Two days ago I applied a coat of satin polyurethane on an oak floor which I had sanded down a year ago and brushed on two coats of polyurethane.
I applied the coat of polyurthane with a roller and I had purchased the roller specifically for this job as the label stated it was made for polyurethane. (big mistake).
The result was There were a lot of air bubbles and the finish has turned out prettty rough. The surface is kind of like a teenager’s face with a bad case of acne). there are a lot of small bumbs or pimples.
Yesterday I got a bright idea and I rolled on a coat of paint thinner over the entire floor and I was hoping this would soften the coat of polyurthane and it would blend together.
I see that it’s dried this morning and may have helped a little but I still have a floor with a lot of dried air bubbles and it looks pretty bed.
Any suggestions on an easy fix for this? The polyurethane is hard as a rock and it’s almost impossible to sand out these bumps with wet-dry sand paper on my hands and knees.
I am aware I can strip the finish and start over but I really don’t want to do that. This is the floor where I live and it’s not for a customer and it doesn’t have to be perfect.
I’m probably going to a tool rental store this afternoon and rent a floor buffer and see what I can do with it.
Thanks for any suggestions.
Replies
Buffer with a pad is where I'd start too. Clean up dust. Then I'd use a flat painters pad (4"x9" I think) with a pole for a handle. Works great every time...good luck... Buic
Try a low numbered screen on the buffing machine. You need to screen between coats anyway.
Use a lambs wool applicator in the field and a clean china bristle (it can be one of those cheap CB brushes...I love them) brush around the perimeter going in the same direction as the grain.
You might need to go through a few screens depending how rough and big the floor is but it should work.
Be floored
andy
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When we meet, we say, Namaste'..it means..
If you used fast-drying poly, it may have started to set before the bubbles could pop and close up. Try thinning the poly with the appropriate solvent.
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
Thank you everyone and yes fast eddie I did use the fast drying oil based poly. I'll do some more research here and thanks again
i'm dealing with similar problem currently. for me, the expensive sheepskin pads i bought for the pole applicator shed. i was so p***ed. for various reasons i decided to just sand by hand, aided by a nice heavy packet of sand from my son's sandbox, wrapped in heavy plastic, same size as a full sheet of sandpaper. just sat it on the sandpaper and "scrubbed" the floor quickly. it didn't take too long really, and worked well. i used 120 grit in worst spots and 220 elsewhere. this time i applied the next coat with a brush, and it looks much better.
Thank you and I appreciate all the advice and suggestions from everyone.I've about had it with polyuretane and I think it's difficult to work with. It's thick and sticky and the smell is sickening. A year ago I suffered through this process and had hoped the finish would last for many years. It didn't. There were places where the old finish had really dulled (these were not high traffic areas). Thanks again everyone.
dulled? immediately, or over time?
i'm really curious what brand you've had bad luck with-
Minwax Fast Drying Polyurethane - it's oil based and I paid $25 for a gallon at Lowes here in Wichita.
The dull spots are small or medium sized 8 to 10 inches or so and could be from me spilling my coffee.Could also be from my dog P*ing on the floor. No, now that I'm thinking about it there is a certain spot where I have cleaned up dog P and that area by the front door is just fine.Thank you again for the responses.
"dull spots could be from spilling coffee..."
LOL, so, like, have you ever mopped the floor then? :-)
i used Varathane Diamond wood Finish, oil base, in a rental house my dad owns out of town and loved how it went on and felt when set, but i don't live there and haven't had a chance to se how it's holding up.here, i couldn't get the varathane and went with Wood Pride oil base, made by zinsser. not happy about how it goes on-- was a mess applying with woolie pad, as mentioned, and when i went back to do touch-ups where i'd either missed a spot or sanded, the touch-ups from the SAME can dried dead flat instead of satin, which has never happened to me before. i kept the poly stirred during the process, but apparently it was a change in temperature between applications that caused the problem. am still trying to fix the mess and get it to match.
in future, i think it would be worth it to do a special order if necessary to get the varathane or the other product mentioned above.
That Varathane seems to be particular about re-coating too early. I rushed a second coat once and it really "went off" on me. The first coat was dry to the touch and had been on just under the amount of time spec'd on the can. But the solvents in the first coat must have still been active because the whole thing turned into a gooey mess. Didn't have the heart or time to sand off, so I let the mess dry for a couple of days and put a third coat on. Looks OK, but there is a definate roughness to the finish.
taking advice from names like fast eddy, sancho, M & M, hey I can't go wrong. Heh heh. Just kidding folks but some of the names in here are quite interesting.Thanks again for all the info - I looked at the instructions on the can and it says that paint thinner or mineral spirits is used as a solvent but that really didn't work for me 100% when I spread paint thinner over the entire floor. My project is oak flooring in combo living room and dining room. Its fairly big and I'm going to rent a floor buffer here in a little while.Thanks again and let's try to work on those names a little bit. I think you'd have more credibility if you had names like "master craftsman"
"Tool Man" "Bob Villa's Cousin Dennis" and what have you.
