Introduction: Fabric Formed Tea Table in GFRC
Runner Up in the
Concrete and Casting Contest
This Fabric Formed Tea Table Project can be completed in a weekend with simple materials.
MATERIALS & TOOL LIST
Materials for this project can be as simple as scrap from other projects. This particular Tea Table was built using material left around the shop. If you prefer you can use newly purchased materials, but the joy of fabric forming is in development of the design. If you have materials on hand you can use this same process to convert your design into a concrete masterpiece.
For this project you will need the following:
Melamine Board or Other Smooth Base
Scroll, Band or Jig Saw (For Round Cuts)
Skill or Table Saw (For Straight Cuts)
Screws ( 1/2" or less)
Screw Driver or Preferably a Cordless Drill
Small 90 Degree Simpson Ties (Minimum of 12)
Staple Gun (Manual or Pneumatic)
Waterproof Silicone Caulk
Standard Flat Bedsheet
GFRC (Glass Fabric Reinforced Concrete) Mix
5 Gallon Bucket (Minimum of 2)
Mixing Tub or Wheelbarrow
1/2" Drill with Mixing Paddle
Decorative Features (Optional)
Small Trowel or Screed
Thick Latex Kitchen Gloves
Water Polisher (Optional)
Hand Sanding Pads (Optional)
Concrete Sealer (Optional)
As Always Do Not Forget to Wear Appropriate Safety Gear for this project!
Step 1: Cut Frame Materials to Specs (Straight Cuts)
Cut Melamine and Frame Details to specific sizes as Listed:
Base (1) 57" x 21"
Ends (2) 20" x 21"
Termination (2) 1 3/4" x 22 1/2"
Preliminary Cuts for Round Pieces
(1) 20" x 20"
(2) 57" x 20 3/4"
Step 2: Cut Frame Materials to Specs (Curved Cut)
Cut Frame Quarter Round Angles (Transition Pieces):
With 20" x 20" Board, Use Straight Edge to Divide into Quarters and Mark Off.
Using Screw as a Center Point with String and Pen, Draw 20" Circle.
Quarter Melamine, then using Scroll (or similar saw) cut the Quarter of each Circle.
Place all 4 Quarter Pieces Together and ensure they are as close in size as possible.
Step 3: Fasten Base and Ends
Ends to Base
Fasten ends to the base using three metal angles per side. The ends should be on top of the base while the base is lying flat.
NOTE!!! I found that standing the boards up on their sides and fastening from the top down the smoothest way.
Transition Boards to the Base
With the base lying flat put the four transition boards in place. Connect the transitions with a single metal angle to the End Boards first, from the outside. After all four transitions have been attached to the End Boards,the next metal angle will go on the inside of the transitions and fasten to the base board...this is where you can check and adjust the piece with a square..
NOTE!!! Make sure that the metal angles are not sticking over the wooden pieces at all or they will interfere with the fabric..
If the transitions have a gap after squaring the pieces up... you can smooth them out using packing or other tape.
Step 4: Fabric Forming
I found a bag of old bed sheets at a local thrift shop for two dollars... I recommend this as these are not reusable. Many materials can be used for this project and each one will have it's own characteristics- especially if you are going with a finished product with no polishing necessary.
Most important for this project is not what the material is made from, but rather that the material does not have much give- as this would ruin the integrity of the curved design.
Start by stapling the sheet across the End Board on one side, then move down toward the Side and across to the other side.
I started off using a hand held stapler by myself...
I have to admit that I got a bit frustrated with this and switched to a pneumatic stapler and asked my wife to staple while I stretched the fabric. I would highly recommend the use of the pneumatic and a second set of hands. It will make things go much smoother.
Getting the fabric in place and sort of tight with as few staples as possible and then pulling and tightening with final staples from one side to the other. The trick is to pull the fabric over the transitions so that it gives a sort of bubbled out look. This is hard to do without the wrinkles (Mind you wrinkles look sweet in a finished piece, that was just not my intention with this particular project).
A side note on the wrinkles... In this project we will be using a GFRC mix with shell aggregate and grinding with a polisher. If you intend on following this project to the letter with aggregate- It is near impossible to make wrinkles look like the rest of the piece, so you should do your best to make sure there are none. If, however, you are going with a smooth out of the mould finish where no grinding is necessary- you can have all the wrinkles you want- and the project will be much more organic.
After the fabric is tight as possible, staple a uniform line down the sides of End Boards about a half of an inch onto the Transition Boards and across the Base Board. There should be no less than a half inch inch gap between the staples. You may need to pull out any staples under this staple line so the last melamine piece (Side Termination Board) fits as snug as possible with all of the staples screws and fabric sticking out. Finally, Trim off the excess fabric.
After all is trimmed up the next step is to attach the (2) 57" x 20 3/4" boards to the sides using only three drywall screws per side making sure that all of the ends are nice and flush. the reason for using only three screws at this point is that this is a temporary installation, you are only making a mark before removing and cutting the curve.
