sweetwater epoxy paint ==need advice

[tank watch]

Sweetwater epoxy paints recommends that after the paint cures for 7 days, to use a non-sudsing ammonia wash of the painted surface for aquaculture use. The problem is I can't find non-sudsing ammonia. Do you think vinegar would yield the same results?

[kureinha]

I've been doing a plywood epoxy build. I have some sweetwater epoxy for the out coats (black). I'm also interested in any epoxy treatments.

Also, I've heard that Sweetwater really smells. I've been using WestSystem Epoxy so far which is pretty mild IMO. I've been doing the work inside in a room isolated from the rest of the house. Even in the room the fumes seem pretty mild for an epoxy. Did you work with Sweetwater inside? If so did you wear a respirator (charcoal filters I'm guessing)? Also, can you do multiple coats in a day like with WestSystem (e.g. 1 day apply base coat with fiberglass, wait ~2hrs apply 2nd, wait 2 hrs apply 3rd, wait >24 hrs, sand continue- all work was done on horizontal surfaces at time).

[tank watch]

I used the West system as well. Sometimes I wore a 3M mask ( a nice one with replaceable filters) and sometimes nothing. I found the paint to be much worse. Working in the garage was my only option. I waited only a couple hours between coats of paint, just long enough so the first coat was touchable , yet tacky. I didn't sand the sweetwater paint. I only got 2 coats out of the gallon, so the tank will look a bit ugly until coraline begins to grow. The paint cures to what feels like rubber, so sanding would be interesting...I hope one of the other guys will chime in on what they did as a final step.

[kureinha]

I may need to invest in a 3M mask or hope for some warm weather and move shop out into the garage or porch.

Did you brush on or spread your coats of Sweetwater?

I spread the first coat of West System Epoxy then brushed on the next two coats.

[tank watch]

brushed everything. lots and lots of those cheap brushes. after 30 to 40 minutes you can just throw them away

[dsandfort]

I don't think the blush from the sweetwater would be soluble in vinegar (acetic acid). You probably need the ammonia to disolve and remove the surface contamination. I found non-sudsing at a local grocery but it took several trips to find an unscented one.

Be careful. The ammonia is a strong irritant and it will get your eyes/lungs fast. You can get ammonia respirators (which I used) and run lots of ventilation.

[Fiziksgeek]

Along the same lines, what do you guys recommend painting the outside of the tank with? I know Dasndfort, you used a spar varnish on the outside so people would know that its a wooden tank. I am not so worried about this, and thought a paint of some sort would give better UV protection than a varnish, and would likely be cheaper. A good varnish can cost as much, or likely more than the Sweetwater paint itself.

Any recommendations??

Sorry if I'm hijacking! :-)

[dsandfort]

From the West System manual. I've used the LP on boats-it's good but not for a one-time/first-time user.

Coating types

Latex paints are compatible with epoxy and they do an adequate job of protecting the epoxy barrier from UV radiation. In many architectural applications latex paint may be the most suitable coating to use. Their durability is limited.

Alkyd finishes-enamel, alkyd enamel, marine enamel, acrylic enamel, alkyd modified epoxy, traditional varnish and spar varnish-offer ease of application, low cost, low toxicity, and easy availability. Their disadvantages are low UV resistance and low abrasion resistance.

One-part polyurethanes offer easy application, cleanup and better properties than alkyds. They are also more expensive and some may be incompatible with amine cure epoxy systems such as WEST SYSTEM epoxy, although 207 Hardener may offer better compatibility. Test first.

Epoxy paints are available in one-part and two-part versions. Two-part epoxies offer many characteristics similar to the higher performance polyurethanes. They are durable and chemical resistant, but offer limited UV protection compared to the linear polyurethanes.

Two-part linear polyurethane (LP) paints offer the most durable protection available. LP's are available as pigmented or clear coatings and offer excellent UV protection, gloss retention, abrasion resistance, plus compatibility with epoxy. However, compared to other types of coatings, they are expensive, require more skill to apply and present a greater health hazard, especially when sprayed.

Bottom paints are available in a variety of formulations. Most bottom paint systems are compatible with epoxy and can be applied directly over a prepared epoxy barrier coat. If you are unsure of compatibility or have curing or adhesion problems with a specific bottom paint, use only a primer recommended for that bottom paint over the barrier coat. Follow the recommendations given for preparation of fiberglass surfaces. Other paints, including marine LP's and primers, are not recommended for use below the waterline.

