Shellac via airbrush

[Swanicyouth]

Has anyone sprayed shellac via airbrush? Mixed information online. Seems like it would be good for small clock cases.

 

[steamer471]

I don't know about an air brush but I like the spray cans. Just can't use them when the humidity is high. I think this is where most people run into problems.

 

[T.Cu]

I also use the shellac in cans and in the spray versions. I have never had problems with the Zinsler products.

 

[TQ60]

We just tried it today.

Works very well.

We were doing the French polish style with a pad and not getting good results after first coat.

Had a brand new estate sale air brush kit with compressor, what a difference.

With minimum spray we can work u the thickness, the alcohol in the finish softens the previous stuff so you can use the air to smooth out previous brush marks.

For our columns it worked mush better than brushing.

Needs to cure a day or three so we can see how it does.

Wish we would have tried it sooner!

 

[TQ60]

Today we sanded the case, had brush buildup and given it is Mahogany, it has a lot of open grain that we want to fill in.

Some areas are back to the wood with the grain filled, looked odd.

Saved the surfaces to smooth.

Shot it again, this air brush has a good pattern, it has a small bowl so easy to use, gave it a couple coats and it came out real good.

It has some spots where it still needs a little work, steel wool should be all that it needs to prep for next coat, will let it gure until next weekend so it should be good to work.

It worked very well on the columns, air brush is a must for larger areas or odd shapes.

 

[leeinv66]

I have sprayed shellac with a small automotive suction feed gun for many, many years. With a little practice, it is an easy process to master.

 

[TQ60]

Nice gun!

We tried the air brush as it was an estate sale find as a kit a few years ago.

The small bowl and direct feed make for easy cleanup.

Shellac is somewhat of a pain for cleanup as it wants to coat whatever it touches.

Cleans well with isopropyl so good thing there.

If we needed to do something large the detail gun comes out.

 

[Steve Neul]

Today we sanded the case, had brush buildup and given it is Mahogany, it has a lot of open grain that we want to fill in.

Some areas are back to the wood with the grain filled, looked odd.

Saved the surfaces to smooth.

Shot it again, this air brush has a good pattern, it has a small bowl so easy to use, gave it a couple coats and it came out real good.

It has some spots where it still needs a little work, steel wool should be all that it needs to prep for next coat, will let it gure until next weekend so it should be good to work.

It worked very well on the columns, air brush is a must for larger areas or odd shapes.

View attachment 762182 View attachment 762183 View attachment 762184

The grain should have been filled with a pastewood grain filler prior to using shellac. Shellac has a natural wax in it and can cause adhesion issues with finishing products. From where you are I would sand the shellac and put a coat of Zinsser Sealcoat on it. It's shellac but has been refined more to remove the wax. Then you will need either a clear or a pigmented grain filler. There is Aquacoat which is clear and Mohawk makes a mahogany grain filler. Most grain fillers come in a natural color which is nearly white. It would make little white lines all over the wood. Another option would be to purchase a grain filler at a real paint store such as Sherwin Williams. It comes in the natural color but they can tint it like they do paint. Once the filler is dry lightly sand the surface to remove any grain filler which may be on the surface. Another note: Once you start back with the shellac allow it to dry overnight before doing any sanding. The solvents in the shellac will make the grain filler swell up and if you sand it immediately when the grain filler shrinks the wood will look grainy again instead of having a level finish.

 

[TQ60]

Never have liked fillers, also never liked Mahogany for this, otherwise beautiful wood.

The airbrush has a very fine mist when adjusted just right, it allows focusing on the areas where the open grain was more open.

The first coat was over where we had brush marks and dragging marks from the pad
.
Both of these processes would drag the finish out of the grain.

The air brush air stream would re-flow some of this as we were applying.

Sanding it down we got a smooth and filled area, some places we had got back to the wood, sanding with 400 paper it does not do much to the wood.

The coat was applied yesterday looked a bit "orange peel" when wet with a couple specks.

We used a stick to apply a drop of alcohol to the specks, they flowed in.

It cured very well, the specks are Dios but overall real good.

Some touch sanding in those areas with light steel wool to prep for top coat and wax.

The trim and bottom still need some sanding and spray, should be easy.

Back and lid comming along too.

