I have this 20-25 yr old Craftsman finish sprayer....
http://www.searspartsdirect.com/part...&prst=&shdMod=

..... that is "spitting" or skipping, as it sprays, leaving small gaps in my application, as I spray. I'm having to make double passes, in order to completely cover the surface area and, in some cases, the double pass results in drips/runs. It started this about 2-3 months ago and I don't know what is causing this. It's been a long time since I've completely disassembled the gun and cleaned it.... Possibly trash in the inside?

I'm spraying lacquer. I initially thought water in the tank may be the, or part of the, problem, but no. I've always liked this sprayer and it had been adjusted to my spraying style/technique/settings.

What might be the cause and might this sort of problem be easily fixable? It may be time to spring for a new sprayer.

Thanks.
Sonny

Sonny wrote:
I have this 20-25 yr old Craftsman finish sprayer....
http://www.searspartsdirect.com/part...&prst=&shdMod=

.... that is "spitting" or skipping, as it sprays, leaving small gaps
in my application, as I spray. I'm having to make double passes, in
order to completely cover the surface area and, in some cases, the
double pass results in drips/runs. It started this about 2-3 months
ago and I don't know what is causing this. It's been a long time
since I've completely disassembled the gun and cleaned it....
Possibly trash in the inside?

I'm spraying lacquer. I initially thought water in the tank may be
the, or part of the, problem, but no. I've always liked this
sprayer and it had been adjusted to my spraying
style/technique/settings.

What might be the cause and might this sort of problem be easily
fixable? It may be time to spring for a new sprayer.


Ok - it's a siphon gun. First thing to always look at with a siphon gun is
whether the cup vent is clogged. It will spit, spray eratically, etc. when
the vent is clogged. Better than 50% chance this is your problem. Next
place to look is at the packing in the needle. If it's leather, they get
dried out and have to be replaced from time to time. It looks like the
packing is no longer available from Sears, but it also looks like it may be
an OEM Binks product - or similar enough to one that a Model 7 packing may
work in your gun.

If it's not these two areas, then it's time for a good old fashioned
breakdown and cleaning. A rebuild kit wouldn't hurt at this point in your
gun's life. I would not be surprised if you can find a rebuild kit on-line
even though Sears doesn't stock all the parts anymore. When I clean a gun
that has gone a long time since a cleaning (not mine - I'm anal about
cleaning my guns...), I take them completely down - completely. Soak them
in lacquer thinner for a day or two and then go at it with cleaning brushes,
etc., to get it all spotless again.

You'll be surprised how much life is in a gun that has been properly
cleaned, and if needed, rebuilt with a kit.

--

-Mike-

On Monday, September 9, 2013 8:44:21 PM UTC-5, Mike Marlow wrote:


Thanks Mike. Yeah, I may have skimped on my latest cleaning efficiency. I may have gotten by with abbreviated cleaning, for a while, but apparently that has caught up with me.

The gun-can gasket is noticeably old and probably needs replacing. In the past, I've removed it for cleaning and it's pretty stiff, not flexible, and is difficult to easily seat it back in place.

It's long overdue for a total break down, also.

Sonny

Sonny wrote:
On Monday, September 9, 2013 8:44:21 PM UTC-5, Mike Marlow wrote:


Thanks Mike. Yeah, I may have skimped on my latest cleaning
efficiency. I may have gotten by with abbreviated cleaning, for a
while, but apparently that has caught up with me.

The gun-can gasket is noticeably old and probably needs replacing.
In the past, I've removed it for cleaning and it's pretty stiff, not
flexible, and is difficult to easily seat it back in place.

It's long overdue for a total break down, also.


You bet - I'm confident a good cleaning will be helpful. Cleaning a gun
well after using it is kind of a pain in the butt, but if done consistently,
it really only takes 5 minutes or so. It really pays off though. I'm not
anal about cleaning my guns because I'm a clean freak, rather so I don't
have to contend with problems.

