Prefinished Plywood?

[Andrew Wayland]

Out of curiosity: when working with prefinished plywood: how do you handle any tear-out or other general nicks?

(Wondering if its worth buying prefinished or if I should just “prefinish” my own plywood, where I can touch up where needed... cost difference is about $35 a sheet)

[Jim Matthews]

That's steep, unless your in high production.
Pre-finished with catalyzed lacquer removes the need for a dedicated booth and sophisticated dust control.

For a duffer like me, I'll stick with Shellac.

I tape off and score my cutlines with a knife before cutting with an edge guide and circular saw. Again - small volume makes that possible.

[Andrew Wayland]

That's steep, unless your in high production.
Pre-finished with catalyzed lacquer removes the need for a dedicated booth and sophisticated dust control.

For a duffer like me, I'll stick with Shellac.

I tape off and score my cutlines with a knife before cutting with an edge guide and circular saw. Again - small volume makes that possible.

Don't get me wrong: I'll be using wipe on Poly or something if I pre-finish my own boards... so the quality won't be as "good". But it's for a closet... so it'll hide behind a door.

[Jim Becker]

Managing tearout is a matter of using tools and techniques that don't cause it. Scoring blades on sliders, the track/saws combination design for that kind of tool, pre-scoring the edge with a knife and use of an ATB blade with very sharp corner or a dado set that scores the edges with bat-wings, using scrap backers at the rear of a cut to prevent damage when the blade exits the material for a crosscut, etc. Lots of different ways to avoid tearout.

[Andrew Pitonyak]

Out of curiosity: when working with prefinished plywood: how do you handle any tear-out or other general nicks?

I do not pre-score, but I probably should. My Forest Plywood Blade is pretty clean. I am likely to use painters tape, it does help. I also might pay attention to which side is down / up based on which side will generate more tear-out and which side will be visible; which is not always relevant because both sides are directly exposed.

(Wondering if its worth buying prefinished or if I should just “prefinish” my own plywood, where I can touch up where needed... cost difference is about $35 a sheet)

The real questions should probably be along these lines:

1. What is your time worth? Will you spend hours finishing something and $35 would have saved you the time?
2. Do you really hate finishing?
3. Will you still have parts that you will need to finish and then you have to match it? This is likely if you have to edge the plywood. Might, or might not, make a difference.

I have only used finished plywood once on some shop cabinets and it saved me a bunch of time. The cost difference was negligible when I did it.

Edit:

I particularly like pre-finished plywood for drawer bottoms, especially when I will not be otherwise finishing the inside of the drawer.

[matt romanowski]

The finish on the prefinished plywood is really hard and wears great. I did some cabinet add on shelving and drawer slides with it and no problems with it tearing out or anything else.

[Bernie Kopfer]

I used prefinished plywood to make a dozen pullout drawers in a pantry. I know that halfway thru the job of spraying finish on them I would have paid a hundred bucks to have it done with. For me it was money well spent.

[Mark Bolton]

We run pre-finished 1 and 2 sided ply almost daily. its a no brainer when it works for what your doing. There is not a snowballs chance in the hot place you can sand, seal, spray, scuff/de-nib, and second coat, a sheet of ply for 35 bucks and I'd bet if you shop around a bit you'd find that its nowhere near that much more than raw. We cut for another shop that insists on buying raw and finishing themselves and they buy a slightly higher grade of Maple than we bring in pre-finished but we often times pay less than they do for pre-finished and if we pay more it may be 2-3 dollars a sheet more than raw. No sandpaper, no labor, no finish at 50-100 a gallon, nada.

Chips and tearout are dealt with by either not letting it happen in the first place or dealing with it in your construction method. Dado/rebate will kill a lot of it but a good blade and sharp tooling and you'll not have to deal with it.

People say you have to be careful of scratches and handling. We never find that an issue but we dont handle material like baboons either. The UV cured finish they can apply at the factory in a controlled environment is far tougher than anything that will ever come out of the average shop.

Its not for everything but where it shines its money in the bank.

[Andrew Wayland]

We run pre-finished 1 and 2 sided ply almost daily. its a no brainer when it works for what your doing. There is not a snowballs chance in the hot place you can sand, seal, spray, scuff/de-nib, and second coat, a sheet of ply for 35 bucks and I'd bet if you shop around a bit you'd find that its nowhere near that much more than raw. We cut for another shop that insists on buying raw and finishing themselves and they buy a slightly higher grade of Maple than we bring in pre-finished but we often times pay less than they do for pre-finished and if we pay more it may be 2-3 dollars a sheet more than raw. No sandpaper, no labor, no finish at 50-100 a gallon, nada.

Chips and tearout are dealt with by either not letting it happen in the first place or dealing with it in your construction method. Dado/rebate will kill a lot of it but a good blade and sharp tooling and you'll not have to deal with it.

People say you have to be careful of scratches and handling. We never find that an issue but we dont handle material like baboons either. The UV cured finish they can apply at the factory in a controlled environment is far tougher than anything that will ever come out of the average shop.

Its not for everything but where it shines its money in the bank.

I guess I should have been a bit more clear in my original post: this is just for a home project: nothing on a production scale! If I were to factor in the labor and what-not, you’re right: the cost of Prefinished would come out ahead.

But, for 2-3 sheets of plywood: a gallon of poly would cover it... and a sheet or two of sandpaper would cut it to.

That all being said: I just bought a new track saw and new blade... so I suppose tear out should be negligible. And it sounds like any the Prefinished material will have a significantly better finish on it than I could ever apply!

I do plan on drilling some holes for adjustable shelving: that might be the only wild-card here...

[Mark Bolton]

I guess I should have been a bit more clear in my original post: this is just for a home project: nothing on a production scale! If I were to factor in the labor and what-not, you’re right: the cost of Prefinished would come out ahead.

But, for 2-3 sheets of plywood: a gallon of poly would cover it... and a sheet or two of sandpaper would cut it to.

That all being said: I just bought a new track saw and new blade... so I suppose tear out should be negligible. And it sounds like any the Prefinished material will have a significantly better finish on it than I could ever apply!

I do plan on drilling some holes for adjustable shelving: that might be the only wild-card here...

Even at 3 sheets of material, if you really pay 35 a sheet more, that'd be $105. Your gallon of poly (even if you buy home center oil or water) is going to eat 40% of that, if your crazy enough to use oil, your talking several days between sanding, drying, scuff, etc... Whats your time worth? If you use water you could probably roll/pad finish 3 coats (minimum with dog poop minwax waterborne) in a day... so 8 hours... give yourself 5 bucks an hour for labor, pads, cleaning out, sandpaper, etc.. $40 for your time, 40-60 for the gallon of material, seems a wash, and as you say, youll have as close to a bullet proof clear as you can get.

Drilling, sharp brad points for your shelf holes and you'll have zero issue.

[Ole Anderson]

Holes for adjustable shelving works best of you have a template and are able to use a plunge router and bit with a template bushing (Woodhaven here). Least amount of tear out. Go with prefinished, proper technique (track saw and a zero clearance insert in your TS) will result in negligible tear out.

[Mark Bolton]

Who the heck edited my post?

[Jim Becker]

Mark, neither of your two posts above are marked as edited...