Would guess this coukd be used with a strong alcohol to shellac mix to re-flow cracked but clean shellac.

 

[TQ60]

Have been working on the finish in small time slots.

We needed to get the brush marks and grain peaks leveled down.

The shellac seems to sometimes react to a dust spec or other unknown item resulting in a bubble.

The airbrush allows TINY amounts to be added to build up a thicker coat and once it hardens it is glass like, except for the bubble.

We have a shaving tool that was a lathe bit, 1.5 wide tool steel with a chisel edge that can carefully shave just the bubble.

Then with a pencil point we can carefully add shellac to the bubble for it to fill in the area.

First photo is after first pass, next is ready for touch up, then touched up followed by our tool.

a good sharp chisel would do same.
Reduces sanding time.

 

[TQ60]

Here is the side, there was some overspray on the base from the side.

It wiped off easy, it still needs a few coats.

One can read the newspaper in the reflection.

 

[Steve Neul]

Have been working on the finish in small time slots.

We needed to get the brush marks and grain peaks leveled down.

The shellac seems to sometimes react to a dust spec or other unknown item resulting in a bubble.

The airbrush allows TINY amounts to be added to build up a thicker coat and once it hardens it is glass like, except for the bubble.

We have a shaving tool that was a lathe bit, 1.5 wide tool steel with a chisel edge that can carefully shave just the bubble.

Then with a pencil point we can carefully add shellac to the bubble for it to fill in the area.

First photo is after first pass, next is ready for touch up, then touched up followed by our tool.

a good sharp chisel would do same.
Reduces sanding time.

View attachment 763658 View attachment 763659 View attachment 763660 View attachment 763661

Bubbles in a finish normally indicate the finish wasn't thinned enough.

 

[TQ60]

Seems to spray well, easy to add some alcohol to thin it a bit.

 

[leeinv66]

Bubbles in a finish normally indicate the finish wasn't thinned enough.

That sounds more like water in your line to me.

 

[Steve Neul]

That sounds more like water in your line to me.

That's possible but the amount of orange peal he has also suggests the finish wasn't thinned enough.

 

[TQ60]

One nice thing about Shellac is you can alter it easily.

We added some alcohol to thin it and got a better spray pattern, but not there is more atomization so some material drift or over spray.

The buildup of material on the case seemed too thin to be effective in that it just did not seem to flow well.

Easy to add a few flakes to thicken it back some.

We are NOT a trained painter, applied lots of paint via detail guns and we prefer a thicker viscosity as it has less misting but greater care needed to avoid runs.

With shellac it is an interesting medium as the fresh wet stuff can soften the existing layer.

The spots that had the bubbles were places where the shellac just did not want to stick, we got clever and scrubbed the area with a tooth pick while spraying.

The air brush can have a pattern less than 1/2 inch wide so we can make a small puddle where the spot was, then scrub with the tooth pick.

The alcohol in the shellac acts as cleaning solvent with the toothpick the get whatever was causing the shellac to not stick to no longer cause the problem.

The spray can be repeated to get a good layer, but given it softens the existing material the part needs to cure for DAYS to get hard.

After 2 days we still can leave a fingerprint in the surface, found this out the hard way when we flipped over the lid after a day to do the other side, it seemed to be fully cured but it got messed up causing us the do a bit of sanding to correct it.

There are great instructions on this forum, but those indicating shellac can cure in minutes is not exactly true.

Yes, you can apply the next coat in short period, but you cannot handle it or sand it for maybe a week, maybe longer to be certain it is fully cured and can be properly sanded.

What should have taken a few days has instead been a month or more!

Granted mistakes take time!

We have a Sonora clock with bad finish, sometime down the road we will do that one...hopefully less mistakes.

 

[Swanicyouth]

I never did try the airbrush with shellac. In know people here love shellac, but depending it can be a lot more work than just using wipe on polyurethane to get a consistent professional finish

 

[TQ60]

Polyurethane is wonderful stuff, used it on many things.

Danish oil used as the wet when whet sanding at 600 keeping it wet until it stops soaking in makes a wonderful finish.

Trying to keep this in original finish so learning to apply it is keeping us busy.

If this was a newer clock it would not matter, this one, 1900 Era so we will see how it goes.

We also are too picky sometimes.