Campaign style desk finished

[Tapper]

Very nicely done - congrats! Unique piece; I'm certain you're daughter will cherish it always.

Doug

[kencombs]

Purpleheart eventually turns brown. Mainly from UV light IIRC. But there seems to be some variation on how fast. I've seen some boards turn pretty quickly. I've been working on this desk for like 2-3 years (I am blaming the time needed on two children and being the head of a PTA) and it was still pretty purple without a topcoat.

My daughter loves purple, so the color change could work in my favor as she potentially ages out of that phase.

Just wondering, if you want to slow the color change, maybe consider automotive clear coat.   They contain UV blockers which shield the base coat paint and the interlocking layer of clear/base from UV degradation.   Down side will be a really  shiny 'plasticy' look unless you do some dulling with abrasives.

I've played with it on cherry and walnut tests.   Seems to work, cherry doesn't darken as quickly and walnut doesn't lighten as much.   At least for short term testing.

[msweig]

I ended up using the UV resistant coating from Osmo to slow it down. We will see how well it works.

[tablesawtom]

Really nice work. I like the design. I will ne interested in how long it stays purple. Thanks for the tip on the finish. I am not trying to be difficult here but I know that spar varnish has a lot of UV blockers. What lead you to chose the finish you used? Real curios. I have wanted to do something in Purples Heart for several years. Your choice of finish might just put me over the top.

Tom

[msweig]

I thought of spar varnish, but the fumes are pretty nasty. I also wanted something I might be able to repair easily (I've seen what her sister has done to her desk, which is finished with shellac. At this point I'm figuring the desktop of both desks will probably.just be repaired/refinished when they are older and take care of stuff better).

Spar varnish might be a better choice, I just decided to try something different. I had asked in the finishing forum, and one person mentioned that some of the UV resistant finishes are softer (which might not be ideal for a desk). We will see how it goes.

[jteneyck]

Yes, spar varnishes are softer because they need to be able to expand/contract in exterior applications.  

Should anyone be looking for an indoor film forming finish that contains UV inhibitors, then look at SW's Kem Aqua Plus.  It has a dual UV package.  One component protects the finish from being degraded by UV, while the other protects the underlying wood, which is just what you'd want for something like purple heart. 

Note that the UV inhibitors in most varnishes are there to protect the varnish itself, not the underlying wood.  I don't know if that applies to Osmo, but it does for film forming finishes.  Unless it specifically says it has a dual UV package,  and says HALS, the underlying wood will still be affected by UV.  

John

[msweig]

Yea, the Kem Aqua Plus looked awesome when you mentioned it before.  But I was scared off by the size of the container and some stuff saying it wasn't the easiest to apply.