Varnishing

My current build is a 1940 Chirs Craft, and I've done a lot of varnishing on full size boats over the years, but never a model. A small defect, the size of a pin head on a real boat, would never be noticeable but would stand out like sore thumb on a model. Any tips or advice would be apricated.
Thanks

Not an expert by any means but i think the right approach would be multiple thin layers, with some very fine sanding and using a tack cloth between layers. You may want to consider using an airbrush, if you have one.

Rob

Try to have a plastic sheet covering the model once you’ve varnished it.
The sheet will keep dust out of the varnish while it dries.
And don’t be scared to sand between coats.
And wet sand the final coat for a mirror smooth finish.

A long lasting answer to your quest
Buy a copy of Flexner
Pay particular attention to the chapter on shellac.

One option is to use what I call the Old Timer's Finish. Wipe on - wipe off until you get the build you want, then just don't wipe off the final coat.

when I built the Amati Riva Aquarama I adopted the following procedure
- after sanding and wiping clear of dust, move to a suitable room, in my case the hall cloakroom which had no carpet or curtain, and use tack rags to wipe clean again.
- using CooVar yacht and flying boat varnish, wipe a coat on the upper surfaces and wipe out until there is total coverage but no drips or runs
- after the surfaces are totally dry rotate the hull to allow applying the varnish to the "new" upper surfaces.
- sand down any defects before progressing to the next coat.
- repeat until the surface everywhere is glass smooth. In my case about 10 coats.
- leave in the dust free room for several days until the surface is fully cured.

I would not use varnish. Try a gloss polyurethane instead. The poly tends to dry smooth easier. I use MinWax gloss polyurethane regularly. I use the matte poly as a regular costing on all pieces and parts including a final finish on my models.

It all comes down to the sort of display look......
Varnish - the noun - usually refers to a layer of clear polymerized matrix on the surface.
Linseed and Tung and other plant oils can leave a bit thinner layer. If none or not enough catalyst is used, you may not live long enough to see it become a solid. If too much - it may look like safety glass that has been shattered but still there.
Polyurethane is probably a sure thing as far as becoming a clear solid, but is thicker.
The scale effect is similar to having a layer of clear thick vinyl - a noticeable layer.

Shellac does not polymerize - it just drys. The more dilute, the thinner the layer.
Scotch Brite can make it satin or at least duller. The auto finish world has maybe 6+/- grits of this stuff.
It does not rust.

If there is no rush to finish- shellac may give a better effect if a few days to a week is the time between layer applications - instead of hours. There is alcohol evaporation and then there is alcohol evaporation at the most molecular scale.

Shellac comes as a range from purple button to almost white - but never water clear.
Mix your own flakes gives the most control. As a gallon - the unit cost for shellac thinner is fairly low.
I am now storing my shellac flakes in Mason jars and pulling a vac with
Mason Jar Vacuum Sealer Kit, Electric Sealer for Wide, Regular Mouth Mason Jars, Portable Vacuum Sealer for Jars, ~$25 from Amazon

Rounding 1 lb cut shellac is ~10% w/v -- a small coin battery scale and a 100ml graduated cylinder = small volumes are easy.

For those who use premixed model paint - a 2qt wide mouth Mason jar may be a longer term way the store them - place an open bottle of thinner in the jar with the paint bottles and pull a vac. Instead of oxygen leaking into the sealed jars and causing them to polymerize - it would be thinner so no polymerize.

I am building the 1930 Dumas Chris Craft Runabout kit. I am a neophyte so take what I say with a grain of sea salt.

Because this is an RC model, I had to make the hull watertight. I stained the hull first as well as he topsides with the stain that came with the kit. Then I fibreglassed the hull and decks with 2 oz. fibreglass. After wet sanding the epoxy to smooth things out, I am now spray painting the hull with 3 coats of gloss lacquer. After wet sanding again, and determining whether there are any defects to be sanded and filled, I am going to paint the bottom paint on top of that layer of lacquer, again using lacquer paints which will adhere, supposedly without sanding between coats because lacquer will attach to itself chemically. Then I will lay down further coats of lacquer and then wet sand and steel wool to a finished state. I am not sure whether I will need polishing compound, but the boats of that vintage that I have seen (there is a Muskoka boat museum nearby) were shiny!

I still have not decided whether to use spray lacquer or varnish on the topsides. I usually use varnish on my models, but because the boat is RC, the hull at least needs to be resilient. My approach would have been different had it just been a display model. But I have launched the boat (in the bathtub) and she's watertight.

jplm said:

using lacquer paints which will adhere, supposedly without sanding between coats

Click to expand...

If you buy a small tube of artists' tubed oil pigment - the original clear lacquer is the only lacquer needed.
The tube will probably be the last of its color that you will ever need to buy. Mix with mineral spirits and it is brush or spray model paint.

I use lacquer as a stiffener and waterproof for 8.5x14 sheets of timber patterns. The price for a quart is shooting for the ionosphere. The first time I used three coats, now just one. The three coat patterns want to stick to whatever they touch for a while and are difficult to separate.

You def cannot use shellac for anything exposed to water.