Spray painting. Rattle Can vs. Paint Spray Air Gun

[OnlyStihl]

I have used my HVLP Spray Gun a modest amount. Mostly for oiling the log cabin. I've got quite a bit of things I need to get painted this spring once the weather warms up.

Q: What are the advantages of a Spray Gun, vs a Rattle can? Certainly, being able to mix and get a precise color, but that is not so important to me. Seems there might be more waste with the Spray Gun, as you can't just pour it back into the can as you most likely had to add some solvent to get the paint to flow right. So, what else is there to take into consideration?

 

[hacskaroly]

What are the advantages of a Spray Gun, vs a Rattle can?

I guess it all depends on what you are spraying and how much you are spraying. Correct that with a spray gun you can mix to your color preference and add hardener, with spray paints you will probably need a good clear coat (like Eastwood two-part), but you have to have everything ready to go when using this as once you activate the hardener in the can, time is limited (I think less than 24 hours) to use what you need before the rest hardens in the can.

Plenty of YouTube videos that show the pros of both and the good results that can be achieved. Right now I am working on restoring a McCulloch and am using rattle cans for this project. Once I get all the parts patched, primed, and painted, then I will get a can of Eastwood and give them a good coat. I may even bake the pieces in a toaster oven I got at the thrift store to see if that helps with hardening the paint.

 

[OnlyStihl]

I guess it all depends on what you are spraying and how much you are spraying. Correct that with a spray gun you can mix to your color preference and add hardener, with spray paints you will probably need a good clear coat (like Eastwood two-part), but you have to have everything ready to go when using this as once you activate the hardener in the can, time is limited (I think less than 24 hours) to use what you need before the rest hardens in the can.

Plenty of YouTube videos that show the pros of both and the good results that can be achieved. Right now I am working on restoring a McCulloch and am using rattle cans for this project. Once I get all the parts patched, primed, and painted, then I will get a can of Eastwood and give them a good coat. I may even bake the pieces in a toaster oven I got at the thrift store to see if that helps with hardening the paint.

Lots of good things to think about. For small parts having a toaster oven in the garage...

I have to replace the wood deck on my trailer this year. The rest of the trailer is a rusted ugly mess. I'll have to remove the rust first, but afterwards is under consideration. I can just paint it with a brush but seems like a good opportunity to learn how to use a spray gun properly. There is all kinds of stuff (on craigslist) that looks ratty (yet works fine) that greatly influences the resale value. Buy, clean, paint is a way to turn perceived junk into real value.

I have plenty of neighbors that never would buy used, partly because of looks, and also because they have near zero mechanical skills. If the price is right, and it looks good it can sell.

 

[Wilhelm]

I "brush" everything, seems to get a nice thick layer with little waste in a single pass.

Not too pretty visually though.

 

[OnlyStihl]

With the trailer, pretty isn't the goal. It's nearly 25yo and used primarily to get firewood. But it does seem a good candidate to learn how to air spray.

One thing about air spraying vs a brush is the speed. Many years ago, I oiled the log cabin with a brush, and it took forever. Last year the oil was a different brand and much thinner. Perfect for the air sprayer, and I discovered I could do the job just as well in an hour per side vs. all day. Before this epiphany I hadn't use the sprayer for over a decade. Now I'm eager to see what it can really do for other applications. Also, a consideration, rattle cans have gotten expensive.

I bought a pint of satin black, and brush painted a drill press stand, and recently the rolling mount for the IdealArc 250 Welder, and after plenty of coats, the small can still has plenty of paint left in it. Seems the rattle cans are quite a bit more expensive than just a can of paint.

 

[WI_Hedgehog]

I use rattle can prime/paint/clear for saws and other small parts; nozzle cleaning between coats is easy for multiple light coats with 15-minute+ setup time. Then a 3-stage bake at increasing temperatures allowing for more complete outgas and hardening. Quality paint is quite good nowadays.

On bigger things I use a small automotive HVLP paint gun with high-end air dryer and air filters. It takes a while to get everything set up vs a rattle can which is shake-and-go, and cleanup isn't "turn the can upside down" so also longer. For me a gun makes sense on bigger projects where it will save time & money vs. multiple cans. If I can spray everything and then immediately go back to start a second coat I'll use the gun. For jobs "this big" I use a Highly Volatile Organic Compound respirator.

On really big things where the time with a small gun means I'll lose time I'll use a full-size automotive HVLP paint gun. If I can spray everything and then immediately go back to start a second coat I'll use the big gun and a tip that matches the project.

