofoam peanuts as filler? I have also pondered if the self leveling sealer for RV rubber roofs would be a good filler. Or maybe more of the the original spray foam is needed. Ideas?

[OverEasy]

Hi Herschel!

Great progress on the 2025 rehab and practice for your MacGregor!

Looks like two part foam fill was used originally.
Personally I’d not use spray foam as most of that stuff is openish cell foam… once water gets into it it tends to stay.
Even that black landscaping and pond stuff (as I’ve sadly found out the hard way )

West Marine and other places have the two part expanding marine flotation closed cell foam the is designed to last longer than some of the older stuff. It’s weird stuff…. It works best if allowed to expand un-constrained. I once tried to fill a box with the stuff and tried to restrict its expansion. While it didn’t damage the box it did affect the foam quality…making it denser than desired.

It carves and shapes easily though as subsequently I just cut, carved and rasped the shape I needed from the expanded foam.
If I were to need to do a conformal type application I’d do it in several small batches and “sneak” up on the final shape to get a lighter density with a higher floatation capability. Only making the last smaller layer batch be restricted to be conformal. Up side to the smaller batches is the natural ‘hard shell’ layer that naturally forms I think would help keep any future potential water ingresses to a minimum as the shells would be a harder barrier to broach.

Just a suggestion….

Styrofoam is steam expanded and there are a couple of different types. I’ve found that the smooth almost slick feeling styrofoam type seems to resist water ingress better than the coarse dry feeling type. Might I suggest do a sorta test with what kind of ‘peanuts’ you’re contemplating to use.? Take a couple and set aside as a control. Then take a couple and place them in a jar you can seal up with and overflow of water as you seal up the jar tightly. Place the jar out where it can get a couple days or more of warm sunlight. Longer is better. Then remove the peanuts from the jar and gently dry the peanut surfaces with a paper towel or tissue. Once dry place the peanut in a dry paper towel and crush it in a vise to see if any water migrated into the peanut.

Just a suggestion….

Best Regards,
Over Easy

[Herschel]

Well, I found a product called Evercoat Fiberglass Spray Foam in 12 oz can. $40 at a marine supply store. WM was out of it. Then I found Great Stuff Big Gaps Ivory Polyurethane Insulating Foam Sealant 12 oz at Ace for about $6. It is suppose to seal areas up to 3 inches. The 2-part Versi-Foam polyurethane spray foam used in racing boats for floatation application appears to be for pro use only and comes in expensive kits requiring large orders and alerts to a ton of chemical warnings. I am thinking I'll try the Great Stuff Big Gaps Ivory Polyurethane Insulating Foam Sealant 12 oz at Ace to fill the cracks in the foam already in place after it has dried out, and I have killed the mildew that has formed in the old stuff. It comes with a nice applicator for getting into cracks. Then apply the Evercoat Fiberglass Spray Foam in 12 oz can to actually fill the whole void. There really could be some Mac applications here to deal with voids and floatation issues when OEM floatation has been removed for mods and repairs.

[OverEasy]

Hi Herschel!

I found from personal experience (to my regret ) that the canned spray foam is:

1) Basically open cell foam and can absorb hold fluid. It apparently relies on the surface skin that forms for most of its water resistance.
I sealed up a door frame with it then trimmed off the excess that extruded to get a flush surface. Be for the final flashing could be installed it rained through the night so we closed the door. When we got back to work we found the exposed spray foam had absorbed water more than an inch into the foam. We ended up tearing it all out with a pick and found the issue to be pretty consistent Al the way around the door frame. We let everything dry out for several days then redid and got the water tight flashing on right away. Spray foam does a good job at restricting air movement but given the water porosities I’d be hesitant for flotation ….

2) I was insulating a building interior surface with foam panels and used spray foam to fill the inevitable gaps to mitigate air migration issues. On of the helpers git to an odd section of the wall that was sort of a place where one wall matched up to each other leaving a void that was roughly 3-1/2” x 3-1/2” floor to ceiling with an exposed gap of about a 1/4” wide. So the helper promptly filled the entire void with multiple cans of spray foam just piling it in one after the other… Not long afterwards I had to cut into that portion to install a corner window. Upon opening the cavity I found that much of the trapped foam didn’t really ‘foam’ like one would expect. It had large cavernous bubbles and some portions had sticky goop at the bottom of these bubbles. Curious I talked to a professional spray foam insulation installer about it and, as suspected, the chemicals within the spray foam that causes the foaming action requires unrestricted expansion and needs to allow outgassing before the final the finished shell form hardens. He mentioned that professional foams come in closed cell and open cell. They recommend that open cell shouldn’t be surface trimmed as that removes the shell and allows air and moisture to move through it and closed cell to be used instead for those situations requiring surface trimming or in potentiall wet locations like below grade basements.

