Association Forum - HULL BLISTERS

Assn Members Area · Join

Home.

Association Forum

Ships Store

Cruising

Racing

Technical Tips

Photo Gallery - New

Boat Search - Updated

Manuals & Brochures

Swap Meet

Links

Officer Flag Line & Staff

Bylaws & Constitution

Members Area

Join the Association

Notice:
The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.

Association Forum

Username:	Password:
Save Password
Forgot your Password?

All Forums

Catalina/Capri 25/250 Sailor's Forums

Catalina 25 Specific Forum

HULL BLISTERS

New Topic

Topic Locked

Printer Friendly

Author

Topic

SALTY SAILOR
Deckhand

Member Avatar

7 Posts

Initially Posted - 10/22/2002 : 21:39:15

GENTLEMEN,
THANKS FOR RUNNING A GREAT FORUM. I HAVEN'T POSTED BEFORE BECAUSE ALL OF MY QUESTIONS HAVE BEEN COVERED BY PREVIOUS TOPICS. I SAIL AN '85 C25 TR SK ON LAKE MICHIGAN'S BEAUTIFUL GREEN BAY. SINGLEHANDING MORE OFTEN THAN NOT. THIS SUMMER WAS MY SECOND SEASON WITH A C25 AND MY FOURTH SEASON AS A SAILOR. NEEDLESS TO SAY I AM HOOKED. AFTER HAULOUT THIS FALL WHILE DOING A HULL INSPECTION I DISCOVERED THE DREADED HULL BLISTERS. I WOULD FEEL LUCKY RIGHT NOW IF I COULD SAY THEY ARE ONLY IN ONE AREA BUT I HAVE FOUND THEM ON EVERY PART OF THE HULL BELOW THE WATERLINE. I HAVE ACCEPTED THE FACT I HAVE ALOT OF SANDING IN MY FUTURE. I WAS WONDERING WHAT TYPE OF TREATMENT ANYONE HAS USED TO REPLACE THE GELCOAT?

Edited by - on

OJ
Master Marine Consultant

Members Avatar

USA
4382 Posts

Response Posted - 10/22/2002 : 22:37:27

KIND SIR,
WE'VE HAD NUMEROUS DISCUSSIONS ON THIS TOPIC. YOU MIGHT SEARCH THE ARCHIVES.
THE SHORT ANSWER - PURCHASE WEST SYSTEMS MANUAL ON BLISTERS - ITS THE BEST $3 YOU'LL EVER SPEND. YOU DON'T HAVE TO REPLACE THE GELCOAT. YOU ONLY NEED TO DRILL OUT THE BLISTERS, LET THEM DRY THOROUGHLY, FILL AND SAND SMOOTH.
AFTER REPAIRING THE BLISTERS, MANY ON THIS FORUM HAVE APPLIED INTERLUX SYSTEM 2000 WATER BARRIER WITH EXCELLENT RESULTS.
AGAIN, PURCHASE THE WEST SYSTEM MANUAL.
GOOD LUCK

Edited by - on

dlucier
Master Marine Consultant

Members Avatar

Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 10/23/2002 : 00:50:43

Gentlemen,

WHY ARE YOU SCREAMING! Just kidding.

Mr. Sailor(or can I just call you Salty?),

Here is an article I found on the Sailnet website under "blister repair", I hope it helps:

Hull Blisters

The hull of my 1981 Catalina 25 has three small areas, about one by two feet, covered with tiny blisters. Should I follow the treatment recommended in This Old Boat or do you have other suggestions?

Bob Schuetz

Don Casey responds:

First, the blister repair information in This Old Boat warned that it would be obsolete by the time the book was in print because it was written when the blister problem was relatively new and no single fix had been established as a true cure. Today I recommend the following regimen:

1. Grind open each blister, removing all damaged laminate (if any, since blisters often involve only the gelcoat) but not removing a millimeter more of the original lay-up than absolutely necessary.

2. Scrub out the open blisters with a solution of TSP (from any hardware store), using a stiff bristle brush. Flush the clean blisters thoroughly with water.

