Painting a blasted hull

[offto]

Ok, I know there's a ton of threads about bottom painting and epoxy coatings but I feel as though I'm off to a rough start because I want to make sure I get this done correctly and without a ton of wasted effort.

I got the bottom of my 33' pearson soda blasted in the fall and I'm preparing to do the Barrier coat followed by some sort of bottom paint in the spring, however, looking closely at the bottom of the boat it appears there are some chips and pieces missing from various places over the bottom of the boat. Now these are rather tiny and not that deep, but I can see fiberglass instead of white ?gel coat? in the spots where I took pictures. There never were any blisters that I was aware of and the hull always was solid and there are no soft spots. I just had a ton of old paint buildup and the anti-fouling properties didn't work too well last year so I wanted to start over since I bought the boat two years ago.

So before I slap a bunch of coats of barrier coat and bottom paint, what (if anything) should I use to fill the little holes all over the boat? I think I should at least get the bigger ones with some sort of epoxy, I'm just not sure which one to use. It's obvious from visual inspection that some sort of epoxy was done in the past, but I want to make sure I do it right since it's a pain and also costly to have a "do-over" later.

I'm tempted to use Interlux Watertite epoxy filler (goes on like butter) sounds easy to use and what I would need, but probably a lot of it.
Also saw some articles and videos using epiglass epoxy resin that I would just roll on. That's also interesting since that would save me a bunch of time. (perhaps I should use both?) There are so many combinations of products that my head is spinning a little bit.

Also there's a strange hole that looks like it's been epoxied over at least twice right along the centerline of the boat, just under the deepest part of the hull but above where the keel meets the hull. My guess is that it was a thru-hull in the past, not any sort of accident damage because it's symmetrically round). Any thoughts? should I just jam a bunch of epoxy over this, barrier coat and then paint that too?

Ok, I'm going to try and attach some pictures to this post so it makes more sense.

Thanks in advance!

 

[Squidd]

That round "repair" looks scary...what does it look like on the inside...?

 

[JohnS]

That round "repair" looks scary...what does it look like on the inside...?

Agreed. What's the diameter of that patch?

 

[25yearslater]

That repair looks more like Duraglass or Bondo with 'blue' cream hardener which is a polyester product. Also absent the characteristic cloth buildup and beveled edge at the hole common with epoxy.

 

[rickbarr]

Does'nt look that bad... as mentioned these are just old Blister repairs where the owner used a porouse or semiporouse repair matierial.. Remove the old repair matierial with a flat- head screwdriver or what have you.. In the areas where the blister goes beyond the first layer of laminate you'll need grind a radial bevel.. Determine how far the damaged laminate extends (theres no point in filling in around damages laminate as soon as your boat goes in the water she'll flux and come to shape and the laminate will expand making your repair weak) after your grind your bevel 6:1 or 12:1 depending on the thickness of your hull, clean the area with T.S.P. let it dry for as long as you can then reclean it with acetone. If you want it done right use a quality Epoxy 6-10 ounce glass cloth and coiloidal Silica mixed for a filler. Wet out the bevel with pure expoxy and resin after about two hours come back and thicken up a pot of epoxy with coiloidal silica to a peanut butter consistancy spread a thin layer into the bevel. Cut out 6-7 pieces of fibergalss cloth (NOT MATT) the first layer should be slightly larger than the bevel you grinded, all subsequent layers should be cut in smaller and smaller radius than the previouse layer. Mix up another fresh pot of epoxy lay the first large piece of cloth on top of the thickened filler..useing a cheap brush wet out the the glass with epoxy then smoothe it out with a plastic spreader or whatever you wish add all six layers in this manner.The bevel should be filled with glass just a fraction lower than your Jel Coat. If you have any thickened epoxy left from your first pot that you mixed spread this over the top of your repair and thicken up anymore uncured epoxy left in subsequent pots and use that to fill if need be. Fill it proud of the Jell coat allmost like a dome and let it set. 3 to 6 hours depending. Come back and sand it flush with a palm sander 60 - 80 grit.. As for the small pox holes useing a spray bottle spray them with xylene ( I found it makes epoxy and Fiberglass resin porouse and tacky wich is perfect for good adhesion. Fill them with thickened epoxy as well and sand flush... After everything is filled and your about ready to say this is just way too much work. As you mentioned before you can barrior coat the Jell Coat. I'm useing epoxy with a barrior coat additive..

 

[Merlin Clark]

I'd check the plugged hole and make sure there isn't a flush fit thru hull under that poor fairing job (I've found this on my current boat), and if so remove it. And if there isn't a thru hull, that plug looks to be poorly bonded and a knock in the right spot and.......
Also, I beleive the other guys are right that the plug is auto body filler, which is hydroscopic and will allow water to migrate into the fiberglass layup and core if you have a cored hull.
Here is a good read on patching holes and dings: http://westsystem.com/ss/assets/HowTo-Publications/Fiberglass-Boat-Repair-and-Maintenance.pdf
I like the West resin and hardener (105 and 205 or 206) and thicken my own (when required) with either high or low density filler, using the high density in wear areas and below the water line. Fast hardeners set up pretty quickly so mix small quantities if you use this type.
I think the seperate resin/hardener/fillers is probably the most cost effective way to buy and gives the user good flexibility in using the materials.
This is just my 2c.

