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Old 10-26-2012, 08:52 PM   #21
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We would powerwash, acid wash and do a decent job sanding and feathering in of flaking paint, getting a smooth-ish surface to paint on. Then three coats.

So. we went to take a look. And while we do have some big blisters, several of which have already been ground out, the biggest issue that we want to deal with is the 26 years of caked up paint.

So, looking at this from a different angle....is there any reason to "not" sandblast all of that old - thick - layers and layers of paint off, get 2 coats of barrier epoxy and start with new paint? Having the biggest blisters ground out while they're visible.

Since our next boat is most likely several years down the road, is there a valid reason to not do this now while she's already out of the water? We're thinking that it will make the future bottom jobs a much easier task.

My biggest disappointment is missing the Fall gunkholing.
Professional soda blast to remove the built up a/f is a good start, old a/f needs removal after years of build up.
You`ll need some kind of sealer undercoat before new a/f.
But first, repair the blisters of any consequence you can see, or you are just painting over defects, as the PO did with my boat after soda blast. Blisters are best seen just after hauling while the surface is still wet.
Blisters should be ground out until the area ceases to ooze liquid and stays dry. Apply local heat periodically to draw moisture out. Leaving the ground areas for months to dry is optimal,but not always possible.
As suggested by others, the ground areas,which should be a saucer like shape achieved by using an appropriate dished grinding tool on an angle grinder ,can be filled with concentric gradually enlarging circles of mat,with epoxy,filling the defect back to smooth.You could use filler on small blisters, but not large ones.
To my mind the problem would need to be very widespread to remove the entire gelcoat, I think you would then be committed to letting the hull dry out over an extended period before epoxy restoration.Yours does not sound so bad. Good luck. BruceK
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Old 10-26-2012, 08:58 PM   #22
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Without removing ALL the gel coat...your hull might take years to dry out. GEL COAT IS USELESS ONCE IT HAS BEEN COMPROMISED OR THE HULL LAMINATES ARE WET.

Might as well get rid of it at that point...and start fresh...otherwise you are just covering wet laminates and spending money for nothing and actually making the situation worse.
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Old 10-26-2012, 09:18 PM   #23
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Without removing ALL the gel coat...your hull might take years to dry out. GEL COAT IS USELESS ONCE IT HAS BEEN COMPROMISED OR THE HULL LAMINATES ARE WET.

Might as well get rid of it at that point...and start fresh...otherwise you are just covering wet laminates and spending money for nothing and actually making the situation worse.
Sounds like you're assuming that blisters automatically equate to compromised laminates throughout the boat. That was absolutely not the case on the boat we repaired. We could easily see where the mush in an individual blister ended and perfectly solid structure began. Big difference between a rash like that shown in your photos and individual localized blisters. The hull we repaired was quite dry on a moisture meter....not that I place much stock in that little gizmo.
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Old 10-26-2012, 09:44 PM   #24
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Does anyone know of a boat sunk by blisters?
12 years ago I had a surveyor warn me of the impending danger of blisters, indicating the boat would probably sink if I didn't take it to the yard he recommended for a full gel-coat peel. The broker said it had already had a life-time guarantee peel, only the owner couldn't find the paperwork and the yard had gone out of business, oh well.
I had 3 bottom jobs done and started moving the boat between fresh water and salt water every year on a trailer. The "blisters" never changed. There are a few, just like the surveyor said, but they are still the same size. The boat still floats.
Terredo worms sink wood boats, but I think it takes rock to sink a fiberglass boat.
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Old 10-26-2012, 10:00 PM   #25
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... the biggest issue that we want to deal with is the 26 years of caked up paint.
Just curious--- what kind of paint has been used on the bottom of your boat all this time? Ablative (sloughing) or hard?
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Old 10-26-2012, 10:04 PM   #26
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Ok kiddies... Here is the story and the pictures.

We drove down today to get a 1st person look at her bottom. When we pulled up we were both most surprised by how much work had already been done. Apparently, they had started to grind out the blisters without having been authorized to do so. Once the yard owner saw what was going on, he stopped it and has said he'll fix what was done. Anyway, it's worse than I thought, but not as bad as it could be. The worst is mostly around the bow.

The big thing is that there is a large amount of thick and flaking paint. Years and years of it can be just popped off with your finger nail. Grab a flat scraper and you can turn a 1" spot into a spot more than a foot across with ease. To us, removing that mess is the highest priority. And from what I am told, media-blasting it to remove it will open many, or most, of the blisters.