My suggestion on the solvent was to mix the solvent with the poly before you apply it to the floor. That will make it thinner ... less viscous ... so it will flow much easier and the bubbles will pop easier on their own.
Applying a flood coat of thinner to a cured coating of poly is a waste of time. There may be some products that you can apply that will re-dissolve the poly, but I think that's called paint stripper, and then you have a whole new set of problems.
I think that the off-the-wall screen names here are much more convincing than the self-agrandizing ones like "Master craftsman" and such. Besides, you can't judge a book by its cover.
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
thanks for the respect, Sharpblade!Fast Eddie said: "I think that the off-the-wall screen names here are much more convincing than the self-agrandizing ones like "Master craftsman" and such. Besides, you can't judge a book by its cover."
i have to agree. what's the point of a having a name like "mr fixit usa" if you roll on foamy poly, and pour thinner onto it after it's dry and cured? ;-)ps mrfixit- i know all to well that those packets of disks are $6 ea., but what was the total? we recently sanded all the wood floors in my 1300 sq ft house at around $400 for the sandpaper alone. that's one reason i opted to sandbag the fuzz out manually.
touche' and you're right msm if I were the expert I wouldn't be asking how to straighten out my messes. I guess I'm more like Tim Taylor on Tool Time.Anyway, I used three pieces of sandpaper at $6 apience and I called it quits. It's not perfect but it'll do.Looking back if I could have just applied one quality coat (over the top of the two existing coats) I would have been done yesterday and with a lot less work and expense.Now I'm looking at one more coat as a top coat and I think I'll be done.Hope this helps someone else - one last thing - I wonder if I could use the water based polyurethane as my top coat over the oil based? I'll go to the store tomorrow and read the label.Thanks again for the help everyone and I apologize if I insulted anyone when I commented about their name.
heck no, mr fixit. sorry, but water over the oil based -- just don't even think about going there.and for future reference, do not try to do one thick "quality" coat instead of 3 thin coats. with oil, you'll have a quagmire that never cures. even if you use water-based, it will pool and be problematic.let us know what quirky new screen name you change to...
WRT Water based poly over oil base poly.
Despite what MSM said (no disrespect here) it can be done, but there's a BUT (a big BUT may I say). The earlier oil based coats must be fairly well cured before you slop on the water based. That stuff will stick to anything, based both on what most manufacturers tell you ("dry, sound surface"), and my personal experience (been there, done that).
I bet your next Q is "how long for the poly to cure". Ah, this will be left as an exercise to the reader, but slopping paint thinner on it ain't gonna help matters for sure.
I noticed several people criticised me for applying paint thinner to the
polyurethane the day after I had applied the finish. Although it helped some, it didn't take care of the problem.One of the reasons I tried this is quite a few years ago I applied a brush on lacquer finish (Deft) and a few days later someone placed a glass of water on it and moisture entered into the finish. It looked cloudy.I called the company and spoke to a chemist and his recommendation was to saturate the finish with lacquer thinner. I did so and it worked and removed the foggy area. I think it softened the finish so that it could breathe and the moisture could escape?Thanks again for the input from everyone!
Mrfixit,The solvent trick works with lacquer because lacquer is an evaporative finish. This means that once the solvent leaves, the finish is hard, and done getting hard. Add solvent at any time (even years later) after application, and it reliquifies.Varnishes, however, are reactive finishes. After you apply them, the solvent leaves, creating a dry film. That dry film then oxidizes, becoming insoluble in the original solvent. If you flood freshly applied wet poly with thinner, it takes it up cleanly. Flood day-old poly with thinner, you get a mess, because it is only partway oxidized. Flood week-old poly with thinner, and you get a nice clean degreased surface on your cured varnish.Hope this helps.Bill
great info bill, thanks.
i am always confused by the difference between "varnish" and "laquer".
