I sprayed out a set of doors the other day,House of colors black base with there Kosmic clear,I had them laying flat on stands,,i put enough base to cover,then i gunned on 4 coats of clear,,figuring there would be plenty there to cut and rub it nice..so the next morning i sanded them with 2000 and buffed them,,and they looked great..I slide them out in the sun,it was pretty warm out,,about 80,sun was strong,,,so about an hour after they were out there i grabbed one of my yellow micro rags and went to wipe them and the rag kind of draged,,the clear was soft ,it didnt smug it but it was soft enough were i could thumb print it,,so i slide it back in the shade and let it cool and it harden again,,,so after doing that a couple of times (figured it would be good to let it cycle) they ended up rock hard and then not affected by the heat of the sun ,,so last night i was slideing them back in under my carport and noticed a weird looking texture on about a 1/4 of one of the doors,so i cut and rubbed it out again till it was gone,and am slightly seeing it appear again in the same spot this AM! (BTW both doors prior to paint were completely catalized primed and blocked,the prime had about a month to dry) Any one ever have a simlar problem,,,its been one of those jobs that just dosnt want to go away!!!,,,thanks ahead for any response,,,jim
Problem may be the 4 coats of clear....and the flash time between them.... I like to do two or three coats, followed by wet sanding and then two flowcoats....
Read the Tech sheet for flash times. Maybe you hit those 4 coats a little too soon and have some solvent trying to escape under there
Read the instructions on the product. House of Color products are especially picky about dry times and number of coats.
I too am an amatuer painter, as I don't have a "shop".....but I have been painting heavy equipment and cars for at least 15 yrs..... Like others have said, read the data sheets.... I've always waited 15 minutes between coats, regardless of outside temp. I will sometimes touch the paint in an incon****uous spot to see how "tacky" it is....if it's 'stringy', it's too soon to spray another coat.
head on over to craig fraser's board www.kustomkulturelounge.com brian lynch, HOK tech guru is a regular on there. but yeah.. possibly not enough flash time between coats, almost certainly not enough cure time. minimum 24 hrs before sanding in proper conditions. did it still smell like wet paint when you started sanding on it? how many coats max does the tech sheet spec? 4 coats can be alot, espescially if you're POUNDING it in there... direct heat source like bright sunlight will flash the top layer off leaving the under coats soft. some hi-solids clears NEVER get completely hard and will take a fingernail impression 6 months later...but they relax and it disappears...not sure how HOK is about that.
i usually wait 45 minutes flash time for between the coats of clear, but i put it on pretty heavy and never had a problem.
The instructions say 2 coats and 3 if buffing,,the temp when i sprayed was in the low 70s,as far as time goes between coats I waited till it was stringy to the touch per Komoski the house of colors guy, I just got a new Devilbiss Millinuim and i did flood it down,got a little carried away probably should have stopped at 3, I put 4 coats on the rest of it without a hitch but it sat in the shade for the whole week,,before i cut and rubbed,,, Im hoping it dosnt move anymore,il keep it in a cool shady place for a few days,if it stays the way it is itll fly no problem,,il post an update thanks for your responses,,,,jim
sounds like you have a solvent coming back through in that area..something that was even under the primer maybe...if it comes back, you may need to strip it down to zero and start over...not good news, but that's what it sounds like to me.
Well i just read this on the tech sheet say sticky not stringy?? Is sticky before or after stringy?From everthing iv heard and read it seems like they more stress on waiting to long,,One other thing to mention I didnt have any solvent poping either usal an indication of enough time?,,,thanks jim 7. APPLYING KOSMIC URETHANE KLEAR (UC35) Apply 2-3 medium wet coats with 50% pattern overlap. Gun distance while spraying should be approximately 6 inches. Allow flash time between coats. URETHANE FLASH TEST - PAINT SHOULD BE STICKY AND NOT STRING WHEN TOUCHED AT THE WETTEST POINT BEFORE NEXT COAT IS APPLIED. (When using the flash test, always touch a new spot.) Monitor closely for maximum merging of coats. NOTE: Waiting too long between coats can cause re-coat problems. If excessive dry time has elapsed and clear coat feels dry to the touch, allow 12 hours before sanding and re-coating to avoid lifting problems. NOTE: Over spray from any catalyzed topcoat material (such as our UB04, UB05, UK Kandys, UC35 Kosmic Acrylic Urethane Klear or UFC19 Urethane Komply Klear® II may lift when base coats are applied. Mask carefully to prevent this over spray when painting door jambs, etc.
Regarding flash times. Longer is better.If your not a production shop (maaco etc), Whats the hurry?I feel advertised flash times are more based on production shops versus us hobby guys. I always wait longer. Mike
sticky is after stringy...again, it may have nothing to do with how you painted. could be a much deeper problem. if something got into your substrate(primer), it could come back up after painting...
I paint with HOK all the time, I have a prob once in a while but it is usually cause im in a hurry, best advice "read the freaking can, every can, teck sheets" #35 clear 2 to 3 coats anything more and yer asking for problems it cant breath and wont set up, let is dry between coats if it says 15 mins, give it an extra 5 Always take yer time, Like *** with a hot chick FRITZ
I've been painting for 35 years. I still read the P-sheets every time I spray. Of course painting for 35 years may explain the need to read the sheets every time!
The best way I have found in my time as a production painter to judge the flash time on clear coats is to spray each medium wet coat and wait till it strings when it is touched with your finger.... though some schools of thought say what till its hand slick I.E. Not increadible wet to the touch aprox 10-15 mins at ideal temps.. But the way I was tought was that if the paint is still stringy... It has a better chance to cross link with the next coat..I.E. melt together because if your flash times are not cordinated you can trap solvents in between coats, which when introduced to heat after your said cure time will bring the solvents back to the clears surface and soften it... Modern Base Clears, full cure times can be upto a few months, i dont mean that you cant buff and wash them. But a cross link and realese of solvents. As a ppg speed clear i use has a drive time of 3hours on it at 70 air dry and a force dry drive/ buff time of an 1.5 hours...But full cure is like 4 months Just my 2cents And most likely irrelevent to subject. But I need something to do My area is in a nasty autobody dry spell
I give about 15-20 min on UC35and I always give it a touch and see how it feels. I like to wait til just after sticky, to the point where I wouldn;t really leave a fingerprint. Your mix was right with the right products? I would let it set some more time and see what you come up with.
Cowboy181d,,,we must have gone to the same school,,recoating at stringy has worked for me too,I am guilty of rushing but dont have the luxury of painting in the best conditions,,so when i start gunning on the clear i do go as fast as i can,the good news is the door looks the same as it did this AM,,its so slight that i wouldnt be alble to pick it up on my digital to show what im talking about out here.Imwith "slowandlow63" on this one im going to give it a couple days and see,,,thanks again everyone,,jim
You guys are getting good advice! Yeah, most times the flash time recommended on tech sheets is for a pro shop. That means painting in a booth with proper (70*) temps and a good airflow to help cure. Most backyard guys (me included) do NOT have these perfect conditions, so rely on the touch test, and some common sense! Colder means longer...but low air flow means even longer! And it's no just HOK paints, either...read instructions, and follow procedures on any brand for the best results.
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