Moisture removal

[Domdom]

Afternoon chaps. A wee issue, which I wasn't aware I had, and need some help please.

Compressor is a Clarke, twin pump on a 270 litre. Drained regularly, and always has a lot in it.
Output is via a 3/4 pipe to the filters.
Filter/Reg is a 15 micron for moisture and dirt removal.
Filter 2 is a 5 micron.
Filter 3 is another 5 micron, same as filter 2.
then a PCL dropout.
Then my "clean" take off - this is where I connect for spraying and dry work like plasma.
then a lubricator for air tools.

I have a new hose for paint, which goes to the belt filter pack on the air-fed mask (devilbiss), and then a short hose to the gun, which also has a small moisture trap on it before the mini pressure regulator.

The problem is a few micro-spots in the paint finish, which I can only attribute to moisture. So my question is, how can moisture get through all these filters? And what more can I do to prevent it please?

Thanks.

 

[JOEPRO]

First question- what prep do you do on the panels being painted before spraying them?

Do you use a tack rag?

Oiler is suspect to me if it is permanently fitted. Sometimes it's best to add a drop of oil into the air tool itself directly.

 

[carbon]

If you dont have a 3 stage filter for breating air you are also breathing in oil and moisture mist when using an air fed mask

 

[Domdom]

First question- what prep do you do on the panels being painted before spraying them?

Do you use a tack rag?

Oiler is suspect to me if it is permanently fitted. Sometimes it's best to add a drop of oil into the air tool itself directly.

Yes, I use tack cloths. No, the oiler is after the take off for painting.

If you dont have a 3 stage filter for breating air you are also breathing in oil and moisture mist when using an air fed mask

3 stage is on the belt pack

 

[JOEPRO]

Yes, I use tack cloths. No, the oiler is after the take off for painting.

3 stage is on the belt pack

What about pre paint wipe? Because that is an essential step to remove contamination from the panels.

 

[carbon]

3 stage is on the belt pack

Usually with devilbiss air fed masks only the carbon filter is on the belt. You still need a coalesing filter to remove the oil and moisture

 

[Domdom]

What about pre paint wipe? Because that is an essential step to remove contamination from the panels.

Yes, always use panel wipe. This deffo looks like miniature water spots, and they are lower than the surrounding paint. It's not dirt for sure. I can sand it out with 1200.

Usually with devilbiss air fed masks only the carbon filter is on the belt. You still need a coalesing filter to remove the oil and moisture

Yeah, I have that, and also a chinesium belt pack before it. Do you think it's worth getting a large 3 stage filter to go after the filers I listed above?

 

[carbon]

If you dont have a coalesing filter, adding one on after the wall mounted filters you have will eliminate moisture to your air fed mask and the spraygun

 

[Slowcoach]

Yes, always use panel wipe. This deffo looks like miniature water spots, and they are lower than the surrounding paint. It's not dirt for sure. I can sand it out with 1200.

Yeah, I have that, and also a chinesium belt pack before it. Do you think it's worth getting a large 3 stage filter to go after the filers I listed above?

If the ‘miniature water spots’ are lower than the surrounding paint, crater like per chance?, I’d say it might be silicon not water.

 

[Domdom]

Hmmmm, I thought silicon was more of a fish eye type of thing? This looks more like a tiny pit, less than 1mm diameter. Where could silicon have come from? I’m not aware I have anything in there with silicon in it.

 

[Slowcoach]

It’s usual more than 1mm diamenter, got any pics. It’s just as soon as you said crater I went for silicon.

 

[Domdom]

It’s usual more than 1mm diamenter, got any pics. It’s just as soon as you said crater I went for silicon.

I haven’t sadly. In all the confusion I forgot to take any. I’ve flatted it with 1200 ready to put another coat on now, but they were tiny. Being so small and the fact they sanded out easily makes me think water rather than silicon.

Can you compress some air, fill a binbag with it with this inside? https://www.screwfix.com/p/htc-1-thermometer-hygrometer/2806x

Now there’s an idea. Just ordered one.

 

[timgunn1962]

OK.

I'll try to explain some of the "why" I'd do it differently.

I'm guessing that you run it it for long periods?

If so, the air will be warm as it exits the receiver and will be at 100% humidity. Run it as far as is reasonably practicable to the Dropout. The distance will allow the air to get closer to ambient temperature and the dropout will remove any condensate that forms. Filter to whatever you have available, which sounds like a 5 micron coalescer. If you can swap the 15 micron element from your filter/reg into the filter, great. Do so. If you do, follow it up with the 5 micron coalescer. Ideally, you then want a .01 micron coalescer. If you can get one for your existing housing, do so. This will remove all the oil and all the condensed water mist. It'll still leave you with 100% humidity at whatever temperature it's at (hence the maximum distance mentioned earlier). THEN you want to regulate down to the pressure you actually need. You can use the filter/reg, but the filter part will do bog all because the upstream filtration is so much finer, but it's what you've got. If you've got everything down to ambient temperature at the regulator with 100% humidity going in at (say) 8 Bar, and you regulate down to 6 Bar, you'll drop the relative humidity from 100% to 75% as you drop the pressure.