Need help with finishing plywood

venk67

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Oct 28, 2010
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Am making a very simple " train table for my son" using a chinese grade birch plywood.

Wife wants dark stain so my plan is:

Sand to 120 grit

Pre-seal with diluted shellac (Denatured alcohol diluted (50:50) with dewaxed ( if that is right term) Shellac to reduce blotchiness of stain)

Then use gelstain ( Java from general finishes) ( which I plan to slightly dilute with some paint thinner)

If that is enough I plan to sand with 220 grit sandpaper lightly then apply a  couple of coats of the water based poly finish from General finishes ( exterior 450-since I have some).

Questions:  1.  Any point in sanding intially to 180, or will that negatively affect the stain uptake

2.  any tips for applying the water based top coat- was planning on using a foam brush ? Bad idea??

3.  Can I buff the top coat with a buffer once the final top coat is done?

Venk

 
For a dark stain on birch, it would be a good idea to replace the shellac sealer coat with a dye stain (General Finishes make some that are very easy to use.)  I find it necessary in order to get any level of saturation from dark stains.  The shellac sealer would also prevent some of the absorption of the Java.

I would :
Sand to 120 minimum, probably 150/180.
Apply dye stain.  If you're doing a large area at once, get their "Extender."
(Next day) Knock down the raised grain with a fine grit paper by hand.
Apply Java gel stain.
Knock down the raised grain with a fine grit paper by hand.
Apply water-based sanding sealer.
Knock down the raised grain with a fine grit paper by hand.
Apply topcoats of poly.

 
venk67 said:
Am making a very simple " train table for my son" using a chinese grade birch plywood.

Wife wants dark stain so my plan is:

Sand to 120 grit

Pre-seal with diluted shellac (Denatured alcohol diluted (50:50) with dewaxed ( if that is right term) Shellac to reduce blotchiness of stain)

Then use gelstain ( Java from general finishes) ( which I plan to slightly dilute with some paint thinner)

If that is enough I plan to sand with 220 grit sandpaper lightly then apply a  couple of coats of the water based poly finish from General finishes ( exterior 450-since I have some).

Questions:  1.  Any point in sanding intially to 180, or will that negatively affect the stain uptake

2.  any tips for applying the water based top coat- was planning on using a foam brush ? Bad idea??

3.  Can I buff the top coat with a buffer once the final top coat is done?

Venk

If you feel the need to buff, you need to make sure the top coat is completely dry. Depending on weather that could take a week or more.
 
Long ago I did finish many cabinets I made from all kinds of plywood.

Then 6 years ago when I resumed building custom cabinets for sale, it turned out virtually all my wholesale clients either wanted to do the finishing themselves or they had a relationship with a finishing contractor. So when I decided to build a large commercial shop, I asked about having a paint booth for finishing. It turns out in Southern California the wait for spray booth permits is over 5 years.

On every cabinet project, I ask for instructions about sanding. Hardly any of the cabinets I make are going to be painted. Virtually all have expensive veneer with will eventually get a clear finish, but sometimes they will be stained first. Usually the finishers do not want us sanding finer than 120 grit if any staining will be done. That is how I used to do it. I would apply the stain at the 120 grit point, then make sure the stain was dry before moving to 150 and 180 grit.

Not wanting to pry, I have never asked the finishing contractors what happens after the cabinets leave my shop or are installed prior to finishing.

By the way, when shelf pin holes are involved, the plywood is pre-finished on the inner face, since it is not effective to use a finish after drilling shelf pin holes. If those cabinets need exotic interiors, I have a vendor that does excellent custom pre-finishing.
 
I always sand to 150 if a dark stain is applied.  With Birch you will be able to see cross grain scratches if you finish at 120 with a RO sander.  If you are using a oil based stain I would start with an oil based conditioner then apply the stain immediately.  Consider a coat of undiluted Sealcoat over the stain after 24 hours, then sand and apply the Poly.

Foam brushes work but can cause bubbles if you overwork it.  A good soft nylon/poly blend brush will keep the bubbles away but may leave brush marks if you are not careful.  As for the buffing...we are talking about a train table right?
 
[big grin]  Thanks for the advice:

Did finish the play table, it was made with some of the plywood ( from Chile not China) I had stuck on my jawhorses to create an extra work-space/ surface while building the toylander.

Sanded to 150 grit around the edges, but the top surface I think I went to 220

I did pre- treat with diluted shellac ( 50:50) then applied the gelstain.  Knocking down any grain with a 3 M pad ( fine sanding pad- "for use between coats")

Once dry, I used a minwax rub on POLY.

Once that was completely dry I used my rotex 90 to apply a glaze autopolish and then some carnauba wax (P21 I think).

I believe the whole surface was buffed with my shinex. ( Kevin- agree it is only a train table, but i had to get wife approval to get it into the house, and she likes high gloss finishes!!)

The pseudo aluminium corners are made of wood, sprayed with autobody primer, then sanded to 600 grit, then aluminium metal paint from rustoleum applied with foam brush- then wet sanded with 600 grit paper

normal_finished_play_table.jpg


normal_finished_palytable_2.jpg


The pseudo metal is pinned in place with my Grex pinner.

Kreg joints and domino used to assemble the table- no glue so it can be dismantled or adapted when his needs change

Venk
 
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