Thank you Bill and MSN. Bill are you by chance an industrial arts teacher? I'm just taking a guess because you are very knowledgeable about finishes.MSN I'm thinking about applying poly over shellac (oak flooring in a house built in the 1950's). Would it work? The old shellac floor is hard as a rock and has wear spots in the "hi travel" areas. I would like to apply a finish over the existing finish and without all the work and headaches of stripping the old finish, sanding the floor, etc.
all accounts are that you cannot put any kind of poly (water or oil) onto shellac, without a proper intermediate layer. you can read the extensive floor finishing and shellac discussions i've started here at BT, or you can fast-forward to the ultimate answer: zinsser's Seal Coat is apparantly the best for this job. i even called zinsser and discussed my plan in detail with the tech department and got the green light from them. but i had just sanded my floors (husband helped! wahoo!), was applying the shellac myself. if your floor is older, do you know what all it has on it? ie, what it's been cleaned and polished with, such as waxes etc? that may make a difference-
If you are going to poly over shellac and don't want to do the work it needs in prep, you should change your name from fixit to broke it.Shellac that is over thirty days and hard cured, can be overcaoted with poly but any floor that is years old and showing wear needs to be refinished to look and wear right
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Mrfixit,Actually I am an industrial arts teacher for 4 hours a week. I have been in construction for all my life; the teaching is a recent gig, and it is a blast. I teach a class on woodworking machine technology and shop layout at Palomar College. My students range from their early 20's to 70's, with the majority being 50-ish wood hobbiests who work in other fields by day.My secret weapon is that my dad is a chemistry professor, retired. He taught me well in the sciences from a tender age, and it has really helped me in my life, both work and hobby.BTW, shellac is an evaporative finish, similar to lacquer. Alcohol will redissolve it at any age. In the old old days, shellac was referred to as "spirit varnish" because spirits (alcohol) was the solvent. This is confusing to us modern types, because shellac is in no way a varnish in the modern sense of the word. Ain't language great?Bill
Bill, thank you for the info on lacquer and shellac. In the 70's I graduated from high school and wanted to be an industrial arts teacher and I got my degree and taught for two years and left the profession.Part of my training was an interesting class on wood finished. We were required to sample 15 to 20 different wood finishes. We had sample planks of wood, oak and pine, and these boards measured about 3" by 6" and some of the guys drilled holes in the planks and hung them on the wall as a reference when considering stains, finishes, etc.It gave us an opporunity to try out finshes such as varnish, varathane, urethane, polyurethane, lindseed oil, and if I remember correctly one wood finish simply involved rubbing in numerous layers of wax.It was interesting to learn about open grained woods versus closed grain.Spray on Lacquer was a popular finish in high school industrial arts classes. It dried quickly and there were no brush marks. I remember going to work for a guy while I was in college. He had a contract to paint and finish the woodwork in a small home development and the homes were small, cheap and poorly made. I was 18 or so and needed a job and went to work for him.I remeber he would add water to paint as a way of trying to make it go further. I also remember varnishing quite a few mahogany doors with a paint roller. I don't rember having any problems with fuzz coming off the roller and I don't remember having air bubbles in the varnish.One last thing Bill. This is something that happened to me about 25 years ago. A relative hired me to help remodel a home. One day my job was to put a coat of varnish on a large built in bookcase. I opened the windows in the house but after a few hours I started feeling pretty sick from the varnish fumes.I finished working that day and felt light headed, upset stomach, and tired. I went to bed early that night and felt sick all night. I felt sick the next day and stayed in bed and slept most of the day.
I went to bed early again that next night and long story short I ended up staying in bed for about three days to recover "getting high" on warnish fumes.Several years later I talked to a doctor or nurse about what had happened and I don't remember the medical diagnosis for what had happened but they explained how serious these chemicals and fumes can be.On a related note I was kicking around the idea of buying epoxy and bathtub refinishing equipment and a business and someone told me "stay away from it - the chemicals are just too hazardous".
Thank you pete - I think I have both a hand scraper and a cabinet scraper somewhere in a box in the garage. I haven't used them in years.
I'll try either the hand scraper or the back of the saw like you've described. I think one of the shows on this old house demonstrated the use of a hand scraper and it's advantages compared to an orbital sander.Thanks again!
interesting to know, but i'd still be afraid to chance it on a big area like floors, without having considerable time and sample space for trial-and error first.
it's common practice, as far as i know, to only use oil over oil, and that's what the tech support reiterated when i was on the phone to Zinsser looking for a product to allow shellac-to-poly (i wound up using the zinsser Seal Coat in between).
thirty days more or less depending on temp and humidity, before I would overcoat oil poly with water besed
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Yes sir Mr Piffin, consistent with my experience.
Also the timeframe when the hardness of an oil based poly finish gets into the 90s%.
I like that varathene too
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Varathane makes an awesome product. Their paint is some of the best around!
You forgot to tell these kids to pick at the lambs wool pad before they use it cause I read somewhere in here one of them had the wool all over his job.
Ya have to pick all the loose fur off the pads first kids.
Also, using a roller is asking for trouble. I've done it many moons ago. Lambs wool pads arent really all that much money especially in the sceme of things, plus you can use them over and over. Thats the right tool for the right job!
I also find that going over your line of poly the last time with the tip of the pad on the back stroke makes it nice and smooth. Use thin coats also.
