Uneven polyurethane finish

Reply

  #1  
Old 09-25-19, 12:32 PM
Member
Thread Starter
Join Date: Apr 2007
Location: Oregon
Posts: 186
Received 1 Vote on 1 Post
Uneven polyurethane finish

Hello all,

I am a furniture finisher novice. I need to protect a dining room table from water marks caused by glass condensation. I know I need to probably apply 3 coats of polyurethane with satin being my luster of choice. To practice for this I applied 2 coats of Varathane oil based polyurethane via brush to a small end table. The result was awful. The polyurethane was very thick but the can said to not thin the product, so I didn't. The finish did not self-level and therefore has a thick wood grain type finish to it (but it is not from the grain below).

Not wanting to ruin a small coffee table I took it to a furniture refinisher to apply 3 coats of satin oil based polyurethane to it. When I picked it up it was smooth as glass. I asked him if he used wipe-on poly and he said that he used a brush. I picked his brain a bit more but I could tell he didn't want to tell me his process.

Now I getting ready to finish the dining room table mentioned above but I am afraid to start because of the bad results I have had. Does anybody have any words of wisdom they could share to help me get a smooth finish?

TIA,
Blane
 
Sponsored Links
  #2  
Old 09-25-19, 12:45 PM
Group Moderator
Join Date: Oct 2004
Location: WI/MN
Posts: 19,308
Received 46 Votes on 43 Posts
Poly can usually be thinned a little bit. In fact, poly labeled for wiping usually has been. One of the problems I see when people apply poly is they tend to over-work it. Additionally, a light scuff sanding with removal of the sanding dust needs to occur between coats to promote adhesion of the layers.
 
  #3  
Old 09-25-19, 01:00 PM
Forum Topic Moderator
Join Date: Mar 2005
Location: USA - N.E.Tn
Posts: 46,059
Received 119 Votes on 106 Posts
You need to have the right brush also. With oil base varnish/poly that would be a natural bristle [hog hair] brush.
 
  #4  
Old 09-25-19, 01:14 PM
XSleeper's Avatar
Group Moderator
Join Date: Dec 2004
Location: USA
Posts: 23,104
Received 189 Votes on 178 Posts
Also known as a China bristle brush.

If you are starting with bare wood that has been stained, you usually want to apply a sanding sealer first. It also needs to be a product that is compatible with your finish... I'm this case poly. The sanding sealer can also usually be made by thinning your poly 50:50. (This is a good reason not to thin the poly you use as your finish excessively- it may not be as hard of a finish if you thin it too much!)

If you are going over a previous and unknown finish, you might want to apply a coat of sealer such as Zinsser Seal Coat, which is a dewaxed shellac, which provides a good bond between 2 dissimilar finishes (Your poly and whatever was used before you).

But imo, no way I would be brushing furniture. Furniture quality finishes can usually only be achieved with spray equipment.
 
  #5  
Old 09-26-19, 12:07 AM
Marq1's Avatar
Member
Join Date: Sep 2016
Location: USA MI
Posts: 4,320
Received 91 Votes on 82 Posts
Go find a Woodcrafters store and pick up a high quality water based urethane that is made for furniture and quit using that general use oil based stuff.

You will be amazed at the quality of the finish!
 
  #6  
Old 09-26-19, 08:22 AM
Member
Thread Starter
Join Date: Apr 2007
Location: Oregon
Posts: 186
Received 1 Vote on 1 Post
Thank you all for your helpful replies. I gather the following:

1. Despite what the can states it sounds like thinning it is what I need to do to allow it to self-level.

2. I will be applying the polyurethane over an unknown finish so I will first put a coat of Zinnser Seal Coat.

3. I will use a natural bristle brush (I think I did but I will confirm).

4. I will do a light sanding between coats for adhesion.

5. I understand to get the best quality finish I would need to spray but this table is going in our vacation rental and therefore a brush finish is good enough, especially after seeing what the furniture refinisher guy did with a brush on another table.

6. Water based poly. The refinisher I went to said water doesn't hold up as well as oil. I also read that online. Perhaps the high quality one you reference does. What brand do you recommend? What is the advantage of water based besides no VOC's and water cleanup?

Thanks again,
Blane
 
  #7  
Old 09-26-19, 08:44 AM
Forum Topic Moderator
Join Date: Mar 2005
Location: USA - N.E.Tn
Posts: 46,059
Received 119 Votes on 106 Posts
I have limited experience with water based polys although I did use one that was a 2 part [catalyst] that seemed to hold up well. I don't remember the brand name.

Generally speaking oil base coatings dry to a harder film than their latex counterpart. Oil base poly will deepen the stain and/or colors naturally in the wood. Water based polys don't change the color any - just give it a sheen. Water based polys dry quicker.
]
 
  #8  
Old 09-26-19, 10:14 AM
XSleeper's Avatar
Group Moderator
Join Date: Dec 2004
Location: USA
Posts: 23,104
Received 189 Votes on 178 Posts
The best thing about any oil based product is that it's supposed to be slower drying so it can self level. Water based coatings often get tacky quickly and so if you are brushing it can leave brush strokes if you don't work quickly or if you overbrush it. You don't want to overbrusg any type of finish.
 
  #9  
Old 09-27-19, 01:27 AM
Group Moderator
Join Date: Oct 2004
Location: WI/MN
Posts: 19,308
Received 46 Votes on 43 Posts
I've switched to just about only latex/water based paints but I'm still an oil based poly guy.
 
  #10  
Old 09-27-19, 05:27 AM
Marq1's Avatar
Member
Join Date: Sep 2016
Location: USA MI
Posts: 4,320
Received 91 Votes on 82 Posts
The refinisher I went to said water doesn't hold up as well as oil.
Please tell me this wasn't your local big box store paint "pro"!

You can debate all you want but until you give it a try I can only make suggestions.

Water based products like anything new have their growing pains and it takes a lot of time to reverse initial performance flaws.

Hope you all know your car is now painted with water based paints!

Brand is "General"!
 
  #11  
Old 09-30-19, 06:20 AM
Member
Thread Starter
Join Date: Apr 2007
Location: Oregon
Posts: 186
Received 1 Vote on 1 Post
Hello all,

Thank you for all the follow-up replies and for the brand name. I think I have enough information to try again. I sure hope I get better results that my first venture into using polyurethane to protect a table top.

Blane
 
  #12  
Old 09-30-19, 03:42 PM
the_tow_guy's Avatar
Group Moderator
Join Date: Feb 2001
Location: SW Fla USA
Posts: 11,808
Received 29 Votes on 23 Posts
I switched to Min-Wax wipe on poly several years ago for most of my projects. I rarely brush a finish on.
 
  #13  
Old 10-01-19, 02:30 AM
Forum Topic Moderator
Join Date: Mar 2005
Location: USA - N.E.Tn
Posts: 46,059
Received 119 Votes on 106 Posts
I've never used the wipe on poly, since it's thin I assume it requires more coats to build up the finish ??
 
  #14  
Old 10-03-19, 05:35 AM
Member
Thread Starter
Join Date: Apr 2007
Location: Oregon
Posts: 186
Received 1 Vote on 1 Post
Hello all,

I took all the advice given above and ended up with great results on my dining room table. I think the biggest help came from the quality of the polyurethane I brushed on (4 coats). I used General Finishes water based satin finish.

I am very happy. Thanks again for all the help.

Blane
 
Marq1 voted this post useful.
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
 
Ask a Question
Question Title:
Description:
Your question will be posted in: