Special Notes for Recovering a Dentist chair
This tutorial is not intended to give all the details of recovering a dentist chair, but on of the part that regards to gluing of the contour area and using a heat gun. Also, if this is your first time in gluing a concave area, or if you have any hestitancy, I'd recommend that you make a prototype. It is extra work, but it could save you a lot of grief.
Also, read through this entire tutorial before starting. Make sure you understand it and have all the necessary tools and supplies on hand.
Special Tools and Supplies needed
In addition to the normal upholstery tools, here are the additional tools and supplies need to remove the old cover and to apply the new foam and cover
- Heat gun
- Foam spray adhesive
- A marking pencil (Don't use a felt tip marker anywhere as that can bleed through the cover.)
- Several sheets of Painter's plastic (to cover and protect the new vinyl during gluing) (We buy the painter's plastic in a 9' X 400 foot role of about .32 mil. We use it for a lot of stuff.)
Remove the Existing cover
Remove the staples from the old cover, as is normally done.
Separate the Old Cover From the Foam
After you have removed all the staples you may find that the existing vinyl cover was probably glued to the cover. (If the cover wasn't glued on, then you probably don't need to read any of this article.) The best way I have found to get the old cover separated from the cover is to use a steamer. Apply steam to the underside of the old viny at the point where the vinyl is glued to the foam. Keep head of steam close to glued edge as you put the cover firmly, but gently away from the foam. The steam softens the glue enough to let you slowly separate the vinyl from the foam. For any areas where the steamer isn't enough to get the vinyl free from the foam, (after applying steam) quickly use a single edged razor blade to carefully scrape the foam off the back side of the vinyl.
Choosing a Glue
There are many brands of foam glues available. Call or go to an upholstery supply house and ask for a good quality aerosol foam & fabric glue that will give a permantent bond.
When gluing foam, only use a foam that is made specifically for glue foam, (often called "foam & fabric glue") which will also glue foam to fabric or to the back side of upholstery vinyl. Foam glue dries flexible so you can't tell that the foam under the cover has been glued. Other types of glues can try lumpy or brittle.
Foam glue comes both in bulk and in spray cans. Unless you frequently are doing a lot of gluing, it is just much easier to use the spray adhesive, which is what we use.
Foam glue can be used for a temporary bond or a permanent bond, depending upon the type of glue you get and how you use it.
For a temporary bond apply adhesive lightly to one side
For a more permanent bond, apply a heavier coat to both sides. This requires a bit of practice. If you put the foam together to quickly, the foam won't be tacky enough to hold together. If you wait too long so that the glue dries too much, then it won't be tacky enough to stick very well. The temperature also makes quite a bit of difference on how long the glue needs to sit before it gets tacky. When the shop is cold the glue takes a long time to get tacky and still might not stick very well. Conversely, in a hot shop (mid Summer) the glue dries very quickly and you need to be right there testing it to see when it is ready. Often, it will be ready within 30 seconds after you have sprayed the glue. Experiment with how to apply it on scrap foam at first to see how it works best.
Smooth Out The Damaged Foam
In spite of your best efforts, separating the old cover from the foam often leaves little holes or tears all over the foam. To smooth out that rough top foam we glue a piece of 1/2" foam over the old foam. Here are the instructions.,
- Use the Painter's Plastic
- Cover your table or work area with the painter's plastic to protect it from the glue.
- Always cover (or remove) any surrounding work area, fabric, foam, or other articles whenever you are spraying.
- Have a sheet of High Quality 1/2" foam handy, (Don't a cheap quality foam here) Make sure that the foam is larger than the total area of the foam.
- Position the foam over the top of the old foam so that it covers and overlaps all the old foam clear around all sides.
- Put something heavy on the end of the foam (but not in the concave area) to hold the foam from moving.
- Fold the foam back off the concave area (Mark the outer edges of the concave area on the underside of the new foam)
- Apply glue to the concave area and to the matching area that you marked of the undersided of the new foam).
- Allow the glue to dry to the dry tacky stage.
- Carefully start to unfold the top layer just litte at first. Press it together just a few inches at first. Then try to gently pull it apart. It is is the right amount of tacky, you shouldn't be able to pull it apart.
