I have a Graco Magnum x9 airless paint sprayer. I have only used it for latex paint. I am planning to refinish my deck this spring with a sealer of some sort. Can I switch back and forth between type of product as long I wash the sprayer out or should I stick to latex only?
If you want to switch back and forth between oil and latex products, it is best to have a separate hose for each (as per Graco).
Graco sprayers, hoses, guns, etc, are designed to be compatible with all of these types of fluids. There are a few other considerations that you should be aware of. Be sure that all equipment is of sufficient size and of a high enough pressure rating to work with the material that is being sprayed. Another issue to be aware of is that no matter how well a sprayer is cleaned out, some residue will remain behind. It is not uncommon to have pigmented paints contaminate a clear coating like varnish and lacquer. Switching between water-based and solvent-based materials can also make the insides of the pump gummy and sticky. Ideally, we would recommend two different sprayers, but at the very least, you should use a dedicated hose for lacquer and clear coatings.
From personal experience (spent two summers in college as an Industrial Painter) here are a couple things I learnt about your question.
- Oil paints can break down latex, which in your current situation is a good thing as it would help clear out the lines. However, if you were to switch back to latex down the road, it could be detrimental as there is always paint and residue left behind which could negatively impact the latex paint.
- Also, oil paints typically require a different cleaning process (post-job) for your machine and depending on the specifications (not sure on Graco, I use Titan) the cleaning solution could be even worse for latex paint than your oil stain.
For my personal use I have a Titan ControlMax 1500 Airless, and like you have done primarily latex. However, I did my fence this summer and to do it I bought a new hose, gun and tip in order to ensure that my spray was clean and relatively uncontaminated. I don't know what Graco offers in terms of accessories, but it could be something to look into for future jobs.
As long as you properly flush the sprayer and hose with each use, you shouldn't have problems with switching. Ofc make sure your Graco sprayer says you can use oil-based products, some sprayers have internal parts that don't handle those solvents well (most Graco sprayers do support use with oil-based products, and maybe all do - but it's wise to verify). With oil based products you'll probably need to flush with mineral spirits unless it specifically states otherwise in the instructions for the product you're applying.