Pine vs Poplar for framing

[13ptbuck]

It looks like most people use poplar for framing. What makes it better than pine? I had 50 2x4x8's in pine given to me. I was trying to decide if I should use them instead of buying the poplar boards. It would definetly be nice to save some cash and put it to use someplace else in the build.

[Talia62]

I can't speak for the use in trailers, since I haven't built one yet. But in home repair or cabinet building, poplar is a little harder and more dent-resistant than pine.

[S. Heisley]

I can't speak for the use in trailers, since I haven't built one yet. But in home repair or cabinet building, poplar is a little harder and more dent-resistant than pine.

...Very true, that.

Also, poplar tends to have less flaws/knots, etc and weighs slightly less than pine. (Knots can sometimes be a bear to drill, screw or nail through.) When choosing, select the pieces that are straight, not bowed; but also, are lighter in color, as I have found that pieces with a lot of green or brown running through them weigh more...don't know why. However, if you are building a woody and want to stain your wood, be aware that poplar doesn't usually stain as well as some other woods do.

[Micro469]

DON'T use poplar anywhere water can get to it. Trust me, I know.....I used poplar on outside trim, and found when it got wet, it really sucked up the water, and then turned to mush as dry rot set in. Had to replace/repair my hurricane hinge because of that.

[S. Heisley]

DON'T use poplar anywhere water can get to it. Trust me, I know.....I used poplar on outside trim, and found when it got wet, it really sucked up the water, and then turned to mush as dry rot set in. Had to replace/repair my hurricane hinge because of that.

I hadn't heard of that one. Sorry to hear of your rot problem. That is a trailer-builder's nightmare!
We do try to build our trailers so that they are water-tight; but, we sometimes get "surprised".

Any wood will suck up water and eventually rot, unless well protected.
Maybe that's why some builders use an oak board at the galley hinge. It is heavier but also a little tougher.

[noseoil]

Poplar is a good, light, relatively strong wood with nice straight grain. As was mentioned, it isn't rot resistant, but is good for framing inside the build. It glues well, but doesn't take fasteners as well as a harder wood like fir or oak. The light colored wood is sap wood (closest to the bark) & the darker, more dense wood is the heart wood. Although it is classed as a hard wood, it really isn't in my book. If it's a simple framing member which won't need to be removed, poplar is fine.

I used red oak for both the hatch spars (cabin side & hatch side) for two reasons. First, it's much stronger & more dense. It takes & holds fasteners better than a softer wood like pine or poplar. Second, it is typically more resistant to rot than a softer wood. Keeping the water out is the first way to keep the wood intact, once it's in the wood, things become different. White oak would be better than red oak, but red is what I had at the time, so that's what I used.

Nothing wrong with poplar, just consider its limitations before using it for everything. I wouldn't use it for a hatch or door jamb, where screws can strip out with use & need to be tight & remain tight. For a nice, light, straight frame member it's a great choice & very inexpensive to work with. Don't buy it from a home center store. Find a cabinet shop supplier or hardwood store for the best pricing.

[tony.latham]

It looks like most people use poplar for framing. What makes it better than pine? I had 50 2x4x8's

I really like popular, I use it for spars. But any straight grained wood will work fine in the sandwiched walls of a teardrop. I am not sure what you are talking about when you say "framing" when it comes to tiny-trailer building (teardrop? standy? but I'm convinced that 2x4's are overkill for sandwiched walls.

Tony

[noseoil]

The 2x4 stuff could be ripped into good material if it's straight grained & free of knots. What type of wood is it? Pine is not a "regular" framing wood where we build here in Tucson. There's SPF (spruce, pine, fir), douglas fir, hemlock fir, etc.

No reason it won't work for internal framing as Tony said, but watch out for knots & grain run-out on smaller dimension pieces. I would still use a hard wood for boards which have to take stress in the build.

