Finishing Question...

[rich]

Hi All,

Having a problem with Spar Varnish and dust motes or very small bubbles. After multiple coats of varnish, I sanded smooth, and applied a coat of just opened Marine Spar Varnish with a new brush. I stirred the varnish in the original can, didn't shake! The wood was wiped down with new cheese cloth dampened with mineral spirits to remove any sanding dust.

This morning the finish was dry and there were minute small dust mites, and very small bubbles. I noticed these bubbles or specks when I applied the finish yesterday. There were there with just barely brushing out the finish, and also when I made more very light passes with the brush to try and smooth the finish.

I'm at a loss as to how to fix this, so any help will be greatly appreciated!

[cavelamb]

A _possibility_...

What is the temperature doing?

I've had that same thing happen when working on cold stuff that warms up while drying

But not when the material is warm, and cooling while drying.

[rich]

Temp has been steady between 60 and 70F, somewhat lower humidity. BTW, these wood trim pieces go back on my boat when done, so they will see sunlight and fresh water. That's why the spar varnish, for durability, and that deep gloss finish.

[SonomaProducts.com]

Well dust is just dust and the finish is actually a liitle bit charged so it will attract dust from the air regardless.

Air bubbles are likely introduced by the brush. Thinning the material can help so bubbles will be able to surface and pop before the finish films over. Can also try soaking brush in spirits first to minimize air in brush. Can try foam brushes. Can try thinner coats. It is just a technique thing.

Can fix current situation with sand paper and elbow grease, then start over.

[cavelamb]

WOOD temperature, Rich.

Is the material warming (bad) or cooling (better)?

[rich]

turned down to approx 60f overnight.

[rich]

I'll look at it again tomorrow. Since it's not house furniture, maybe I can tolerate a lesser standard. I also have to learn when good is good enough. Glad the whole boat is not varnished mahogany! We have two of those on Flathead Lake, but I try and stay away, to keep my drool from staining their decks.

[Lew Hodgett]

I guess it would be cooling. The shop is 68f when I'm working, then turned down to approx 60f overnight.

----------------------------------------------- As cavelamb has suggested, wood temperature is probably the culprit.

Keep the heater running for 24 hours prior to application of finish and at least 8 hours afterwards.

If that is a problem, wait for warmer weather.

Lew

[Lew Hodgett]

I'll look at it again tomorrow. Since it's not house furniture, maybe I can tolerate a lesser standard.

-------------------------------------- Surely you jest sire.

When furniture grows up, it dreams of being good enough to become boat joinery.

Lew

[David Nebenzahl]

On 4/5/2010 11:02 AM rich spake thus:

So far as fixing it goes, dunno what you could do short of stripping off the finish and starting from scratch. (Yuck!)

As others have implied, dust is just a fact of life. The only way to

*reduce* (not eliminate) it is meticulous prep and care in your workspace. Tack cloths are your friend. Working in a clean place that's been vacuumed free of dust helps. If you have to work outdoors, all bets are off. You might just have to live with those dust specks. How bad are they, anyhow? Might not look so bad once you get the pieces installed where they go.

Regarding bubbles, it pays to go over the piece after you've applied varnish and try to pop what bubbles you can see. A needle of some kind works well here. Since the varnish takes a good deal of time to set and will still be flowing, any bubbles you pop will end up invisible.

[SonomaProducts.com]

Oh yes... the pinnical of my sawdust making career will result in a copy of this

... someday

[Lew Hodgett]

Oh yes... the pinnical of my sawdust making career will result in a copy of this

... someday

------------------------------------------ Understand there is quite a collection at Tahoe.

Otherwise, there is a real hotbed for restoration on L Huron near the western inlet to the North Channel.

Starts getting nippy there along about mid Sept.

Lew

[Matt]

Lew - I like that ... When furniture grows up, it dreams of being good enough to become boat joinery

So here is one for you - BOAT is an acronym for Bring Out Another Thousand

Matt

[Lew Hodgett]

------------------------------- You're dating yourself, these days it's more like $10K.

Lew

[cavelamb]

That's too big of a boat!

Here's mine...

[nailshooter41]

Sonoma - what a great goal to shoot for in skill mastery.

I was in Lake Tahoe a couple of years back after they had just finished "Wooden Boat Week". They had a Chris Craft that was out of the water and was in the process of being lovingly wiped down and prepared for winter storage.

There are dozens of restored Chris Craft boats on the lake at that time, but this one was the show stopper. They told me it is owned by the Lake Tahoe Yacht club, and it is used every year for the Grand Marshal to ride in for every event that requires a marshal.

The boat was varnished mahogany, and the finish looked like poured glass. Every thing about that boat was no less than beautiful. The appointments (and their condition!), the actual wood, the joinery (fit and finish - incredible), and the overall condition of the boat was breathtaking.

They told me it had been about 4+ years or so in professional restoration, and that it had its own warehouse where they hang it up out of the water during storage. I saw it when it was out of the water but not hung up, so I was able to see everything. Sadly, in its display area, I was not allowed closer than 24" to the boat, and no touching.

They told me that was actually a good deal for me as the boat was off limits to just about everyone as that was their flagship.

It was a *real* treat to see that kind of craftsmanship. As Lew noted, there are a lot of wooden boats out there, but this one was the stuff.

Robert

[DanG]

I would thin the material to allow a bit more flow out. There should be very little brushing. Apply and "tip off" with very light strokes. Do not hurry. Thin coats with light sanding or steel wool (depending on type of wood) between coats. A box fan with a furnace filter on the intake side pointed away from the project will catch a tremendous amount of dust if you don't have a dust system.

[J. Clarke]

Just you wait 'enry 'iggins, just you wait.

[dadiOH]

If you have a boat you really should research what "spar" varnish is and what to put it on. Answers, soft and spars. It is no more durable or glossy than non-spar varnish.

[dadiOH]

1. Varnish in a clean room to avoid dust - AND/OR -
2. Sand and polish.