3. Allow the blisters to remain open as long as practical. It is important to allow the laminate to dry completely before filling in the blisters or you will trap moisture inside the repair, which will likely to lead to a recurrence. A simple test for moisture is to tape a piece of clear plastic over a sample blister in the early morning of a sunny day. Seal the plastic all around with electrical tape and make sure the sun will hit the plastic. If moisture forms on the inside of the plastic, the hull is still damp.

4. When the hull is dry, wipe each blister with a clean rag dampened with acetone. This is mostly to remove air pollution.

5. Epoxy is the resin to use for blister repairs. It is less permeable than polyester, or even vinylester, and it forms a much stronger bond. Wet out each blister with epoxy.

6. Now thicken some epoxy to a peanut-butter consistency with colloidal silica and fill the cavities with this filler, using a squeegee to compress and fair it. Silica-thickened epoxy is difficult to sand, so fair the repairs well. Never use microballons or any other hollow or absorbent (talc, for example) fairing compound to fill blisters.

7. Before the repair reaches full cure, paint it with at least two coats of unthickened epoxy. In your case, since the blisters are concentrated in three areas, I would coat those areas with 20 mils—about seven coats—of unthickened epoxy. The most effective application technique is to paint on the epoxy with a foam roller, then immediately squeegee the wet epoxy with a 1/3-section of foam roller. You make the needed squeegee by cutting a foam roller in half, then slicing the halves lengthwise into thirds. "Squeegeeing" the epoxy forces it into the pores of the hull and removes most of the bubbles that rolling has introduced, thus making the epoxy less permeable.

There is no benefit to returning the hull to its original makeup. After all, you already know that configuration is susceptible to blistering. Filling the blisters with epoxy resin will not lead to new problems, and epoxy barrier coats have proven quite effective provided they are thick enough—at least 20 mils.

Don Lucier, 'North Star'
Catalina

Edited by - on

jm
Captain

Members Avatar

Canada
290 Posts

Response Posted - 10/23/2002 : 09:47:20

And you've got some local expertise right in your back yard.

check out http://www.gougeon.com/

Edited by - on

RichardG
Admiral

Members Avatar

USA
990 Posts

Response Posted - 10/23/2002 : 14:34:45

Which is the preferred method: drilling out the blisters (with a drill, as OJ suggests), or grind open the blisters (with a grinder, as Don Casey via Don Lucier suggests)?

RichardG 81 C25 SR/FK "Sanity"

Edited by - on

Dave Bristle
Master Marine Consultant

Members Avatar

Djibouti
10005 Posts

Response Posted - 10/23/2002 : 14:54:43

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>
Which is the preferred method: drilling out the blisters (with a drill, as OJ suggests), or grind open the blisters (with a grinder, as Don Casey via Don Lucier suggests)?
<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>
DRILL??? Wow, does that sound dangerous! Have you drilled into fiberglass recently? It grabs the bit and GOES! I think I'll use a grinder--gently.

BTW, Don, his name is Steve... I looked it up for ya.

Dave Bristle - 1985 C-25 #5032 SR-FK-Dinette-Honda "Passage" in SW CT

Edited by - on

Douglas
Master Marine Consultant

Members Avatar

1595 Posts

Response Posted - 10/24/2002 : 03:04:59

I have repaired countless blisters. There are two ideas on blisters. If they are surface blisters and only the size of a fingernail to a quarter leave them alone and keep an eye on them. OR LIKE ME fix evey last one and do a new epoxy bottom. DONT drill anything. I used a small dremel tool with a ball shaped stone and only took off enough material to remove the delam and moisture. If you want the scoop on Barrier Coats go to Yahoo and search Barrier Coats. You will see an artical called the great Barrier Coat Rip off. Read it and go to the companies link. I used their product and got a first class result. Prep Prep and more Prep is the key.<img src="http://im1.shutterfly.com/procserv/47b2dd25b3127cce9c8cfe7f178a0000005410" border=0><img src="http://im1.shutterfly.com/procserv/47b2dd04b3127cce9d4cdf96ce5f0000005410" border=0>

Doug&Ruth
Boatless in Seattle
Tacoma Wa.