[13ptbuck]

I was thinking of ripping them down and using them for the framing in the sandwich walls and floor. I would sort thru them and pick the best before I ripped them and then again before I used them. They are southern yellow pine. I would use oak for the hinge spar.

[MtnDon]

If those 2x4 are construction lumber you will need some luck. When working with small sized members as you do in a TD you will need luck to be able to rip the 2x4 down and not include the knots. The knots are weak points. Then there is the issue of ripping const grade 2x4 and not ending up with a lot of warped pieces from what once was a straight 2x4. Ripping releases stresses that were contained by the entire 2x4. Ripped, they often produce curved and twisted pieces. Personally I'd go with the poplar or whatever other knot free species you can find where you are.


Just a note, there are hardwoods and there are softwoods as we know. However, the term does not mean one wood is harder, more dense, than the other. A hardwood is from a broadleaf tree. The seeds from a hardwood have some sort of covering, either a shell, pod or a layer of fruit. Hardwoods are classified as angiosperms. A softwood is from a conifer. The conifer seeds have no covering. Softwood seeds are simply left to the elements when the tree disperses them. Softwoods are classed as gymnosperms.

Southern yellow pine ( one of either long leaf, slash, short leaf, and loblolly pines ) is a softwood. Basswood and cottonwood are hardwoods. Southern yellow pine (SYP) is denser, harder than basswood or cottonwood. You can easily bend 16D nails when hammering them into dense grade SYP. Then there is balsa which is a hardwood according to the tree species rules.

S-P-F is simply a classification that allows loggers to not have to sort the western spruces, pines and firs into separate grades. The strengths are very similar and that saves some money. Note that Douglas Fir is stronger than SPF and is actually not a true fir.

[noseoil]

Southern yellow pine is great stuff. Better in strength than hem fir or SPF grades in general. It is also more dense at about 52-53 pounds per cubic foot. If you can find good straight lengths from your ripping of this stuff (as Don said, waste!) I would say to use it. It is heavier than poplar (at 38#/cu.ft.) by about 15% but much tougher than poplar.

All in all it's a good structural material. We use it in trusses for a stronger grade of 2x8 when needed, for multiple ply girder trusses which need to carry heavy loads.

[VijayGupta]

Red oak lacks the tyloses that white oak has. Tyloses are stops in the pores (early wood) If the grain is straight, you can put a 2' piece of red oak in a glass of water and blow bubbles out the submerged end.

There was a good article on "home center wood" in the most recent Wood Magazine. They suggested if you want to use a softwood, buy some 2-bys with pith in the center and trim off the quartersawn stock on the edges, and trim away the knots. You'll probably loose 1/3 of the wood but end up with a clear, stable product.

Years ago, the manager at my local lumber distributor said that cypress was a wood that had a very high strength to weight ratio. Never checked this out, but another option.

More than you'd ever need to know about wood. If you have a question, the answer is probably in here somewhere:

http://www.fpl.fs.fed.us/products/publications/several_pubs.php?grouping_id=100

I used red oak for both the hatch spars (cabin side & hatch side) for two reasons. First, it's much stronger & more dense. It takes & holds fasteners better than a softer wood like pine or poplar. Second, it is typically more resistant to rot than a softer wood. Keeping the water out is the first way to keep the wood intact, once it's in the wood, things become different. White oak would be better than red oak, but red is what I had at the time, so that's what I used.

[Jdw2717]

I used 3/4" pine boards for the sandwich wall construction and ripped 2x4's for my roof spars. No problems yet after 3+years and 6500 miles. Just use pieces that don't have a lot of knots.

[13ptbuck]

I think I will go thru them and pick out the best ones and rip them down and let them sit. Then I can look at them and see what shape they are in before I start frameing things. It will be a couple of months before I am ready for them. I have to finish the frame first. Thanks for all the input.

[backstrap bandit]

A little tip for your ripping or planning is rip or plane the same amount off of both sides of a board or the wood will be more inclined to warp or twist old cabinet builders trick to straight boards