Comparison of Barrier Coats

[steve.garlick]

Hi all,

I'm doing a bottom job - bottom has small blisters in just a few areas (rudder, keelson ). The bottom has been Gelshielded maybe 10 years ago.

I'm not intending to grind out all the blisters.

What are the differences between different types of epoxy barrier coats.

Is Gelshield plus different to Gelshield 200. What's the difference between that and Interprotect. Are any of these better than West's system 205?

Even International yacht paints don't spell out the differences between their own products?

Help?

regards,

steve

[lancelot9898]

Within the next year I too will be putting on a barrier coat(s) after doing a gelkote peel. I'm looking at West System, Interprotect, Petit, Mas and something called water guard 300. The application technique is somewhat different for most cases and I'm still trying to get a handle on the best system for water exclusion. Mas is the only one that gives a water absorption of less than .05 %, but who knows how that compares or what than means? West System gives the best description for applcation technique whereas some others are very vague even though those systems may in fact be easier to apply. ?? I need to google Gelshield 200 since I haven't heard of that one.

Depending on the condition after the peel, I too do not expect to grind out all the blisters. The woven laminate is fine per the laminate profile, however there are some resin loss in the chopped matt fiber. I want to have the epoxy penetrate that fiber prior to putting on the barrier epoxy. Interlux seems to have a low viscosity epoxy(Epiglass) that can do this and then their interprotect epoxy can be used as the barrier coat. Something is similar with the west system whereas the mas epoxy seem to use the same suff without any additives. After talking to the tech support at Mas, there seem to be a metal roller called a bubble buster that is good to use in application however the only place where I could find it is in Australia. Lot of things to learn...good luck.

[minaret]

Originally Posted by lancelot9898

Within the next year I too will be putting on a barrier coat(s) after doing a gelkote peel. I'm looking at West System, Interprotect, Petit, Mas and something called water guard 300. The application technique is somewhat different for most cases and I'm still trying to get a handle on the best system for water exclusion. Mas is the only one that gives a water absorption of less than .05 %, but who knows how that compares or what than means?

My personal experience with MAS has been very bad, I would stay away from it. Full disclosure it has been about ten years since I have used it and they may have changed the formula, but all the boattoms we did with it then were a problem and it was a huge pain to use compared to the tried and true WEST. We swore never again even though we were getting large samples and a large price break from the manufacturer as they were trying to break into the market.

West System gives the best description for applcation technique whereas some others are very vague even though those systems may in fact be easier to apply. ??

WEST is the way to go for the resin coat and for fairing IMHO. I have had the least trouble with blush and great longevity, it is a known factor.

I need to google Gelshield 200 since I haven't heard of that one.


Gelshield you will note is made by International, the makers of Interlux and Interprotect 2000e and 3000. It certainly can be confusing as to why the same company puts out several different barrier products, and there is not much info to be had without talking to their techs. Basically, Gelshield was formulated to be applied on new boat bottoms which of course still have their gelcoat, not to repair boats which already have prexisting osmosis and have thus been peeled. Gelshield is intended to be applied by airless spray rig, though it can of course be applied by roller as well. I would leave it to it's intended purpose of commisioning new boats and use Interprotect 2000e to repair your osmosis problem, as that is what it was formulated for. 2000 is very good stuff and quite easy to work with.

Depending on the condition after the peel, I too do not expect to grind out all the blisters.

Once you've gone to all the trouble of a peel, I would recommend taking the time to grind out and repair any blisters of any depth. It will not add much time to the overall job, as most of that will be peeling, fairing, and coating. And if you have a blister problem you may never get a dry hull unless you open them all up first. We always grind out all blisters before drying.

The woven laminate is fine per the laminate profile, however there are some resin loss in the chopped matt fiber.

