Blister Filler Material – What to use?

[sgharford]

Blister Filler Material – What to use?

I had the bottom paint removed over the winter as there was probably 20 years worth of paint with acne all over the place. Of course being a vintage 1976, she has the Pox pretty bad. Based on threads I have read here just going to epoxy coat over all of them with the exception of about 5 that actually popped on their own (or maybe they were just dings?). Anyway, will grind ‘em out a bit with a dremel tool and clean ‘em up with acetone before filling. Was thinking Marine Tex for filler as it seems to have right consistency our of the jar, but also got a gallon of West Systems on the shelf so thought I would ask the guru’s what you thought best for filling blisters below water line. Thanks – Scott.

 

[stormchaser]

Re: Blister Filler Material – What to use?

If you already have West epoxy, just mix it up with some 407 Low-Density filler. Makes it the constancy of "Bondo"...perfect for fairing/filling.

 

[sgharford]

Re: Blister Filler Material – What to use?

407 is not recommended for below the water line. Read somewhere else not use microballons anywhere below waterline, or talc based thickeners for that matter, as they absorb water.

Lots of articles on how to repair, but no one seems to suggest what product(s) to repair with specifically.

 

[mobilemn1]

Re: Blister Filler Material – What to use?

I have been researching painting and repairing for about two weeks now trying to decide what to use. Go to the Interlux web page. They have a full system from top to bottom and video's on the how to's and wherefor's. I think I may be going with this system for my entire project. They also seem to have a good system for top and bottom paints with everything you need from prep, repair, primers, top and bottomcoats, antifouliing. It may be worth you time to check this out.

 

[stormchaser]

Re: Blister Filler Material – What to use?

407 is not recommended for below the water line.

Strange that http://www.westsystem.com/ss/filler-selection-guide/ makes nio mention of that. I would think they would mention it?

 

[mobilemn1]

Re: Blister Filler Material – What to use?

After the last post, I went back and looked at the West Marine Site. Instead of the 407,,,,use the 406 colloidal filler, it is high density. They do not reccommend using the low density below the water line. They also have some good videos http://www.westsystem.com/ss/repairing-individual-and-early-stage-gelcoat-blisters/ this is the link to the blister repair section. Hope this helps

 

[sgharford]

Re: Blister Filler Material – What to use?

Thanks Daryl for the link and info - looks like I'm not the only one wondering what to use. I called West Systems (talked to a Jim Watson) just now and they in fact said 407 is just fine and dandy to use below the waterline. However, after skimming West System article you suggested would definitely use 406 for same reasons I read about using mircoballon filler products. Just out of curiosity (will spend the $8 for 406 filler), anybody any feedback on Marine Tex for blister repair?

 

[67hat34c]

Re: Blister Filler Material – What to use?

Epoxy Cabosil and mix it to consistancy of penut butter. Mix in small amounts as it will harden fast and smoke in the pan. I would mix epoxy in about cup size then put in pie pan and then mix the Cabosil , if you spread it out more in the pan it does not heat up as fast.

 

[fissioneng]

Re: Blister Filler Material – What to use?

I've used 406 for years with no problems. If you choose the right hardener, you won't have to rush and it won't get hot enough to worry about.

I've never heard of anyone using MarineTex for blister repair. Not sure it is the right thing.

 

[sgharford]

Re: Blister Filler Material – What to use?

I feel like Marine Tex is the JB Weld of the boating world. I have had so many good experiences with JB Weld figured Marine Tex may work for this somewhat obscure fix (blister repair). Thanks all - think I will go with 406 as easy to get locally.

 

[jim rosenthal]

Re: Blister Filler Material – What to use?

Use what they say, 406. Over that, use their aluminum barrier coat mixture if they still make that, for your fairing coats. You should have something over the repaired areas besides bottom paint. NB: Is your hull dry- really dry? It needs to be. Mine spent five or six months drying out before they filled the blister gaps with VC Watertite and then faired the whole hull. Mosture trapped inside the hull will lead to blisters later on.

I think you will be fine with West products. Their stuff is very reliable and if used as directed very predictable. Should be in there for decades.

 

[Maynard Rupp]

Re: Blister Filler Material – What to use?

West System's microplatlet material is #422. This stuff is exactly wat you want to add in with the #406. I personally use #410 for filling and fairing underwater areas. 410 is what all sailors use to fair their racing bpttoms. It is alot easier to sand than 406. 410 wa introduced by West as a better sandable filler than 406. I would thiken with 410 and add 422 to keep the water out.

 

[Brian Degulis]

Re: Blister Filler Material – What to use?

For something simple take a look at Interlux VC Watertite epoxy filler I think it's made for this purpose. It's a simple 50/50 mix no fillers to add just mix and go it handles and sands very well.

Brian

 

[sgharford]

Re: Blister Filler Material – What to use?

Thanks again everyone. I picked up 406 last night and will hopefully get to filling the 5 or so blisters that really need it this weekend. The boat has been on the hard since October, so I think hull is pretty dry. She spent 6 months out of water last year too (she was in the water for 2 years straight prior to that). As for the rest of the 'pox' - probably about 150 or so on hull - none (except about 5) are raised and/or have popped thru. In fact, I thought the boat had a blister job done by prior owner(s) after they sanded bottom paint off in December. Thought what I was looking at was the filled areas as they were all smooth and flush with rest of hull. Yard manager told me not the case. Since consensus from past threads are these are mostly cosmetic, not going to fight this fight. Anyway - she is getting 10 mil barrier coat so I don't really expect those 150 or so to get much worse.

 

[jim rosenthal]

Re: Blister Filler Material – What to use?

VC Watertite works fine. It has been on my boat for ten years or longer. I think the dryness and prep matter more than anything.

 

[Vincentc]

Re: Blister Filler Material – What to use?

