What Did You Buy Today?

[coolidge]

I ran a professional spray booth and was the licensed Paint Spray Supervisor

I did...well none of that lol. About the only victory I have had of late is baking small rattle canned parts in the oven to cure them. Though the paint which allegedly is a paint and primer in one still chips off cast iron with ease. I'm temped to start blasting everything with Rino truck bed liner.

 

[GrifterGuru]

sounds like you have a lot more experience than I do with spraying. biggest problem with rattle cans to me is I can't add a hardening agent. I mostly do automotive polyurethanes but when I shoot alkyd enamels, I always use a hardener. and usually, a small amount of Penetrol. I don't find rattle can paint to be anywhere near as durable as other products I use.

The old adage of "you get what you pay for" is one aspect in terms of paint quality. Prep and application is another.

Personally, I have won competitions with bikes (bicycles) that have been painted with rattle cans against guys who have had a professional spray job done. I also find it does not chip any easier than a proper spray job either.

Then again, I do heat-cure the paint. I find hot-air clothes-drying "wardrobes" heat up to just the right temp range. Have painted many a bicycle frame as well as other things and cured them in one of these andnever had a problem or issue with the paint.

 

[Eddyde]

I did...well none of that lol. About the only victory I have had of late is baking small rattle canned parts in the oven to cure them. Though the paint which allegedly is a paint and primer in one still chips off cast iron with ease. I'm temped to start blasting everything with Rino truck bed liner.

I proposed using bed liner for my lathe a few years ago and got a lot of push back for making such a scandalous suggestion. However, I still think it might be a good idea...

 

[coolidge]

I proposed using bed liner for my lathe a few years ago and got a lot of push back for making such a scandalous suggestion. However, I still think it might be a good idea...

Right, it takes a beating while living outdoors in the sun, rain and snow. I recently made a chip guard out of a sheet of aluminum and applied a 1/8 inch thick sheet of rubber to it with spray on contact cement. That should hold up for quite a long while vs the chips stripping paint right off it.

I think I derailed the 'what did you buy today' thread though so I'm going back on topic.

 

[Eddyde]

sounds like you have a lot more experience than I do with spraying. biggest problem with rattle cans to me is I can't add a hardening agent. I mostly do automotive polyurethanes but when I shoot alkyd enamels, I always use a hardener. and usually, a small amount of Penetrol. I don't find rattle can paint to be anywhere near as durable as other products I use.

Yes, urethanes especially catalyzed, are extremely tough. No contest there from a rattle can. However, those finishes are not easy to work with and beyond the scope of many hobby or small shops.

 

[yota]

as far as prep goes. I usually clean anything oily or greasy in the parts cleaner, then wash in degreaser. old paint is either removed by media blasting or paint remover (I almost never use paint remover). if the old paint is well adhered and doesn't have gouges and scratches that I can't completely sand out, I might leave it and just sand. typically, I don't sand smoother than 250 or 400 grit. want some "tooth" for the primer to grip.

if blasting to bare metal, you want to prime fairly quickly after to prevent flash corrosion. if painting bare aluminum or magnesium, I do an Alodine wash and rinse before priming.

I always use a tack cloth before spraying primer or paint. when I need to do a solvent wipe down, I use acetone. mineral spirits or paint thinner is actually a very light oil, so keep that in mind if you use it to wipe down before spraying. won't hurt if you're shooting alkyd enamel but dunno. opinions on this vary.

sanding is the work. if you have any low spots in the old paint (like afore mentioned gouges), they will look like craters in the primer unless you sand them completely out to a very long taper. if the old paint starts flaking when sanding then it all needs to come off. primer will show every defect. if you have any defects then start over. do not shoot the topcoat. be picky. why go to all the trouble to do this if you're going to have defects? I do use high quality light weight body filler and then spot putty to fill voids in metal, esp if I blast castings. filler does not work well for getting rid of gouges and scratches in the old paint layer though. they need to be sanded out.

painting is a learning process. I'm self-taught, which means I had to do a lot of things over after effing them up in the beginning. there are really only 2 settings on an automotive type spray gun, fan and material. the fan knob can give you a wide fan or a small round spot by turning the knob. the material knob can be turned to spray nothing to flooding. a wide fan is good for large areas, a spot is good for narrow work, say the pickets in a gate. if you have the material set well for a wide fan and then set the fan to a spot, you will flood the work and have a huge run. so, if you change the fan, you must change the amount of material coming out of the nozzle. oh, there are different orifice nozzles for different paints. I always have a large sheet of cardboard set up near what I'm shooting to set fan and nozzle. if the paint comes out looking dry, you need more material, if it floods then less, of course.

if you are spraying and get a run, STOP. do not try to fix it, you will fail. do not wipe it off. let the work set up until you can sand it off and do it over. several light coats are better that one heavy coat when you are learning. to get good gloss, you need to lay on enough paint to get some flow, just not to the point of running. if you make mistakes, don't give up.

 

[yota]

Yes, urethanes especially catalyzed, are extremely tough. No contest there from a rattle can. However, those finishes are not easy to work with and beyond the scope of many hobby or small shops.

don't necessarily agree with that. mixing a catalyst into the paint isn't rocket science. I did that yellow chainsaw in a single stage urethane, in my home shop. shot everything outside and then brought each piece inside my shop and hung up to cure. I've also done base coat/clear coat urethane at home. I will agree that you don't want to shoot it indoors without the right ventilation equipment, and a good respirator with painting cartridges (not dust cartridges). but honestly, you should take the same precautions when spraying alkyds and esp rattle cans. protect your lungs people.

for those following the discussion, a single stage urethane is still a multi part material (paint and activator), it's just not base coat/clear coat, which also uses activators but is 2 separate steps.

 

[4WHLDRFTN]

Some rattle cans are shet. If it dries in minutes, its not going to be durable.
Automotive rattle can like VHT ( not ceramic) most Rustoliums, Krylons are very durable
Rustolium Farm Implement paints are very good.

Did you ever wonder why it sticks and is there forever on everything but what you’re painting. ?

 

[woodchucker]

I wish I could paint outside, but I have had too many things get ruined by the bugs, leaves, floating stuff, blowing breeze. The most outdoors I'll shoot is in the garage with the doors open when the wind is coming from the west.

Would love to have a big spray booth. Years ago, I had a tower of filters, and a HVAC blower, it worked well but, it took up a huge amount of space.

I now have a blower and it's maybe 30 inches , but it is not as efficient for the needs... full height is way better than floor height at moving the air the way I want it. I would rather have the air pull 90.. I can adjust for that.

 

[pontiac428]

VHT cured with a heat gun is the bomb. Allow the paint to flash dry to the touch, then hit it with the heat gun (gently until you figure it out) until the surface dulls as the solvents come out, then heat it until the surface gets shiny. It's tough as nails.

I prefer to shoot when I can, because I can add adhesion promoter and hardener (acrylic and isocyanate, respectively) plus some naphtha for leveling to the mix. You don't get that in Krylon or Rustoleum, and it makes a huge difference to how thick and tough the result is. It works with primers and brush jobs too.

I'm no Rembrandt with the paints. Just a lot of botched work and short-lived paint jobs to learn from.