# Thinning polyurethane to make a wipe-on



## Tinyshop (Sep 1, 2007)

Anyone know if I can do this? I really don't see why I couldn't but I figured I'd better ask my fellow LJ's as I am sure someone has tryed this. Would I just use laquer thinner?


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## sbryan55 (Dec 8, 2007)

Of course. You could use lacquer thinner to do so but it tends to flash off pretty quickly. I generally use mineral spirits since it is less volatile than lacquer thinner. I generally mix oil base poly and mineral spirits 50:50. You will have to add more coats to build a finish since (1) you are only putting it on at half strength and (2) wiping deposits a thinner coat as opposed to brushing.


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## Tinyshop (Sep 1, 2007)

Hey Scott! I appreciate your prompt response! I figured that was the case but I needed some reassurance. I will go with mineral spirits then!


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## GMman (Apr 11, 2008)

Scott you should know this what do they use on furniture you buy like a dining table (light).


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## GMman (Apr 11, 2008)

Scott I mean the finish (varnish)


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## hObOmOnk (Feb 6, 2007)

Note: Polyurethane is an ingredient not a product.

Wood finishing products that contain polyurethane can vary greatly between brands. The amount of polyurethane actually used is not consistent across all brands. It is not uncommon for finishes that denote "polyurethane" in their label to contain other resins such as alkyds.

Other components, such as oils, flatting agents, levelers and driers can also vary greatly.

I use a polyurethane varnish that is 50% solids and is manufactured with pure oil-based polyurethane. Most consumer brand varnishes contain half that amount of solids and may contain a blend of cheaper ingredients.

If you dilute a consumer brand varnish and an artisan brand varnish with the same amount of mineral spirits you may get different results.

Start your wiping varnish recipe with a blend of about 1 part mineral spirits and 2 parts varnish. Only prepare enough to test and experiment on scrap wood until your technique achieves the results you want. Slightly increase the amount of mineral spirits if the mixture is a little too thick. Decrease the amount of mineral spirits if it is too thin.


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## trifern (Feb 1, 2008)

You can also add either tung oil or BLO to the recipe. Turpentine can be used instead of mineral spirits and will give you better flow and a higher gloss. The introduction to oils and or turpentine will slow the drying time.


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## PurpLev (May 30, 2008)

I also use mineral spirits to dilute poly oil varnish for wiping applications, and like Barry, I brush the first 1-2 coats in order to create a thick uniformed surface on which you can wipe poly for faster/cleaner additional coats (with no brush strokes)


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## Max10 (Aug 31, 2009)

Years ago I read an article by a professional finisher, Jeff Jewitt I think, who recommended a 1:1 mix of naphtha and PU. I tried it and liked it a lot. One of it's great features is that it dust dries so fast, about two minutes. As a result of the quick dry time is that it greatly minimizes dust imperfections. You'll have to apply probably six coats to attain is good sheen, but the application is so easy, you might enjoy it. So far as I can tell the finish sets up after a few days to be as hard as PU can be. By the way, if your front wooden door is a bit weathered and needs a coat or two of PU, no need to procrastinate thinking it'll be a bear to take the door down and finish it in the shop. With this recipe you can finish the door in place and even close the door after twenty minutes after each coat.


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