Primers are usually not needed to help a paint film bond to epoxy, although interfacing primers may be required with some specialized bottom paints and high-build primers are useful for hiding scratches or flaws in the substrate. If the instructions on your paint or varnish recommend a specially primed surface, follow the recommendations given for fiberglass preparation. Self-etching primers do not work well on an epoxy coating because of epoxy's chemical resistance.

Polyester gelcoat is a pigmented version of the resin used to build fiberglass boats and other products. Gelcoat is sprayed into a mold before the glass fabric and resin are applied to provide a smooth pre-finished surface when the part is removed from the mold. It is not often used as a post-production finish coating, but it can be applied over epoxy and is useful in some repair situations. Refer to 002-550 Fiberglass Boat Repair and Maintenance, published by Gougeon Brothers, for detailed information on patching gelcoat over an epoxy repair.

[tank watch]

dsandfort: thanks for stopping by. I used your thread as a guide for my tank. MY local glass tank builder suggested that I remove the sweetwater paint and epoxy in the area where I wish to silicone the glass. He said it would be best in contact with the fiberglass. What do you think? Sand it down or will I have problems with adhesion?

[dsandfort]

Yep, I remember your handle. You must be getting close to water. Glad the fiberglassing is done???
I put the silicone directly on the fiberglass/epoxy. I just roughed up the final coat of epoxy to give it some "tooth". When that cured, I painted with Sweetwater and let that dry. Then washed with the dreaded ammonia and let that dry. Finally, I put a big cove of silicone all around the inside of the glass over the Sweetwater. I could draw it better than I can explain it.

Del

[kureinha]

dsandfort- Thanks for chiming in. Great info.! Are you going to be celebrating the 1yr anniversary of your tank? I guess you could celebrate when it was first filled... Man you really know your paints/epoxies. I'm a bit behind "tank watch" but with any luck I'll be adding Sweetwater in a week or two. So these tips on the ammonia are perfect.

[tank watch]

dsandfort: So, silicone right on top of the sweetwater? No need to remove paint in that area? Or did you say you did not paint the area intended for silicone?

Yes, my large piece of glass is ready for pick up. I added a smaller window in the side for the kitchen, but it broke during tempering , so a slight delay with that.

[tank watch]

self bumping mechanism

[dsandfort]

Oops, sorry, not very attentive.

Silicone on fiberglass/epoxy/glass first. Let it set up and trimmed the silicone to a nice bead. Then painted Sweetwater up to the silicone. Then more silicone over the old and coving up the Sweetwater.

[tank watch]

thanks dsandfort. I will be sanding away some paint then. That sweetwater paint seems kinda soft and rubbery when it gets a bit thicker.
I found sudsing ammonia and clear ammonia at the local grocery. I shook the sudsing ammonia and it bubbled up like a soap bottle. Then I shook the clear ammonia and it made what only appeared as air bubbles...took that one to the house. Thanks guys, always a pleasure...Matt

[kureinha]

Okay, I've got a complete knucklehead question.

The Sweetwater can says that the "pot" will last 8-10 hours once mixed. Does this mean that I need to mix small batches? Did you guys do all you sweetwater applications at once and apply it on vertical & horizontal surfaces? I've been doing one side at a time with the West System epoxy (i.e. apply 3 coats to one horizontal side then next day turn the tank and epoxy another horizontal side). I've only been painting horizontal sides.

When I built a 120 epoxy tank awhile ago, I used a 2 part epoxy for garage floors from Homie Depot. I mixed it up and it lasted for months.

Before reading the instructions and seeing how long the pot would last, I was planning to mix up a whole gallon and do 4 applications. Day 1 apply two coats to the back (while laying tank on its back making it horizontal). The next day turn it on its side repeat. Turn it on its other side then repeat. Now add the glass like dsandfort mentions, let silicon cure/dry, then sweetwater around glass.

Am I making this too complicated? I'm thinking that you guys mixed the whole gallon and applied it to all surfaces vertical and horizontal.

To conserve epoxy, did you only apply it to the viewable sides (left, right, back, and around glass for UV protection)? I'm wondering if it should be applied to the tank bottom (inside) and inside of the overflow box. It seems the purpose is to color the tank, add additional abrasion protection, and help protect from UV.

[dsandfort]

Pot life is just that. Once you mix it, you got just so much time to use it. Air temp will determing the range but use it or lose it.

I was able to get 2 complete coats on all interior surfaces from 1 gallon (560 g tank). If you decide to mix small batches, be durn shure you maintain the proper proportions of part A and B. Otherwise, it may never cure.

It's just like paint. Use it on all surfaces, vertical and horizontal. I don't recall much running or sagging.

Good luck guys. But, be careful. this is some volatile, stinky stuff.

Del