Pre-finishing plywood for cabinet carcasses

[William Powell]

In my market, one needs to buy a unit of 30 sheets to acquire maple pre-finished plywood. I am not at the point where I need that many. So, I think I will pre-finish it myself. I don't believe I can apply an industrial finish like Columbia and others do. Also, I'm thinking that the finish I apply needs to be resistant to abrasion as it will be machined afterwards. I'm thinking a floor approved clear finish might be best. I know there may be an issue with out-gassing. Yet, if one has a thousand or more feet of flooring, how much of a problem could out-gassing be? Anyone have any recommendations? Let me say this. I am looking for commonly found clear finishes and not those made by Target, General Finishes, Hood and others which I would have to order on speculation. I am also leaning towards cheapness. Though that may be an issue of which I just have to get over.

As always,
Thanks for your input
Bill

[Todd Burch]

What is your objective with prefinished ply? The interiors?

[William Powell]

What is your object with prefinished ply? The interiors?
Yes.

Thanks for the question, oddly the system would not let me simply answer "yes".

Bill

[Todd Burch]

I have prefinished ply (interiors of cases) quite a bit in the past for high-end projects. I cut all parts to finished size, then tape off any glue surfaces, the apply the finish. After assembly, I tape off the inside and finish the outside.

One time I needed to prefinish a countertop. I did it, and then cut it onsite to perfect size using my Festool circular saw and guide system. No tear out at all.

Since all my parts were already cut out, I didn't need any fancier (or tougher) finish that what I was applying to the rest of the pieces.

Todd

[William Powell]

I have prefinished ply (interiors of cases) quite a bit in the past for high-end projects. I cut all parts to finished size, the tape off any glue surfaces, the apply the finish. After assembly, I tape off the inside and finish the outside.

One time I needed to prefinish a countertop. I did it, and then cut it onsite to perfect size using my Festool circular saw and guide system. No tear out at all.

Since all my parts were already cut out, I didn't need any fancier (or tougher) finish that what I was applying to the rest of the pieces.

Todd
Yes, I understand. I mean to pre-finish the entire 4x8 sheet. Any advice?
Thanks
Bill

[Todd Burch]

Yes. I would never do that. LOL. What's your motivation to do the whole sheet?

[Jim Kountz]

I understand your idea of trying to pre finish the entire sheet first. I tried this in the past with mixed results. The first thing is trying to keep it from getting scratched while machining it as you mentioned. The table saw does the worse damage. My router table wasnt so bad since its plastic laminate.
You have to be really careful in just normal handling, dings and dents really show up bad.
My suggestion would be along the same lines as Todd described. Do your machining first then finish the components prior to assembly. This will yield you the best results imo.

[William Powell]

I understand your idea of trying to pre finish the entire sheet first. I tried this in the past with mixed results. The first thing is trying to keep it from getting scratched while machining it as you mentioned. The table saw does the worse damage. My router table wasnt so bad since its plastic laminate.
You have to be really careful in just normal handling, dings and dents really show up bad.
My suggestion would be along the same lines as Todd described. Do your machining first then finish the components prior to assembly. This will yield you the best results imo.

Okay, then why does one see on the TV shows as well as on this board the recommendation to use pre-finished? After cutting and machining, the glue area should be mostly clear of the finish for the carcass. Yes? or No?

My question has to do with what type of finish since I cannot do the industrial type the manufacturers use.

A floor poly maybe?

Thanks
Bill

[Julian Nicks]

If you want a tough finish, you can't beat laquer. Poly takes too long to dry for casework. You can finish a cabinet using laquer in only a few hours, versus a few days for poly.

[Jim Becker]

I have prefinished ply (interiors of cases) quite a bit in the past for high-end projects. I cut all parts to finished size, the tape off any glue surfaces, the apply the finish.

Exactly what I do. Taping off the glue areas takes time, but spraying into a closed box is not my idea of a "fun time"...

[Todd Burch]

My question has to do with what type of finish since I cannot do the industrial type the manufacturers use.


You hit the nail on the head. You can't do an industrial finish, and most finishes you can do (and I can do) won't hold up to what you want to do.

I have no facts to base this on, but my hunch is that the parts of the industry that do use prefinished ply (AKA, the segment of the industry the 30-sheet minimum prefinished ply is marketed to) are not moving it while it is being machined. I suspect CNC routers are doing the machining while the piece is held in place with vacuum.

Todd

[jim carter]

i built an entertainment center where i figured every single piece going into it ,cut every single piece and sprayed sanding sealer and laquer and assembled afterward but i have never sprayed an entire sheet. too many scratches,nickes and other things happening to do that.

[Jim Kountz]

Okay, then why does one see on the TV shows as well as on this board the recommendation to use pre-finished? After cutting and machining, the glue area should be mostly clear of the finish for the carcass. Yes? or No?

My question has to do with what type of finish since I cannot do the industrial type the manufacturers use.

A floor poly maybe?

Thanks
Bill

Pre-finished ply is recommended because its a great time saver and overall money saver too. Im not knocking the use of it, just most finishes one would apply in a home shop wont be anywhere near as hard or durable as the factory applied. The pre-finished ply Ive used is hard and can take alot more abuse than say for example a poly finish you apply yourself.

[John Lucas]

I have not heard of the 30 sheet min. Here, I bought 10 sheets for minimun purchase. If you cant get few sheets, call around at the cabnient shops and ask them if you can piggyback their next order. I also have a lumberrard who stocks the stuff...at a bit of a premium but better than buying quantity some times.

[Larry Fox]

Premium plywood in quantity and variety of face veneer species can be a bugger to find and I second John's advise to hook up with a local cabinet shop. Once you manage to convince them that you are not in the same game and going to be competing with them in any way they should have no issue with your piggybacking on an order. You can also order it a sheet at a time through Woodcraft but for more than an ocassional sheet it gets VERY expensive.

Finishing an entire sheet at a time seems like a pretty brutal way to go and were I in your shoes I would entertain it only as a last resort ... oh, and I would use a Target Coatings product (probably their conversion varnish).

[Howard Miller]

I buy pre-finished ply by the sheet from this company:


http://www.hardwoodweb.com/

Call the company and get name and number of the sales rep that covers your area.

They sell to many of the cabinet shops in my city, and have a delivery at least every two weeks.

[Prashun Patel]

I also think you should break down the sheet before finishing.

If you rough cut it a little wide and long, then you don't need to be persnickety about keeping finish off the edges.

Do your final cross cuts on a sled lined with cardboard, and tape down cardboard strips on the your table saw for the final rips.

A waterbased softer resin product like Polycrylic might be appropriate in this case. It'll dry quick, won't gas, and will be marginally more flexible than some of the harder finishes (lacquer, shellac) which MIGHT provide marginal protection during final machining.