Preparation is critical and sanding cured filled epoxy, expecially overhead is a major pain.

After the cavity is cleaned, I would wipe it with acetone and when that was dry apply a coat of unthickend epoxy resin and hardner. As soon as that had set up and while the first coat is still green I would apply the filled epoxy (peanut butter consistency) Use an 6" plus plastic spreader. If you can get some before the weekend, you might try using "peel ply" a cloth like material that epoxy does not stick to. You lay a piece larger than the area, over the uncured epoxy and smooth out the epoxy putty, and when it cures, peel off the peel ply. It would help you "fair" the epoxy putty into shape.

After the putty has set up, several hours but is not yet fully hard you can shape off the high spots with a Stanley "shureform" scraper. Kind of like a cheese grater. Smoother you get it the less you have to sand. You can be cautious and fill the holes in multiple steps. Just recoat while still green and you will get a chemical bond and avoid having to wash of the "blush" residue that forms on cured epoxy.

You might want to mix up some epoxy and filler and experiment with it on something less dear than a Hatteras. Spread some on a piece of plywood, observe how and how long it takes to cure and practice technique. You can throw away the plywood if you screw up.

Buy a box of nitrile disposable gloves, and use a new pair with each application, and keep the epoxy off your skin. Use an lanolin HD hand cleaner rather than a solvent to clean your self from the epoxy. Be carful to accurately and completely mix the resin and hardner.

Coat the filled epoxy with 2 or more coats of unthicked epoxy.

Epoxy is an excellent tool for boats, and not difficult to use, but can hurt you or your boat if used improperly. Most every epoxy label: West/Gougeon, System 3, Mas, Raka has information available on their websites. It is well worth reading and pondering the pictures. I believe Jamestown Dist. may have a video.

Have fun,
Vincent

 

[Pete]

Re: Blister Filler Material – What to use?

I have redone the entire bottom on our 48 myself, with the help of one young yard worker on the clock doing the heavy sanding. West epoxy was the weapon of choice. I fully agree with the advice Vincent posted. Let me reinforce and add a few details. First, there is a thick bottom on Hatteras boats. Be sure to grind away the blister fully, until you have nothing but good fiberglass showing. Once opened, wash with a hose, detergent, and scrub brush. Rinse very well and let dry. Let it stand overnight and see what you have the next day. Inspect in particular the edges of the openings you have created. Be positive no void exist and no brown liquid is evident, even the slightest amount. If either of these conditions are noticed, grind some more to get only good/solid fiberglass. Then use West epoxy with no additives to seal the opening and proceed to build up as Vincent described. Finish with a couple of coats of West epoxy and only West System's microplatlets, #422. If you have to go deep to get good glass in some cases, add three or four layers of biaxial glass between the seal coat and the thickened epoxy, using unthickened epoxy with the glass. Marine Tex was used on some blisters by the PO of our boat. I have had to redo all of these with the process described due to adhesion problems after several years. My recommendation is the West System, in the process described. I know this works at least 8 years of year round floating. For a barrier coat, I recommend Sea Hawk Tuff Stuff. I was very pleased with the results on our boat.

Pete

 

[sgharford]

Re: Blister Filler Material – What to use?

What do you guys think of using a heat gun on a low setting to expedite drying after grinding blister open?

 

[REBrueckner]

Re: Blister Filler Material – What to use?

Drying with a blow gun can't hurt....it could only help initial adhesion of any filler...but not long term success...A small light bulb,say 15watts, taped to the hole and left overnight is another alternative....I've used that in superstructure situations with good results...an acetone wash/brush will aid drying as well....

Nothing beats a moisture meter for determining hull moisture when an entire bottom is being done....either buy one with some buddies and share it's use or hire somebody with a moisture meter to check when you think things are dry enough to begin recoating....If the boat has been recently hauled, don't bother...it will be very wet....

there are specifications for hull moisture prior to recoating...maybe some one can post specs as I have not fussed with this for some years....I'll guess it's somthing like 10% or 15%...but do not use that as a criteria....it may also vary by coating product....

 

[sgharford]

Re: Blister Filler Material – What to use?

Just thought I would follow up – 406 is wonderful to work with, I will never use Marine Tex again. You can really get consistency just where you want it. I would recommend using a syringe to place the epoxy in ground out divet too, it’s much easier than trying to fill with plastic spatula. You can overfill with syringe, then spread even with spatula. You don’t get air bubbles this way.

Also, there is allot of advice in other threads saying not to worry about blisters on old Hatteras’s. If you have your bottom stripped I would have to recommend filling any blisters as they can go pretty deep when you start grinding them out (I used a sanding drum on a Dremel tool). What I thought were Pox on my boat was actually a previous blister fill job. They did not grind enough away (Article in previous post from on this thread from West Systems says you should grind out circle diameter 20 times depth of blister. The previous blister job repair may used a factor of 3 to 1 and as a result seeing those filled in areas cracked (Well, guess cracks could also be from inferior fill material too).

Biggest thing I wanted to point out if you have bottom stripped – look out for any hair line cracks in gel coat and grind a bit out near center. Nearly everyone I found had a significant defect in glass under them, especially ‘spider cracks’ – those cracks eminating from a central point. One hair line crack was about 3” long. By time I was finished grinding out bad glass it was nearly ½” deep (thank God these are thick hulls). Originally I thought I had about 5 blisters to take care of, turned out to be about 40 (about 10 where hair line cracks with significant rot underneath). Granted, there were about 150 more that were already filled, but It’s really not that bad a job – Between circling areas with marker, grinding out, cleaning with acetone, initial fill with un-thickened West systems, and then another round thickened with 406 probably took me about 4 hours to do 40. Will have to go back and sand what I did, add another coat to some and sand again- so add another 2 hours.