Phoenixed

Setup - House of Color traditional Kandy Apple Red 3 part system.
Asturo mini gun
http://www.spraygunworld.com/product...exMiniGun.html
I am using carbon filters for ultra dry and clean air.
Using a downdraft bench paint booth.

Problem - everything going on fine until color sanding. Small white spots starting showing up after just a few strokes with P1500. At first I thought I was getting clearcoat balled up and shoved into the finish. You can't see the spots when they are wet, so I went ahead and flow coated hoping they would go away - they DIDN'T. I changed sandpaper - went with the expensive 3M stuff. Finally sanded back down until I was starting to get into the color, but the spots finally sanded out. Re-cleared, stayed with the 3M trizac paper and spots are back. Thought it might be solvent pop - so I backed off the reducer by 30% - sanded and re-cleared - spots are back... ugh...

I have not painted for years, but I am also not new to it. I feel like I am making a rookie mistake here... not sure what is going on.

Any thoughts???!!! THX!!!!

alek72us

How long are u letting the clear coat dry before u start sanding it? I'm thinking also balling up. u try a finer grit. after u sand the clear coat and get the spots what happens to the spots if buffed?

i know nothing about House Of Kolor.

Also welcome to Classic Oldsmobile. u should let everyone know who u are and introduce yourself.

Phoenixed

Thanks for the fine welcome! I will introduce myself when I have a minute free of sanding!

First incident had days to dry and I have allowed more time to make sure it is properly cured. Shop stays in the high 60s at night and gets into low 70s during the day. I use 1000 Watts of halogen to help things along (two 500 watt).

All things equal - this is also my first HOK paint job. I am wondering if I am over catalyzing??? This has never happened to me before. I have no idea of what too much catalyst will do - I will do a small practice panel to find out.

Spots stay if buffed... VERY visible in daylight. Looks like albino flies have been crawling all over it.

Aron Nance

Welcome to CO, Phoenixed! Glad you are here, and hope someone with the paint knowledge signs on shortly and shoots you in the correct direction! Once again, Welcome!

alek72us

Do u think they are fish eyes?

do they only show up when u start to color sand?

Phoenixed

Thanks for the responses! I am familiar with the common painting issues; fish eye, orange peel, runs, nibs, dry coating etc.

Not fish eye...

I cannot detect them until I hit it with wet sandpaper. I am down to using a magnifying glass to look for them... no clue where they will turn up.

I just shot a practice panel with under catalyzed clear... graduating to 2X catalyst.

FYI - I am shooting EXTREMELY SMALL shots... many small, complex pieces to paint. I am using 3.5ml transfer pipettes to measure the paint. Biggest mix was 15X3.5ml of color. I have a chemistry background and know how to use these. If I am off more than 1/4 a pipette I am screwed - but I have done this before, several times with great results.

compedgemarine

are you using House of Kolor clear? if so I have never had luck with it. every time I used any of their clears I had all types of issues. I started using Southern Polyurethanes clears or PPG clears and have not had any of the problems with the HoK stuff

Phoenixed

I am using the entire HOK system for this job, including the clear. I don't like the different catalyst for the Kandy VS the Klear (wish they would just spell it correctly!). Not sure of the impact of the different catalysts... but am being forced to find out.

Practice panel update - in the curing process... area with 2X catalyst is still very soft... not what I expected!

JRVintage

Can you post some pics.

compedgemarine

HoK was bought out years back by Valspar I think. when the buyout happened they made a big deal of reducing the cost. what they did was add a bunch of fillers. we did several boats with the new "lower priced" stuff and we ended up using 4 times the material to get any coverage. you basically have to under reduce it and then use light coats but it will take 20 coats to get good coverage. the HoK clears had the problems you encountered. the flow coat clears never cured out and we had solvent pop issues with the others. on the flow coat after two months it still felt like rubber and I ended up peeling it all off with a razer blade color and all. if you like the HoK color (they do have some really nice ones) just use the basecoat and then clear it with Southern Polyurethane high body clear or PPG Glamour clear. those two clears will harden and buff out to a great shine.

Phoenixed

Your history is correct. I have found that I need to under reduce! Nice to hear... I not so crazy! I am also using a LOT more color to get the proper coverage.

I have yet to sand out my practice panel, but the over catalyzed portion still feels rubbery but the under catalyzed portion was ready to sand just hours after shooting.

Love the HoK Kandy - but almost impossible to get a good photo! Here is what I have:

The link to the photo won't load the photo into this reply - so here is the link you can follow -

http://www.dreamyreflections.com/sho...fbbc1873c9a692

JRVintage

If your clear is over catalyzed you can get small particles that bond too fast and spray out in little spots. The rest of the chemical reaction has nowhere to go so there is improper cureing { rubbery finish }. Under catalyzing will take longer to harden and may not cure all the way. Make sure your clear is mixed well and I would also suggest a very fine strainer. I have seen some clears that definitely need to be strained more than others. If the mixed clear has set awhile it could be at the end of its pot life and may spray small particles. Most products today are to mixed be ratios; try to stay close to the mixing ratios. Remember reducer is the transfer agent, too little too dry, too much can die back. These don't appear to be solvent pop. Hope this helps. Good Luck.

Phoenixed

Thanks a lot! All info is very helpful, and your time very appreciated.

Practice panel is not showing the spots, I think I am close to the right ratios now. I believe a little over solvent and catalyst caused the issue. If the next spray of clear over the Kandy shows spots again, I will bail on the HoK Klear and go with the PPG Glamour Clear.

Back to sanding.......

Phoenixed

Okay. After a lot of investigation I discovered a desiccant filter was shedding particles - causing the spots. I verified this by setting up everything as if I were going to spray - then spraying into a large cookie sheet full of water. WOW! It was amazing to see how many particles it was putting into the air stream. Filter was replaced and system tested with the same water method - no more particles.111

Now I am having issues with the buffing process... similar spots but from the compound??? Not sure if I am ever going to get this done!