dry spray issues

[jxke]

Hi all,

Sorry for long post but hopefully the info helps to help, I’m trying a cheap and cheerful respray on my daily driver. Using an Optiflow LVLP gun, I had results that I was really happy with in epoxy primer (1.8mm) and then Nisocoat 2 (1.4mm) over that.

Since then I’ve just not been able to get it to spray nicely, it’s way too dry. I’m a novice with a small budget which doesn’t help but I got a really good gun finish gloss with no effort or practice which is amazing for the project I have, so what I have should hopefully do the job if I can find where I went wrong?

As mentioned im using the Optiflow gun, I have a 50 litre 9.6cfm 2.5hp compressor, 9.5mm id 10mt air hose, and a regulator at the gun. I’m painting outside as it’s all I’ve got but when it worked the results were so good for me. I can’t remember how I had it set up when it worked well as I expected it to work that well the next time but just not been able to repeat it. I cleaned the gun with gunwash and brushes/needles after use, I mixed about 40% thinner in both the Lechler and Nisocoat

Thanks all for any input, pics from when I got it to work. When it didn’t it was very dry/rough :/

 

[norsa]

Unfortunately, there are a miriad of reasons for dry finish from gun set up to technique to mixing ratio. You will need to address all the above one by one to eliminate the issue. I would start with a gun set up, see what pattern you get. Post a pic of your test spray and we can give you a pointer from there. Nick

 

[jxke]

Thanks for the response, I got another of the same gun and it went down flawlessly again, I can’t remember but I must have soaked the gun in thinners and borked a seal or packing nut or something.. I made sure to clean the new one properly so it should be good for next use.

The paint is awesome, I’ll share some pics when I’m finished but got the rear quarters and tailgate done today, got to do the bumper and lower brace to finish the rear then onto doors, bonnet etc. Thanks again

 

[badabec]

Hello, by mistake I left a spray gun soaking in cellulose thinners. A couple of days later (oops) it was completely trashed. Some of the metal had fallen apart.

 

[marlinspike]

That looks really good to me, especially as done outside with a 50 litre compressor.

 

[norsa]

Never leave a gun in soak. It doesn't clean the solids out and knackers the packing washers and seals. Strip immediately and washq all the component parts then run gun wash through forwards and backwards. Store the gun without thinners in it. Lesson learned eh.
Nick

 

[jxke]

Thanks all, yeah definitely lesson learnt and enjoying it.

 

[norsa]

And of course, do a spray out before approaching the panel every time.
Nick

 

[charlysays]

Thanks for the response, I got another of the same gun and it went down flawlessly again, I can’t remember but I must have soaked the gun in thinners and borked a seal or packing nut or something.. I made sure to clean the new one properly so it should be good for next use.

The paint is awesome, I’ll share some pics when I’m finished but got the rear quarters and tailgate done today, got to do the bumper and lower brace to finish the rear then onto doors, bonnet etc. Thanks again View attachment 412015View attachment 412016

Looking great mate.
HMG nisocoat 2 is such an underrated paint for DIY shoestring budget resprays, I'm not sure why it isn't the default paint for DIY resprays where the cost of airfed etc can't be justified or the location precludes use of isocyanate paints. Probably because it's marketed as an industrial paint.

I did my daily car in it 2 yrs ago which does high miles and sits outside 24/7 and there's absolutely no sign of weathering etc. I would have had to polish celly twice or more by now and apply way more coats etc in the first place and have the associated risks of reactions etc because celly never cures per se.

Looking forward to seeing more pics as the project progresses

 

[norsa]

I suspect and hope its the way forward, developing non Iso hardener. Iso 2k has been around for the best part of 5 decades now and contrary to our American friends HSE standards, it is harmful to health. Water based paints were supposed to eradicate the danger but, and I'm sure Parm will agree: Anything other than fresh air in the lungs can be harmful, water based paints are not thinned with tap water and they still need a 2k clear to seal and protect the colour. I'll be fully retired a year or so from now and am from the generation of old skool painters who would drink a pint of milk then blow a car over in celly because it was better for the health, but future generations, I'm sure will have and deserve healthier lungs than I have.
Nick

 

[jxke]

Unfortunately I’ve not solved this yet and it’s driving me nuts trying to figure it out, I’ve tried a few times to paint the bonnet and just can’t get it to go down well at all, it seems fine when spraying a test panel but then it’s very obviously not right when starting the panel

I’ve tried various pressures and various % thinners. Gun is clean as a whistle, pattern is good. Had no issue when I sprayed some epoxy primer the other day, I’m sure it’s user error/inexperience rather than equipment as I did the back half of the car with no issues somehow, but I do wonder if I should fork out for an upgrade from the 50lt/9.6cfm compressor I have.

