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Refinishing Old Varnish Surface

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Riviera Wish
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Refinishing Old Varnish Surface

Post by Riviera Wish » Mon Jan 01, 2018 3:28 pm

I am attempting to refinish a year old Interlux Schooner 96 varnished sides on my '52 Riviera. Some areas of the sides had gone dull (sucked up) and a re-coat was in order. I had 'blocked the sides with 320 grit sandpaper before reading the table on the Schooner 96 can which says "Sand old finish thoroughly with 120-150 grit production sandpaper" for 'previously varnished surfaces'. Sides of the boat are currently sanded to 'white out' condition in 320 grit. I'm afraid to go back and sand the sides with 150 grit paper for fear of breaking through to the mahogany stain.
My question is: Will the Schooner 96 varnish adhere properly to a year old varnish surface that is sanded thoroughly with 320 grit sandpaper?
Suggestions will be appreciated. I do not want to strip the sides and redo the stain, etc. Thanks in advance.

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Brian Robinson
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Re: Refinishing Old Varnish Surface

Post by Brian Robinson » Mon Jan 01, 2018 6:12 pm

It will be fine, anything rougher than 320 will show through a final coat anyway.
-Brian
1923 Hackercraft 23' Dolphin #03
1938 Gar Wood 22' Streamliner #6256 Empress
1952 Chris~Craft 19' Racing Runabout #363 Thunderstruck
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Captain Nemo
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Re: Refinishing Old Varnish Surface

Post by Captain Nemo » Mon Jan 01, 2018 6:26 pm

It should stick just fine, especially since it’s not a recoat of an old, hard, dried out finish.
Boats are to be made of wood, otherwise, God would have grown fiberglass trees.

Riviera Wish
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Re: Refinishing Old Varnish Surface

Post by Riviera Wish » Mon Jan 01, 2018 10:52 pm

Thanks for those replies, I can proceed with confidence.

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Don Danenberg
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Re: Refinishing Old Varnish Surface

Post by Don Danenberg » Tue Jan 02, 2018 8:31 pm

A 320-grit "mechanical tooth" is more than adequate for a 1 or 2 year old varnish coat.

The can instructions are written to cover their arses for an 'old coat'.

What you should do (another 320-sand, if its been more than a year) is provide the best "Chemical Tooth"!

Wipe it all well with 3M-333 (Brushing Thinner, possibly 'Stodart's Solvent?)

This 'Chemical Tooth' is also mentioned on the can directions.

It will give good adhesion, and allow better flow into any grit-scratches that might show after.

Riviera Wish
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Re: Refinishing Old Varnish Surface

Post by Riviera Wish » Wed Jan 03, 2018 12:29 pm

Thanks Don. I have some '333' thinner and will wipe the surfaces down thoroughly before varnish application.

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tkhersom
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Re: Refinishing Old Varnish Surface

Post by tkhersom » Sun Jan 07, 2018 8:05 am

All great advice!

I am glad that you have the brushing thinner. I have done some tests myself and find that the brushing thinners are MUCH more pure than the generic "Mineral Spirits" paint thinner that you find at the hardware store. I will use "Mineral Spirits" for clean up and whipping down a sanded surface but always use brushing thinner for thinning my varnish and for the final wipe down before application.

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1957 CC 21' Continental "Yorktown" (Mom's boat)
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