Getting rid of amine blush

[DayTripper]

I've read much about having to use green scrubbers to wash hulls that are fiberglassed using epoxy, to get rid of amine blush. (cured epoxy)

Since boats are normally built indoors, often in garages, how does one wash the hull without water getting on the garage floor and then spreading out to get everything on the garage floor wet? Not to mention the garage floor getting super slippery by the water and soap agent used being a safety hazzard.

I'm asking because if I coat my boat's hull with epoxy and let it cure prior to applying the cloth, I would need to scrub the hull and rinse it off in our carport.

I realize that cloth can be laid over the bare wood and then epoxy applied, but I'm asking about applying epoxy on the bare wood first and letting the epoxy cure. Then laying the cloth on the hull and appying another coat of epoxy.

[nrs5000]

What are you trying to accomplish by putting down a layer of epoxy before glassing? Seems like that is going to make the fiberglassing process more complicated than it needs to be.

[StevenBauer]

No soap needed. Just water. I don’t see how a few cups of water would hurt a garage or carport floor.

[neil.henderson]

No soap needed. Just water. I don’t see how a few cups of water would hurt a garage or carport floor.

Yes, you don't needs buckets of water to remove amine blush - just a panful will be fine. I prefer to use warm water rather than cold.

Regards Neil

[stromborg]

I agree with nrs5000's comment that you don't need to lay down a layer of epoxy first. You are just adding extra steps to the process. If you feel you must, epoxy has a window of cure time (varies by brand) and as long as you work inside the window you don't need to worry about amine blush. The blush is also usually associate with cool moist curing environments, pick a warm day when the trades are blowing and you should be just fine.

[DayTripper]

What are you trying to accomplish by putting down a layer of epoxy before glassing? Seems like that is going to make the fiberglassing process more complicated than it needs to be.

I did a test and fiberglassed a scrap piece of plywood at noon. Applied PeelPly on top. Squeegeed the surface and it was very smooth with the cloth and PeelPly fully saturated but all excess epoxy had been removed by the squeegee. After curing, a lot of small raised blisters (about 1/16" wide, 1/4" long and 1/32" high) had occurred only in the center area of the plywood. The perimeter (about 3" of the plywood was smooth with no blisters.)

After peeling off the PeelPly, the small blisters are resin above the cloth, the cloth had not been lifted. However, the smooth perimeter when sanded with 120 grit is really nice and smooth without cutting into the glass cloth. I really liked the surface left by the PeelPly with no amine blush and very easy to sand smooth without multiple fill coats of epoxy needed.

My evaluation is that out gassing caused the epoxy to create the small blisters in the center area of the plywood. Since the outer 3" perimeter is blister free, it appears that outgassing was released by the edges of the plywood so no blisters formed on the perimeter.

I've read that pre-coating the hull with epoxy can prevent outgassing problems. I'm also going to try the same test after sunset when things are cooling off to see if the tiny blisters still happen. I'm going to get it right on test pieces before I glass the hull of my boat.

[DayTripper]

No soap needed. Just water. I don’t see how a few cups of water would hurt a garage or carport floor.

Yes, you don't needs buckets of water to remove amine blush - just a panful will be fine. I prefer to use warm water rather than cold.
Regards Neil

I thought that rinsing using a garden hose would be necessary to get all of the amine blush off since using a green scrubber is recommended. I assume that you both scrub with a green scrubber but wipe off using a rag that is constantly rinsed in a bucket or pan of water.

Thanks.

[DayTripper]

I agree with nrs5000's comment that you don't need to lay down a layer of epoxy first. You are just adding extra steps to the process. If you feel you must, epoxy has a window of cure time (varies by brand) and as long as you work inside the window you don't need to worry about amine blush. The blush is also usually associate with cool moist curing environments, pick a warm day when the trades are blowing and you should be just fine.

Please see my reply to nrs5000.
Thanks for the help.

[wizbang 13]

Put three coats of epoxy on the garage floor first to protect it from the fire hose required to remove the blush.

[Dave Hadfield]

You could wash the amine off a canoe with a gallon of warm water -- not a big deal for any floor.

[Breakaway]

What others said.

Do a section at a time. Wipe on wet scrubby; wipe off dry towel. Only a little will hit the floor.

Opinions vary on pre-coating plywood with epoxy. I have found that it prevents the ply from soaking up resin and creating dry spots in the first pass with the cloth. Also makes it easier to slide the dry glass around and reposition if needed.

Also, you can pre-coat, and then plan to apply the cloth and resin once the resin is firm, but still green, without any worry of amine.

Kevin

[Autonomous]

I have never pre-coated a panel but if I did, I'd take a cabinet scraper to it while it was still green to knock down any high spots and put on the glass right away.

[nrs5000]

I did a test and fiberglassed a scrap piece of plywood at noon. Applied PeelPly on top. Squeegeed the surface and it was very smooth with the cloth and PeelPly fully saturated but all excess epoxy had been removed by the squeegee. After curing, a lot of small raised blisters (about 1/16" wide, 1/4" long and 1/32" high) had occurred only in the center area of the plywood. The perimeter (about 3" of the plywood was smooth with no blisters.)

