I am finally getting around to putting new wood in my 56 F100. I have sanded the wood smooth and read that I should thin the varnish 50/50 for the first two coats. I looked at some Spar varnish but it said "don't thin". Any suggestions on which product to use and whether to use water or mineral spirits based products. Is varnish better than polyurethane? I want the oak to show it's characteristics but at the same time have good protection.

 

This subject has come up a number of times and there are plenty of opinions.

First you need to go to the MAR-K site and look at their test results on finishing products and processes. They have made quite a study of it and have some very good results. Here's the link:

MAR-K Classic Truck Parts made in Oklahoma City, USA

And not to be lazy, but I'm just going to post the last two bed finishing threads to save typing - good info:

https://www.ford-trucks.com/forums/8...od-finish.html

https://www.ford-trucks.com/forums/7...d-install.html

Have fun!

 

I will agree with Julie. As far as varnish vs. polyurethane it boils down to what youre comfortable with. None of the products are good if proper prep isnt done. With oak find a compatible sealer to raise the grain, sand, and put your topcoat on. Seal top , bottom and ends. I personally dont care for varnish because of the drying times. Good luck.

 

If you are not spraying it, might I suggest that you consider rolling it on with a "purdee" weeny roller. It was suggested to me by a cabinet maker, and worked great for me. It came out looking like it was sprayed on.

 

six coats of Helmsman spar urethane by Minwax, using the above method.(purdee weeny roller)

https://www.ford-trucks.com/user_gal...113996.520.390

 

Thanks for all the advice. It sounds like the process is more involved than I initially thought. I still have some questions though, Spar varnish says "don't thin" on the label, can you still thin it so it soaks into the wood?
If you soak in Watco will or Tung oil will it significantly darken the oak? Thanks for all the links by the way.
Chris

 

The process is kind of a "pay me now or pay me later" kind of proposition. If you really want a nice result that will last and not turn black, then it will pay off to do the extra steps now.

Tung oils and WATCO are available in colors and shades. But the regular clear WATCO is like water, and it will not darken the wood any more than a clear varnish or laquer.

If you use the Watco or tung oil THAT is what will soak into your wood and form an internal finish inside it. It is what will be your best prevention as far as the mildew that forms in oak pours and will keep the wood "supple." Don't spare the oil in the process, and I would definately take the time to "wet sand" it on. That will help fill those pours with oil and sanding dust. You won't see that, but it will seal them up.

The Varnish is actually put on to protect the oil and provide a "Sun Block" for it. After oiling and letting the oil dry for a few days and then oiling again, there shouldn't be a whole lot of room for the varnish to soak into.

I don't see why thinning would hurt it and I would think that if you sprayed it you would have to. If you thin it I might be tempted to use a higher end poly reducer available at automotive paint stores rather than off the shelf paint thinner/mineral spirits.

 

I went with the Pelucid and Spar Urethane per the Mar-K site's suggestion. After one year of sitting on the shelf in the garage, it is holding up well!