# Applying polyurethane on old trim without sanding



## New_builder (Mar 11, 2013)

Hello all, been reading good threads here for a while.

I just bought a house which is finished in all oak trim (base trim is 3 1/4"), the house is ~45 years old and the trim is very dull looking, even dry looking.

To me it seems this trim was stained without any coating put over it.

The previous owners painted a few times and there are speckles of paint on every piece of base and brush marks on the sides of the trim around the doors and windows.

I am getting ready to paint several rooms. I would like to take the trim down, paint and put it back up. But before putting it back up, I want to clean it up a little.

I took down one small piece and used steel wool with some mineral spirits and the paint came off pretty easy. After it dried I took some Minwax polyurethane (oil based gloss) and coated it using a foam brush. After drying it looked much better than it did before, but the polyurethane didn't seem very hard, it came off with my fingernail.

Maybe it wasn't dry yet, I let it sit for 24hrs...

I was thinking about sanding down every piece and re-staining, but not only am I on a budget, I don't have any help so that seems like a huge task for one person.

My question is, is there a way or process to accomplish what I am trying to do, does it even make sense to do this?

Thanks.


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## tcleve4911 (Dec 16, 2006)

First of all...did the drying time help with the poly adhesion.?
I think you need to get that part solved first.


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## Leo G (Oct 16, 2006)

You might try this

http://www.wmbarr.com/product.aspx?catid=32&prodid=91


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## Steve Neul (Sep 2, 2011)

Let it dry for a couple more days and see if the finish is adhered well. Cleaning it with mineral spirits may not have been strong enough of a solvent if the wood had any kind of wax on it. Temperature may also be a issue. If it was 50 degrees or lower it would take a long time to dry. 

If it turns out the finish just needed more time to dry, I would suggest you use a very soft natural brush to put additional coats on. Also apply the finish with as few brush strokes as possible.


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## New_builder (Mar 11, 2013)

Thanks for quick responses, I did have a typo in my response, I meant to say I will wait 24 hrs then check again, and maybe a few days even.

Also, the temp was about 50 degrees most of the day at least in my garage so maybe that is playing a part. The temperature is going to drop this week also.

I just thought of this, but IF I determine to use the mineral spirits or something else like what Leo G suggested, would it be a pain to apply the polyurethane with the trim already hung? That way I don't need to remove it.

I would be fighting gravity and there might be more chance of runs I suppose.


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## GoIrish (Jan 29, 2012)

Leo G said:


> You might try this
> 
> http://www.wmbarr.com/product.aspx?catid=32&prodid=91


+1 this works well. Strips dirt and grime and softens the finish so next adheres well. Do it in sections since it seems to reduce it effectiveness over a few hours. By the next day it needs to be reapplied.


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## Leo G (Oct 16, 2006)

That's what the deglosser is all about. Ease of refinishing. It says it's good for deglossing poly. I'd find a pc of trim that you don't normally see, like the inside of a closet and try it on that. If it works great, if not, you won't care so much and will have the opportunity to try something else without screwing something up that is quite visible.


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## Steve Neul (Sep 2, 2011)

If it were me since you don't know the history of how the woodwork was taken care of, I would wash the woodwork down with Dupont Prepsol Solvent in addition to any other cleaning product you might use. It's a wax and grease remover available at most places that sell automotive paint. If you're going to use thinner to clean the woodwork and it doesn't have a protective coating on it, it would be better to use lacquer thinner, frequently changing rags. Mineral spirits is too mild of a solvent. 

As far as applying the poly while the woodwork is hung, that shouldn't be a problem. You should start by masking off the wall surrounding the woodwork. Then when you apply the poly you don't want to put a real thick wet coat on anyway. Use a very soft natural brush and brush it on as thin as possible with as few strokes as possible. You kind of apply it and move on. The more you brush it, the more air gets into it and it sets up faster and makes more brush marks. It's better to put more thin coats on than a thick coat.


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## HowardAcheson (Nov 25, 2011)

Couple of hints;

First, let the trim fully dry for at least 2-3 days after you use mineral spirits to clean it up. 

Second, Poly varnishes have a relatively low degree of adhesion and only develop their full adhesion after 2-3 weeks of curing. In fact, oil based finishes will continue to cure and off-gas for a long time but the majority of their curing will be over in 2-3 weeks.


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## Rick Mosher (Feb 26, 2009)

You might want to consider a wash coat of dewaxed shellac as a seal coat first. Shellac sticks to almost anything. You can buy Zinnser Seal Coat at the Box stores and thin it 100% with denatured alcohol. After the seal coat dries scuff sand with 320 grit Fre-cut 3M sandpaper and then apply your polyurethane finish.


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