Therefore, we are leaning toward going ahead and getting the whole job done. I will let Bess explain more of the arguments for and against. We saw a few boats in the yard that were in various stages of the same-ish job and the results look very, very good.

There are more details than just this, but we spent 8 hours in the car today and I am tired of thinking about this. All of your opinions are read and we take them in and discuss them. We want to make a good decision, but in the end, it will be OUR decision based on what WE need to do. Skinny Dippin' is 26 years old and is probably reaching the golden years. We plan to keep her for a few more years in hopes of PERHAPS finding a boat with a few less compromises based now on our new experiences. Still, nothing is certain.

Thanks for all your help... Bess may continue this later. Me? I have a few more Dark-n-Stormy's to drink.

So here are my photography-challenged pics:


P1010982 by GonzoF1, on Flickr


P1010985 by GonzoF1, on Flickr


P1010970 by GonzoF1, on Flickr


P1010971 by GonzoF1, on Flickr


P1010976 by GonzoF1, on Flickr


P1010977 by GonzoF1, on Flickr


P1010978 by GonzoF1, on Flickr


P1010972 by GonzoF1, on Flickr
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Old 10-26-2012, 10:04 PM   #27
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Just curious--- what kind of paint has been used on the bottom of your boat all this time? Ablative (sloughing) or hard?
Cheap CPP ablative. We figured if we were hauling yearly, we'd use the cheap stuff.
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Old 10-26-2012, 10:10 PM   #28
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I'm surprised ablative paint built up that much since it goes away as the boat moves through the water. We've been using ablative paint (Petit Ultima SR until this year) since we bought the boat 14 years ago and the buildup is minimal. In fact if we let the paint go too long we start seeing the blue hard paint that was on the bottom when we bought the boat.
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Old 10-27-2012, 12:29 AM   #29
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Originally Posted by Marin
I'm surprised ablative paint built up that much since it goes away as the boat moves through the water. We've been using ablative paint (Petit Ultima SR until this year) since we bought the boat 14 years ago and the buildup is minimal. In fact if we let the paint go too long we start seeing the blue hard paint that was on the bottom when we bought the boat.
We have the same build up and issues as Tom and Bess and really need to being it down to gel coat and start over. So yes it happens. Luckily we have no blisters but the many layers of crappy paint make it hard for new paint to stick and a new bottom doesn't last long. We're on the second new bottom in two years and really need to suck it up and spend the money to take it down and start over.
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Old 10-27-2012, 12:45 AM   #30
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Well, at least removing a bunch of excess layers of paint is a relatively simple and inexpensive (more so if you do it yourself) process compared to a hull peel, repair, re-gel coat, and barrier coat.
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Old 10-27-2012, 12:58 AM   #31
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While I've no concern with blisters, I do about rust.

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Old 10-27-2012, 01:06 AM   #32
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Nice pics Gonzo, I`m having a deja vue moment just seeing them. Naughty of the Yard to start without authority( you are only liable for work done at your request),but seems it helped clarify the issue.
Although my boat had been soda stripped( not very well,and not repaired) before I bought(we renegotiated price post survey), we repaired all apparent blisters individually, as described. The hull was still rough and uneven after the osmosis work and we (ourselves) did the major dry sand back, pre painting with a vinyl and then a/f. Good effect on the boat but not on us(cough/splutter);we regretted not doing a soda strip first. Without intruding on your decisions,food for thought.Result was a nice smooth faster hull. Best of luck with it. BruceK
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Old 10-27-2012, 06:49 AM   #33
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Well, at least removing a bunch of excess layers of paint is a relatively simple and inexpensive (more so if you do it yourself) process compared to a hull peel, repair, re-gel coat, and barrier coat.
Once the gel-coat comes off and the repairs are done, you do not re-gel-coat. The barrier coat is the replacement.
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Old 10-27-2012, 09:23 AM   #34
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Result was a nice smooth faster hull. Best of luck with it. BruceK

So, how much did you gain? 1/2 knot? A whole knot?

The sandblasting, blister repair, barrier coat and paint is just....(cough cough) $3500.00. As opposed to a full peel at 8-10k. I think we'll go for it. The two boats that we saw at the yard that were done this way looked great! really great. I think that not only will the money be well spent for our own maintenance, but when it is time to sell her, it can only help. Maybe not in price, but perhaps in a quicker sale.
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Old 10-27-2012, 09:57 AM   #35
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My experience

I went through the same thing you're going through when I bought my boat. The surveyor showed me several dime to quarter sized blisters which he wrote up as being mostly on the starboard side.

When I hauled the boat 6 months later I found 150 blisters pretty much equally spaced between starboard and port. I did the internet research thing and ended up calling West Systems. They have a pretty good site explaining how to do with this.

I ground out each blister with a grinder. You know it's a blister when yucky fluid comes out. I filled each with West Systems Six/10 epoxy, an easy way that automatically pre mixes the 2 part epoxy. I did not dry the area, rather I just ground out the area until I got to dry fiberglass. Filling the ground out area is like putting a plug in the cavity and I was concerned that the plugs would fall out under use. That never happened. I had to fill each ground out area twice to get it to fair with the hull using 60 grit paper between fills to ensure a tight bond between fills.

I also considered soda blasting, but decided against it due primarily to cost. The blaster did some test areas on the boat as shown in the second pix. I covered that area with a thin coat of Six/10.

Almost 2 years later I've had no problems and the hull looks good. I won't know for sure if the blisters have returned or I've gotten more until I pull the boat again, of course.

This was a messy time consuming job, but not really difficult or expensive. If you can hire a grunt to help you, it doesn't really take much experience or knowledge, the job will of course go much quicker. I had to experiment with the grinder and type of grinding material, but once I got that part figured out, the job went pretty fast.

I'll estimate the total cost to be under 1.5 boat bucs inc the paint & haul out, but I did all the work.
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Old 10-27-2012, 10:30 AM   #36
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...The sandblasting, blister repair, barrier coat and paint is just....(cough cough) $3500.00. As opposed to a full peel at 8-10k. I think we'll go for it. The two boats that we saw at the yard that were done this way looked...
I don't think the price sounds bad considering all that is to done. And an other plus is you no longer have to haul every year.
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Old 10-27-2012, 10:37 AM   #37
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I also considered soda blasting, but decided against it due primarily to cost. The blaster did some test areas on the boat as shown in the second pix. I covered that area with a thin coat of Six/10.
Excellent...someone with hands on experience with blasting. Were you able to clearly distinguish blisters after the area was media blasted, or had those blistered spots already been ground out before the blasting? Did the blasting open any blisters? It apparently was deep enough to disrupt the contour of the bottom if you had to fair it with putty? Also I wonder if the factory used a poly or vinylester resin? Thanks...very helpful photos and info.
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Old 10-27-2012, 10:38 AM   #38
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I did a full peel, post cure with the Hot-Vac system, and relaminate. That was about $25k 10 years ago.
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Old 10-27-2012, 12:16 PM   #39
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Excellent...someone with hands on experience with blasting. Were you able to clearly distinguish blisters after the area was media blasted, or had those blistered spots already been ground out before the blasting? Did the blasting open any blisters? It apparently was deep enough to disrupt the contour of the bottom if you had to fair it with putty? Also I wonder if the factory used a poly or vinylester resin? Thanks...very helpful photos and info.
As I recall the blisters were already ground out. The soda blasting as I remember does nothing to fix blisters, it just removes all the paint and gelcoat so that when you put the barrier coat on, nothing is between the barrier coat and the fiberglass hull. The blisters must be ground out either before or after the soda blasting, however I would check with the soda blaster before I dealt with the blisters. The idea here being that blisters won't form under the barrier coat.

The soda blasting removes a thin layer, you should not need any filling after the soda blasting, except of course for the ground out blisters. After the soda blasting is complete and you've filled and faired all the blisters, you will need to apply a barrier coat, which is just a thin coat of 2 part epoxy. It will of course need to be sanded smooth, and that will be a job.

Soda blasting and the application and sanding of the barrier coat adds greatly to the cost and work involved. That's why I chose to skip it. Time will tell if that was a wise decision.
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Old 10-27-2012, 12:49 PM   #40
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Tim,

I was trying to determine from the second photo if the blaster only took off the paint and stopped before ripping off the entire gel coat. That appears to be the case, although it's difficult to tell for sure. The reason I ask has to do with determinihg the best method for removing paint only. I would never remove the entire gel coat for a barrier coat job unless I determined there was a massive blister problem or delam issue. If the majority of the gel coat is solid, fix the blisters and put the barrier coat over the existing gel coat. But again, it's crucial to be able to identify blisters in the gel coat after the paint is stripped (and it's impossible to identify the extent of the problem without removing bottom paint). If blasting erases all the telltales, then chemical strip might be a better approach (for a barrier coat over existing gel coat). Also, I believe most yards would use the peeling machines to remove an entire gelcoat.
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