Varnish and Sanding

goldencub

Carpenter
Hello - I am about to the point where I will start to varnish. I have new wood and some original varnished wood. For the new wood, why do I have to sand between coats? And more important, what happens if I don't??? Is it simply a question of surface smoothness, or has it something to do with the bonding of the new coat to the previous coat applied perhaps a few hours earlier??? As you may guess, I hate to sand those uneven interior ribs/planking surfaces. Thanks for your guidance!! Al
 
Sanding between coats isn't as big a deal as you think. It only requires a light going over with some partially worn out sand paper. Be sure to vacuum and tack rag between coats. You just want to remove the roughness that occurs when the varnish is applied. Of course you can also clean up runs and dust spots. That takes a little more effort.
 
Sanding between coats is mainly for bonding purposes. The subsequent coats of varnish will not adequately bond to the previous coats unless you rough it up a little. Some finishes (shellac/alcohol used in French polish is one example and some modern plastic finishes) will chemically bond to a previous coat but none of the standard varnishes I've use in canoe or furnature building will to any acceptable degree. Thus roughing the finish up is needed.

Like Andy says, it doesn't take more than a light going over. I just knock down the gloss and level any drips, remove missed brush hairs and what not. I've used steel wool (not always the best as little bits of steel can be left behind if you don't clean well), used sandpaper or my personal favorite, sanding pads.

http://www.vermontabrasives.com/xcart/main.php

You don't have to use this brand in particular, I just posted the link to give an idea of what I'm talking about. most paint stores have a selection of inexpensive pads. I've even used those green pads found in the grocery store for doing your dishes.
 
As we all know the true reason for sanding between coats is a myth created by the greedy capitalistic varnish manufactures that is as old as the shellac beetle. Workers of the world need to unite to throw off the yoke of excessive varnish created by the profit takers of varnish, sandpaper, dusk mask, masking tape, rubber gloves and hand cleaner!
They say its for "Bonding". They say its for "Smoothness". They say its for "Quality". But who has ever tried not doing it! They also say they can prove the existence of Black Holes because you can't see them! How long can we be controlled by the "They"
YOU have been called, Al, to lead the movement toward the light. Stand for the new new movement, WCHA Workers United- NO SANDING- NO MORE!

Well, its back to the shop. I have to sand and varnish two more boats before the customers come. :)
 
Yeah, but some thoughtful person pointed out that nothing ever happens unless first a dream! KEEP IT UP ROLLIN!
 
I WILL LEAD THE WAY TOWARD THE LIGHT OF NO SANDING --- starting tomorrow! But today I sanded and put on the second coat. Except, that is, on the underside of the seats, where coat #2 is applied directly onto coat #1. I suppose I will have to put a mirror on the floor under the seats so I can watch the defoliation process and report to the WCHA Workers United. Regards, Al
 
Your leading the way Al! As chairman Mao once said "The first non sanding stroke does not begin with a thousand steps" ...or something like that.
The Epiphanes No Sand varnish is a false "profit" leading the World Of WCHA Workers (WOWCHAW) to the brighter path chosen by "THEY".
Follow Al- NO SANDING-NO MORE!
 
Sanding song

To the tune of Rawhide (appropriate eh?, ever get hooked on an improperly clinched tack?). This little ditty really get's the sanding juices flowing.
There are more verses so please edit and add to suit your fancy. The simple refrain does go a real long way though. Try it:D I've been sandin, sandin, sandin for hours and see no end in sight......

Sandin’ Sandin’ Sandin”

Keep sandin', sandin', sandin',
Though your disapprovin'
Keep them wood blocks movin' Rawhide!
Don't try to undersand 'em,
Just sand and clean and sand em,
Soon we'll varnish high and wide.
Boy my heart's agitatin'
My tack cloth is a waitin', waitin till the end of this chore.

Sand a rib, Sand 'em up,
Sand a deck, Sand 'em out,
Sand a plank, Sand 'em out Rawhide!
Sand a rail, Sand 'em in
Sand a stem, Sand 'em out,
Sand a thwart, Sand 'em in Rawhide.

Full Lyrics

Sandin’ Sandin’ Sandin
Sandin’ Sandin’ Sandin
Sandin’ Sandin’ Sandin
Sandin’ Sandin’ Sandin
Rawhide!
 
Holy Mackerel!! The first really warm day must have just hit Spencerport and brought out huge swarms of black flies and that, apparently, has caused one good paddler to go over the edge already!!!!!
 
Sandin, sandin, sandin

It was indeed a warm day. And better yet, it will be warm tonight. I was inspired enough to get all of the sanding done (finally) and I also managed to get the first coat of varnish on. There is an incredible relief that comes along with putting all of the various sanding implements away,

Sandin, sandin, sandin :rolleyes:

Too early for the black flies.
 
MGC, that song will have a whole new meaning if you ever make yourself a cedar stripper boat. My first couple boats were those and the sandin' came within one sheet of 220 grit of nipped the boat building dream in the bud!

That's why god invented cedar canvas canoes...too much sandin' on those other things.
 
OK, first of all, STAY AWAY FROM THE LIGHT!!!!!!!!!! Second, Rollin, how many times have I told you, stop huffing the fumes, it's bad for you!!!!!:( :eek: :eek:
 
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