After peeling off the PeelPly, the small blisters are resin above the cloth, the cloth had not been lifted. However, the smooth perimeter when sanded with 120 grit is really nice and smooth without cutting into the glass cloth. I really liked the surface left by the PeelPly with no amine blush and very easy to sand smooth without multiple fill coats of epoxy needed.

My evaluation is that out gassing caused the epoxy to create the small blisters in the center area of the plywood. Since the outer 3" perimeter is blister free, it appears that outgassing was released by the edges of the plywood so no blisters formed on the perimeter.

I've read that pre-coating the hull with epoxy can prevent outgassing problems. I'm also going to try the same test after sunset when things are cooling off to see if the tiny blisters still happen. I'm going to get it right on test pieces before I glass the hull of my boat.

In that case I agree with the several others here who have suggested puting on the glass while the seal coat of epoxy is still green.

[DayTripper]

You could wash the amine off a canoe with a gallon of warm water -- not a big deal for any floor.

Jon boat, not a canoe but I get the idea. Thanks.

[DayTripper]

What others said.

Do a section at a time. Wipe on wet scrubby; wipe off dry towel. Only a little will hit the floor.

Opinions vary on pre-coating plywood with epoxy. I have found that it prevents the ply from soaking up resin and creating dry spots in the first pass with the cloth. Also makes it easier to slide the dry glass around and reposition if needed.

Also, you can pre-coat, and then plan to apply the cloth and resin once the resin is firm, but still green, without any worry of amine.

Kevin

Thanks for your always helpful advice Kevin. I've decided to definitely pre-coat with epoxy to minimize the chance of any bad air bubbles lifting the cloth. The extra work is a non issue for me since my labor is free and we enjoy building a boat don't we? Extra cost of epoxy will be minimal since less epoxy will be needed when applying the cloth and it should be easier to saturate the cloth with the pre-coat underneath and also avoid epoxy starved areas. I had not thought of it being easier to slide the dry cloth around to reposition but now I see that that is also a good advantage.

I'll let the epoxy get hard and scrub the entire hull using a scrubber, buckets of warm water and wipe dry with a towel. I want a dry, stick free hull that will allow the cloth to slide easily for repositioning.

[DayTripper]

I have never pre-coated a panel but if I did, I'd take a cabinet scraper to it while it was still green to knock down any high spots and put on the glass right away.

Thanks for your perspective. I'm going to let the pre-coat epoxy get hard, remove any amine blush, sand and then apply the cloth. Dry hard pre-coat epoxy will make it easier to reposition the cloth to avoid wrinkles.

[DayTripper]

In that case I agree with the several others here who have suggested puting on the glass while the seal coat of epoxy is still green.

I'm going to let the pre-coat epoxy get hard, remove any amine blush, sand and then apply the cloth. Dry hard pre-coat epoxy will make it easier to reposition the cloth to avoid wrinkles.
Thanks though for your perspective.

[DayTripper]

After the pre-coat epoxy dries hard, I think I'll wet sand to get rid of amine blush instead of using a green scrubber. That will also sand the epoxy in prep for applying the cloth. Or is just using a green scrubber effectively the same as sanding?

[Benny]

If you seal the ply with a coat you should let it cure for a week or so before sanding. And no you will not achieve a mechanical key without sanding. To remove amine I have just sprayed water on and wiped it off with paper towels, be thorough and that seems to work just fine

[Autonomous]

IMO you are creating extra work, mandating a week downtime and giving away the chemical bond.
Green does not equal sticky or even tacky.

[wizbang 13]

If you seal the ply with a coat you should let it cure for a week or so before sanding. And no you will not achieve a mechanical key without sanding. To remove amine I have just sprayed water on and wiped it off with paper towels, be thorough and that seems to work just fine

Have you never gotten a drop of epoxy on a thing by accident that popped off easily because it did not have a “mechanical key”?

[DayTripper]

If you seal the ply with a coat you should let it cure for a week or so before sanding. And no you will not achieve a mechanical key without sanding. To remove amine I have just sprayed water on and wiped it off with paper towels, be thorough and that seems to work just fine

I'm thinking that "wet" sanding will eliminate the need to wait a week for full cure to avoid green epoxy dust in the air. I will of course be wearing nitrile gloves while wet sanding.

[DayTripper]

IMO you are creating extra work, mandating a week downtime and giving away the chemical bond.
Green does not equal sticky or even tacky.

Extra work is totally not a concern for me. If I "wet" sand the pre-coat the next day and then apply the cloth the following day, is that still considered "green"?

[stromborg]

I don't remember which brand of epoxy you are using. I use System 3 who say you have 72 hours to recoat with more epoxy before sanding is required. West Says you can recoat until the base is no longer tacky and/or firm enough you can't dent it with a thumbnail.

[Todd Bradshaw]

Wet sanding epoxy to try to remove blush is absolutely stupid. One of the reasons you use the scotch brite pads is because blush quickly plugs up sandpaper, making it worthless. you are also wrong thinking that wet sanding green epoxy makes it non-toxic. In terms of exposure, getting it on you wet might even be worse.

