Does anyone use rattle can lacquer?

[Frank Ford]

I'd review your spray technique. Bubbles can result if the spray mix is too thick, gun too close, pressure too high, coat too heavy, etc. As you've seen by brushing, the thickness of application alone can cause bubbles. Quality of the gun itself can also be an issue, along with its adjustments.

[Wozer]

25' of hose from compressor to separators is sufficient...50' of hose is just robbing you of air flow caused by the friction of air moving in the hose.

to further help separate water and oils run the hose straight up out of the compressor, run it around up high, and drop it down to the separator(s)...being that water and oil molecules are denser ("heavier") they will have a harder time going uphill...make sure you designate your hoses for their individual uses (e.g. only use a clean hose to your spray gun...once it gets used in the separation stage you can consider it contaminated)...also keep the spraying hose closed on the ends by connecting the male to female connectors when not in use...if in doubt just go get a new hose.

[Quickstep192]

So, here's the report from the most recent test coat.

I shot a quick coat befor I left for dinner earlier. It looked great; a couple of big bubbles, but otherwise looked pretty glassy.

Upon returning, the tiny bubbles are back. When Steve asked before if they were bumps in the surface, I said no, but I may have to rescind that. The tiny bubbles do make bumps in the surface, but they're just very slightly proud of the surface. They do not appear to leave pits when sanded.

As for my technique, I've got the fluid knob Backed out one full turn, just enough to provide a wet coat with a slow pass. I can shoot it on a vertical surface and make it wet without sagging. I've got air pressure set at the manufacturers recomendation and I chose a tip based on the viscosity measured in a ford #4 cup.

[mirwa]

That's very interesting. It almost sounds like a gassing out problem rather than a mix problem or air supply problem.

So when you sprayed it appeared clear, as it's dried it's left lots of small bubbles, these bubbles have not peirced the skin coat.

What are you using as a sealer coat on the surface under the clear ? Are you using a wax and grease remover prior to clear ? What type of sandpaper are you using ?

Steve

[Quickstep192]

Steve,

For the sealer coat I used the same finish thinned 50%. I considered using dewaxed shelllac, but didn't want to risk adhesion problems with the varnish.

The surface I'm finishing is raw wood, so I didn't de-grease, just worked my way through the grits.

Sandpaper is 3M sandblasted pro 320 grit. It seems to level nicely and I wipe off the dust before re-coating.

As an aside, while I'm spraying the sample piece we're discussing, I'm doing another test piece - same wood, same sanding, same process; only difference is the finish. The finish on the second piece is Deft rattle can lacquer. It looks lovely. That's all we'll and good, but would still like to master the spray gun.

[charles Tauber]

How old is the lacquer you are trying to spray and what brand?

I had a heck of a time last fall spraying Target 7000 with an HVLP gun and turbine, trying all sorts of different combinations, etc. to resolve the problem. When I had eventually exhausted all of those, I ordered a new can of 6000 and it went on fine. I chalked it up to a bad/old batch of finish. I'd never had that specific problem before, or since.

Another thought might be the size of gun tip (orifice) you are using for spraying. Is it the right size for the viscosity and material you are spraying?

[mirwa]

That is good news then if the rattle can spray went on perfectly, it does not completley eliminate the body prep but does put it in the least likely category.

Different lacquers react with different base coats / pore coats / fill coats.

From my reading deft is a nitro-cellulose lacquer. Epifanes varnish is an oil base. Oil bases float dust real easy if its not meticulously clean, - definitely not dust particles ?

Shame you could not capture the appearance in a photo, but I do understand when its very small, almost impossible to see.

On the rattle can one, how did you prep the surface, you mention earlier you thinned the first coat down when using the spray gun.

On the airline that feeds now from the oil/water seperator to the gun is that old hosing or new, if its old, just go grab a cheap 10 dollar hose from your local auto store or something.

You dont have any other finish laying around that you can put through your gun, example some nitro, then you can get a true comparison between the ratlle can and your gun.

Steve

[murrmac123]

Originally Posted by Frank Ford

Taku Sakashta comes to mind - that guy could work miracles with rattle cans:

He appears to have worked miracles with his scroll carving as well ... difficult to tell from the pic , but will a strap actually attach to that scroll ?

[Quickstep192]

Originally Posted by mirwa

That is good news then if the rattle can spray went on perfectly, it does not completley eliminate the body prep but does put it in the least likely category.

Different lacquers react with different base coats / pore coats / fill coats.

From my reading deft is a nitro-cellulose lacquer. Epifanes varnish is an oil base. Oil bases float dust real easy if its not meticulously clean, - definitely not dust particles ?

Shame you could not capture the appearance in a photo, but I do understand when its very small, almost impossible to see.

On the rattle can one, how did you prep the surface, you mention earlier you thinned the first coat down when using the spray gun.

On the airline that feeds now from the oil/water seperator to the gun is that old hosing or new, if its old, just go grab a cheap 10 dollar hose from your local auto store or something.

You dont have any other finish laying around that you can put through your gun, example some nitro, then you can get a true comparison between the ratlle can and your gun.

Steve

I'll shoot another coat and make sure everything is meticulously clean.

I'm pretty sure the rattle can is nitro; it sure smells like it.

The rattle can sample was prepped the same as the varnish one, except that the first coat was shellac, then the lacquer.

I've shot Behlen's Instrument lacquer with the same setup before and also saw the tiny bubbles. I had attributed it to my poor spraying skills and thought varnish might be more forgiving, but when I saw the same tiny bubbles in the varnish, it re-confirmed my suspicions about my setup.

[Frank Ford]

Originally Posted by murrmac123

He appears to have worked miracles with his scroll carving as well ... difficult to tell from the pic , but will a strap actually attach to that scroll ?

It will, but has to thread through the hole. When Taku told me he wanted some ideas of mandolin styling, I said he should make F-5s because his instrument designs were a sometimes a bit too unfamiliar to American players. He said he wasn't interested in "ordinary" and went away. Some weeks later, after talking to a lot of other folks, he called to ask if he could come into the shop to measure some F-5 style instruments. As he left that day he said, "OK, everybody convinced me to make F-5."

A moment later he opened the door, stuck his head inside, "But I also do crazy one!"

So, at a time when everybody was trying to find a way to please the F-5 crowd and still make a living by simplifying the design, he found a way to make the F-5 even MORE difficult.

That was Taku, one of the best craftsmen I've known.

[murrmac123]

Originally Posted by Frank Ford

So, at a time when everybody was trying to find a way to please the F-5 crowd and still make a living by simplifying the design, he found a way to make the F-5 even MORE difficult.

That was Taku, one of the best craftsmen I've known.

I love it when somebody thinks outside the box, and does so with resounding success. Shame he is no longer with us.