Small Blisters

[ron7546]

Hi to all,
When I purchased my 1976- E27 five years ago I did not have any blisters at haul out or I did not notice them ( it was about 24 degrees and freezing rain). She is totally a freshwater boat.The previous owner had just carbide scrapped the bottom down to the VC Tar,added 2 additional coats of tar and followed with 2 coats of VC17. I now have many B-B to pea size blisters.When I break them I get a little fluid . The depth seems to be just to the tar but in some cases to the gel coat. Also my boot stripe looks like it has been shot with a 12 GA. Not blisters but little chips
Should I break the blisters this fall and treat them in the spring ? ? I do not want to get into a full blown bottom job at this time.Can I somehow just treat each blister on an individual basis ? ?

Ron Wallace
" Bluenote"

 

[Frank Langer]

So if the blisters are only as deep as "to the tar", does that mean it's only the VC 17 that is blistering? If so, then that doesn't sound serious. Even if the blisters go through the tar, but the underlying gelcoat is solid, that wouldn't worry me either. If there are only a few blisters and you can fix them in the spring, that should be fine.

I'm also wondering why the previous owner applied so many coats of VC Tar--was he just quite particular, or was he trying to fix a blistering problem that he didn't disclose? Your statement that the blisters only go as deep as the tar would suggest that the hull itself is fine.

Others may have other comments as well.

Frank

 

[Walter Pearson]

I would think that if you are getting fluid out of the blisters, they should be treated as osmotic blisters. My '76 E27 had mostly small blisters, only some of which actually had fluid that came out. I often did not see them until the hull warmed up in the sun while on the cradle. I opened, ground out, filled and faired on an individual basis for a few years, but they kept coming. Finally had to go the full Interprotect route. I am fresh water; boat originally had some thin and sparse Micron 66; I tried Fiberglass Bottomkote after the barrier job, but that always wanted to delaminate. Now have good success with VC17m Extra.

 

[ron7546]

I am going to open them now and let them dry through the winter. Come spring how deep do I grind ?? And what to use as a filler ? Also should I spot each "blister" with VC tar before total repaint.
As far as the boot stripe problem- - I primed with Pre-Kote and used Briteside as a top coat. I don`t remember what was under that.There could be some tar because there was no boot stripe when I bought her. The VC 17 (and most likely tar ) went up to where the top of where the stripe is now. The spots never appear to be a blister just " tiny round chips " in the briteside down to the primer.
Thanks in advance
Ron
PS Where can I find info on creating a profile, avatar,photos and etc.

 

[Emerald]

You will want to grind the blisters just to the point where the laminate is stable and sound. Do the grind now and let them air out over the winter. If they are small as you describe, you can do fine with a Dremel. Big blisters can be quickly opened up and ground out with a stone wheel on an angle grinder, but you need to have finesse or you'll take away too much material. You will want to fill with a high quality epoxy thickened. I suggest West System and 406 filler for small stuff. Use 410 for final fairing. You will want to keep other products e.g. your VC tar seperarte from the repair. If you find that your bottom is covered and you are doing the whole thing, you should put a final barrier coat over the whole thing using something like Interlux Interprotect 2000. This is a time consuming job, but done right, it should last. There are members of this site that have had a terrible time with blisters coming back (Ragdoll, If my memory serves correctly, but appologies if my memory is wrong). I would say this was an unusual situation without good explanation. Time and patience are your friends on a job like this. Here is a very good detailed write-up from West System on using their products. No affiliation here, just a long time happy customer. Of note, I did a blister repair some years ago grinding and filling the individual blisters, and 3 coats of the Interlux Interprotect. It's been about 4 years, and there are not any signs of blisters showing back up.

http://www.westsystem.com/ss/repairing-individual-and-early-stage-gelcoat-blisters/

 

[ron7546]

David,
Thanks for the info. I have started opening the blisters and indeed they are 1/8 to 1/4 in.dia. Some have liquid behind them , NOT ALL . As I stated,I have several coats of VC Tar topped with VC17.The blisters so far seem to go only as deep as the tar and in some cases only to the Gel coat not thru.I haven`t found anything that is thru the Gel coat, YET! Sorry, I don`t understand what you mean by,"keep the tar seperate from the repair "
You mention using Interprotect 2000. Is this in the event that I remove the VC17 and VC Tar ? ? When you did individual blisters did you strip the whole botton to the Gel coat before applying Interprotect 2000.
Thanks Again
Ron

 

[Emerald]