This is very common. Have you considered a double peel? In many cases the skin layup is all chop matt and is the source of the problem, and often a double peel will remove all of the questionable material. Usually we laminate 2 layers of matt in vinylester resin after a double peel to make up the lost material, followed by the normal full barrier job. This is a great permanent cure.

I want to have the epoxy penetrate that fiber prior to putting on the barrier epoxy.

Good luck! The problem is thousands of micro air bubbles trapped in the laminate. No matter what viscosity you use epoxy resin will not penetrate these air pockets. I have seen cases where people squeegeed a resin coat over the hull and you could still clearly see the "dry" laminate under the resin. The only way to make a "dry" chopper gun laminate go away is to remove it.

Interlux seems to have a low viscosity epoxy(Epiglass) that can do this and then their interprotect epoxy can be used as the barrier coat. Something is similar with the west system whereas the mas epoxy seem to use the same suff without any additives. After talking to the tech support at Mas, there seem to be a metal roller called a bubble buster that is good to use in application however the only place where I could find it is in Australia. Lot of things to learn...good luck.

MAS misleading people as usual. A bubble buster is a very common type of laminate roller and can be aquired at any fiberglass supply store, but it is specifically designed for rolling out chop matt. It will do you no good whatsoever on a resin coat, it is a laminate roller for doing chopper layups. "Bubble Buster" is a common nickname, which is why you can't find one. It is properly called a bristle roller as opposed to a fin roller, although there is a newer model fin roller also called a "bubble buster" (Bodi bubble buster). The bristles aren't going to penetrate the laminate to introduce resin into the air bubbles, which is what it sounds like they are suggesting. I don't like MAS, I have heard too much BS from them.

Hope that helps!

[lancelot9898]

Thanks Minaret. Alot of good info! I'm leaning toward the interprotect product line and tying to find the pros and cons of 2000 vs the 3000. The 3000 can also be rolled on and has a somewhat thicker coat than the 2000. Seems like that would be a plus even though prior to bottom paint a coat of 2000 has to be applied over the 3000. Another thing that I've found is that a 3/8 inch nap roller is suggested rather than the foam rollers that I associate with epoxy application. Having never applied exoxy before and since I will be doing this by myself, I'm a little concerned about the need to tip the epoxy with a brush after rolling it on and the the amount of work time before it sets up.

After the initail peel, I'll decide if anothe peel is necessary and make sure that all the blisters are opened up and allowed to dry. Drying everything out is probably the key to a good job.

[bruce smith]

Pure epoxy resin (WEST 105) is an excellent product, but pure epoxy resin drips , and sags. It goes on like glue, because it is glue.
Epoxy coatings (paint) are made for painting on .
Whatever, epoxy has success in thickness, you are going for the mils. Lots of coats.

[minaret]

Originally Posted by lancelot9898

Thanks Minaret. Alot of good info! I'm leaning toward the interprotect product line and tying to find the pros and cons of 2000 vs the 3000. The 3000 can also be rolled on and has a somewhat thicker coat than the 2000. Seems like that would be a plus even though prior to bottom paint a coat of 2000 has to be applied over the 3000.

3000 is just 2000 made VOC compliant for the California market. It also has some anti-corrosive additives that make it slightly better as a primer for metal hulls, something which 2000 was being used for a lot. Stick with 2000, I don't like when they change a formulation that works so well for VOC compliance. 2000 has been used for many years now and is a known factor, don't gamble on a new formula unless you have a very good reason.



Another thing that I've found is that a 3/8 inch nap roller is suggested rather than the foam rollers that I associate with epoxy application. Having never applied exoxy before and since I will be doing this by myself, I'm a little concerned about the need to tip the epoxy with a brush after rolling it on and the the amount of work time before it sets up.