 

[minimutly]

How hot is your panel/booth? I did some 2k iso outside last summer, first time ever I got a dry coat. Had to add a load of thinners and just throw it on. Worked out ok in the end, but it wasn’t until I picked up the panel I realised how warm it was. Black will always attract the sun.

 

[jxke]

How hot is your panel/booth? I did some 2k iso outside last summer, first time ever I got a dry coat. Had to add a load of thinners and just throw it on. Worked out ok in the end, but it wasn’t until I picked up the panel I realised how warm it was. Black will always attract the sun.

just ambient temperature so about 17-20 degrees outside, seems pretty good not hot at all thanks to dull english weather.

it’s so dry i couldn’t get a run if i tried, definitely seems worse at an angle doing the bonnet than on the scrap front wing test panel i have. i’m gunna give it another go next weekend and go through absolutely everything and if it still doesn’t work i’ve got to try a different gun and/or compressor.

 

[norsa]

See if you can do a little vid of your spray out then the panel paint. There are so many things that can cause it but it's all fixable. I've visited various members on here to observe and rectify issues. Sometimes, it's an obvious issue, often caused by watching too many you tube vids. It's all fixable. What part of the world are you?
Nick

 

[jxke]

See if you can do a little vid of your spray out then the panel paint. There are so many things that can cause it but it's all fixable. I've visited various members on here to observe and rectify issues. Sometimes, it's an obvious issue, often caused by watching too many you tube vids. It's all fixable. What part of the world are you?
Nick

Thanks yeah I’ll do that and post it up - I’m in Bedfordshire, that’s really nice of you to help people yeah the forum is great. I’ve always just taught myself by having a go and seeing what works and what doesn’t and hit a wall with this one, but it’s part of the learning process

 

[norsa]

It is a good way to learn but as you say, sometimes frustration gets the better of you. I've got many years in the trade and know pretty much most of the pitfalls. If at some stage during the panel paint, it's obviously dry, give me another test spray immediately. Feel free to P.M me.
Nick

 

[charlysays]

Unfortunately I’ve not solved this yet and it’s driving me nuts trying to figure it out, I’ve tried a few times to paint the bonnet and just can’t get it to go down well at all, it seems fine when spraying a test panel but then it’s very obviously not right when starting the panel

I’ve tried various pressures and various % thinners. Gun is clean as a whistle, pattern is good. Had no issue when I sprayed some epoxy primer the other day, I’m sure it’s user error/inexperience rather than equipment as I did the back half of the car with no issues somehow, but I do wonder if I should fork out for an upgrade from the 50lt/9.6cfm compressor I have.

Could it be temperature?
Nisocoat is known for flashing off very quick which would be worse at high temps. Use slow 2k thinner to combat this. I found the passes had to be slow to get a nice wet coat with minimal orange peel, much slower than videos of people spraying automotive 2k.
Hope you get to the bottom of it.
Keep an eye out for a bigger used compressor. 200ltr one linked with your existing one would give you enough flow to do one panel at a time without relying on the pumps to keep up so your limiting factor would then be your lines and couplings/ separators etc .
You can sometimes get them really cheap. Even just a 200l tank would be a good test as even with the one pump it would allow you to paint the bonnet at the max flow rate of the gun.

 

[richie00boy]

40% thinner is a lot, I wonder if that amount of thinners is masking a problem that you would have had the first time if you used a more normal amount of thinners, but just got lucky.

Have you been filtering the paint?
Are you setting pressure with the trigger pulled?
Have you got a proper regulator ? As you mentioned one at the gun, but those little block things with a dial are usually just restrictors.

I've painted large areas of a car with a 50 litre compressor and had no issue with a cheap LVLP gun and better quality low pressure gun.

 

[julianf]

I swapped to slow thinner the other day when it was baking. Less issues.

I don't have the cleanest work environment so normally like stuff to flash off quick as, otherwise it just gets more surface contaminants in it, but there are limits...

 

[Keithmac]

Thanks for the response, I got another of the same gun and it went down flawlessly again, I can’t remember but I must have soaked the gun in thinners and borked a seal or packing nut or something.. I made sure to clean the new one properly so it should be good for next use.

The paint is awesome, I’ll share some pics when I’m finished but got the rear quarters and tailgate done today, got to do the bumper and lower brace to finish the rear then onto doors, bonnet etc. Thanks again View attachment 412015View attachment 412016

That looks fantastic for being painted outside (inside for that matter!).

Hope you get your issues sorted our with the rest of it.

I've got mine to do as well outside, still weighing up best options / paints etc (no air fed mask and need to respect neighbours etc).