I posted this in another section and think I may have erred. Any feedback given is greatly appreciated. I’m new to this site and am very impressed and comforted by the amount of knowledge floating around the airwaves.
Not sure which category this should go in but I am looking for some guidance on making a redwood slab coffee table. I’ve purchased a large slab (pictured) of original growth redwood from the Northern California Coast. I’m very excited about making this into our dream coffee table but have never done anything like this. I’m leaning towards sanding the piece all the way down to 120 or 150 sandpaper and then using tung oil instead of urethane/lacquer/varnish. There won’t be a lot of liquid spilled on the table. I’m interested in protecting the wood and bringing out the color and grain. Would you use tung oil or something else? Also, planning for a more contemporary look so I’ll be going with metal legs. I’ve found several places online that sell legs like this. Is there any problem with screwing the legs right into the table or should they be mounted differently. Thanks for the help.
Replies
I believe I'd go to at least 220 on the sanding. I have done a pretty spectacular 7 foot slab of burl walnut and finished it with wipe on varnish (non-poly). I can't imagine why you wouldn't at least do a modicum of a protective finish for a coffee table. I have also sanded redwood and I think you will want to seal it well, which I don't think pure tung oil will do adequately.
I'd be interested where you found legs, if you would post that.
"I can't imagine why you
"I can't imagine why you wouldn't at least do a modicum of a protective finish for a coffee table."
Well, the reason that I wouldn't is because I really don't know what I'm doing. I saw some people on the internet reccommend tung oil and thought it sounded good. I'm definitely up for suggestions. I'd love to hear any advice that more experienced people want to share.
Thanks for the sanding advice.
As far as legs, I've just barely begun my search, actually saw some stuff on Amazon.com that looked promising. I'll post more as I come across them.
Protective finish
Listen to Gretchen, she knows what she's talking about.
Tung oil is not a satisfactory finish, that is if you mean pure tung oil. It provides only the slightest bit of protection, and then only after you have applied about 5 coats with several days of drying between each one. If you are set on the minimalist look, with only a "in-the-wood" finish, then an oil/varnish mix gives a virtually identical look compared to pure tung oil, but with significantly more protection, and a much longer interval before the finish dulls enough to need "refreshing". An oil based varnish would provide dramatically more protection and longevity, but would build a film on the surface.
Unless you were very careful in your choice of tung oil finish you wouldn't have gotten real tung oil anyway. Most of the common brands don't contain tung oil, they are "Tung Oil Finish", where "tung oil" isn't a noun but an adjective by which the manufacturer hopes to describe the product. Minwax Tung Oil Finish, for example, is a mix of oil and varnish. I doubt there is much if any actual tung oil in it. Formby's Tung Oil Finish is actually a varnish--not mixed with oil, the only oil is used as an ingredient in manufacturing the varnish.
As far as the legs go I would certainly not use any screws or other metal to attach them to the slab. Personally, for such a natural slab, I would do something like attach the legs using a wedged through mortise, giving the legs enough splay so that the mortises are sufficiently inboard of the edges (especially since redwood would need plenty of "meat" around mortises for strength", The spaly would allw the bottom of the legs to be just under the edge of the top by a small margin, so that the table will be stable. There are other methods, of course. You could use an apron under the table and mortise that into the legs. (I would choose a hard wood for legs--red wood is pretty soft), The legs could be trestles with the top attach in such a way that it's seasonal movement across it's width is allowed.
EDIT: I see I overlooked the part about metal legs. If your top is thick enough you can screw into the bottom. Alternative, you can glue on patches of hardwood--being sure that the grain runs the same way as the top--and use them to provide a bit more solid piece of wood to hold the screws of the legs. Alternatively, you could imbed threaded inserts to increase the holding power of the attachment.
