Replies

1. 
   uncommontree | Sep 17, 2002 02:47am | #1

   Dale......

   Yes you are right. Walnut will lighten over time and exposure to sun light. Cherry will darken with same.......From what I have read and learned is this will happen anyway what one can do is slow down the process. I have heard Watco oil ( natural) helps slow down ageing, also acrylic based varnish helps preserve wood origional color. There may be some other ways also so I will watch this post to see what others have to add. IMO I feel the natural ageing process of wood only gives it more character. This is why I avoid using stain only as a last resort. Rick

1. 
   jonsherryl | Sep 17, 2002 03:34am | #2

   Rick, you're right that cherry darkens when exposed to sunlight, while walnut will tend to bleach out. A UV blocking varnish will retard (but not totally stop) these woods from changing color as they age...Their long term patinas are also impacted by oxidation.

1. 
   uncommontree | Sep 17, 2002 04:36am | #3

   Jon .........

   Could you in your words tell more about oxidation. I know some but maybe you could teach me more. Allways interested in learning new things. I have worked in the antique world off and on for some 20 years and I am always interested in what others have learned along there path. Thanks Rick.

1. 
   jonsherryl | Sep 17, 2002 05:07pm | #4

   Rick, I'm not enough of a chemist to give you the details, but the patina forming process in woods is a very complex thing. Wood derives its heartwood color based on the chemistry of its extractives and these extractives vary from species to species. In most woods the pigments result from the polymerization of the extractives (they develop color as they form more complex molecules.) In most woods, exposure to free oxygen in the air causes the polymerization to occur...but oxygen is not the only trigger. Some species, such as cherry, contain compounds that are photosensitive, while the chemistry of other species might react with other gases or compounds in the environment. For example, the tannic acid in woods like oak will react with ammonia and also even with various metals to form a wide range of pigments.

   To complicate matters, the long term patina of most woods results from a combination of more than one chemical reaction...for example, even when light causes the dominant pigmentation, oxidation over time also contributes. This seems to be the case in cherry. Light dramatically affects the heartwood color by creating reddish brown pigments, but oxidation also seems to contribute in causing some yellowing over time, as evidenced by the sapwood in cherry. Cherry sapwood lacks the photosensitive extractives found in the heartwood, so it can't darken like the heartwood when exposed to light. However, it does yellow over time as a result of the oxidation of other compounds. The heartwood probably also develops some of these yellow pigments, but they are less obvious. Being masked by the heartwood's more dominant dark pigments, the yellows tend to give the wood that warm amber glow seen only in well aged cherry.

   ...And finally, in many woods the pigmentation created by the polymerization of its extractives is fugitive, meaning it will break down after long exposure to light (sun bleach) or it might undergo further changes with long term exposed to UV light or various gases in the atmosphere (as in purpleheart)...And the great mystery is that virtually every species has its own unique patina process.

   Edited 9/17/2002 10:15:19 AM ET by Jon Arno

1. 
   DaleKrech | Sep 17, 2002 06:11pm | #5

   Jon,

   Thank you for the great explanation!

   While my original inquiry concerned a friends blinds that would have considerable exposure to the sun, I am working on a different project utilizing both Cherry and Walnut.

   I'm building a dining room set, for myself. The top will be resawn, matched cherry veneers, running across the top. The "field" will be bordered with solid Claro Walnut. I've started dimensioning the Cherry, and have noted the terrific range of colors in the freshly planed Cherry. I put some turpentine on the boards to approximate a clear finish, and I like what I see. The room in which the table will sit, is on the North side of our house, and receives no sunlight. Understanding that color change in Cherry is affected by both UV and Oxidation, what finish would you recommend to give me the greatest degree of stabalization of the original colors.

   Thanks again!

   Dale

2. 
   jonsherryl | Sep 17, 2002 07:42pm | #7

   Dale, a UV blocking varnish would be your best choice for stabilizing the color...But with cherry, the beautiful long term patina it develops is one of the primary reasons for using this wood. If the table won't be exposed to a lot of direct sunlight, the walnut shouldn't bleach badly...so I'd use a finish that allows the cherry to do its thing. There are a number of choices; a penetrating oil or shellac really brings out the best in cherry...but you may want a harder finish for a table top. Table tops are the only place where I use a polyurethane varnish (otherwise I use the old solvent based alkyds.) I don't like poly because it is difficult to rub out.

   ...Hopefully you'll get other finishing suggestions as this thread continues.

3. 
   DaleKrech | Sep 17, 2002 08:56pm | #8

   Thank you for your help!