I have usually found that the biggest drawback to pre-coating is that it raises the grain, making it much more difficult to move the cloth around on all those little stickers. If you are doing any sanding between the various parts of the glassing process you are doing it wrong. Any and all sanding should only take place after full cure - like 7-10 days.

[Autonomous]

Green is the stage when the epoxy has become a solid but is not hard yet. It is easy to cut, scrape, etc. but clogs sandpaper and is toxic to breath the dust. Your fiberglass should slide on it. If you don't have a cabinet scraper, get one, they are brilliant at smoothing green epoxy.
Different formulations will have different time windows. Suggest you do some test pieces and make up your own mind.

[ShorelineJohn]

Wet sanding will make a bigger mess than using water to clean amine blush, and is really for making something really pop once you lost all sense of perspective. To wet sand and then recoat is wasting time but if you want a good work out.
I have pre-coated fir plywood sometimes to keep the plywood from starving the cloth of resin, but see Todd's comments, I had that problem.

[DayTripper]

I don't remember which brand of epoxy you are using. I use System 3 who say you have 72 hours to recoat with more epoxy before sanding is required. West Says you can recoat until the base is no longer tacky and/or firm enough you can't dent it with a thumbnail.

I'm using West Systems epoxy. I remember reading about being able to dent the epoxy with a thumbnail to allow recoating.
Thanks.

[DayTripper]

Wet sanding epoxy to try to remove blush is absolutely stupid. One of the reasons you use the scotch brite pads is because blush quickly plugs up sandpaper, making it worthless. you are also wrong thinking that wet sanding green epoxy makes it non-toxic. In terms of exposure, getting it on you wet might even be worse.

I have usually found that the biggest drawback to pre-coating is that it raises the grain, making it much more difficult to move the cloth around on all those little stickers. If you are doing any sanding between the various parts of the glassing process you are doing it wrong. Any and all sanding should only take place after full cure - like 7-10 days.

I'll wait 7 days after pre-coating before I sand. I've decided to pre-coat to minimize the chance of air pockets forming under the cloth due to outgassing, and also to prevent epoxy starvation due to wood absorption. Yes, extra work but I don't mind the extra work. Thanks.

[DayTripper]

Green is the stage when the epoxy has become a solid but is not hard yet. It is easy to cut, scrape, etc. but clogs sandpaper and is toxic to breath the dust. Your fiberglass should slide on it. If you don't have a cabinet scraper, get one, they are brilliant at smoothing green epoxy.
Different formulations will have different time windows. Suggest you do some test pieces and make up your own mind.

Thanks for taking the time to advise. Appreciate it.

[DayTripper]

Wet sanding will make a bigger mess than using water to clean amine blush, and is really for making something really pop once you lost all sense of perspective. To wet sand and then recoat is wasting time but if you want a good work out.
I have pre-coated fir plywood sometimes to keep the plywood from starving the cloth of resin, but see Todd's comments, I had that problem.

I'll wait 7 days after pre-coating. Then remove the amine blush using the scubber and water. Next day when dry, I'll dry sand to remove the hairs and get a keyed surface. Thanks.

[DayTripper]

Wet sanding will make a bigger mess than using water to clean amine blush, and is really for making something really pop once you lost all sense of perspective. To wet sand and then recoat is wasting time but if you want a good work out.
I have pre-coated fir plywood sometimes to keep the plywood from starving the cloth of resin, but see Todd's comments, I had that problem.

Other than the extra work, I think the pros out weigh the cons for pre-coating for a novice like me. Guess for pros, it's needless extra work.

By the way, Russel Brown in his youtube video said that he pre-coated the two hulls prior to glassing to minimize outgassing. He also said that it helped prevent outgassing since he was heating the hulls during the winter. He had no problem with pre-coating the hulls.

Thanks.

[Todd Bradshaw]

Remind me again, what sort of boat is this? It doesn't really matter, pro or beginner, the idea of pre-coating, waiting a week and then sanding before finishing the job makes no sense at all. If you really want to pre-coat, then go for it.

Just understand that it can make sliding the cloth around somewhat more difficult - but it is hardly a deal-breaker. There simply isn't all that much cloth sliding needed during the initial draping part of the job.
Applying and saturating the cloth as soon as your pre-coat has hardened enough that you won't disturb it makes drastically more sense - and will likely make a better boat with less work and no mid-job sanding.

I still think the peel-ply may be your biggest danger. As you have already seen, problems which hide under that stuff until the resin hardens and it is too late to correct them is not a formula for good glass work.

[cyclone]

If using WEST System epoxies, consider using the 207 hardener, less amine blush to begin with. No harm in precoating then removing blush from cured layer and applying fiberglass later. You end up with a mechanical rather than chemical bond to the first layer and you need a well sanded surface to bond to. Overall more time, effort, and epoxy. Precoating helps pre cutting or pre assembling when you can take advantage of a horizontal surface.

[jpatrick]

One can talk and debate the idea of pre-coating all day long and never really know what the result will feel like. But if a simple test is done on a scrap of similar material, then the conjecture gives way to real knowledge. Sure, it's just one test, one example. But it's also real personal experience gained for little time and material expense.

Jeff