Edited by - on

OJ
Master Marine Consultant

Members Avatar

USA
4382 Posts

Response Posted - 10/24/2002 : 22:57:59

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>
Which is the preferred method: drilling out the blisters (with a drill, as OJ suggests), or grind open the blisters (with a grinder, as Don Casey via Don Lucier suggests)?

DRILL??? Wow, does that sound dangerous! Have you drilled into fiberglass recently? It grabs the bit and GOES! I think I'll use a grinder--gently.
<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>
Sorry, for those who haven't read the West Systems manual on blister repair - they recommend drilling open blisters with a countersink bit, applying just enough pressure to make headway. A carbide countersink bit doesn't drift, leaves a clean edge and is quick - I stopped counting at 300 plus blisters! <img src=icon_smile_dead.gif border=0 align=middle>

Edited by - on

Douglas
Master Marine Consultant

Members Avatar

1595 Posts

Response Posted - 10/25/2002 : 00:50:02

Sorry but if you go telling people who have never done glass work to use a drill your going to have holes through the hull. Its safer to use something less pointed and go slow on smaller boats. Im realy not impressed with West systems to start with. Look at the amount of solvent in their resin. Why pay big bucks for something thats going to evaporate. Thats how they make their money. Using a round stone as I recomended will open the blister slowly, exposing more as you go and will give you a good visable idea of how much you need to remove. The drill on the other hand may open the blister to drain but you cant see how deep you go or know when is enough. It also only opens the blister . You will still need to grind away the delaminated area. Its all about confidence and experiance. Take it easy and go slow. Kind of like measure twice cut once.

Doug&Ruth
Boatless in Seattle
Tacoma Wa.

Edited by - on

OJ
Master Marine Consultant

Members Avatar

USA
4382 Posts

Response Posted - 10/25/2002 : 13:42:47

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>
Sorry but if you go telling people who have never done glass work to use a drill your going to have holes through the hull.
Douglas, I had never done glass work before when I first used a drill. If you think about it, a dremel tool and a drill produce the same action.

Its safer to use something less pointed and go slow on smaller boats.
A 1/2" diameter countersink has a 5 blades, a lot of cutting surface, which requires constant pressure to make headway - a very controlled process.

Im realy not impressed with West systems to start with. Look at the amount of solvent in their resin. Why pay big bucks for something thats going to evaporate. Thats how they make their money.
I'm not advocating people use West System products, however, their manual does an excellent job of explaining the causes of blisters and how to repair and prevent new ones.

You will still need to grind away the delaminated area.
Good point - I must have been fortunate as I had no delamination outside the blisters themselves. I used a 4 1/2" angle grinder on my rudder. That also works well on opening up fiberglass delamination. 
<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

Edited by - on

SALTY SAILOR
Deckhand

Members Avatar

7 Posts

Response Posted - 10/25/2002 : 22:22:17

GENTLEMAN,
WHETHER I DRILL OR GRIND OUT THE BLISTERS THE RESULT WOULD BE THE SAME. I WOULD HAVE MORE OPEN HOLES THAN ORIGINAL GELCOAT. ALL OF THE BLISTERS I OPENED UP ARE IN THE RED COAT (LAYER) BETWEEN THE FIBERGLASS AND THE GELCOAT. I AM MORE INTERESTED IN WHAT OTHER GUYS WERE USING TO REPLACE THE GELCOAT. I NOW HAVE MORE INVESTIGATING TO DO. MY LOCAL MARINA IS SUGGESTING 2 COATS OF INTERLUX EPIGLASS AND THEN 4-5 COATS OF INTERPROTECT 2001 AND THEN 2-3 COATS OF VC17M.

DOUG, IS THE PRODUCT YOU USED MEANT TO GO DIRECTLY OVER FIBERGLASS OR DO YOU PUT A LAYER OF RESIN INBETWEEN ?