   I've played around a little with some "home brew" finish recipes. I did a coffee table 8 years ago with a 50-50 mix of Watco and poly. I wiped on 6 thin coats, light 400 grit between coats and finally 4/0 steel wool. Finish has held up great, and was fairly easy to apply.

   In a recent FWW article, I read about a 50-50 mix of Naptha and fast dry varnish, I found that on some small boxes, the secrets are thin coats, and freshly made "brew". After a couple of months, previously mixed finish stayed tacky.

   Comments?

   Dale

4. 
   davamoore | Sep 17, 2002 11:34pm | #9

   Dale, like John I tend to be reluctant to put anything on cherry and walnut that might affect the natural color of the wood.  For cherry, I tend to go with a simple oil/varnish topped with paste wax.  A cherry end table I built about 18 months ago, that sits in a north-facing window, has finally come to a really beautiful color/figure.  It tanned up pretty quickly, but the richer, deeper color has taken this long (so be patient... it will happen).

   As for walnut, I've found that kiln-dried walnut tends to be a bit on the gray side of the scale, for me.  I'll sometimes give it a coat of orange, dewaxed shellac, just to warm the tone up a bit.

   I realize that you're talking a dining table that will see lots of use.  My understanding is that oil-based polys tend to yellow a bit over the long range, while water-based polys tend to stay "white" but are sometimes a bit less clear (someone please correct me if I'm wrong).  You'll need to decide what's most important to you.

   DavidHmmm... the garden or the workshop today?

5. 
   booch | Sep 18, 2002 12:27am | #10

   Great info.

   Just a thought on the Poly. I tend to use Polyurethane varnish as a top coat after pumping up the visual with Natural Watco. I just put one coat of Watco on to wet the surface wipe it off and a few days to cure then I go to the topcoat.

   Thin versions of Polyurethane like the Flecto Varathane Professional are not as ... phlegm like? It really goes on lightly flows well and allows a normal buildup. As for the rubbing out (I take that to be removal of the dust particles and the curtains, drips, etc.) I take water with wet/dry 200 to 600 grit sandpaper on a block of maple and sand floating on the water adding water as you start to suction down. Wipe, rinse, repeat til you get to the level of smoothness required. I'm talking about a coffee cup of water here.

   Recoat with Flecto after the water evaporates and redo the sanding with water til it is dead flat. Final coat gets no sanding just my best effort with every lightbulb in the house trained on the surface.

   Benefit to this is you can develop a glass like finish that rivals Formica for hardness. Unfortunately the pores of the wood and grain surfaces are no longer textural. Depends on the finish you are striving for. I use the same finish but fewer coats on sides of cabinets.

   Last benefit is you can do this wetsanding on the polyurethane within 8 hours or so of the previous coat. The water keeps the paper from loading up or leaving impressions on the surface.

   Like most, I've had enough wine bottle marks in my work not to tolerate any other finish on the topsurface.

   Thanks for slumming with us.

   Edited 9/17/2002 5:30:12 PM ET by Booch

2. 
   DaleKrech | Sep 17, 2002 06:17pm | #6

   Rick,

   Thank you for your reply!

   I also avoid the use of stains. I choose species for there natural look. In other words, if you want a different look, use a different wood. Right?

   I posted a follow up to Jon's last post. If you get a chance, maybe you can offer an opinion.

   Thanmks again!

   Dale

1. 
   uncommontree | Sep 18, 2002 04:46am | #11

   Dale.

   I have in the past combined Walnut with Cherry and found that in the beginning they looked well together but as each aged they became more and more the same color and stayed that way for what seemed like forever. Its like using Walnut with Butternut they will age to the point that one can not tell the 2 apart. Been there done that. I like the mix that Cherry and Maple achieve, a very nice look IMO. It does however sound like the table will be fantastic when it is done. My expression is only that , Through the years of combining woods in both trim and in furniture and cabinets I have developed my own tastes on which woods look the best combined.

   As far as finish I like using Velvit oil following there application instructions, allowing this to cure and applying a durable finish like a spar varnish. This is going to be a table top so it will need to be as hard a finish as possible. Even a marine spar in gloss will do the trick. Others have some great ideas also.

   Back a couple of years ago I did a home theater room 16x32, all the cabinets and trim were Walnut and Red elm. This room was fantastic, I used 6" elm crown and built a wall using elm and walnut with stained glass panels this separated the theater room from the outside entrance, the effect was awesome. Have fun. Rick.........