Best way to pre- finish plywood?

[Dengue]

hi, I am making a 18mm plywood cabinet that I am going to paint. My previous experience with plywood is that no matter how well you sand the bare timber, after the first coat all these little cracks appear that need to be filled

Can anyone please advise a good way of finishing so that I get a nice smooth glossy paint finish that doesn't look anything like plywood?

What do you recommend for finishing the plywood edges, as I use this timber for the drawer fronts too

[Master Splinter]

The best way to get a smooth 'doesn't look like plywood' look is to not use plywood in the first place; use MDF.

If you've got a good quality ply (ie not cheap structural/non-structural ply from a hardware store) you can use something like Timbermate (see - http://www.youtube.com/watch?v=aF5t__N3q3M ), but if it's cheapus pinus crapiata ply I'd be tempted to use an epoxy as the grain filler as this would toughen the surface (and the edges) up a bit.

[Matador]

Hi Dengue,

When you finely sand your ply wood down after using all your different grades of sandpaper. Try this if you have brown paper bags cut it up like you would use sandpaper. Than by hand go over your finely finish to get a beautiful smooth finish and be surprise how smooth and shiny it gets for a finish. I have used it on MDF, Ply and other timbers. It is cheaper than steel wool. I use the inside of a brown paper bag first which is a bit coarse than I use outside which is finer. I was toll about this awhile ago I finely tried it and I got a shock how the timbers came up smooth with a shiny surface. Let me know how it works it you do try the brown paper.


Cheers Graham.

[goldcoast]

Great discussion over here..i also find best way to pre- finish the plywood to make that safe from outside damages and attacks.

[soundman]

First of all plywood aint plywood sol.....there is a great variation in surface quality between different products.

Almost all plywood will have microscopic cracks from where the veneer has been rotary cut then laid flat.

you can put a hell of a lot of work into ply and still have the cracks re-appear.

the better plywoods for the purpose will come from timbers that have less tendancy to open up in cracks.
radiata is a shocker for it.

euro burch is probaly as good as it gets...this us a much more dense and closer grained ply...and heavier than lots of other plies.

if the job is interour and will not be exposed to sun or heat.....you can go at it with a sealer of choice.
Thin the sealer down for the first couple of coats and let it soak in..then go to a less thinned mix.
do not even think about top coat products till the surface is fully choked out.

You need to sand between coats..but be carefull....if the ply has soft and hard bits..you will get an uneven texture.

ply is realy hard work getting a good stable fully choked out finish.

now if it is outdoor you are talking about, there realy is only one choice and that is marine epoxy.....if you realy want it stable, you may as well lay up a sheet of 200GSM glass with a couple of coats of epoxy, before you tray and sand to a smooth finish...done properly you will not see the glass mat.

sand this all flat...making sure you do not sand thru the epoxy and coat up with a good quality marine varnish.....AND expect to resand and reapint every 2 years.

there is no such thing as a long term weather stable clear finish.

If you want a long term weather stable finish it has to be opaque.

cheers

[Robson Valley]

Which species of wood/tree is used for the surface veneer in the sheet?
That will tend to dictate the possible finishing strategies.
If you had G 1 S Dougfir plywood from my place, piece of cake if you want a hard, glossy finish.
If the surface were pine, cherry, oak, walnut, apple or what ever, all bets are off.
I can do them all (the way I want to see them).
But a little more up front wood stock info would help a lot.