OK I pretty much lurk in the shadows here... I love all the build threads. I finally signed up a little while ago, Figured maybe I should post something, even if its not car related. (I dont have any real go fast cars now... I have a 4runner that gets most of my work)
I wanted to show off my latest project. I have been thinking of doing concrete counters for my house, so this was a trial run for that more or less. I think it turned out pretty neat.
Finished product:
Figured I would do a little write up, it was way easier than I thought and not too expensive. You will need some basic tools, I used a drill and paddle to mix the concrete, a skill saw to cut the form material, and drill and screw gun. That’s pretty much all the specialized stuff needed.
Materials are concrete, welded wire mesh, (I used fibermesh also, but don’t really need to, it adds a bit of cost, and really only helps if there are tiny surface cracks.) a piece of melamine to make the form, screws, and whatever you choose for legs. I used 3x3’s and some steel plates at the top.
First step make a form, use melamine, its slick enough that the concrete releases well and it makes a good finished surface. I didn’t take any pics… But screw together a box, pretty simple. Next caulk the corners, this gives a little radius and makes the form water tight. I used a painters caulk, would do a polyurethane or similar next time, the caulk bonded to the concrete too well and pulled some off in places. Here is the bottom of the form (top of table) after it was poured to give you the idea.
Support the form well, concrete is heavy! And get it as level as possible, pouring the concrete wet, it will want to run to the low side.
Mix the concrete wet, very wet, it needs to be able to flow well. The key to the top being smooth is getting the trapped air out. Needs to be runny concrete and vibrated very VERY well. I used an air chisel and pounded on the bottom of the table that I poured on. I would probably just rent a vibrator next time.
Poured
Fill the forum half way and vibrate it well, then add a piece of welded wire mesh. It should be cut to about 1” back from the edges on all sides.
Fill it the rest of the way up and vibrate more. Be careful not to hit the wire and sink it to the bottom. It wont move much if you don’t directly vibrate on it.
The top is the bottom of the table, so the finish isn’t critical, I didn’t bother with it much beyond making it smooth-ish.
I used the steel plates to locate bolts for my legs. I used the same plates screwed to the top of my legs. I used wedge anchors for the bolts, they are 3/8” and are designed to tighten in a drilled hole. Glad I did since one wanted to spin, but a bolt should work just as well.
Sorry for the terrible picture (I was having too much fun)
After an overnight dry, you can carefully strip the forms off. The concrete will still be quite soft. If you want to ease any edges you can do it now. Work from the corners in, as not to break the corner off. You can rub with your hand or use sandpaper if it needs a bit more.
Top after stripping.
Now it needs to dry and cure so it can be stained. I chose to do an acid stain after the concrete had dried instead of an integral color. Acid stains usually give a bit more surface variation, where the integral color will be pretty even. However with the bottom of the concrete being the table top, and having no toweling on it, it came out quite even.
After a couple hours with a fan on it.
On to the stain. Its acid, protect anything you like. The literature will tell you to let the concrete fully cure, 28 days, before staining. I didn’t wait… I stained the 3rd day after pouring. Use a spray bottle to apply the stain, use a acid safe brush (no artificially colored bristles!) to scrub it around some. I used the whole bottole of stain on mine as I wanted it pretty dark. The stain reacts with the concrete so the color of the stain may be completely different from the final color. I did black, although it didn’t end up really black, somewhere between a black/brown mix.
After a couple coats of stain, note the plastic covering everything.
The longer the stain is left to react the darker it will be. It will continue to change for quite some time after as well. You can apply as much or little as you want depending on the color. It will penetrate the concrete so if you wish to sand the surface to expose some aggregate the color will continue down.
After it has been left to sit for as long as you want, the acid must be neutralized and the satin washed off. Use baking soda and water mix to neutralize then just a couple of water rinses to get the excess stain off.
After cleanup, starting to dry. Looks very brown.
Next step is to seal and wax it. I used an enhancer on mine; it’s a product for stone usually that deepens the color a bit. It also adds some sealant, I used a DuPont one. Followed by another sealer just for good measure, I used 511. Then wax, wax and more wax. I like the Johnson paste wax for this. I put a few coats on by hand, really heavy, then one more light one and bit it with my buffer. The wax adds the wear layer to it.
Finished, well I will add a little shelf underneath, but done for the most part. You can see the stain has continued to react and has become a bit blacker.
I may try counter tops after I see how this wears. The counters may pose a problem of being HEAVY. The table top I made is 30x48 and weighs 250 pounds…. It was a fun project. Hope its not too off topic here!
