How long does it take pre-cat lacquer to cure

[Alan Lightstone]

I've run into this a couple of times this week. I sprayed some pre-cat lacquer (Chemcraft is what my local supplier has) on some cabinet doors, and when I flipped them over to spray the other side, the painting triangles left some indentations.

This was after 3 coats of lacquer, all sprayed the same day. So the lacquer was sitting for at least 3-4 hours after the last coat before I flipped the boards.

I know I can usually recoat with this lacquer after about 20-30 minutes, but how long until it is cured and resists marking from the triangles or other objects?

I actually did some work on another piece today which was sprayed two days ago. I set it down over a cutting mat for a couple of hours. There were some stray pieces of scotch tape remaining on the cutting mat.

When I lifted up the piece, the tape left indentations on the piece, and it needed to be re-sprayed. That's nuts.

When in the world will this stuff cure. It certainly feels bone dry to the touch.

[Wayne Lomman]

Alan, pre cats vary a lot from one product to the next in the time required for full cure. Applying multiple coats in one day also extends final hard dry time. It will work better to apply the first coat in the afternoon and the rest of the coats the next day. Make sure you have good air circulation. If it is a solvent borne product, a fume laden atmosphere slows down curing. If it is water borne, high humidity may slow it down. Horizontal surfaces such as table tops cure slower - tilt such items so they don't trap a layer of VOC's above the surface. There are many different pre cats so with a bit of research you may find one that works better for you. Even Chemcraft have a range of them. Cheers

[Prashun Patel]

I have had the same thing happen with shellac and deft lacquer. I find it now preferable to lean the piece against a wall to dry so the contact point is the edge of the board. This means you have to spray the edges separately.

[Mark Kornell]

I quit using painters' triangles due to the same symptoms you observe. Typically you use 3 or 4 triangles on a piece, and the entire weight of the piece is borne on those spots. And most finishes, even 2K ones, take well over a day to cure fully.

What I've taken to doing is making my own "bed of nails". Take a piece of plywood/MDF scrap and fire a bunch of 2" 18g brads through it (23g pins are too weak) - about 1 brad per 3-4 sq. in. When spraying a piece I can spray the B side, immediately flip and spray the A side. The large number of points distributes the load much more evenly and the small size of the points makes them much less noticeable.

On everything but nitro, you'll sand between coats which gets rid of any nibs that might be there. With nitro, the nibs get melted down and go away.

On the final coat that I change it up and spray one side, wait for 4 hours and do the other side.

And scrap sheet wood plus brads is way cheaper than painters' triangles...