spraying gesso

[Linda]

Help!! I'm trying to spray my obeche wood frames with gesso paint. I have purchased a spray gun but can not get it to work correctly (it is spraying out the gesso, then stops and then sprays out more paint again). The paint ends up splattered in watery pools rather than neatly layered on. I've also tried it with just water and it does the same. Help.

I've attached a photo of the spray gun and my pump. What do you suggest e.g. do I need a better spray gun (the one I have is a silverline 750cc) or do I need a better pump?

Finally, what mixture do you suggest for the gesso for use with a spray gun?

Thanks for any suggestions as this is driving me mad.

[prospero]

I had a compressor like that. If I'm right it's a direct blow one without a tank. And is very noisy. If I remember rightluy, you need a tiny hole in the brass fitting that fits on the compressor or it doesn't give a smooth air flow. Have a look and see if there is one.

Could be the gun. Only way to test it is to try it with a different compressor.


** Never tried spraying gesso. It's something that I'd like to try out when I get somewhere to do it....

Are you using 'proper' gesso or the acrylic stuff?

[Linda]

Thanks for your suggestion. I will try and get hold of another compressor. You are right, my compressor is really noisy.

The gesso I am using is made up from rabbit glue and whiting. I even filtered it to remove bits (using one of my kids vests!!!).

I've contacted the spray gun company to see if it is faulty.

[Not your average framer]

A LPHV (Low Pressure High Volume) type spray gun may be a possible way to go with this, but it may still be possible to try a few more variations on how you are using your existing set up, to see if any further improvements are possible.

I've heard it said that it can help to add a compatible solvent to the water used in the gesso, but I've never tried spraying gesso, so I don't know why this would be any advantage to do this. If this was part of the solution to the problem, I would be very careful to choose a suitable safe solvent and to construct a suitable spray booth with suitable fume extraction as part of a possible essential health and safety requirement.

[JFeig]

Gesso has to be warmed to spray on a finish.............. as well as the spray gun. Place the gun in a pail of warmed water before and in between spray applications.

[Linda]

Brilliant idea, I'll try that as the spray gun is cold. My husband had a look at the spray gun and compressor last night and actually took a knife to it. Well in a good really and replaced the narrow bore tubing and replaced it with a short wider tube. Will feed back shortly to let you know the outcome. Thanks though for all your help.

Any idea of the perfect ratio of size to whiting for spraying with a gun??

[vintage frames]

If you are going to spray gesso you will need a better compressor. Best is a compressor with at least a 50litre tank; buy one off e-bay.This will give you a smooth continuous supply of air. Make geeso with rsg 1 part to 10 parts water, mixed 50:50 whiting to glue.Heat up to 70C and fill the spray gun. Adjust a air pressure( on the compressor) so you have a fine and even application. Best of luck.

[Linda]

Thanks for your suggestion. I'll have a go with my pump first with the shorter lead. If this does not work then I'll go for the 50 litre compressor. I'm determined to sort this out. I'll try out the RSG mix as well. Next step is gilding (gulp!!!!).

Many thanks to you and everyone who has responded, it is really appreciated.

[prospero]

I used to use my little tankless compressor with an airbrush and it was OK as far as I remember. But I have a feeling that it would have struggled to drive a big spraygun. Especially with heavy paint.

There are airless sprayguns which may work with gesso.

http://www.machinemart.co.uk/shop/produ ... -spray-gun

Worth a punt for 20 quid (????)

[CalicoFraming]

this may be of interest:
http://www.youtube.com/watch?v=veNZ84J8 ... el&list=UL

Laying gesso on with a brush is messy and boring IMHO - I'd love to have spray facilities!

[prospero]

That's a very interesting series of vids.

Nice to have a big workshop.