Proper way to sand, seal and poly with oil based product - for hardwood floors
I have a 120 year old brownstone and am refinishing two rooms that needed a light sanding. The pro doing the job wants to use a water based sealer and immediately apply oil based polyurethane. I thought the sealer was supposed to be oil as well and that it was important to wait a day until the sealer was dry. Please help as they are somewhat insistent that they want to seal and poly the same day and I do not have enough floor left to have to do this again. (Not to mention the ordeal of doing it all).
lwbgeupvt
in General Discussion 3 years and 8 months ago
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andriywww1990 | 3 years and 8 months ago
OP, i have done a little reading since i posted that last reply last night.
i would not have brought the name bona up myself but it has been mentioned here so be aware that Bona states on their website that the Bona Water Based Sealer is made to be used under Bona water based product. with that statement alone, as a professional, i would not use that product under an oil finish and i would not waste my time calling bona to ask them if it can be.
Bona does make a fast drying oil modified product. it says it is for use under their oil modified and water base products but if one were to call them, they may find it may be acceptable for use under other manufacturer’s oil base product (they may state that they cannot guarantee it) but it might be worth the phone call. i believe oil modified product use water as a vehicle; i once used an oil modified paint about 5 years ago (i prefer real oil based product outside).
keep something in mind if something happens and you end up using an oil modified product that uses water as a vehicle (and i am still against using anything with water under oil for other reasons): yes, the water will go into the wood – and yes, some moisture will disperse and might hang around and it will want to get out. but so long as the initial coat is dry and whites over when sanding (that is how we know a coat is dry) and all successive coats white over, the finishes should be dry enough. keep in mind, people like us have been trying to keep water out of wood for hundreds of years and no matter what we seal it with it finds its way in, swells the wood, even when it is sealed, and leaves – without pushing the finish off. In my opinion, the issue with failed finishes may not be the water or mineral spirits remaining down in the wood from the first coat (so long as it whites over when sanded) because it will disperse and move anyway; wood breaths like this all year long (ever notice how the floors creak more in the dry heating season? or a door swells?). the issue is the successive coats; the successive coats are where something still wet can become trapped under even more coats and cause failure later. Some people might debate that with me a little and in truth, i might actually know less than many people do about failed finishes because having followed manufacture’s directions (with adhesives and finishes) all my life, i have never had a finish fail and have never had to analyze such a situation (i have had to analyze other contractors failures and it is not easy to figure out what they did wrong – though usually seems to be poor surface prep). that said, always wait until one coat is dry before applying the next one.
i could be wrong with something: a day ago i did not even know that water based sanding sealers existed and i did not know bona makes one (this new found knowledge is not going to change my life in any way). i still do not believe they should be put under an oil finish: Unless your contractor has been doing this forever and has a track record to prove it and will guarantee the finish and replacing the floor if the finish fails, even 5 years from now, i would move him off any idea of any water base sealer. if he insists (he won’t; once you ask for the guarantee, you will get all sorts of back peddling and double talk), YOU call the manufacturer and see what they recommend (i am 57 and have been working with finishes and other things related all my life and still call manufacturers). If you do not want to make the call, post the name of the product on here and i will call for you and tell you what they said.
do you want me to tell you a trick so see if your flooring contractor is a real flooring contractor? ask for his insurance certificate and call the insurance company and see if they cover floor sanding and refinishing. if he does not have insurance, show him to the door. if his insurance says they do not cover wood floor refinishing show him to the door. because of all these issues and all these products, some that are not compatible with others, flooring has been and is even now so, more specialized. the insurance companies are aware of the issues and they do not all insure flooring work.
stevecym | 3 years and 8 months ago
OP, If the contractor goes to use the bona sealer and the directions state to wait until the following day to screen the floor off, see if they will switch to the alcohol based sealer. It can be screened off pretty soon after applying and coated as soon as it is screened.