Edited by - on

Douglas
Master Marine Consultant

Members Avatar

1595 Posts

Response Posted - 10/26/2002 : 00:18:58

I recomend you go to Yahoo search. Type in Barrier coat. In the resulting pages you will see one that says the great barrier coat rip off. Read it and have a look at their site. It will save you a lot of money.

Doug&Ruth
Boatless in Seattle
Tacoma Wa.

Edited by - on

Douglas
Master Marine Consultant

Members Avatar

1595 Posts

Response Posted - 10/26/2002 : 00:28:53

<img src="http://im1.shutterfly.com/procserv/47b2dd04b3127cce9d4cdfa8ce610000005410" border=0><img src="http://im1.shutterfly.com/procserv/47b2dd04b3127cce9d4cdf94ce5d0000005410" border=0><img src="http://im1.shutterfly.com/procserv/47b2dd08b3127cce9d701d1fe8f90000005410" border=0><img src="http://im1.shutterfly.com/procserv/47b2dd04b3127cce9d4cdf974f6e0000005410" border=0><img src="http://im1.shutterfly.com/procserv/47b2dc09b3127cce9c9a3ea16d940000006410" border=0>I dont know this is how she turned out. The epoxie was applied with a roller of epoxy quality. he paint went on 12 to 14 mills thick and was easy to work with.

Doug&Ruth
Boatless in Seattle
Tacoma Wa.

Edited by - on

RichardG
Admiral

Members Avatar

USA
990 Posts

Response Posted - 10/28/2002 : 16:08:43

Putting aside for a moment the question of which barrier coat is preferable on the whole hull, what product(s) are people using to fill the holes after drilling/grinding/dremeling the blisters? In choosing this product, does it matter whether you are putting on a barrier coat or not?

RichardG 81 C25 SR/FK "Sanity"

Edited by - on

OJ
Master Marine Consultant

Members Avatar

USA
4382 Posts

Response Posted - 10/28/2002 : 20:16:01

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>
what product(s) are people using to fill the holes after drilling/grinding/dremeling the blisters?
Holes? Did you really say holes? You're not suppose to drill holes in your hull when opening blisters <img src=icon_smile_wink.gif border=0 align=middle> !
I used the West Systems products because of the knowledge gained from their manuals, plus they made product selection so straight forward for the novice (i.e., smart marketing.) If you have the time for further research, I'm sure you'll find others for less money.

In choosing this product, does it matter whether you are putting on a barrier coat or not?
You don't have to cover the repaired areas with water barrier. I applied it primarily to prevent more blisters from forming and going through the whole ugly process again.
<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

Edited by - OJ on 10/28/2002 20:18:12

Edited by - on

RichardG
Admiral

Members Avatar

USA
990 Posts

Response Posted - 10/29/2002 : 15:41:31

Steve:

Yes -- holes, deep enough to remove the wet material, like the three Douglas ground out as shown in the last picture he posted. <img src=icon_smile_wink.gif border=0 align=middle>

While the West manual recommends drilling blisters out with a countersink bit, two years ago I used a grinder (as recommended by the yard guy) because he felt it's more versatile than the limited size of a countersink bit in thoroughly clearing all the wet material out just underneath the surface of different sized blisters without going too deep. That's important because West's recommended "drying time" at $50/day around here isn't very practical (yard storage fee). However, a grinder doesn't always produce symmetrical holes -- but I honestly don't know if this is necessarily not good. So far, so good -- but until I pull the boat, I really won't know. The dremel seems like a good alternative.

Almost all the blisters were spread out on the port side -- go figure<img src=icon_smile_question.gif border=0 align=middle>

Douglas:

I, like many, used West Systems products to fill the holes. Most people seem to like West -- this is the first I've heard that you can do better. Did you use Progressive products to fill the blisters, as well as their barrier coat products?

Barrier coating is a larger job than I want to take on right now, given all old paint must be removed. Maybe someday.

RichardG 81 C25 SR/FK "Sanity"

Edited by - on

Topic

New Topic

Topic Locked

Printer Friendly

Jump To:

Association Forum

Notice: The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.