As already mentioned, if you use a oil/varnish finish, you should sand to at least 220 grit. If you decide to use a film finish such as varnish, you could by OK sanding to just 180 grit. While a ROS is OK for much of the sanding--be sure to finish by hand using a sanding block and sanding only in the direction of the grain.
Wow! Fantastic advice here. Thanks to all who have provided it.
Here is the workflow that I am envisioning based on the provided info
1) Sand, Sand, Sand - Random orbit for the rough stuff, hand finish with the grain
2) Finish slab on both sides (I'm definitely leaning away from the polymerized tung oil finish I was considering) my wife has now stated that she wants it "shiny" so I'll probably go with some sort of urethane product (any brand recommendations would be appreciated)
3) Affix the legs in some manner. I'm leaning towards the suggestion of screwing the legs into hardwood and then glueing them to the slab. The slab is thick, almost 3 inches, but I'd prefer not to damage it with screws if I don't have to. Threaded inserts also seem like a good option.
Keep the advice coming. I'm very excited about this project and extremely grateful for the help. I'll make sure to post pictures of the table as I go. It may be a couple of weeks until I can really get going as we have just moved into a new house and are unloading boxes stacked to the ceiling.
I would use a wipe-on varnish for the finish. Foolproof. The wipe-on aspect will give you less finish build and thus more resemble an "oil" finish. A waney edge slab wants to be as close to natural as possible so be cautious in finishing too much.
Legs: Doug Mockett carries some very nice metal legs that you may be interested in. http://www.mockett.com
They can be screwed directly into the slab. At three inches thick there is plenty of wood to hold screws. If you are in doubt you can saturate the drilled hole with epoxy or super glue prior to inserting the screws. The adhesive will bind the soft redwood. Unless the mounting plate is very large, I wouldn't bother with elongating the holes. At most I would drill the holes in the mounting plates oversize and use washers under my pan head or truss head screws. Attaching hardwood mounting blocks is a total waste of time and may very well compromise the design. I've made and attached several sets of steel legs and have never had any problems going direct.
Legs
I really like a lot of the legs at Mockett.com. It will be hard to choose. I imagine that it will be a bit of trial and error.
Really interested in the advice about saturating the hole with epoxy/super glue.
Any recommendations on what brand of wipe on varnish?
Thanks very much.
On our redwood slab we found the wood to be VERY fine--not saying this quite right, but it is sandy/fine dust. You will really need to vacuum the slab (I use the brush attachment and PUSH the brush down hard to really get it sucked up) and THEn wipe it down wit mineral spirits. when you do that wipe down, by the way, you will see what your slab is going to look like when you put your clear finish on, and you may be VERY surprised at how dark and rich it is. It will bear NO resemblance to whay it looks like when you sand it.
Interesting
Do you think that the dark color looks good or bad? In general were you happy with your finished product? I'll make sure to keep the shopvac busy while I'm sanding and before applying the mineral spirits. Thanks again for the great advice.
There
You do have a choice. Water borne finishes don't darken the wood nearly as much as solvent finishes.
You will want to experiment. Do samples. If you don't have extra wood then use the bottom of the table as a test surface.
I may have overstated, but my real point is that when you wet the bare wood you may be surprised by what the wood looks like. It will not be that light sandy pink look. I have NO experience with water borne finishes so only know what I read that they don't yellow and are lighter. But I still think there will be signficant darkening of the wood. But it's really the grain of wood that is pretty and that will still be there.
There
You do have a choice. Water borne finishes don't darken the wood nearly as much as solvent finishes.
You will want to experiment. Do samples. If you don't have extra wood then use the bottom of the table as a test surface.
There's always a choice.
You do have a choice. Water borne finishes don't darken the wood nearly as much as solvent finishes.
You will want to experiment. Do samples. If you don't have extra wood then use the bottom of the table as a test surface.
Drinking water.......
......through a firehose.
Lots of great info here for a newb like myself. Sounds like i should do quite a bit of experimentation on the bottom of my slab. Thanks again to all who have contributed.
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