Just as a suggestion might I suggest making a trial test of the particular foam you want to use to see how it may function for your application? Might be a small cost/hassle vs compromising all your hard work.

Definitely not tell anyone what to do or not do! Just wouldn’t want you to be disappointed… Your boat - Your rules

Best Regards
Over Easy

[Herschel]

overeasy reported:

West Marine and other places have the two part expanding marine flotation closed cell foam the is designed to last longer than some of the older stuff. It’s weird stuff…. It works best if allowed to expand un-constrained. I once tried to fill a box with the stuff and tried to restrict its expansion. While it didn’t damage the box it did affect the foam quality…making it denser than desired.

So, the $40 Evercoat fiberglass spray foam at marine supply stores is closed cell? Right? And the deal is to let it foam up unconstrained and then cut to fit my stern seat? Will a simple hand saw cut the stuff?

[OverEasy]

Hi Herschel!

Yes I believe that the Evercoat fiberglass spray foam should work.
This is primarily marketed as a closed cell foam sealant and should have buoyancy capability.
Here is some information on it from West Marine for those interested:



This is another product that is a two part expanding closed cell expanding foam that is typically and specifically utilized for buoyancy as well as insulation that may be of interest:



Both are closed cell foams and both appear to be appropriate and suitable for purpose as far as the product description goes.
The spray foam is targeting the gap filling and caulking type applications where as the two part is more applied for floatation application.
Both can be cut, carved and sanded. Both are better products for marine applications than the Great Foam building products would be.

Specifically the Evercoat product states that it:
Cures to a firm semi-rigid closed cell mass. (Meaning it is somewhat compliant or flexible which is a good thing when sealing up gaps at the edge of panel joints that may have some limited flex aspect.)

Specifically the two part foam from Total boat states that it is:
94% CLOSED CELL FOAM: Perfect for marine applications; resists water absorption and damage from gas, oil or solvents; once cured, foam can be coated with polyester, epoxy or vinyl ester resin; can also be easily cut or carved to shape. Total Boat has additional information on this product and they are available to chat or talk with about your specific application in better detail if desired.
(This material would be more rigid and supportive. It would be better able to hold shape after cutting or shaping operations.)

Best Regards,
Over Easy

[Herschel]

Thanks for finding the 2-part foam designed for marine use at a reasonable price. Ordered same along with another tube of life calk. Really appreciate your experience in this area. Report to follow as I begin to prep area. One issue that is puzzling. How to get the foam into small crevices and cracks in the stuff that is already there. The self leveling calk used on RV rubber roofs looks tempting. The cheap stuff at Ace hardware at least had a pin point applicator. I'll read the instruction on these cans and see how they recommend doing the little crevices and cracks.

[OverEasy]

Hi Herschel!

Glad I could be of some help!

The two part foam pours in as a liquid so if the surface is gravitationally oriented the fluid phase will flow into textured surfaces before expanding. The important aspect is having clean surfaces if you want the foam to adhere to them.

Along the same lines I’ve utilized mold release grease and even petroleum jelly to keep the foam from adhering to surfaces.
This comes in handy when I’ve had applications where I’ll need to have a removable service panel etc…

Best Regards
Over Easy

[1st Sail]

I used NewGlass for several years. It holds up for 6mos. on the white gelcoat but 3-4 mos. on the black stripe. Several years ago I stripped the NewGlass and switched to Glidecoat. Glidecoat is a marine specific ceramic product. Not cheap but worth the time and effort. Now I just do a light buff/polish with Presta Cutting cream and a Lake Country firm foam pad to do a clean and restore. I don't buff/polish to a deep shine just remove any minor oxidation and surface contamination/stains. Then reapply Glidecoat. Glidecoat totally stops the black strip oxidation which was my goal vs. polishing off gelcoat oxidation and gelcoat every season. No more chalked black stripes after 6mos of Northern Illinois sun. I would think those in the southern latitudes may restore / reapply after 6mos.

