Final Preparation for Paint

SPECIAL 9/10/14 UPDATE  

If you are following along with this restoration as a means of obtaining information for your own project - and perhaps you've already read this post - I want to add some additional information that I've only realized since I have proceeded to actual painting.

First of all:  220 grit sandpaper is probably okay for knocking off the high spots on your primer.  Finish up with 400 grit.  I'll show you the results of stopping with 220 grit in another post. Sanding scratches are going to show through in your first coats of paint, but we are going to gradually work the paint down between coats with 600 grit for our final sanding.  You can go finer, but for a working carriage, this may be good enough for you.  More details when we move on to painting.

I have certainly learned that following this next procedure will not necessarily give you a perfect surface but it will be very good.  It may take 3-4 coats of enamel and meticulous sanding between coats to get the glassy surface we all want.  Please be patient and don't get discouraged.  I have already done that for you!


Three coats of primer and a guide coat when last we met.

Following an overnight dry, the seat was moved into a nice patch of shade.  Got my stool, got my 220 grit wet sand paper, got a couple buckets of water, a chamois and assorted sanding blocks.  Forgot the sponge until a little later.

The task is to get all that dark stuff off.

The paint manufacturer recommended 150 grit sandpaper but that seemed much too coarse, so I started with 220 grit, and this is what began to emerge after just a few strokes.  Hmm, I think, this is going to be easy!  Yeah, right!

With a lower quality paint, even sanding scratches from 220 grit will show through in the final coat.  We'll see what happens.  We do have to be concerned with adhesion, so while we want a smooth surface to paint, it still needs to be rough enough to grab and hold the coats of paint we'll be applying.

Unfamiliar with "wet sanding"?  A moment to explain.  Wet sanding is a process that is used to produce the best quality surface for painting, and for sanding in between coats of paint.  A special type of waterproof sandpaper is used.  One needs a bucket of water, to which they have added a small amount of hand soap.  Just rolling the wet bar of soap between your hands and rinsing them in the water is usually enough.  This lubricates the sandpaper and makes the work go more easily.  Alternatively, you can occasionally swipe the sandpaper over the bar of soap.

Usually the sandpaper is wrapped around some sort of "sanding block" which can be a purchased sanding block, or any number of items you have on hand, including paint sticks, putty knives, and in tiny places, fingernails!  In most cases you do not want to rub the paper over the surface with just your fingers, because you will not get a flat, level surface this way.

As you sand, you will want to continually wash away the sanding sludge, by holding a big water soaked sponge over the area you're working on, to continuously wash away the sanding sludge.  You want to stop sanding as SOON as you have sanded away all the guide coat, because it is so very easy to cut through to the bare wood.  Sometimes it's hard to stop the motion of your hand soon enough to make that one extra swipe.  Washing the sludge away constantly is the only way to see exactly what's going on with the surface!

When you are satisfied with your work, you can go over the entire surface with a clean chamois skin to help dry the surface and finish up.  If you have compressed air, it's a very good idea to blow any water out of cracks.  At any rate, the sanded part needs to be left to dry thoroughly before coating with paint.

Getting back to the task at hand, here is the first panel completely sanded.  The only bits of guide coat left remain around the edges of a large bolt head, and around a hole that will be covered up by another bolt head.  Right now I'm thinking this is a piece of cake.

On to the seat back.  The first few strokes once again make it seem easy.

By now I'm beginning to bog down around the edges and the bolt heads.  Such care must be taken not to cut through!  My sanding blocks are becoming smaller and smaller as I have to work into more and more fragile places.

But eventually the job gets done.

On to the much maligned repair panel.

By now the work was becoming enormously tedious.

And the last panel was absolute misery.

But the edge around the bottom of the seat remained.

And as you can see, there are a few places that still show some black.

So the difference between a truly meticulous restorer and me is those specks of imperfection, which I fully intend to leave.

The time to sand this seat smooth was a ridiculous four hours.  And it is as done as it is going to get.

And I also need to be honest and report a potential Abatron fail in the seat corner above.  There is a hairline crack developing at the upper edge.  It is an inch long and nearly invisible.  I believe that I may have stressed the repair before it was fully cured when I rejoined the two panels with the metal strap and the corner block on the inside.  All I can do is hope that nothing else lets go.  Next time I glue or "fill" a defect with epoxy, I will wait at least a WEEK before I put any stress on it.