Sorry for the confusion. I think it would be better to say keep them as two separate projects, even though they are interconnected. Treat the grinding out and filling and fairing of the gelcoat blisters as taking care of hull issues, and then the VC tar/barrier coat as part 2. Without seeing it, I don't want to guess too much, but it sounds like the VC tar barrier coat is failing and needs to be removed. If it's forming blisters e.g. coming up from the underlying gelcoat, then there's an adhesion or contamination or some other issue causing a failure. A properly applied barrier coat should be somewhat permanent if done right, hence the thickness and need to build up with 3+ coats typically. If your barrier coat is coming apart in a blister like fashion, I think the only lasting solution is to take it off and start over. I suggest the Interlux Interprotect 2000 only because I've used it successfully (4 years out now) and it has a very good reputation as I talk with local yards and owners. I don't have any hands-on experience with the VC tar product.

When I did my blister repair, I had the whole hull soda blasted to remove all prior coatings to the bare gelcoat. This left a nicely etched surface with tooth for adhesion, and some reasonable number of blisters already opened up. From there, I ground out and filled with West epoxy and 406 and did final fairing with West and 410. Once I had the hull faired, I applied the Interlux Interprotect 2000. Of note, it's available in white and grey, and I alternated between the two to be able to tell I had full coverage and for future wear indication. The first layer of bottom paint was applied with the last barrier coat finger print tacky. Knock on FRP, but there hasn't been any sign of blisters returning.

 

[ron7546]

Did I hear someone mention using a truck leaf spring as a scraper ? ? ? I don`t know if it was this forum or elsewhere . Maybe someone just trying to be a PITA.
Ron

 

[kari]

I remember that, it sounds like a good idea, a piece of leaf spring ground off to a nice square end edge . . a good size one as in truck etc. the weight/mass really help . . . round off the sharp extreme corners to avoid obvious dig in issues, haven't tried it yet myself but I will next haul out . . .

 

[ron7546]

Any recollection as to finding that post ? ? ? anybody.I really think that would have merit . Has anyone tried that method ? ?
Ron

 

[Guy Stevens]

That was me

I use a truck leaf spring as a scarper when removing old paint. The leef springs I get for free, a broken one and then grind it nice and flat on the broken end and friction tape up the other end as a handle.

It works wonders. Catch an edge of the old paint where it is flaking and go to town. You will have a few spots that are stubborn and have to be sanded off, but as you get better and keep the tool sharply square to the work it goes quick on heavy bottom paints!


Guy

 

[ron7546]

Guy,how wide of a spring worked for you ? ? ?
Thanks for the input
Ron

 

[Guy Stevens]

Scrap

I just go to the spring place, ask them to look at their broken leaf springs, and pick out one that fits in my hand.

If you take some beers you generally have no problems picking several and a couple of times they even insisted on grinding the end flat for me!

Guy

 

[ron7546]

Along with stripping the bottom I have started stripping the boot stripe also. What the " H " I seem have all paint and primer off but the blue color remains on the boot ? ? ? Did Ericson somehow add color to the Gel Coat for just the boot ? If so how ?
Thanks in advance
Ron

 

[Loren Beach]

Yup, it's probably gel coat

Along with stripping the bottom I have started stripping the boot stripe also. What the " H " I seem have all paint and primer off but the blue color remains on the boot ? ? ? Did Ericson somehow add color to the Gel Coat for just the boot ? If so how ?
Thanks in advance
Ron

Get coat comes in many many colors.

I have found that most higher-end builders always used a separate gel coat color for boot striping. (Many did so for a cove stripe also.)

Plastic tape is cheaper but gets UV-degraded after a couple decades.

LB

 

[ron7546]

How do they do that ?

If I understand you correctly they are able to spray more than one color of Gel Coat into the mold.I always thought they sprayed one color and painted any accents. Interesting ! !
Thanks
Ron

 

[Loren Beach]

You just need a steady hand.....

If I understand you correctly they are able to spray more than one color of Gel Coat into the mold.I always thought they sprayed one color and painted any accents. Interesting ! !
Thanks
Ron

IIRC, they would first completely mask off the nearby hull areas in the mold, and then spray the colors for the cove stripe, waterline stripe and any other such contrasting color. Absolutely precise accurate taping was a necessity!
Then they'd pull off all the tape and plastic, and then spray the main hull color.
It was a long time ago, but I used to visit the Ranger Boat plant in Kent WA, when I was selling Rangers (about '79 - '81). All of their contrasting hull "trim color" was gel coat - they did not use any plastic tape at all.

Loren

 

[ron7546]

Wow-Wow

Thanks, I`m glad to know that.