thinning epoxy

thinning about 10% will flow a little better, but the viscosity of the paint has nothing to do with the adherence. what are you spraying?

rolling floor coatings. For some reason I am have it in my brain that thinning something thick like epoxy will help it bite better to concrete. Will a scuff sand between coats be beneficial for 2nd coat adhesion?

well the next one I am doing is a pizza place floor (not like pizza pit or hut but a nice place). I have the day before and of thanksgiving to do it. Grinding off rustoleum epoxy which is over acid stain (both are failing, not due to moisture). Do I need to be worried about grease penetrating the concrete farther than grinding will take down? Will grinding off the epoxy be real hard? I don't want to etch because not enough time for the concrete to dry.

Thinning epoxy, depending on the type, will only reduce the solids content and make the film thinner, however may help drive the system deeper into the concrete. If you over thin, it compromises the resin and weakens the resins manufactured intentions and strenght. Grease will penetrate bare concrete. You must clean first. Imbedded grease contamination takes a while to occur. There are microbial degreasers that have enzymes in them to "eat" grease. There are de-greasers that turn hydrocarbons, blood, fat, oil, and grease into a soapy solution and can be rinsed away down a drain without environmental contamination. As for grinding, I personally own an On Floor Prep 16 Grinding Machine. OnFloor 16 - Concrete Floor Prep - Hard Wood Floor Refinishing - Exterior Wood Deck Resurfacing This machine and many like it will quickly remove high performance epoxy, thin mil systems, stains, mastic, etc with excellent results and with very little dust. I have installed over 200 100% solids epoxy floors over the last 4 years, and this machine has ground every one. Why is the floor failing? Not moisture? What is it? Contamination, inter-coat adhesion, compatability or incompatability of the systems. If you are doing a pizza shop and need to thin the epoxy for the first coat, remember the odor may contaminate food. What kind of system do you plan to use? Is a waterborne polyamide epoxy a consideration?

To be safe, I would read the epoxy's data pages and see what they say about reduction. Tinkering with the composition of these coatings can compromise their performance. Do your homework before you play chemist.

grind floor to a surface profile of minimum of 80 grit. first test for sealers using acid. reaction equals no curing compounds. test for moisture content. I use a Tramax non destructive concrete moisture encounter. concrete should measure 4% or less. larger floors with more than 5000 square feet should have anhydrous calcium chloride test. floor needs to be de-greased prior to any grinding. we use M83 Oil & Grease Emulsifier @8:1 mix ratio. floor may need to have second degrease step if pockets of grease are released from grinding or blasting. all bare floors are primed with Moisture Tolerant Waterborne Epoxy Primer Sealer @ 900 sq ft per 3 gallon kit to a maximum DFT of 2 mils. this is applied by mixing the epoxy, poring it opposite the grind profile, squeegee the floor with an 18" mid west rake gray straight rubber squeegee wearing spikes. after that, back roll with 3/8" nap high quality shed resistant cover. allow no more than 24 hours for epoxy to cure, and topcoat after 4 hours of dry time. 100% solids is applied using same method. squeegee and back roll in the opposite direction of the primer. broadcast aluminum silicate aggregate using a Scott's grass seed spreader at the lowest setting if anti-slip is needed, and back roll over the aggregate to encapsulate. have porcupine roller handy to back roll any bubbles that migrate to the surface if epoxy heats up concrete and creates bubbles from trapped air. our epoxy, for a 3 gallon kit spreads at 500 sq. ft per kit @ 8 mils. I always measure out a 500 square foot box to insure I am putting on 8 mils, or if the epoxy needs to fill in a greater surface profile, I may spread it thicker. any pockets or divets in the concrete can be repaired with a matrix made of 100% solids clear and an aluminum silicate garnet aggregate to make a concrete patch or slurry. cracks should be ground out and primed before applying top coat. key cuts should be made around drains or impact areas such as sills and transitions, especially if tow motors and forklifts are in use. a clear aliphatic urethane can be used for UV resistance, chemical resistance or additional abrasion resistance. I put that down at 2 mils. sit back and enjoy after a minimum of 24 hours. 48 hours is best for high abuse floors.

dang Nace, sounds like your the person to talk to about 100% solids floors. No one around here seems to know much or is confident about them. The floor is getting shot-blasted at 9pm till 1 or 2 am. So you are are saying we should degrease the bad spots first? We were going to lay the floor at 8 am (thanksgiving day). We only have until the next day at 4 pm before it gets used. Do we have time to prime and lay the floor still? When they spill flour, it acts as an abrasive. Do I need to put a catalyzed urethane to protect it?

Preparation should always include SSPC-SP-1 Solvent Cleaning before any prep. If you have an environment that has had animal fat, hydrocarbon based grease or oil or food prep where vegetable based oils were used, you should pre-degrease before shot blasting to avoid blast media embedding grease and contaminates into the fresh concrete. Some say that shot blasting removes all these contaminates. I did a bakery floor, about 6000 sq ft that had 20 years of embedded grease, flour, and butter in a section, and had to use mastic removal blades to shave off the grease, then degrease several times to get it clean. A black light is used to determine the presence of grease. Just like the one we had in our bedrooms from the 60's on Jim Hendrix posters. After blasting I would prime immediately after insuring that all shot media has been removed with a magnet. I like the P41 Waterborne Epoxy Primer Sealer Finish. This is a 30-45 minute epoxy that spreads very far and can be topcoated within 4 hours depending on surface and air temperature. I like it to be a little tacky so that the 100% solids marries to the primer and forms a monolithic system. This system depends on the blast profile that is left. If they blast to a 3 mil profile, then you have to put down a primer that is 3 mils thick, than at least an 8 mil 100% solids system. Not sure you want to use a urethane in a food prep environment. If it has to be put back in service that quickly, stick with 100% solids. Watch your surface, humidity and air temps. Too cool or humid and you risk the epoxy blushing (amine blush), flashing, or not cross linking and staying tacky. Hope that helps. Call me if you have any questions or need help with anything.