Which is less likely to cup on a 9" deep shelf, SYP or poplar?

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Forum topic by 404 - Not Found posted 315 days ago 707 views 0 times favorited 11 replies Add to Favorites Watch
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404 - Not Found

2544 posts in 1554 days

315 days ago

I have a customer who wants long shelves made, supported by wooden brackets that use diagonal braces. The shelves and brackets will be painted white.

They are going to hold books and one of them is also longer than 8’, so man made board is out of the question.

My timber supplier has nice 10” wide 4/4 planks of SYP at 16’ long or there’s a few wide poplar 4/4 planks, 16’ long in the bale. Both are kiln dried and show no sign of cupping even though both are tangentially sawn.

Normally I’d make a shelf this wide by ripping a plank in half and gluing it together heart side up/heart side down to eliminate cupping. I don’t think there’s going to be the money in this little job to do that. Is it sufficient to have the shelf heart side up – and attached to the brackets with a screw in the centre to keep the middle pulled down flat? Or do I need to get my biscuit jointer out?

Which would you use?

11 replies so far

View kdc68's profile


1924 posts in 862 days

#1 posted 315 days ago

Your statement says both the shelves and brackets will be painted white. IMO, poplar has the advantage over pine for painting. Pine will have knots and would be more work for you to prep them so they don’t show when the paint is applied. If you are buying pine that is as clear as poplar, you may be paying more for the pine

-- Measure "at least" twice and cut once

View Buckethead's profile


1800 posts in 454 days

#2 posted 315 days ago

I’m thinking poplar is more stable than pine to begin with.



Pine might be less expensive though

-- Bucket, any person that spends 10k on a bicycle is guaranteed to be a $@I almost started to like you. -bhog

View jap's profile


1224 posts in 639 days

#3 posted 315 days ago


-- Joel

View redSLED's profile


683 posts in 478 days

#4 posted 315 days ago


-- Perfection is the difference between too much and not enough.

View BentheViking's profile


1735 posts in 1149 days

#5 posted 315 days ago

poplar seems like the popular choice here

-- It's made of wood. Real sturdy.--Chubbs Peterson

View DKV's profile


3056 posts in 1089 days

#6 posted 315 days ago

But, which is less likely to cup?

-- 2014 will be a different least for me it will.

View cutmantom's profile


269 posts in 1620 days

#7 posted 315 days ago

It really depends on the direction of the growth rings ,plain sawn vs quartersawn,but for a painted project poplar will give the better result

View NiteWalker's profile


2642 posts in 1162 days

#8 posted 315 days ago

I use a good amount of kd poplar and have had little to no cupping, even on 8” wide boards. So I’d go with poplar. I don’t work with a lot of pine though, but like I said, no issues with poplar for me.

-- He who dies with the most tools... dies with the emptiest wallet.

View RussellAP's profile


2935 posts in 872 days

#9 posted 315 days ago

If cupping is a concern, dado a small depression about 2” from either end of the shelf and screw in a flat metal bar. Keep it flush with the wood and you can paint right over it. Guarantee it wont cup in a bog.

-- A positive attitude will take you much further than positive thinking ever will.

View 404 - Not Found's profile

404 - Not Found

2544 posts in 1554 days

#10 posted 315 days ago

Poplar it is then, it’s a few euro less than the pine as well. Thanks for the input.

View Don W's profile

Don W

14497 posts in 1153 days

#11 posted 315 days ago

I agree 100% with poplar being the better choice.

-- Master hand plane hoarder. -

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