Mottling/poor atomisation in basecoat

[carbon]

Try this video from ppg about setting up a spraygun. They did have one that was a bit more detailed.

 

[Edward Yemm]

Try this video from ppg about setting up a spraygun. They did have one that was a bit more detailed.

All my test areas on cardboard look like the far left unless I hold trigger for 2-3 seconds. Just wasn’t getting the wet coat I needed. Thanks.

 

[carbon]

2bar should be a good starting point but you may find adjusting air pressure can help with finish. I’ve never used bar coat but would too much thinners cause the reaction you have as it looks like you have lots of basecoat applied if it’s taking a long time to dry

 

[Edward Yemm]

2bar should be a good starting point but you may find adjusting air pressure can help with finish. I’ve never used bar coat but would too much thinners cause the reaction you have as it looks like you have lots of basecoat applied if it’s taking a long time to dry

I don’t know if it’s thinners that have caused some of the issues for sure but I have blooming on a test panel with 120% as well. Maybe it’s just where I pilled on too much paint trying to smooth it all out to no avail. I just broke my regulator trying to get it past 60psi. Perhaps I couldn’t get enough pressure because of the small coil hose leading up to it. I know those coil hoses are rubbish for trying to gun off bus wheels etc at work. I’ve got the hose running directly to the desiccant filter and the mini regulator on my gun now. Finally getting 30psi trigger with 80psi input pressure.

 

[carbon]

Rather than connect the regulator on the wall to the regulator/manifold on the compressor connect it to the end of the tank.

Replace the hose with something less restrictive if possible

 

[Edward Yemm]

That’s what I was thinking until I ******** up the regulator. I’ll try repairing it later but it’s not letting any air through now so I think it’s irreparable. Ill look at getting another regulator/water trap soon. Ill use my other standard rubber airline up to it. Daily compressor tank draining and the desiccant filter will do for now. I haven’t done anything else to that panel for now. I’m knackered today and I’ve been playing with my daughter instead. I’ll update you when I finally get around to putting base on again. Thanks for the advice everyone! I’m definitely in the right place for advice!

 

[Edward Yemm]

Rather than connect the regulator on the wall to the regulator/manifold on the compressor connect it to the end of the tank. View attachment 228452

Replace the hose with something less restrictive if possible

I don’t have a clue how to connect it to the end of the tank? Is there a spare plug I can remove from the tank then? I’ll have to have a look.

 

[Edward Yemm]

So, screw this
Image 1:

into this port
Image 2:

instead of the manifold:
Image 3:
Then I’ll still have pressure relief valve on manifold as necessity as cut off to stop over pressure explosion of tank.

Have I got it right?

 

[Edward Yemm]

Image 3

 

[carbon]

Yes that correct, the manifold on the compressor looks fairly small. The two can be directly connected but you need to be careful nothing drops on it and damages it. Also make sure compressor tank is drained before removing the end plug

 

[norsa]

show us your test spray pattern on the wall, we'll be able to see from that where the problem lies.
Nick

 

[Edward Yemm]

show us your test spray pattern on the wall, we'll be able to see from that where the problem lies.
Nick

Top right is indicative of what I was getting if I pulled the trigger in for 1 second. The other 3 spots took 2-3 seconds to build up. I’ll retry at 30 psi.

 

[norsa]

Definitely lack of material mate. assuming your viscosity is good> {2.5 second drip test} I would suspect restriction somewhere in the gun between cup and cap but probably not in the cap itself.
The others, being base coat, if you triggered for 1 second with full flow of material, it should have a run at the bottom.
Nick

 

[Edward Yemm]

Thanks for the help guys. Whacked the pressure up to 30psi and I now have this type of finish with 1k products. About the same amount of orange peel I’m seeing on a lot of cars. It will do with the cheap gun I’ve got. Finally I can see my reflection without having to cut and polish.

 

[Edward Yemm]

It’s definitely better than this rubbish from when the pressure was too low.

 

[carbon]

Thanks for the help guys. Whacked the pressure up to 30psi and I now have this type of finish with 1k products. About the same amount of orange peel I’m seeing on a lot of cars. It will do with the cheap gun I’ve got. Finally I can see my reflection without having to cut and polish.

Definitely lots better.

 

[Edward Yemm]

Definitely lots better.

I’ve got some tiny solvent pops across the surface but they can be cut out a week or two after I spray the boot. I’ll just make sure I do a few coats of lacquer. I was having to slow the gun down a bit to get coverage. I wound out the fluid needle but it doesn’t want to give me a great deal more paint. I might leave it to flash off for 15-20 minutes between coats. Give it a bit longer for solvent to evaporate. Bit longer than 10. I’ll have a play around again tomorrow.

 

[carbon]

Does the compressor run constantly when spraying?

 

[Edward Yemm]

Does the compressor run constantly when spraying?

No. It will let you do a coat of paint before it cuts in again. I’ve got a desiccant filter at the gun for now. My new regulator/water trap arrived. Finally. I can’t fit it directly to the tank yet because I need a 1/2” - 1/4” reducer. I was spraying 3 ft away from a flood light. The thermometer was showing 23 degrees and that was no where near the roof of the car where I was spraying. The temperature could have been over 30 up there. I felt hot when I was sanding it there. I waited about 10 minutes between each coat so it may have been too much heat causing the solvent pop.

 

[Edward Yemm]

I think plan of action for tomorrow is. Play around with the fluid needle to see if I get better coverage at 1 second test. Turn the garage lights off for a while if the thermometer shows high 20s or more up there. Pull the trigger on the gun until the compressor starts up and begin painting after it’s blown off.