[OP]
Contributor
Just watched Ng's video on making a sled and he used a flat chunk of maple as a flat reference for the glue up of his fence. I'd like to make a similar fence, 4"x6"x30, out of a stable wood, but one that is not as pricey as maple. Any suggestions?
How long do you think this hunk of wood will stay true once machined?
I used straight grain fir and have only had to joint the fence once in several years.
"A hen is only an egg's way of making another egg".
– Samuel Butler
Contributor
Ash is very stable.
Moderator
mdf or plywood would be meet the stability and price criteria (but not the pretty criteria so much).
Although, 4x6 is a mighty thick fence. Consider the weight.
[OP]
Contributor
Just to clarify, the 4x6x30 will be a reference slab to be used as a clamping base for gluing up 3 layers of 1/2" ply for sled fences. As I will be using the slab for present and future fences, I want it to hold it's flatness over time, as much as possible.Originally Posted by Prashun Patel
Member
you want long term flat & stable nothing beats BB ply - I take scraps all the time - rip to common width & length - glue up & put into a vacuum bag on a flat platen - can make a slab as thick as you want but I have found that after 2 1/4" (3 layers of 3/4" ply) it is a waste of time making it thicker - i have not been able to deflect a 2 1/4" slab with any clamps i own
Moderator
Then mdf seems like it'd be perfect. Sealed and waxed, it'll be a great clamping form.
Member
Box beam made from plywood. Cheap and rigid, as accurate as you make it, build it off your jointer table or similar flat surface. That's been my approach for door stiles. Works well. Think small tortion box.
Member
Your shop's "climate control" is going to be a huge factor....just sayin.Then,to a slightly lessor degree how you finish the pce.And "finish" here isn't about any clear coats,although this is a factor.It's about how you go about surfacing the pce.There are marked differences when comparing a planed surface vs scraped....and if "grinding"(sanding to some)...what grit.It's how the surface finish reacts to your shops range of humidity.....and how much "stress" is involved with attaining that particular finish.Which is why sometimes grinding can be better than planing.Tough subject.
Contributor
+1. I glued up the first pairs of laminates for my bench tops this way.
Brian
"Any intelligent fool can make things bigger or more complicated...it takes a touch of genius and a lot of courage to move in the opposite direction." - E.F. Schumacher
A granite or quartz countertop offcut from a large kitchen sink would trump any of the other suggestions as to being stable. At least you would start with a flat glue-up, no guarantee it would stay that way. Cheap if you can snag one from the fabricator. Otherwise I would go with 3/4" MDF, 2 layers sandwiched together with a third piece at least 4" wide with a very straight edge glued perpendicular to the other two to form a Tee or Angle.
Last edited by Ole Anderson; 02-19-2014 at 6:00 PM.
NOW you tell me...
Member
I just watched William Ng's sled video too and I have the same question. What are you using as a "Flat reference"? How about a 4" piece of square aluminum tubing?
Any other ideas?
How do they grind granite counter tops? Do you think those are really flat?
Built guitars in my basement for 10 years, mistakes went in the wood stove, was rarely cold.
Best funny woodworker line: "My worst fear is when I die my wife will sell all my tools for what I told her I paid for them"
Contributor
QS old growth redwood with no knots. AKA "clear heart" Can not buy big beams anymore will have to find used ones. Less weight then the other species mentioned here.
Contributor
Check with a Restore . They often have granite and marble used counter splashes....for some reason it does not last as long in today's kitchens as laminate did. But might work for your fence.
Contributor
Nothing made of solid wood, especially a 4x6, will be completely stable. Some woods will be more stable than others: red oak, walnut, ash, white pine, basswood for example; and some are less stable than others: beech, birch, hard maple, can be challenging. The moisture content of the center of a 4x6 will probably be a season out of sync with the outside of the board, depending on the size of your seasonal variations.
For something that size, a box beam of baltic birch or fir core plywood will be much more stable than any solid wood. No thick center to be out of sync with humidity, but still quite strong. Not to mention much cheaper and easier to make.
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