Using an HLVP sprayer for Liquid Light

In another (related) thread, I stumbled upon a reference to using an HLVP sprayer to coat Liquid Light emulsion onto various surfaces. What a (simple yet) brilliant idea! I've been thinking of experimenting with Liquid Light for a while now yet somehow I couldn't quite see how I'd coat a surface evenly. Using an HVLP sprayer certainly seems to answer that question - at least in theory.

I'd love to hear about fellow Apug'er thoughts & experiences with this process. I know that Liquid Light can be a lot of fun and if this technique actually works, the possibilities are truly endless!

Seeing as I don't know the first thing about HVLP systems, here are some of the questions in my head:

What are the specs that a given HVLP sprayer would need to have for it to be optimaly suited for Liquid Light? Any recommendations?

What are the pitfalls of the method?

Has anyone had any real-world experience using this technique and if so, what advice might be offered?

Thanks in advance & happy coating!

g'day i
what's a HVLP?

why do need even/perfect coverage of liquid light?

Ray Heath said:

what's a HVLP?

why do need even/perfect coverage of liquid light?

Click to expand...

HVLP = High Volume Low Pressure (paint sprayer/atomizer)

Why does one need to get a perfectly distributed coat of emulsion? Well.. I suppose one doesn't "need" to per say as such would depend on the task at hand and the sought effect. I suppose I should've said "If one needs.."

my point about a perfect coating is that maybe imperfections make alternative processes special

so, an atomzer or something similar, how would you keep the emulsion warm enough to spray and not clog up the sprayer?

I've done it, it works great. You need to thin the emulsion, I use Everclear.

I don't think I want to atomize any of the alternative processes.

There are chemicals in most of them that I choose not to inhale.

Wearing a respirator for the hours I print would be uncomfortable to say the least. I will just stick with a brush, a glass rod and care and patience to achieve a smooth coat.

magic823 said:

I've done it, it works great. You need to thin the emulsion, I use Everclear.

Click to expand...

Could you elaborate on what you mean by "thinning" out the emulsion? I'm new to Liquid Light and I don't fully understand how to use it yet. Wouldn't adding something into the emulsion contaminate or otherwise alter it?

Ray Heath said:

so, an atomzer or something similar, how would you keep the emulsion warm enough to spray and not clog up the sprayer?

Click to expand...

I can't imagine that being overly difficult. One idea might be to keep the sprayer's reservoir in a hot water bath until just before you're ready to apply the coat and return it to the hot water bath in between coatings.

It sounds like the HVLP method would make it a lot easier to coat larger sheets of glass (for positives). Another possibility I've always wanted to explore was printing on an actual wall or ceiling.

(yes I'm crazy enough to try something like that)

This is covered in the book "Silver Gelatin" including painting on the wall and ceiling.

And this should be in the emulsion making and coating forum IMHO.

PE

Everclear is 100% grain alcohol. I use it to thin the emulsion so it sprays better. The alcohol then evaporates.

I use it when I spray emulsion onto canvas. Only way I've found to give a good coation onto the uneven surface.

I suspect a fine mesh silkscreen, about 300 polyester and a sharp edge polyurethane squeegee might to a pretty good job applying emulsion. Only thing is if the emulsion can be kept at the right temp. I know silkscreen is realy good at applying inks and resists on flatwork using offcontact printing.
Screen tension, mesh count, squeegee edge and stroke pressure are the main variables in this action.

Gary;

With an emulsion in gelatin, this will probably give a nice silk screen effect. Viscocity is an important factor as is surfactant. The lower the viscoscity the lower the silk screen effect.

PE

Yep. It would be an interesting experiment to see what kind of effect this would have with a print emulsion. Do you think an emulsion could be modified to smooth out well after screen application? A 300 mesh screen would give an extremely fine pattern which may not be objectionable in a print image.

Gary;

Yes, this is a rather trivial exercise. In fact, you will often see small coating defects that fill in or smooth out if the formula is correct (viscosity and surfactant effects). You could also make a formulation that retained the full silk effect.

Of course, it is better to do it in the paper surface itself. I have coated on canvas and kept a rather nice canvas effect, but the rate of coating defects goes way up. Again, it depends on the formulation being laid down.

When there were canvas, suede and silk finish papers, the finishes were made before the paper was coated.

PE

I have logged hundreds of hours using a HVLP unit(s) (I like the "Croix" the best) and can offer a few general tips that might help you out here.

One needs to thin the material out so as to get the proper flow. W/O knowing the viscosity of liquid light (or the makeup of it, I will yield to the everclear suggestion but be aware of the fire hazard created.

What you have to do is first to turn the (unit)air on and just let it run for a few minutes to get it warmed up. This is important as that helps the "flow" of the material. While it is warming up, a great rule of thumb is to thin the material till you can put a stir stick in it and pull it out and hold it at a 45 degree angle resting on the rim of the bucket and watch the material run off of it .......... when it turns from a small stream to a drip you will want roughly one drip per second, that's perfect.

Fill up the cup (I really would use a cup gun) and turn the air all the way down and set the fluid knob on the gun till the material comes out in a stream about 2 1/2" before it arcs down. You will have three settings on the tip of the gun ....... horizontal, vertical and round ......... use the round for the last step.

Then turn on air to the unit and slowy dial it up till you get the proper pattern. You adjust the SIZE of the pattern by screwing the knurled outer ring holding the air tip in. Closer to the gun = wider pattern ........ Further from gun = narrower pattern.

Maybe try out with some water first to see how everything works and practice a little with it so as not to turn the project into a fish fry!! Hope that helps.

Good Luck,
Mike