I am having an issue with a polyurethane finish on red oak floors. We had water damage in our house from a fire. We sanded all of the floors in the house with 36, 60, 80, 120 grit paper on a floor sander. The floors were stained. We then used zinsser sander sealer for one coat. We put on one coat of polyurethane cut with mineral spirits (2 parts urethatne, 1 part mineral spirits). On the edges of some boards, in only 3 of the 9 rooms (and not the rooms that were damaged), we are getting a light haze (almost looks like no urethane or a slightly discolored urethane) that you can see when you look at an angle. It is only on the edges of the boards where the seams are and soem ends. We sanded the entire floor with pole sanders and put on a second coat of poly cut the same way. The spots look better in one room, about the same in one room, and maybe a little worse in one room.
Any ideas what the issue is or how to fix it? Our current thinking is to try to sand down the poly in the 3 rooms with 320 or 400 grit on a random orbit sander and then apply a 3rd coat of poly throughout the house. Will this fix it? Are there other solutions?
We are trying to avoid refinishing the entire house again.
Help!
Replies
It is oil based, Minwax, Satin finish. The water damage occured mid february. The entire house was dried out and cleaned by a restoration company. The floors and walls all showed 8-10% moisture back in February. Some of the rooms have brand new hard wood. The wood has been in the house for months in a storage room, so it is more than acclimated. None of the wood in the rooms that are having the problem got wet.
We installed the new wood in 2 rooms 2 weeks ago, then I got stuck in Europe for work and delayed by the Volcano. We sanded Thursday, Friday, and Saturday. Stained Sunday morning, Sealed (Sander Sealer) Monday mid day (30 hrs post stain), first coat of poly Monday night (4 hours post sander sealer). I am really confused as to why some rooms are doing this but not all.
First, why did you use the Zinnser Sanding Sealer (really just a dewaxed shellac)?
When you stained, what stain did you use? If Minwax, did you thoroughly wipe off the excess after letting it sit for 15-20 minutes?
If I read your post correctly, you only have one coat of poly varnrish applied--and a highly thinned coat at that. It's not unusual for the first coat to not look particularly good. At least two full strength coats are required and three is actually better unless the product label specically says to use only two. I would scuff sand with a 220 sanding screen on a pole sander and then apply at least one full strength coat before doing anything else
Finally, a gray, cloudy look can occur if you did not thoroughly stir the flatteners into suspension. You should stir 100 strokes in one direction and then 100 strokes in the other keeping your stirrer in contact with the bottom of the can. Re-stir every 10 minutes or so during application. The final sheen is determined by the sheen of the last applied coat.
Howie,
Thanks for your reply.
We did not wipe off the stain. We brushed on a thin coat and have done this several times before without any issues. We just let it dry for a longer time. We also use the small cans becasue the larger cans have the low VOC that is a pain to work with and must be wiped off. The floor looked great after staining, it looks great when the poly is wet. It is jsut when it dries that you see the amrks along the edges.
We have 2 thinned coast of poly down now with some improvement in some rooms. The cans of poly were well stirred and the marks are only on board ends and seams, which leads me to belive it is a penetration issue with either the sealer of poly.
I used the sealer simply because that is the way I was taught by my Dad. He always uses it first.
We will try to scuff sanding a full strength (or at least much thicker) coat tonight.
Ii wonder if your floor was thoroughly dry from the water damage.
Not wiping off the stain could be a big part of your problem. It's not meant for excess to be left on the surface. The solvents in the poly, especially with added thinner, will reactivate the stain and lift it. A coat of Zinser won't be enough to seal the stain completely from the poly and it's solvents. A uneccessary step in my opinion and the alcohol in the shellac will also lift the stain. This can result in cloudyness in areas. There is also a good chance the stain didn't fully dry, particularly on ends and edges where more would accumulate and not have enough exposure to dry. You just got lucky in the past, may have had more drying time but you should always wipe that product.
Minwax is Minwax, it's the same product regardless of what size can it comes in. Many modern poly products are not exactly the same as they were just a few years ago, let alone in the distant past. It's not uncommon for handed down information to be out of date or incorrectly applied. There is a balance of ingredients in a can of poly. When you add something, it can effect that balance. For example, there is a specific amount of drier and a specific amount of light absorbers in a quart. By adding solvents, you reduce the proportions of these and other ingredients. Products may stand some alteration and still be acceptable but it's also possible to create an imbalance that will adversly effect the product. It's not likely the solvents you buy off the shelf will be the same as the manufacturers and in some cases they may be incompatible. Never listen to anybody, read the can, follow the directions. If you have questions, contact the manufacturer, if you don't and have issues, you are SOL.
If you frequent this forum, you will see a never ending string of posts where people are having problems with finishing. Most of the time, they have taken advice from a magazine article or someone they know, mixed this, did that and are now in trouble. Very often, they have done something fundamentally wrong in the process, such as you not wiping the stain. I'm not sure why folks think they can improve on the work of competant, experienced, coatings specialist, chemical engineers.
I'm sure you are anxious to get the job done and don't have time on your side. There really isn't anything you can do at this point but continue. The final top coats should reduce the visibility of your problem. Once the furniture is back, you'll probably be the only one aware of the imperfections. In 10 or 12 years you may have the opportunity to try it again. There is a lot more to it than buying a can of DIY product off a shelf and a big part is familiarity with a variety of products and experience. We've all been there and had our piece of humble pie. Welcome to the club.
hammer,
That was one of the best posts I've seen on any forum. Common sense, practical and informative. Great job!
I teach a fair amount and a lot of it's breaking it down to common sense.One thing I emphasize is "when all else fails, read the directions" Why many feel the need to alter a product is "somebody once told me...." Your statement of why folks think they can improve what the chemists and coating engineers produce should be the heading for this forum.
One of the finishes you'll see touted is the Maloof finish. Of course, I'd be a pariah by questioning it but it never made sense to me chemically. Like you said the properties and proportions of a coating are radically altered to what end? It's a great marketing tool though as it's a special mix. This is just the thing in my mind that makes finishing so confusing.
I really think you said it all. Great post.
Peter
Thanks all for your replies.
Most of what I did, was handed down. Grandfather to Father, Father to me.
My Dad specializes in stairs and stair railings. He always uses the same method we used and has no problem on the railings. We have used this same method on at least 3 other floors. I guess we were lucky. I think the coats were jsut too thin and when we used the lamswool applicators we ended up with a thinner caot than we would ahve brushing.
We sanded the entire floor with 220 yesterday and brushed on a full thickness coat of the poly. Sanding and brushing 3800 sq ft of floor may be the least fun woodworking activity ever.
It fixed the problem completely. There are no spots that can be seen. The floors look great. Especially the brazilian cherry in-lays we put in the rooms as borders.
As far as Minwax being Minwax, I am not completely sure of that. My understanding is that the gallon containers are now a newer low VOC mix. The smaller containers, I beleive, have the old, cheaper to make, higher VOC formulation. I could be wrong, but a few years ago somes tates changed their laws and required the companies to use formulations that released less volatile organic compounds. From my O-chem days the less VOC the longer it will take to "dry" or evaporate. In my limited experience the lower VOC formualtions are harder to work with. However, I only tried the low VOC once and have tried to go abck to the higher since then. It amy be the same stuff, but it behaves and smells very differently in my experience.
Thanks again for all of the help! I look forward to getting my shop finished once our house is back to normal and getting back into the fun wood working.
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