Oil based sealer made by mixing spirits and finish might take 6 hours to dry. Give or take.
Cutting it with toulane may speed it further. .
And i still doubt I would put oil over the bona water sealer. I have never used a water based sanding sealer anyway (so maybe there is something i am missing) and whenever using water based product, I used the first coat as the sanding sealer.
Also, if staining is involved, it might be better screen after the first full coat so as not to damage the stain.
A good contractor should be able to address these issues and more.
Augustiner | 3 years and 8 months ago
Btw. Water based sealer, eg. Bona will raise the grain of hardwood floors and needs to be sanded lightly the next day before applying a finding coat.
This is printed on the product, so the idea to immediately apply a finishing product is certainly not the way to go
andriywww1990 | 3 years and 8 months ago
bob, things that we do not touch tend to hold the latex over oil better. Priming does not hurt. but a lot of times where you see latex paint peeling off of doors – either painted or varnished, that is because the old oil coat had not been sanded lightly with like 150 and not been primed. years ago, we were told “do not do it”. back then, i did not always ask questions because i was not always in a position to and the people telling me may not have known the why.
stevecym | 3 years and 8 months ago
Basic coatings street shoe. It’s a commercial product for retail wood floors Commercial price as well. But worth it.
Water has come a long way and in 1998 if you had asked me if I thought i would use water based floor finish in my house in twenty years, i would have said no. Now, that is pretty much all I would use.
cate | 3 years and 8 months ago
In any case, I would use four coats of best-quality water-based poly, not oil. Allow adequate drying time between coats and it will last forever. We’re going on twelve years and it is still as good as the day it went on. I wouldn’t use oil based because it takes forever to dry and you cannot be in the house until it stops off gassing.
RobertGMarvin
in General Discussion 3 years and 8 months ago
Steve,
I assume your caveats about not using oil over water-based coatings only apply to coatings over wood. I’ve successfully used latex paint on my walls over the oil-based paint I used to demand.
andriywww1990 | 3 years and 8 months ago
so what whoa is saying is why we do not recoat any finish – oil over oil, water over water – until the previous coat has fully dried. the wet product is always trying to escape. it leaves the previous coat soft. the first time i did a bar top in manhattan i was told “you make sure the previous coats are dry or someone will drop a bottle on the bar and it will chip off and reveal something that appears soft and it can happen years later”.
but this putting oil over water base or water over oil. people my age were told never to do it. never ever (well, we were told that oil paint was ok over latex). but in recent years some people, possibly younger people with new ideas, are beginning to say that it can be done; a tech person at a polyurethane manufacturer told me it can be done so long as the old poly had been dried and cured for years. i recently visited the Epifanes facility in Maine and was talking to the tech guys there and i asked them, what do you all think of this thing of maybe fixing an old finish by going over it with a water base or an oil over water and they agreed, “some people are doing it, but we do not recommend it”.
time may tell us something different and in most cases, with all the epa regs, i do not see oil products going over water based, but water based being made to slap on oil based. as for myself, i doubt i will be doing it in this lifetime.
andriywww1990 | 3 years and 8 months ago
i called two flooring places. the first one was smaller and i think the idea of using oil over water – even if it had dried for months – sounded foreign to him so he admitted he had never heard of such a situation. so i called PC Flooring and i asked them “you have water base floor sealer?” and i knew he would say yes and did. but then i said “is there a water base sanding sealer that can go down under an oil base product the same day?” to which he replied “oil and water don’t mix” and i said i am a woodworker and that is my belief as well, “but is there a water base sealer that oil can go over in two weeks and he said “no”.