- Now, starting in the center, press it into the concave area, keep the sides of the top foam up until you have the center pressed into place. Press down the rest of the foam that had glue applied to it.
- The glued area will serve as an anchor to hold the foam in place.
- Now fold back the foam that covers the other top area of the chair seat or backrest.
- Apply the glue (as explained above) to the top area of the old foam and to the bottom of the new foam (which is now on top).
- When the foam is sufficiently tacky, unfold the foam and roll it into place, press down on top to secure it firmly in place.
- Cover the top of the foam with painter's plastic to protect it from the following steps.
- Then, doing one side at a time, fold the loose sides of the foam up and spray the back of the foam layer and the old foam, which will be beneath that foam. When the glue is tacky, roll and press it down into shape.
- Repeat with the other sides.
- Trim the edges of the foam so it doesn't overlap the wood frame.
Applying the Cover
It is assumed that you already know how to cut and sew the cover, so that won't be covered here.
These instructions assume that you have already cut, sewn, and tested the new cover to make sure it fits. (Make sure the new cover fits good before you start putting it one. You won't be able to easily get it back off to fix something.) We also assume that you have made the new cover with some type of fitted corners.
Carefully check all cording seams to make sure that they are sewn correctly.
- Lay the chair seat/back flat on the work table.
- Put the new cover onto the chair, pull all the corners down into place. Carefully check that the viny is long enough to reach the wood where it will be stapled, and is longer by at least a couple inches all the way round. This is your last chance to make sure everything fits correctly and is properly aligned (all corners are exactly lined up, etc.)
- Making sure that nothing moves out of place, put some flat heavy items all over the end of the cover opposite the concave area. Put the heavy objects almost to the very edge of the concave. (You may even put one temporary staple at each of the two corners (at the edge of the vinyl way in from the edge of the frame) at the opposite end as the concave area.
- Put the painter's plastic over the cover and all the items on that end. (Also make sure that the work table is covered with the plastic.)
- Slowly and carefully fold back the vinyl cover (on the end with the concave) over the other end. (You are folding the cover in half.) As you fold the cover, mark around the outer edges and sides of the concave on the back side of the vinyl cover.
- Before you apply the adhesive in the next step, practice unfolding and rolling the cover down into place as you pretend to press the glue into place. (If you have someone to help you, have them practice this step with you.) Once you have the cover all rolled down into place, check the corners and see how they line up. (In fact, check all four corners of the cover to make sure they are all alligned with the corners of the frame.) If needed, you may practice this step several times. When you are finished, carefully fold the cover back in place, as you did in step 5.
- Spray the adhesive onto the concave area of the foam and onto the corresponding area (that you marked) on the back side of the cover.
- Let the glue dry to the tacky stage.
- (It would be useful to have someone help you at this point.)
- Carefully begin to unfold and roll the cover down, while pressing the cover into place, beginning near center of the cover at the fold. As the cover comes down, check the corners of the cover to make sure they stay aligned with the corners of the frame. As you are pressing the cover into place, begin in the center and move your hand out towards each side.
- When you have the cover all unrolled and pressed into place, put the corners down into place. Check the alignment. Make sure all four corners fit and that everything look good.
- At this point, you can decide if you want to glue the other end of the cover in place, or not. Since, whenever I glue a concave in place, I generally would glue the other end, I'll continue with the instructions.
- Put one temporary staple at each corner of the concave end, as you did above.
- Now the glued end will be the anchor. Remove all the heavy items off the other end. Remove the temporary staples. Cover the concave end with plastic to protect it from glue. Now Carefully fold the loose end of the cover back over the concaved end.
- Practice putting this down into place, as we did in step 6 above. Finish up by folding it back in place as we did in the preceding step.
- Spray the adhesive to center areas of the foam and the back side of the vinyl cover.
- Unfold and roll as you did in 10 & 11 above.
- Depending on how stiff the vinyl is and what style of cover you have made you may need to use a heat gun, especially on the corners. Read these pages: Heat Gun, and Using a Heat Gun in Upholstery.
- Finish the job as per regular upholstery techniques.