Some confusion here. To be clear, when we do a peel job, after drying and reapiring all blisters we apply a coat of WEST and then immediately apply a double slick of WEST with 407 for fairing. Then we sand the whole bottom nice and fair. Then we start to apply barrier coat. A 3/8" nap roller is a good tool for applying the straight WEST resin coat, as it has lots of payload and the nap works it into the pores as much as it's going to happen. But for applying 2000 you want to use a "candy striper" or 1/4" nap roller. The problem with a nap roller for 2000 is that you can't get a nice finish with one and will find yourself having to sand your barrier coat to get a nice bottom. Stack on all coats with the striper and you will get a nice fine even stipple that looks good with no sanding. Don't use a foam roller at all, it will melt. Don't bother trying to tip the straight WEST, it will run and sag to some degree no matter what you do, although a little MEK reduction can help. Just get it coated quick so you can catch the chemical bond window with the 407.


After the initail peel, I'll decide if anothe peel is necessary and make sure that all the blisters are opened up and allowed to dry. Drying everything out is probably the key to a good job.

That's how we do it, the decision to double peel or not is made by the operator after peeling a few feet. If you double peel a little spot and it takes you down to nice clean laminate it's probably worth doing. I also feel in some cases a double peel can really accelerate dry time, as all that porous matt is often full of moisture and peeling it off allows the nice laminate underneath to dry more efficiently without being covered by a layup which is full of trapped water. On a bigger boat you can also probably get away without doing a layup to replace material removed, the external matt skin doesn't add much to the structure in that case. On smaller boats (under 40') we always do the layup as the thickness removed can account for a substantial portion of the hulls stiffness. In fact we always do it period because we warranty, but I have helped some DIYers who have skipped that step on larger boats and I was OK with it. Make sure to use a moisture meter and get that hull nice and dry before coating, that's where most yards blow it. Good luck!

[steve.garlick]

Some great information here, thanks Minaret.

My situation is I have a few small pin head size pits just on the rudder and keelson. The hull has been gel shielded about 7 years ago. I want to sand the bottom down to the gel shield, grind out and fair any remaining pits. Then barrier coat again, fill the pits, barrier coat, prime then anti foul.

Would you go with Interprotect 2000 for the barrier coats, wests 407 for the filler? Is the Interprotect sufficient for a primer coat? or should I use Primacon. I plan to put a coat of hard, then 3 coats of Micron 66 soft.

Thanks for the info.

Steve

[minaret]

Originally Posted by steve.garlick

Some great information here, thanks Minaret.

My situation is I have a few small pin head size pits just on the rudder and keelson. The hull has been gel shielded about 7 years ago. I want to sand the bottom down to the gel shield, grind out and fair any remaining pits. Then barrier coat again, fill the pits, barrier coat, prime then anti foul.

Would you go with Interprotect 2000 for the barrier coats, wests 407 for the filler? Is the Interprotect sufficient for a primer coat? or should I use Primacon. I plan to put a coat of hard, then 3 coats of Micron 66 soft.

Thanks for the info.

Steve

Yes, just like that. Except that you should only need to fill once, and not fill between coats of barrier. Though it shows some experience and wisdom on your part planning for that just in case, often there are lows in a DIY job that aren't noticeable to the uninitiated until a coating is applied. 2000 is fine for the primer coat on gel, no primacon needed. Good luck!

[AussieWayne]

Hi Steve
Well its been about 18 months since you posted about your barrier coating and then using Micron 66. Is there an update that you could share with us as to what you actually used, how it turned out and what lessons were learnt along the way. I am about to do a similar procedure so very interested in your thoughts.
Specifically have you been happy with the Micron 66 in Med waters?

Hope to catch up somewhere next year.
Wayne

[steve.garlick]

Hi Wayne,

We're currently back in Ballina, NSW for a few weddings and a Xmas break. Nice to get out of the cold! Boat is in Bozburun boatyard on the hard.

We had a turn-around in our decision about our bottom. We were going to do a complete gel-coat strip and osmosis job, so last season, we just wacked on one coat of Cruiser Uno, which lasted exactly six months (its designed for charter boats that come out of the water every season). It worked brilliantly for that time, but we were in the water for about 8 months, got a little soft growth on the bottom. So, thumbs up for single season use, and it was as cheap as chips (I think 100 TL for 10 litres).

