HI! im kamren from utah, im almost 17 and have been doing basic woodworking for my whole life, but just started to get into the finer stuff about a year ago.
Im in the process of buying and prepping stock for my hardest project yet, a triangular end table with a bloodwood/ebony top and ebony edges, veneered onto hockory as a base, it will have a pedestal stand of walnut. I’ve figured out what to do for jigs and stuff to do the veneering im set there.
my question is: I live in a very dry climate, its not humid the whole year through except for minor bouts of a few hours of humidity around the time of storms. The outside temperature however ranges from -5 in winter 105 in the summer, so will i have wood contracting problems with this table? im really trying to do it with zero clearance between stock on he top. i just dont want to put this sucker together and have it shatter in winter because i didnt build it right.
thanks!
-kam
Replies
Kam,
Sounds like a cool project.
You mention temperature changes outside, but I'm assuming it will be in a home, and not outside. So it will only be exposed to swings of the living environment. If it is ever put in storage that is not environmentally controlled, then problems may occur. I personally would build it for standard living environment and not the extreme.
You are planning on veneering onto hickory? Is it solid hickory or plywood? I ask because I have never seen hickory plywood but I am sure someone makes it.
I imagine Hickory ply is expensive. If you are using Hickory plywood, unless you have a supply of it or can get it cheaply, or have a piece but just don't like the look of what you have, I'd go with something like appleply — not Apple wood, just a name for cabinet grade plywood with no voids. Around here we get mostly birch.
The next factor is how thick the veneer is. Wood has the propensity to move. A thinner cut with a good bond will still try to move, but will not generate enough internal stress to break the veneer bond. Are you buying factory cut veneer or resawing yourself?
Although the internal stresses of the veneer trying to move should not cause the veneer to break away, these stresses can cause the core to bow. So, remember to put a veneer on both sides of your substrate. This balances out the stress on both sides of the substrate and keeps it from bowing.
It's way cool that you have been exposed to woodworking at an early age. Please post some photographs of your project. It's OK to share construction progress as well.
Good luck. Let us know how we can help.
Greg
•••••••
Exo 35:30-35
ok thank you, well i chose hickory as a base to glue the veneer to due to it's resiliance, it sounds like ply migh be better than solid in that case i will surely use it.
i plan on farely thick veneers actually, but im not againts halving them in fact im resawing the bloowood my selv and can get it as thin as i want and im getting the ebony 1/2" thick from bell forest products just so i have that versatility. should i halve the ebony and then get the bloodwood to match?. that would beablut 3/16" which is about as thin as id like to go.
maybe veneer isnt quite the right word for what i had in mind (But ive leaned alot since i dreamed this table up) i was actually kind of thinking basically tiling the pieces on there.
3/16" is really too thick for a veneer. If you want to glue the wood to a stable substrate, like plywood or MDF, then your veneer should be no thicker than 3/32".
-Steve
but i dont plan of plywood or mdf, im tiling the stuff on top, to a thick substrate to give the illusion of a thick tablen (1 3/8"), then going around the edge with angled homemade ebony edge banding.
i dont see how this tiling wont work if done right, as long as i keep it indoors like the others said. i should also mention this surface will not be curved at all, i plan on going dead flat with this one.
my jig set up is this 3 pieces of 2" wide stock 1/2" thick, mitered with one with 2-22.5's and 2-with 1-45& 1-22.5 matching the inside distance to go around the aoutside of the substrate. This will hold the tiles flush with the edge as i piece them onto it, then i can glue with a piece of stock to match the substrate to put on top of the tiles and then use lots of weight on top of that to apply the needed pressure while the glue cures.
If you glue each "tile" to the substrate so that the grain of the tile and the grain of the substrate are aligned, it will probably work. If you glue a tile so that its grain is perpendicular to the grain of the substrate, you are likely to have problems down the road, unless you keep the piece inside a sealed chamber where the humidity never changes.
Let's work through some numbers to get an idea of the magnitude of the problem: Let's assume that the atmospheric humidity will vary from 40% to 50% RH (this is a very mild swing--you can expect to see at least this much, even in a climate-controlled environment). Let's also assume that the table is 18" wide, and is made of flatsawn hickory.
First, I use my handy-dandy wood movement tables to see that at 70°F, a humidity change from 40% to 50% will cause the moisture content of the wood to change from 7.7% to 9.2%, a delta of 1.5%. I also see that the expansion coefficient for flatsawn hickory is 0.0032 per 1% change in moisture content. So my overall expansion coefficient is 1.5 * 0.0032, or 0.0048. Next, I multiply that number by the width of the table, and get a total movement excursion of 0.0864", or a little under 3/32".
So even under pretty ideal climate conditions, our table is going to change in width by close to 3/32". Our ebony edgebanding, on the other hand, isn't going to change in length at all. This is a problem.
