How long for green poplar to turn brown under varnish?

[mark mcfarlane]

Will green poplar turn brown under a clear-ish varnish (GF Arm-R-Seal in this case) over time?

How long? 6 months? A year?

I bought some poplar for shop drawer fronts and after 3 weeks in my workshop they are still very green.

They aren't going to get much if any UV after installed. I don't really want to 'sun them' for fear of warpage, which would defeat the 'browning' if I have to plane them further after sunning.

[Mike Henderson]

I don't know exactly how long it will take, but the green of poplar will turn brown. You just can't keep light from the wood, even with finish with UV inhibitors. I've used a fair amount of poplar and none if it has any green in it anymore.

Mike

[Cary Falk]

I have some drawers made from popular. They hardly ever see any light of day. They are still green after 10+ years. They are finished with water based poly.

[Jim Becker]

Probably hours in sunlight... :) Seriously, the greenish heartwood will turn brown relatively quickly unless they are locked in darkness like Cary speaks of. Oxidation and UV are what does that. There should be no harm in exposing them to sunlight. It's probably best that you do that after you've assembled the drawers or at least done final sanding of those drawer fronts and just flip them a few times to provide for even heating if you're concerned with wood movement. Doing this after all final sanding is important because otherwise, you'll expose more fresh heartwood.

[mark mcfarlane]

Thanks Mike, Cary and Jim.

I need about 2 days to complete the milling and finishing tests, then I can sand and put them out for a suntan early next week. I have about 15 drawers to front and a couple of them are going to require glue-ups (18" tall).

Flipping regularly is a great idea, I'll see if my grill spatula is big enough :). Hopefully it will stay dry next week. Today was nearly perfect weather, fairly rare for Houston, which is either hot, cold, wet, or some combination of those.

[Curt Harms]

Will green poplar turn brown under a clear-ish varnish (GF Arm-R-Seal in this case) over time?

How long? 6 months? A year?

I bought some poplar for shop drawer fronts and after 3 weeks in my workshop they are still very green.

They aren't going to get much if any UV after installed. I don't really want to 'sun them' for fear of warpage, which would defeat the 'browning' if I have to plane them further after sunning.

I had poplar boards in my basement shop. There was enough UV from the fluorescent lights to turn the green parts brown. I don't really know how long it took. If you have enough spare poplar, mill some up to flat & square then put it out in the sun. You'll find out whether/how much it's prone to distorting.

[mark mcfarlane]

Well, the poplar suntan exercise worked satisfactorily.

I did have to flip the boards every hour or they warped, confirmed by leaving them on one side for 3 hours the end of the first day, and, oops. So judiciously flipping once per hour over a 2 day period (~6 hours per day of sunlight, overcast on one day) produced the results in this picture.

The suntanned wood below has one heavy, brushed on coat of semi-gloss arm-r-seal applied.

383242

I think 2 more days would have eliminated more of the green cast, but my patience ran out after the first 2 days and I am calling them 'good enough' and will let them mature on the drawer fronts over the next 20 years.

Some of the panels were glue ups, with alternating growth rings, and they have a slight remnant waviness to them, but these drawer fronts are for shop cabinets...

They actually look pretty nice.

I'll try to remember to post in a few days after they are installed.

[Rob Young]

Not suitable for the "under finish" requirement, but I've read (never tried) that a weak solution of nitric acid can be used to brown poplar very quickly.

[mark mcfarlane]

Here's the finished bank of cabinets.

I made a huge mistake and tried too freehand sand the drawer fronts on an edge sander, which threw all the drawer fronts out of square. This made mounting the inset drawers a bit of a challenge to distribute the error. Live and learn, the reason I made inset drawers for the shop cabinets. Good practice and learned a bunch.

Anyway, few will notice the error. On first impression they look awesome.

I had to move my main bench to take this picture.

383315

[Jim Becker]

Wow...that looks OUTSTANDING, Mark!! Don't sweat any of the little boo-boos, either. Each project is a learning experience/opportunity for anyone, regardless of skill/experience and this one is no different.

[mark mcfarlane]

Thanks Jim. I am still amazed at how aggressive my Jet edge sander is. I had a 90 degree guide sitting right next to the machine, and thought,... I can just whip these out without taking them out of square. Never again :).

[Jim Becker]

Never underestimate how abrasive a sander can be... ;) :) :D

[Lee Schierer]

I really like how the lighter wood works across the drawer fronts in sequence, well, almost any way.

[mark mcfarlane]

Thanks Lee.

The drawer fronts are from three 12" boards. After rough cutting parts, I glued up the bottom two boards first, then cut them to the proper drawer heights. This was done because my drawer heights were built to fit specific 'stuff' so some are 18" tall, some are 10" tall,...

Another lesson learned: I should have been more careful and used narrower and more uniform 'wastage' on each vertical segment, then the sapwood/heartwood lines would have matched up better. When I did my rough cuts (prior to planing/thicknessing) I had about 2" excess on each side of each drawer bank (thinking about snipe and the need to do glue-ups). This meant 4" of waste between each bank of drawer, which throws the pattern off since the width of the stiles is only 1.5".

[Jim Becker]

I actually think you did an excellent job spanning this cabinetry with those boards with multiple drawer heights while keeping the structure of the original boards flowing across all the faces together. You will certainly know where there are minor things that are not "perfect" and another woodworker...if they actually took the time to closely examine it...might recognize some of those little things, but otherwise, nobody's going to see any of that when gazing at this beautiful bench and storage!

[Warner Harris]

Will green poplar turn brown under a clear-ish varnish (GF Arm-R-Seal in this case) over time?

How long? 6 months? A year?

I bought some poplar for shop drawer fronts and after 3 weeks in my workshop they are still very green.

They aren't going to get much if any UV after installed. I don't really want to 'sun them' for fear of warpage, which would defeat the 'browning' if I have to plane them further after sunning.

Try this trick. Mix 1 TBL. of Oxalic Acid (I found this at Rockler Woodworking) .. https://www.rockler.com/oxalic-acid-for-wood-bleaching .. in a pint of water and use a foam brush to liberally apply to the green board. Like magic .. the green will turn to a beautiful pale brown right before your eyes. A second coat won't hurt. Let the board dry and sand down the raised grain caused by the water and you're ready for staining.

[Warner Harris]

Of course .. this oxalic acid procedure will only work on boards before they are stained and finished.