 

[hacskaroly]

Then a 3-stage bake at increasing temperatures allowing for more complete outgas and hardening.

What are the temp differences between the stages? Do you use the same amount of time for all three stages?

 

[OnlyStihl]

I use rattle can prime/paint/clear for saws and other small parts; tip cleaning is easy for multiple light coats with 15-minute+ setup time. Then a 3-stage bake at increasing temperatures allowing for more complete outgas and hardening. Quality paint is quite good nowadays.

On bigger things I use a small automotive HVLP paint gun with high-end air dryer and air filters. It takes a while to get everything set up vs a rattle can which is shake-and-go, and cleanup isn't "turn the can upside down" so also longer. For me a gun makes sense on bigger projects where it will save time & money vs. multiple cans. If I can spray everything and then immediately go back to start a second coat I'll use the gun.

On really big things where the time with a small gun means I'll lose time I'll use a full-size automotive HVLP paint gun. If I can spray everything and then immediately go back to start a second coat I'll use the big gun and a tip that matches the project.

Yup, cleaning the gun is a chore. I remember my first use of this gun and getting it all jammed up. Since then, only paint that can be cleaned with water, and spay a lot of water thru the gun til it is absolutely clear.

Like you say, one of the best reasons for a rattle can -- Shake and go, and upside-down spray til clear.

 

[WI_Hedgehog]

What are the temp differences between the stages? Do you use the same amount of time for all three stages?

I use high-temp paint which calls for 3 heat-cool stages, if it's "around" 250 for 30 minutes, 400 for 30 minutes, 650 for 30 minutes with full cooling between cycles--but don't quote me on that because that's part temperature so parts with more mass could take longer to come up to temperature. I go to the manufacturer website and get the latest/full specs from them along with any special cases and go with that. Here's VHT for example, found under "Applications."

Less paint is almost always better as it outgasses better when cooking and doesn't shrink/grow as much during use (so there is less chance of chipping).

Heat cycles allow the paint to grow, outgas, shrink, making it conform to the metal properties better and not crack under later heating/cooling cycles (from what I understand).

The reason I use high-temp paint is "in my opinion" it works "pretty good" when compared to 2-part epoxy with much less cost and easier cleanup when something goes wrong. High-temp can be removed by soaking in Xylene for 30 minutes if not baked, 90 minutes if baked, 2 pair of thin high-quality gloves (at the same time) or 1 pair of thick gloves, and a brass brush. I'm not saying it's better than epoxy or powder-coat, just saying it holds up "pretty well" and is a lot less work/expense depending on the use case. I've not had it soften with gas/oil/exhaust on it.

I'm not an expert, but so far I've not had to use 2-part epoxy so if it saves you time/effort/expense and still does the job you want, there you go.

 

[hacskaroly]

I use high-temp paint which calls for 3 heat-cool stages

This is good info, so far I am just using rattle cans and want to do what I can to make the paint as tough as possible (within the limits of what you can get from a rattle can). How soon after painting do you start the bake process, do you let the piece dry completely (no tack) or sooner?

 

[WI_Hedgehog]

This is good info, so far I am just using rattle cans and want to do what I can to make the paint as tough as possible (within the limits of what you can get from a rattle can). How soon after painting do you start the bake process, do you let the piece dry completely (no tack) or sooner?

The paint has to completely dry before curing in the oven, so at least an hour if the coats are all light. (3 light coats is better than one thick coat.) If this doesn't happen an outer skin can form and the paint can blister.

I generally prime 3 very light coats with 15 minutes between each, let it set up for 1 to 2 hours depending on temperature, mask, paint, unmask, paint, unmask, paint, allowing each layer to cure longer than the last since the base layers are still outgassing.

I let the paint set up for at least an hour, likely 1.5 to 2 due to multiple different layers of color. Then clearcoat.

If it's prime/paint/clear it sits a day before going in the curing oven. If there are multiple color layers it sits for a week to allow it to outgas though all those layers.

Thorough prep and cleaning is important, I've heard it said painting is quick and easy by comparison to prep.

In my experience (to borrow a saying), "Slow is smooth, smooth is fast." The more time taken (within reason) the better the result. Patience is a virtue I had to learn.

 

[hacskaroly]

In my experience (to borrow a saying), "Slow is smooth, smooth is fast." The more time taken (within reason) the better the result. Patience is a virtue I had to learn.

Yes, I am learning this too, painting is almost a let-down compared to the amount of time it takes to prep for good results. Luckily I have some extra chainsaw parts that I can practice on, work out the bugs and see what works best for the result I am looking for!