We kept all the product, not wanting to waste it if we completely redid the bottom. We've now decided that all the worry about osmosis is a waste of time, and decided not to strip the gel-coat. I found a turkish ship wright who had a gel-plane, 3000TL to strip the boat, but decided that if he botched the job, it would be a huge fairing effort.

So, we just sanded the hull to gelcoat and left it to dry as best as possible while we enjoy sunny Oz. When we get back, it will get alternate layers of green and grey Interprotect, then a coat of Primacon, then a coat of Ultra hard, then 3 - 4 coats of Micron Extra (They don't sell 66 in Marmaris, but a special turkish formulation called 77) I can't figure the difference.

I'll let you know how the bottom lasts next season. We want to stay in the water next winter (We'll be at Lefkas), so it will be interesting to see if it lasts. The idea behind the hard anti foul was so that if I scrubbed through the ablative, there would still be a layer of protection left.

I had really bad fouling of my prop last season. I'd just fitted a rope stripper, and it all got lots of hard growth. I'll try one of those spray on products this year.

Steve

[colemj]

Originally Posted by steve.garlick

When we get back, it will get alternate layers of green and grey Interprotect, then a coat of Primacon, then a coat of Ultra hard, then 3 - 4 coats of Micron Extra (They don't sell 66 in Marmaris, but a special turkish formulation called 77) I can't figure the difference.

The coat of Primacon doesn't make sense on top of Interprotect. You will end up needing to sand that fair before antifouling. What purpose are you applying it for?

Micron 77 is a slight reformulation of Micron 66 so that it works in brackish and fresh waters. It is not a Turkish formulation - It is made by Interlux and sold world wide. It is a straightforward replacement for Micron 66 with equal chemistry and physical properties.

Mark

[AussieWayne]

Thanks Steve for the update.
I found this on boatpaint.co.uk Seems like it is the enviromentally friendly version for European waters (without tin) as Mark has just pointed out.

International Micron 77
Micron 77 replace Micron 66 with the added advantage that it is suitable for fresh water. It is a true SPC (Self Polishing Copolymer) Superyacht antifouling that delivers the same outstanding level of antifouling protection as TBT SPC antifoulings, but without the negative environmental impact of tin.

Based on patented Biolux SPC technology, it lasts for 2 seasons and beyond and even protects over prolonged stationary periods, making Micron 77 the intelligent TBT replacement antifouling.
Micron 77 maximises speed and fuel efficiency because it smoothes continuously ensuring drag is always minimised.
Suitable for freshwater use.
Not suitable for use over Aluminium/Alloy substrates or zinc sprayed surfaces.
Coverage by roller is 2.5 square metres per litre - it is a 'gloopy' product that goes on thick International Antifouling Compatibility Chart

I am looking at scraping back to gelcoat, fairing then applying Gelshield 200 x 6 coats with Micron 77 x say 6 coats over the top. I might also investigate your idea of applying the first coat of anti foul as a suitable hard type. Problem is it so expensive in Marmaris to buy the paints I am wondering now if I should wait till I get somewhere more economic to do the full epoxy barrier thing and just apply some more Micron 77 over the old Micron Extra.
Regards
Wayne

[krissteyn]

Help ???
Thanks for all the previous info here.
I am in Cyprus , have taken the old shyte off down to the previous barrier coat which appears to have been a west system epoxy over the soft gelcoat.
No osmosis but the old barrier is holy and not continuous - probably 50 % .
was hoping to re-barriercoat with interlux 2000 and fare out the numerous dips n bumps.
Q. I will obviously do a test to see compatability , but what else is out there - 2000 is damned expensive here and I have a 36' catamaran (2 hulls - ouch)

thanks in advance

Kris SV Footprints