As you have probably guessed - you'll want to find a replacement for that
seal (that seal should be available at NAPA - it's a common size cup),
and like I said in my last email - see if you can find a kit for that
gun. If you go the route of super cleaning and installing the kit, you can
take the cheating way out and clean the gun, then just replace the needle
packing and the cup seal, and you stand a good chance of being fine. Do get
after that cup vent though - it's your most likely suspect.

BTW - if you don't have a brush kit to clean your gun, the Harbor Freight
brush kit is dirt cheap, and is every bit as good as any brand kit. I have
one, as well as brushes that came with expensive guns - same brushes. Don't
waste money on brand name brush kits.

FWIW - when I strip a gun down, I take all the normal things apart - needle
removed, air cap, etc. Throw all of those into a 3lb coffee can that is
half full of clean lacquer thinner. Take the trigger off the gun, and
anything else you can easily remove. Pay attention to how it comes apart or
have the IPB on hand for later reassembly. Digital cameras can be your
friend if you're unfamiliar with how a gun works inside. Everything goes
into the lacquer thinner. Last, put the body of the gun into the thinner
upside down so the nose of the gun is in the bottom of the can. Let it soak
for a day, and pull it out as you happen to walk by, or think about it and
give the inside passages a run through with a brush - then put it back in.
Clean your cup really well too. I'm a believer that every part of the gun
should look as close to brand new as possible. Contamination, and all that.
Dried and built up finishes on the outside of a cup can result in a bad
mating surface between the cup and the gun. Plus - depending on the finish
you have been shooting, old finishes on the gun can become dissolved by the
solvents in what you're currently shooting, and mix into your current
finish.

Don't use tools that can scratch or gouge the gun. Time, lacquer thinner,
and some brushing is what you need here. Paint guns are a lot more
sophisticated than one might think, and gouging up a mating surface, or an
air passage is a good way to turn a good gun into something else. If you
have to pick at something stubborn, do so with extreme care and try to use
the softest tool possible to get the job done. Finally, remember...
something that you loosen up in the cleaning process is going to get lodged
somewhere inside your gun. Never fails. Blow the gun out as best you can
by hooking up your air in the normal way, before you assemble the gun.
Then, gently blow everything out as best as you can from the outside of the
gun before reassembly. It's amazing how small of a booger will screw up an
otherwise perfectly workable gun.



--

-Mike-

Unlike Mike, I am not so fussy.

I usually just fill the paint pot up with cold water and ice cubes, add some rock salt and screw it all back together. Shake like hell, and pour it all out. Never seem to have problems.

Wait a minute... maybe that's my coffee pot I'm thinking about...

So how ya doin', Mike? =8^)

Robert

On Wednesday, September 11, 2013 3:42:28 AM UTC-5, wrote:
Unlike Mike, I am not so fussy. I usually just fill the paint pot up with cold water and ice cubes, add some rock salt and screw it all back together. Shake like hell, and pour it all out. Never seem to have problems. Wait a minute... maybe that's my coffee pot I'm thinking about... So how ya doin', Mike? =8^) Robert

These past few days, I've had a chair to upholster and needed to refinished the woodwork. I had the spraying problems with the first spraying. Since Mike's reply, I cleaned the vent and gun-can gasket and was able to finish the spraying with no problems.... very minimal spitting/skipping of the spray stream.

Last week, I had a roccoco sofa to upholster and woodwork to refinish, so my spraying problems had gotten to the point that something needed to be done. I was at a loss as to what the problem was. Previously, I had thought my cleaning had been good enough and had assumed, maybe, the gun unit (something internal?) was wearing out.

For the past few months, there were signs of the gun not performing properly, which became worse and worse. Initially, I didn't pay it too much mind, until the finishing results were more than sub-par and not acceptible.

Sometimes, I take a day or two and devote to cutting tools sharpening, including garden tools, mowers, etc. Time to devote some quality time to thorough cleaning of these other tools. I spent time, yesterday, giving the air compressor a good maintenance going over, though it's been working fine.

I usually keep up with preventative maintenance of stuff. Apparently not so with the finish sprayer. I'll do a complete cleaning this week, sometime..

Sonny