FYI ceramic coatings essentially come either premixed (one shot) or two part (mix as needed). I recommend the two part as you can mix on an as needed basis. In either case if you seal either the premix or two part mixed in its bottle and store in the freezer it will stop the chemical curing process. Ceramic coatings cure rate is dependent on temperature and humidity. Temperature of course accelerates heat of reaction and humidity is actually needed to cross link the chemistry.

[Herschel]

I used NewGlass for several years. It holds up for 6mos. on the white gelcoat but 3-4 mos. on the black stripe. Several years ago I stripped the NewGlass and switched to Glidecoat. Glidecoat is a marine specific ceramic product.

Well, this brings us all back to the reality that this is a Mac forum and not a "dinghy repair" forum after all. I did use the Newglass product for several years on my Mac back when I had some teenage relatives anxious for some spending money to help me out. I went back to waxing when they aged, and I got a little too old to tackle it by myself, and I could get a local detailer to clean and wax it for me at the slip for $400. But he moved on to a better career, and now the local guys want $2K to do a "total redo" type piece of work. That is out of the question for me. I have some areas on the foredeck where you can see the dark shadow of what I think is core showing through, so I think I do need to get some paint on my upper deck. It's especially noticeable on the forward hatch in these two pics. The young man in the second pic helps me wax it it twice a year. He's the son of a friend. So, back to my dinghy repair as a warm up for the main event. Turns out the floatation I had put in the stern seat 10-12 years ago is waterlogged and useless. I will have to dig it all out and start over with fresh foam. But, the stuff I bought requires totally dryness, no moisture at all and less than 70% humidity because water spoils the chemical action between the two part liquid. In the process of watching Youtubers doing foam, I discovered that Styrofoam is no longer a USCG approved floatation for marine use. I think that is what my Mac has crammed into it's voids that makes it "unsinkable" according to the Mac video! So, I am stuck in Central Florida summer weather patterns that constantly bump up against or exceed 70%. So, back to chipping waterlogged foam for awhile. Thanks for the tip on the new product; I don't want to appear ungrateful. But I fear that ship has sailed for me.

[Herschel]

Don't know if anyone is following my little project on my O'Day Sprite any longer, but I thought I would post a status report in any event. I have been hacking away at the old floatation foam to get it completely purged from the cavity under the stern seat. I determined it was compromised by moisture absorption and would likely render ineffective any attempt to add new floatation foam. I am using an adze, a pruning saw, and an electric hot knife to claw the stuff out. It is still slow going, but I am about 1/2 way through the mess. I do feel good about the effort because I have learned from YouTube podcasters dealing with this stuff that the new Coast Guard regulations for boats under 21 feet is that they must have flotation foam. I assume that goes for remodels of old boats, too, not that i think the Coast Guard will ever check me. Still it is important for the safety those that will use the boat after I am...you know, sailing in the great hereafter!

[OverEasy]

Hi Herschel!

I eagerly await your updates!

Battles removing old adhered foam are legendary!
Your not alone. Yes you have the right tools set!
I’ve used a ‘hot wire’ cutter loop to help with that task in the past and a heated blade tool I cobbled together.
There must be a utube tutorial out there describing how to make one if you want to go that route.

I’ve staged my pours in the past to kayaker a void I may need future access to by lining the void with poly sheeting, making a partial fill pour, letting it cure out, the folding the poly over it and repeating the process with another poly lining and pour.
That way it doesn’t bond to the void space surfaces and can allow for geometry like corner voids.
Yes it’s a 3D puzzle of sorts but it does facilitate future removal should the need arise if that is a concern one has.

Yes a surface bonded void structure can be a bit stronger, quieter and less vibration potentially but it’s a pain to re-access in the future.
There is no rule that requires the foam to be bonded to surface that I am aware of.
Do what works for the application and future anticipated needs.

I’ve even pre-placed empty conduit through voids to be filled should I some time down the road want to route wires or plumbing. But that me….

I await you progress reporting eagerly!

Good people always try to make the world around them better for those that follow whom they will never meet, nor be remembered by except for their good works discovered.
It is a poor, shallow, worthless and generally reviled individual who lives only for their own end.

Best Regards,
Over Easy