OP, something is wrong with what you have been told and unless that is alcohol sealer they are talking about – and people use it a lot and i have used it and would still if i had a need, you need to find another contractor.
markwalker | 3 years and 8 months ago
Any water based finish will cause the wood to absorb some of that water. The application of an oil based product over it right away will keep at least some of the water from evaporating. The water wants to come out so it has to go somewhere and can make the wood change dimension or cause the finish coat to flake off I confess that I never tried water based stains or seen what happens but it doesn’t make sense logically to me. You might get away with it in the short term but in the long term it will be problematic.
andriywww1990 | 3 years and 8 months ago
even though i do not use water base products in my work, i now will use them in my home. i should know if there is a water based sealer that oil can go over, the same day. i will make a phone call to a flooring finish retailer and get the truth and report back.
andriywww1990 | 3 years and 8 months ago
augustiner, that may be true. but the question the op has is using the two different products in the same application and on the same day.
op, it sounds like they want to move on it and oil slows everything down. listen, there are premium water base products out there – so why not move to those. well, firstly, water base has come a long way since it was introduced in the 80’s ( i did not touch it until 1997 and it was a long time before i used it regularly). but to top it off there are things like Basic Coatings Street Shoe. i use it. i did a stair case with it in 2012 and had the people send me a photo of it last year to show (on here) that it looked brand new, not a scratch (i did my own kitchen with it last year). these products have tint in them to make them look like oil and a couple more drops of tint can be added to give it a more yellow amber look (if your floor guy does not know about tinting finishes, he is not a floor person. tinting a finish is a pretty basic concept). and two coats could be put on in a day where as in humid weather like t his, 24 hour dry times may not be enough with the oil. and do not fall for marketing: do you know what i mean by that? everyone on here touts “bona”. Bona is a mass market product sold in home depot (what i mean is it is a good Home Depot Product but home depot will not seek out real quality). i work with wood and finishes all year long, want to guess how many times i go into home depot a year? do you want to guess how many times a year i buy a wood finish in home depot?
as for the Basic Coatings Street Shoe i mention. it costs more. but if i were the contractor i would pay that difference just so i can move on to other jobs. the humidity, maybe you have ac, but the humidity right now will slow any oil job down – they might not be able to recoat but every other day. ac will help if it is working right. dehumidifier.
something else that might help. if the contractor has not told you EXACTLY what products he or she will be using and i mean manufacturer and the specific product, they should have written that into the quote. for us to help you on here, you would have to then bring that information to us on here. i am still trying to figure out if there is a water base sealer (is he making his own sealer using a water poly and will he put oil over it? or is there a water based sanding sealer i do not know about? i have not found one and this all sounds like a recipe for disaster but hey, i resisted water base poly for decades so maybe there is something or some process i do not know; i tried an outdoor water base product out doors and dropped it fast and will not recommend it to anyone). (if i am wrong about this oil over water thing, this contractor has every right to be very angry with what i am saying here; i did some reading last night and still want to know; maybe there is something i do not know; i might be sticking my neck out here)
there is another red flag here about your contractor. so i bet he or she did not specify what products he would be using by name and you therefore can not tell us. but another thing, there should be no reason at all that you have to come to this board and confirm something your contractor is telling you. if you are that suspicious of your contractor’s ability, you have the wrong contractor. if he did not specify those products in the quote and has not begun work yet, rip the quote up and find someone who will walk into your house and sell the job by specifying each and every product they will use and be willing to put that in writing and tell you about the product and the process to the point you know they can do this in their sleep.
i work on exterior doors and would be horrified to find a potential customer on here reconfirming something i said to them as i sold the job; it means i did not do my job explaining something that i do every day of the week. if they had to come on here behind me, something is wrong with me, not them.
Augustiner | 3 years and 8 months ago
Water based sealer and finish is the way to go
stevecym | 3 years and 8 months ago
Are you sure it is not an alcohol based sealer? I have not really heard of the water/oil combination but unwaxed shellac, which is alcohol based, yes. And yes, if it is alcohol, it dries in minutes.
The idea of using oil over water or vice versa seems odd to a lot of us who recall a time when all poly was oil based. But you never know; when I bought the house I am in, I would only use oil. If I do any of these floors over with a full sanding, it will be a high end water base product.