Like Sancho said you "can" use your ROS to sand. I've done that alot to screen between coats because I don't feel like renting a buffer for rooms under 400sq ft. Its just not worth it to me. By the time I go back and forth to the rental place I could be finished already.
Rollers are for painters by the way : )
Be wearing a resperator (yeh sure lol) ;: )~~
andy
The secret of Zen in two words is, "Not always so"!
When we meet, we say, Namaste'..it means..
I honor the place in you where the entire universe resides,
I honor the place in you of love, of light, of truth, of peace.
I honor the place within you where if you are in that place in you
and I am in that place in me, there is only one of us.
i put both my pads through the washing machine first, to really remove the loose fibers. then i let them air dry (the natural sheepskin took a few days), because i figured putting into the dryer might damage the fibers and make the shedding worse. then went over them by hand to check for loose fuzz. the natural skin still shed terribly; all i can figure was something about the poly loosened it up? possibly a flawed product? it was frustrating, 'cause i know what i'm doing just enough to have taken precautions.mr fixitusa, i'm guessing the varnish you rolled on years ago was thin enough that any trapped airbubbles popped on their own easily, especially if the varnish was slow to dry. polyurethane is thicker and the bubbles are more likely to get trapped long enough that the thin skin of poly hardens first, leaving "pimples".
a fuzzy pad works okay, because it stays in one position allowing bubbles to gravitate upward and the heavy poly to flow down. a roller, tho, keeps rotating and redistributing the bubbles to the bottom where they contact the floor.
I use that for trim. I pre-finished a bunch recently and noticed some bubbling on the back side, but a very smooth finish on the front side and edges.
You really need to get a polyurethane that is formulated for floors and high-wear areas. I had really good luck with Mautz brand poly. Applied with a roller and then "struck" with a china bristle brush.
Edited 11/11/2005 11:13 am ET by johnnyd
Id sand it, smooth, If its not a huge area I would use my ROS (dont laugh guys I did it before)
Then I would reapply the poly with the roller and do a small area at a time maybe 3' X 3' sq. Then tip it off with a brush and go on and do the entire floor that way.Long Live REZ.........ROAR
I used the same Minwax product recommended by paint dept at Home Depot and also got the pimples effect. Called Minwax and she said "If you choose to use this product again ..." Strange comment. Went to local paint store and told of my plight without naming brand. Paint store guy said let me guess "You used Minwax." Sanded and used Benjamin Moore brand. Also, did floors of two other large rooms with BM. No problems.
I just refinished my floors and one of the problems I see is that some products go on with air bubbles, but they smooth out and you have a smooth finish.I applied two coats of stain, one coat of sanding sealer, and two coats of shellac and I had air bubbles but they smoothed out this time and I have a nice finish.Sounds like you are happy with polyurethane, as long as you don't use minwax brand?Thanks for your information.^^^^^^
a Smith & Wesson beats four Aces
There is nothing wrong with that brand of poly, unless it had been on the shelf too long. I'm not sure, but I see clues to yourproblemI use a brush or lambswool. never did see a roller job I liked, but nonme as bad as you describe.Also, you need to sand or screeen, vac, tack, an wipe betwen each coat.And you need to do three coats anyway, so start sanding.
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did't want to dis anyone for using a roller earlier, especially since the dee was done, but i agree with piffin that using a roller to apply clear varnish is not a good idea. do not roll fast!, but even if you roll extremely slowly, the roller is aerating the viscuous liquid and you may as well have put it in a blender.
oddly, the cheaper applicator pad that i used out of town, a synthetic one, laid the poly down beautifully with no shedding.
I got the floor vibrating sander and some 120 screens and it looks like it'll do the trick. Costs were $32 for the machine for 4 hours and then about $6 per sanding pad/screen.Thanks for the tips on the other applicators folks I'll use one of them for the second coat!
Coming in late, has been pretty well covered so far...
WRT using a roller, good point MSM (capitalized for respect), IIRC many brands advise against it, says so right on the can. Not sure who could have said its OK?! Lambs wool is best as piffin said for oil base, synthetic best for water based.
WRT the stink, next time use water based poly. Different animal altogether in my book, but sometimes the way to go (no smell, faster application, easier application, easy cleanup...) My preference for my own house is the oil base, love that amber look.
Next time run the sheepskin pads through the washer. I did that and it turned out great.
to address the bump issue, a hand scraper - like the cabinet scrapers will knock them down and half sand the floor at the same time. though you'll be on your hands and knees for a while, it goes remarkably smoothly.
if you have an old hand saw you can use the back edge as a large scraper ( watch the teeth) or even a thick hack saw blade upside down. (by arching the larger scraper as you use it, blade remains ridgid enough to use on the pull or the push.
it'll warm up in your hand though.
oh yeah, you know when you want to 'fair' some bondo? use that hack saw blade the same way with the teeth down.