Need Advice Help please

[John Jimenez]

All you finish gurus, I need some help. I am making a book shelf with a cabinet on the bottom on a commission job.. I made the cabinet door panel with 1/4” plywood. It’s the same plywood I used for the cabine5 backing. I sanded the plywood with a quick 220 and wiped with mineral spirits. I used minwax red mahogany stain and it looked good. When I sprayed it with lacquer, these lines showed up on 3 of the 4 door panels. Since these don’t show up on the cabinet backing panels, I’m thinking this section of plywood may have had packing straps across it at one point and that caused some imperfection in the top player of the plywood. I tried to touch it up with a light stain coat but to no avail.

I’m thinking about remaking the 3 doors and using a new plywood sheet. I’m worrried if I tried to sand it out then the finished product would look like total butt. Any thoughts on causes? Any suggestions on fixes?

View attachment 1788457613888.jpeg

 

[Henry W]

Hate that for you, but agree with your assessment of the likely cause and the likely best solution. Recovery from that seems unlikely to me.

 

[ChemE75]

Since you’ll be making new doors, maybe try using a cabinet scraper on one panel to get down to a clean surface then restain - if no good, you’re only out a bit of time. But it does look like some coating or residue from strapping or stickers soaked into the face veneer. Optionally, a heat gun may soften the door frame joint glue just enough to take apart frame so you can slide out the panels, veneer, stain and reassemble.

 

[Charlie]

It looks like divots from a drum sander or something from the manufacturig process. The sander had coaser grit than 220, therefore it would take stain differently.

 

[Oka]

Agree with Charlie. Might buy Polar or Maple. Then, sand, scrape & then seal.. Might consider Baltic or MDF for the panel. Most big box ply is usually 120, or 150 grit.... higher end ply is usually 180 with tighter QC

 

[old and in the way]

John Jimenez:

I suppose what I would question is your sanding sequence prior to finishing. To give a piece "a quick 220", without starting with coarser grits to remove those scratches and imperfections that 220 grit will not touch, and then working your way up to 220 grit, might be asking for trouble. A lot can happen between the time the plywood leaves the press and the time it makes its way to your shop.

I generally start with 120 grit to remove obvious imperfections, then a very thorough sanding with 150 grit, and then 220 grit to prep before finishing. If I were staining the piece, especially with a dark stain, I might consider going to 320.

Even with all of that, I have had issues with rotary cut veneers. Sometimes, a nick in the veneer knife will cause a lot of problems that don't get noticed until it is too late, although this looks more like a post-pressing scratch of some kind.

Might it be possible to tint a lacquer topcoat to cover the scratches? I suppose that you would have to tint the entire piece to match, but if it works, and that is acceptable, it may save some trouble.

FWIW. Just trying to help.
Tone

 

[John Jimenez]

Thanks everyone! As usual, y’all are very helpful and knowledgeable. I had a thought about maybe sanding the panel and gluing a veneer on and then restaining and lacquer. I’ve only done a little bit of veneer work. Thoughts? It’s what I get for buying the 1/4” oak plywood from big box store for furniture

 

[Craptastic]

If the uneven stain pickup is due to compressed wood fibers from packing straps (your original guess it sounds like) you could try relieving the the compression in the wood and then restaining. You could test this on a small area to see if it would help. First, sand the test area. Then try heating an iron to a moderate setting and after laying some moist cloth on the spot use the iron to heat the moisture and the wood together. This should help the wood fibers expand with the moisture/steam (same technique many door manufacturers use to "pull" dents back out of wood veneers so don't be surprised if the wood shows bumps or raised areas afterwards). Make sure you sand again before re-applying stain/finish (I know, duh. But you wouldn't believe...).

May be worth the try, especially if you are resigning yourself to veneering the piece to cover the area.