Some possible solutions:
Use quartersawn stock as the substrate (quartersawn stock has roughly half the movement of flatsawn stock). It might be hard to find quartersawn hickory, though.
Use a stable substrate, like plywood or MDF. This works, but now you have to be concerned about the movement of the applied pieces, so that's why you want to only apply relatively thin veneers, which are thin enough that the substrate will constrain their movement.
-Steve
ok thanks guys, im thinking i will definately use some sort of higher grade plywood instead of solid wood. and definately go thinner with the boards, that's no biggie, i guess i was just under the wrong inpression that thicker=equals quality cuz i want this to be a high quality piece that will look great and last.
so what plywood would be best at holding the glue?
After understanding a little more of your design choices, Steve and others are correct - this construction won't work unless you keep it under glass in an absolutely controlled humidity environment.
So long as you're careful to keep the grain orientation of the "tiles" and the hickory substrate the same, the top will probably survive some mild humidity swings, but the edge banding won't. I'm assuming that what you're talking about here is essentially wrapping a long, thin band of wood around the outside edge. When the humidity changes, the table top will expand and contract, and the edge band will pop off, no matter what type of glue that you use.
There, is, however, a way that you can sort of get what you're after and still use a solid wood core - you can dye the hickory core with a black aniline dye so that the edge that shows around the table top will look like ebony.
so what your saying is that even with a little thinner tile/veneer, and plywood the banding wouldn't stay on not to mention tight at the miters?
No - I was basing my prediction on his original construction of a solid-wood hickory core.
I've built quite a few "edge-banded" plywood panels where the edge banding is 1/2" wide maple or oak edging, and it seems to hold up fine, though I haven't tried to intentionally stress these parts with humidity changes.
I have had some weird effects with this construction method, though. Every now and then, one of these 4-sided panels will warp (usually in a twist) immediately after construction. Just antecdotally, it seems like if the panel is still flat after a couple of days after the glue dries, then it stays flat. If it's going to warp, it does so in the first 24-48 hrs. after the clamps are off.
Theoretically, the solid edge banding shouldn't shrink in length, and the plywood center shouldn't move at all, but that's exactly what seems to happen in about 10% of these constructions I've made.
OK thanks guys! I know how to do this better! it will last longer! so is there a specific glue to use tht will work better?
also on the same pinciple if my pedestal was walnut could i dado all four sides and inlay a band of bloowwood into it or would the walnut expand breaking the miters of the bloodwood?
If you're talking about horizontal banding on a vertical pedestal, then yes, the banding will fail at the mitered corners. The key point to remember here is that you cannot glue together two pieces of wood with the grain in the 2 pieces perpendicular to one another - a humidity change will always break the glue joint.
The only way to safely attach two perpendicular grain directions is to do it with some sort of sliding attachment - and example is a breadboard end on a table top, where the end of the table proper can move freely within the mortises cut into the breadboard end.
well that sucks cuz this would look really cool... what if for the sake of color i cut the bloodwood with the grain parallel with the pedestal?
what if i cut the 4 sided dado's deeper than the thickness of the bloodwood?
or is the only way to remedy this to do it the hard way and cut a super thing slice....
If you cut the bloodwood as a cross-band (i.e., the grain runs vertically in both the band and the pedestal), it will be reasonably stable. Note, however, that different wood species have different expansion/contraction rates, so there is still a possibility of checking in the band over a number of years.
Cutting the dado deeper won't do any good, as the expansion and contraction is across the width of the walnut grain. In effect, your bloodwood band will be alternately shorter or longer than the width of the 4-sided pedestal as the seasons and humdity change, and this movement will most definitely open up a miter joint at the 4 corners of the bloodwood band.
A couple of books that would be well worth reading to clarify how the grain of wood influences what you can and can't do in furniture construction is Bruce Hoadley's "Understanding Wood" and Taunton's "Working with Wood", both of which should be available at your local public library if you'd rather not purchase them.
is there a differant joint i can use?
im just saying that would look cool. i mean wouldnt it? maybe ill just cut it and sandwich the bloodwood in there.
im gong to take y'alls advice....but im still gonna do this project and its still gonna look good and last too...so im saying you guys have, but dontdiscourage me from doing this project because once i get the desing in my head...its over it's going to happen. and honestly even if it doesnt last as long as some traditional simple oak furniture it will still be handmade higher quality than walmart crap and that is what im going for.
but yeah thanks for the help
Go for it. Think about how wood moves and try to design around it.Pay close attention to what you do and the choices you make so you can learn from your decisions.Greg
<!---->•••••••
Exo 35:30-35<!---->
thanks for the advice and encouragement dudes!
but dontdiscourage me from doing this project .. GREAT..
and honestly even if it doesnt last as long as some traditional simple oak furniture'' Some of it really nice but not what I like...
it will still be handmade higher quality than walmart crap and that is what im going for.