 

[BarryL]

Hello,

I believe you need a 'fairing compound.' In the past I have used Quickfair from system 3. You can read more about it here:

http://www.jamestowndistributors.com/userportal/show_product.do?pid=757

If you want to see some before / after pictures on my keel, go here:
http://www.sailnet.com/forums/gear-maintenance/42402-bottom-paint-1-me-2-all-done-test.html

Barry

 

[jibes138]

I would consider using WEST epoxy or equivalent, then mix it to a thick paste like consistency using microballoons, put a light coat of plain epoxy first then put the thickened mixture on and use a soft plastic tool to smooth it in place. Next take some Saran wrap and tape it over the area so it won't run out on you. after it cures you peel off the Saran wrap and have a nice smooth surface requiring minimal sanding. Sand it smooth and your ready for the barrier coat.
Regarding the hole...if it was in front of the keel it was most likely a speed transducer paddle wheel that was removed. With GPS these aren't all that useful any more and not that accurate any way. They are nice to see changes in sail trim effects but that's about it. If mine fails I will most likely not replace it, value versus cost is not very effective.

 

[Snotter]

I thought you were supposed to avoid using microballoons below the waterline.

 

[offto]

Wow thanks for all the quick and great responses! This seems like a big project but I think I'm able to tackle it myself over a few weekends.

if it was in front of the keel it was most likely a speed transducer paddle wheel that was removed.

Yes, I left that part out. The patched "hole" is in front of the keel right dead center bottom of the boat. I didn't know it was there until after the boat was blasted, as I've never seen (nor really really looked) on the inside of the boat to see what was there. On my next trip down I'll take a peek at it and measure it and see what I can find. If my memory serves me correctly, it was around an inch to an inch and a half diameter. If I had to bet it's a plugged thru hole with a poor fairing job. There is an existing paddle wheel style speed transducer on the starboard side of the boat (which doesn't work). Perhaps on the Pearson 33 of this model there might have been two, or perhaps since the boat is 30 years old someone along the years of owning it decided to move the speed transducer to get a better reading. Unfortunately I don't have any history on this so It's all guesswork unless someone remembers the Pearson 33's from 1973.

I'll look at a fiberglass patch if the inside of the boat doesn't reveal anything conclusive or shoddy work. - good catch guys.

Now my concern wasn't really this particular part of the boat - I was concerned about the other little holes in the pictures. I think there's a bunch of good things proposed here that don't seem like too much work that I'll throw my hands up in disgust, but is enough work to keep me busy for a bit in the spring. I suppose if I get the biggest ones and use a bunch of layers of barrier coat I should be ok. My memory says there are thousands of these little chips - but the pictures I took says there are only a few areas of this chipping or pitting.

 

[Shoaldrafter]

microballoons

I thought you were supposed to avoid using microballoons below the waterline.

- - - - // - - - -

That is correct, should not use microballoons below water line generally. May be used in a suface fill to allow for easier fairing if underlying surface is water proof.

Also consider using marine tex for the final layer as it is fairable.

Slilica is the medium for waterproofing although it is hard to fair.

West makes a quality product but it contains wax and should be washed with acetone between layers to remove wax blush.

I prefer an epoxy without wax such as the marine epoxy from

http://www.epoxyproducts.com/noblush.html

But all the mentioned products will do if used correctly.

Ed K

 

[Merlin Clark]

The depthsounder transducer on my GS 41 was mounted centerline just fwd of the keel. Generally a paddlewheel is mounted somewhere that is easy to get to so it can be pulled when not in use.
Some people just use the word "microballoons" when talking about fillers. From reading Jibes's post we can tell this isn't his first rodeo. I use the 404 filler for blisters and patching below the waterline and it's always done what I want it to.
Ed, seen the price of marinetex lately? http://shop.sailboatowners.com/prod.php?12947 OUCH!

 

[jibes138]

Fillers

I guess I was thinking of colloidal silica for the thickening agent to make it like a putty for filling in the holes. I have used this extensively in boat building projects to cover screw heads in wooden boats, basically filling in the countersinks. I checked the WEST System website and it doesn't mention microballoons, #407 filler as not being for underwater? Why do you guys suggest that is a problem? Given that these repairs will be covered by a multi layer barrier coat application I wonder if it would matter?

 

[Merlin Clark]

I guess I was thinking of colloidal silica for the thickening agent to make it like a putty for filling in the holes. I have used this extensively in boat building projects to cover screw heads in wooden boats, basically filling in the countersinks. I checked the WEST System website and it doesn't mention microballoons, #407 filler as not being for underwater? Why do you guys suggest that is a problem? Given that these repairs will be covered by a multi layer barrier coat application I wonder if it would matter?

I don't know, I just always use high density for below the water line and wear areas. Maybe I just like sanding!

 

[25yearslater]

If I may so bold as to cover the diffence between polyester and epoxy bonding. First an understanding of the 'bond' are in order. There are several types of bonds. Atomic, molecular and mechanical. Atomic we won't delve into. Molecular bonds rely on chemical interactions between elements. This is where polyesters find their place as a cost effective boatbuilding medium. The interaction during the curing process forms long chain molecules that bind the polyester together. The mechanical bond is the repair type of bond most of us will at one time or another will be concerned with. Polyester is a relatively weak substance when it is used in repairs. It's ability to key into and adhere to a cured surface is far surpased by epoxies. Epoxies offer exemplary strength in both long chain molecule formation and adhesion. Most high end boats are now composed of epoxy composites. Not bad for the one off, money is no object crowd but a budget buster for most of us. Several epoxies also exhibit the 'amine blush' that Shoaldrafter mentions. This is a byproduct of several brands of epoxy during the curing process and contact with atmospheric moisture and is normal. The standard removal method is scrub with warm water and Scotch Brite pad and wipe off the residue with a clean paper towel. Follow this with a wipe of acetone and you are ready for subsequent sanding. I hope this helps answer your question why epoxies seem to be preferred for repairs.