Contamination issues

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PostPosted: Sat Apr 07, 2018 5:14 pm
hey guys (and ladies) just signed up here seems like a great forum with active people. So ill go ahead and say i'm probably not as seasoned as most of you but still learning the ropes. so heres my dilemma. Starting this year ive transitioned from an detail shop over to body shop. my shop was neglected for years prior to me so ive been fixing its issues as ive been going along. ive been silicone free in my shop for about 6 months now yet every once in awhile a job will come out like garbage (fisheyes). today for example i was painting this ford escape and the basecoat came out great. yet the clear came out terrible, like im going to have to scuff/spray it again tomorrow terrible. ive already resolved previous issues with water in my lines (rerouted the compressors plumbing so i have one designated compressor for the booth/one for shop). i am pretty confident its silicone related.
the two things i can think of is while i was waiting for the base to dry i changed out a bumper on a scion tc (outside with closed doors). i saw the engine was detailed and shiny (most likely silicone) although it looked like it had been done awhile ago. now i didnt touch the engine much if any (maybe removing a clip or two). is barely touching something that has silicone on it from a long time ago enough to ruin 4 panels while you're spraying? im also pretty sure i changed out my gloves.

the next thing i can think of is maybe when i did the wax and grease removal on the quarter panels the inside lip had some silicone sling on it from being tire shined at one point? although im pretty good about hitting areas like those last to prevent that sort of thing.

i sprayed a c10 the previous day and had zero issues. if anyone has any other suggestions i would appreciate it.



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PostPosted: Sun Apr 08, 2018 6:41 pm
could be a million things, but I would think touching the car outside would not cause problems. you should have cured the problem with your W/G remover if done properly, and some times it doesn't hurt to go over it a second time. be sure your rags are clean and you wipe on with one rag and wipe off with the other. now you need to let it set for at least a half hour or more to make sure the W/G remover has evaporated. I like to go over it with an air hose especially any cracks or seams that might hold W/G remover. this is just a starting point could be in your mixing or still in your air system.
Jay D.
they say my name is Jay



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PostPosted: Tue Apr 10, 2018 12:53 am
A picture is worth a thousand words! like to see the Paint problem please.

This kinda sounds like its an on going problem. Is it?????

What kind of water trap are you running ? how far is it from compressor? How many feet? where are the filter assembly located in the system how many feet from compressor?

How old are your hoses for spraying ? Once they are contaminated they are worthless for Painting.

Also what Air compressor are you running? how big? brand? Model? age?

Silicone is not the only driving factor for Fish eyes.

My shop is a small dual use shop I do regular every day auto repair in there engines Transmissions clutches brakes welding Glass beading even electroplating, I also do a fair amount of auto body work and Paint work out their, I use Silicone's in there all the time, Sealers, lubricating Sprays, detailing materials and I never have Fish eye problems, Maybe I'm just lucky???? But I don't think so! I always wash and De-grease / De-wax every thing I am gonna Paint But I use very dedicated Dry filtered Air system for painting this includes Air Hoses and I use the same Air compressor for the whole shop.
Dennis Barnett
A&P Mechanic, FCC General radio Telephone Operator
Line Maintenance A&P Mechanic and MOC Tech specialist.

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PostPosted: Tue Apr 10, 2018 10:59 pm
Years ago, our big main wood shop compressor started failing and really crapped up both our hard lines and our hoses. We were getting intermittent fish eye problems much like you. I ended up tearing out all of the hard lines and getting rid of my hoses. Never had fish eye anywhere in the shop since then......
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PostPosted: Wed Apr 11, 2018 4:01 am
DarrelK wrote:Years ago, our big main wood shop compressor started failing and really crapped up both our hard lines and our hoses. We were getting intermittent fish eye problems much like you. I ended up tearing out all of the hard lines and getting rid of my hoses. Never had fish eye anywhere in the shop since then......


Kinda what I was getting at, could be compressor doing it could be contaminated hoses & lines, could be the heat in the shop, there is a lot to go through to find the cause.
Dennis Barnett
A&P Mechanic, FCC General radio Telephone Operator
Line Maintenance A&P Mechanic and MOC Tech specialist.



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PostPosted: Wed Apr 11, 2018 11:33 am
:goodpost: :goodpost: i'm with these guys, and i'm thinking if you used the wax & grease remover properly then its probably something that came after the W/G remover. like a dirty air system or not enough dry time for the W&G remover. this can sometimes be really difficult to pin point.
Jay D.
they say my name is Jay



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PostPosted: Fri Apr 13, 2018 12:02 pm
i have two 5 hp compressors for the shop . one is for the booth from 1990............. kicks on a few times a day unless im spraying obviously. it probably 40 or so feet away if you measured the plumbing on the walls to the booth. my solution to my prior issues with water issues was separating the compressors like i said which is what my paint rep recommended. ill generally drain the tank once a day or let it drip. ill also dump the air using a hand valve located right before the air goes into the booth every few days (basically pushes anything out of the air line going to the booth). i also have another dump right at the compressor for water to collect at. i have 3 inline filters, one cheapo toilet paper one which i change every couple days, another charcoal one, and desiccant one. now the charcoal and desiccant are about a year old so i'm sure they are worn out. ive been meaning to order them but wanted to figure out the whole water issues like i did before so i didnt go and ruin 150 bucks worth of filters right away. my air hose is a new 35 foot flexzilla that i filled with wax and grease remover and flushed before i started using it (ive heard people do this to make sure its clean inside).

The next day after i orginally posted i resprayed everything and it came out perfect. last night i sprayed this c10 roof and i removed both of those worn out charcoal/desiccant filters and also put one of those disposable filters on my gun and. the paint came out flawless just a couple dust specs. can old filters hold and release contamination at random times? or could my compressor be spitting out oil? ive also considered getting a refrigerant dryer that cools down the hot air before it even hits the tank. says it removed 90%. would you guys like some pictures?



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PostPosted: Fri Apr 13, 2018 7:00 pm
Yes dirty filters are a problem. what you should do is when you take out the old filters cut them open and see if you have oil contamination. if so you'll need to do something with the compressor. an oil pumping compressor can cause major problems.
Jay D.
they say my name is Jay



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PostPosted: Tue Apr 17, 2018 10:01 pm
Refrigerated water seperator's are expensive, I use an 2 large Air tanks welded together with a 1 inch pipe to form a large water trap located about 20 feet from the compressors each has a drain then I filter the air with a simple air filter water trap combo then into a Devilbiss DAD500 air filter system which is about 40 feet away from the Main water trap filter system attached to the paint booth its used exclusively for the Paint booth and now my Plasma cutter only! I keep it shut off by Ball valve when not needed to keep the desiccant from trying to dry out whole system.

I use Auto drains on my compressor Tanks, and I have plumbed in numerous air taps around the shop after the water trap but before the DAD 500 I never get any water from any of the Taps.

Clean dry air is a Must! Got enough variables to deal with.

Pictures are worth a Thousand words
Dennis Barnett
A&P Mechanic, FCC General radio Telephone Operator
Line Maintenance A&P Mechanic and MOC Tech specialist.

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