Oh geee You must really be 17 .. I wish I was with that spirit!
Go for it!
By the way.. "simple oak furniture'' NOT! That simple once you try to do one!
well at least some of you have constructive criticism...
and yes ive done my fair share of traditional furniture, nough to know i want to branch out...and if i learn the hard way, i learn the hard way.
Thanks guys!
Edited 7/20/2008 3:38 pm ET by cedar920
well at least some of you have constructive criticism...
Did I say something good or bad?
well you tell me... sure im 17 and stubborn, so sue if i wanna work outside the box...
As i recall I said something like ...
Oh geee You must really be 17 .. I wish I was with that spirit!
Go for it! <<<<<
By the way.. "simple oak furniture'' NOT! That simple once you try to do one!
....
No hate here but if you want to fight.. I'll give up right now and say you won before it started!
You have to learn that not everything said is AGAINST you!I was rootin' for you!
OH in that case, i obviously misunderstood, sorry.
I know it's no excuse but im a little hardened from other forums about my other hobbys where people never wanted anybody new...so i obvioulsy jusmped the gun.
once again i apologize. Thanks for the ecouragement
once again i apologize. Thanks for the ecouragement
None needed!!!! Ever.. OK unless ya' tell me I'm ugly!
I do tend to go off the deep end sometimes thought. So had to ask if I offended ya!
No mean folks here that I know of!
You WILL NEVER find a bunch of nicer folks (even if ya get pissed off a bit at them.. Makes life real!)
You may NOT agree with what they said... Tell them.. However, all are COOL! Old 1950' word... And stand back and put your helmet and eye protection on if they respond!
None have Hate.. JUST THEIR OPINIONS!
I HAVE MINE!
Edited 7/24/2008 8:51 am by WillGeorge
uhh i think i get what ya mean lol...i think... but yeah i just hate people who dont want new people in their craft... like some other people ive met on OTHER forums.
could i leave some clearance space between the banding and the supstrate if i figured out how to do that would it work?
"could i leave some clearance space between the banding and the supstrate if i figured out how to do that would it work?"
I'm sure you could figure out some kind of mechanical arrangement where the tiles and banding "float," but it's going to be complicated, weaker, and prone to problems. Why bother? Plywood and MDF are the substrates of choice for parquetry, marquetry, and just about any other kind of veneer work. Historically, before there were such things as plywood or MDF, the substrate of choice was crossbanded lumbercore. Like plywood, this is a stable material. Yes, people have attempted to do this kind of work on solid wood substrates, but those are the pieces where the glue joints fail in just a few years. Don't you want your piece to last at least a few generations?
-Steve
|KAM,There are really several design decisions you are making here.Understand the Characteristics of wood:Wood dimensions change with moisture content (humidity). You have to make allowances for this movement in your furniture design.Plywood movement is negligible. So choose plywood as a base for veneer instead of a glued-up or solid board.Put a piece of veneer over both the front and back to balance the tendency of the veneer to warp the substrate. Make sure you get 100% glue coverage on both the plywood and the veneer.Veneer is wood and it tends to move too. But thin slices will not generate enough internal stresses to change the "wood sandwich". IF you are buying commercial veneers, they are about 1/42" and will not cause a problem. If you are re-sawing your own, I generally recommend 3/32" re-sawn slabs sanded to about 1/16 by the time you get to the veneering stage.FYI: The DIY networks run a show called "WoodWorks" with David Marks. He does a good job teaching about veneering principles. They are all re-runs as I believe he quit making shows about 12 years ago. Do a google search and find it in your area. Norm talks about wood movement as he does his projects too. I recommend you watch them until you grasp the principles they teach.Greg
<!---->•••••••
Exo 35:30-35<!---->
Kamren -
When I read your post, I puzzled over what you meant by "zero clearance" between stock on the top. If you mean you're going to glue the ebony and bloodwood veneers on the top to each other, that's no big deal, even with humidity changes. The reason is that the veneers are very thin and will largely expand/contract based on the veneer substrate rather than the veneer wood properties itself. Since you're using plywood as a substrate (which doesn't move very much with changes in humidity, though it isn't completely static as some books might imply), solid wood movement isn't an issue.
Moreover, wood movement in response to changes in humidity isn't instantaneous - it usually takes several days unless unfinished wood is directly wetted by water. So a humidity change from a passing storm probably won't cause any issues on a table with a film finish on it. The film finish won't keep the wood from changing moisture content in response to the humidity, but it will slow down the change considerably.
ok thanks for the info, i definately plan to keep it inside, will have any problems with the swamp cooloer?
im debating whether to go 3/8" or 3/16" im doing the surfaceing and reswing myself so that i have that capability. Any opinions?
yeah what i mean by zero cleance is not having any sort of space between tiles or expansion joints .
is there a better species to us as a base for this tabletop?
This forum post is now archived. Commenting has been disabled