Cut a 1" gauge out of a scrap piece of wood to mark off the 1" termination on the sides. Do this by sliding the gauge against the Fabric Lined Form with the sharpie pressed to the Side Termination Board to mark your cutting line..
Before removing the sides, mark where the sides are so they end up going back on in the same place after cutting. Remove both pieces and cut out terminations using a jigsaw.
Line up the pieces and sand a bit to ensure they are at least close... as you did in step 3 with the other transitions.
Reattach the Side Termination pieces and snug them up with drywall screws (more than three this time). Just so you know... you don't want to screw through the fabric lined portion.
Finally, we can attach the (2) 1 3/4" x 22 1/2" to the top of the End Boards with drywall screws completing the 1" termination on all sides.
Step 5: Caulking and Optional Decorative Accents
Using 100% Silicon Caulk (I recommend black since it easier to see what you are doing) seal up the gap between the melamine Side Transitions and the Fabric Lined Form. The four Interior Transition Pieces can be tricky.
REMEMBER, what your caulking looks like is how the finished piece will look. Note that if you fill up the deep transition corners it will give you a round edge while a little bit of Caulk will give a sharper almost 'fin' look end the end- this is your preference.
A Note on Decorative Elements:
There are tons of things that can be used to fit your personal likes, but note that this piece is only an inch thick. In this piece I decided on using ground scallop shell as the aggregate so the Ammonite Fossils seemed to fit. I like to put four layers of tape on the decorative pieces when I'm grinding to expose the aggregate. This puts the piece deeper into the surface so you're not grinding it down while working on grinding the surface.
Step 6: GRFC Mix
I could go on and on about my ups and downs with regards to GFRC mix design. My advise while starting out is to get your materials from one of the larger established companies like the Concrete Exchange where they have a more user friendly mix and you are sure to have a great completed project without any problems with your formula.
For those of you are not familiar with GFRC, see this link : http://en.wikipedia.org/wiki/GFRC
I mixed all of the dry goods (180 lbs.) for the job and added a small amount of iron oxide colorant (chocolate brown) so that the entire batch of materials would be be the same throughout.
Using a 5 gallon bucket, I portioned out about 3/4 of a bucket for the face coat (no fibers) and added about 25 pounds of ground shells til the bucket was overflowing. Using this material, I then coated the entire form about 1/4 inch thick.
NOTE: Pay Specific Attention to the upside down parts as they tend to slide.
After the entire surface was coated, I used a small slightly moist chip brush to even it all out and push out any unwanted trapped air. Use a brushing motion on the flat parts and sort of a dabbing or taping motion on the sides. This coat needs to set up a bit before spreading on the next coat. I let this one sit for about 45 minutes before moving on to the next coat.
The next layer of mix I used included what was left over from the face mix. I added enough dry goods again to bring the bucket almost 3/4 full and added 5.5 pounds of 3/4 inch AR Glass fibers. Remember that there are NO SHELLS in this mix since this is the interior of the concrete and we are looking for strength for the body of the project. This mix will go on about 1/4" thick bringing the pour up to approximately half way full.
While this layer is still wet, I made yet another 3/4 bucket batch of AR Fibered Mud and added four layers of Scrim (Fiberglass Mesh sold in rolls) with very thin coats of mix between. This was consolidated using a fiberglass roller. Now the pour should be about 3/4 full. I made one final 1/2 bucket batch still using the AR Fibers to bring the pour up to 7/8 full.
Finally, I mixed a half bucket of the Face Coat Mix to finish the fill -as done in the first part of this step. And while this is not totally necessary. I also added Shells to this mix because I wanted to finish out the bottom the same as the top. After all the mud is smoothed out, cover the entire structure with plastic and wait 48 hours to de-mould. This is the hardest part IMHO.
Step 7: Optional Water Polishing and Sealing
I have to apologize for not getting any photos of the de-molding... I got kinda excited.
Taking it apart is really just going through the putting together parts... but in reverse.
Just don't force anything or use metal objects to pry. If you do this correctly, the melamine materials can be reused.
Polishing isn't really necessary since the sheet gives a great textured finish, but in this instance we are trying to expose the aggregate so we have elected to polish. This can be done with inexpensive diamond hand polishing pads or if you prefer and you have one a water polisher.
Sealing is an option as well depending on the items projected use, but I recommend it because this is a tea or coffee table...right?
That said, I sealed mine with a Acrylic Based Sealer sold for counter tops.
There is a great instructable showing the process.
I recommend following the directions on the label of the sealer that you choose.
G'luck and enjoy your tea table.
Step 8: Finished Tea Table
Now, I am only human and while I believe I have covered all the bases- it may be possible that I missed answering a pertinent question you may have. If so, please feel free to comment and I will do my best to respond.
And please enjoy these lovely pictures my wife has taken of the Fabric Formed Tea Table Projectin GFRC.
We have a be nice policy.
Please be positive and constructive.