UV light exposure prior to vehicle reassembly

EPfiffner

Member
I had taped around this oval hole (for windshield wiper stalk) with blue hardware store tape as an attempt to protect the paint during assembly.

IMG_20200707_095531066.jpg

The tape was on for probably a week, which may have been my mistake. The pic shows how the tape has left an imprint in the clear.

I have similar marks on the trunk lid from where I had it sitting on a padded work stand.

The car was painted in August 2019. 50% reduced epoxy sealer, set overnight, 3 or 4 coats Motobase activated, set overnight, then 4 coats UC, cut and buffed fall 2019.

Pretty limited exposure to UV light, it's been outside for 8 hours at the most.

Is it normal that the clear is this soft almost a year later? I don't see any way to correct this, I don't feel comfortable sanding it out so lesson learned, I'll live with it.

I guess with as much as I have learned from the forum, I still had not picked up how important it is to get a car out in the sun before you put it together.

Thanks to SPi for fantastic products, and the forum has taught me so much.
 

cmfisher4

Active Member
Huh. I taped off a lot of edges while putting stuff together and left it on for too long (longer than a week) and didn't have any marks that I noticed. And my car has spent under an hour in the sun and the doors and such not at all. Of course, I'm having adhesion issues so UV exposure may have been the trick. Kick myself if so.

But, like you say, great forum and so. much. learning.

She's still going to look great!
 

EPfiffner

Member
Thanks Chris, part of the reason for the post was that I remember your experiences and wondered if they were somehow related. We will see what we receive for feedback.
 

rdransman

Member
How accurate were you when you measured the clear and the activator? If that were mine - and proportions of clear and activator were spot-on - I'd get it out in the summer sun for a week, let it cool, then lightly block it with 1500. If the paper easily cleans with water, it's cured. Remove scratches with 2000, orbit it with 3000 Trizact, then 5000 Trizact. (This all assumes you shot at least 4 wet coats of clear.) Buff. If you feel you might cut through, spot the area with clear after the 1500.
 

EPfiffner

Member
How accurate were you when you measured the clear and the activator? If that were mine - and proportions of clear and activator were spot-on - I'd get it out in the summer sun for a week, let it cool, then lightly block it with 1500. If the paper easily cleans with water, it's cured. Remove scratches with 2000, orbit it with 3000 Trizact, then 5000 Trizact. (This all assumes you shot at least 4 wet coats of clear.) Buff. If you feel you might cut through, spot the area with clear after the 1500.
I used DeKups, and used the measuring card that slips in to the hard plastic outer housing. I made sure to zero the scale on the measuring card against the bottom of the disposable liner.
I'm currently in the process of getting it to be a roller again so I will get it outside.

The clear seemed to sand OK when I cut/buffed it last fall, so I thought it was cured. Thanks for the suggestions.
 

EddieF

Top Banana
Looking at reflection, what was cut grits & buff procedure?
Looks like it would benefit from another light cut session for sure.
 

EPfiffner

Member
Looking at reflection, what was cut grits & buff procedure?
Looks like it would benefit from another light cut session for sure.
I used 1500 eagle yellow film, pink tolex, green bufflex, and meguiars m100/wool, then CG products.

I think what you are seeing in the reflection is my cheapass 8ft LED bulb, it has a clear lens so each individual LED shows.
 

Jim C

Oldtimer
yes! many times if the clear is cured and you get imprint you can take a heat gun, warm the paint up and it will all come out. while universal is softer i dont believe it should be printing if its that old. if you posted these pictures and said the clear was 1 month old maybe 2 then i would believe it but that is 11 mos old now. even if it hasnt been outside i dont think it should be doing that.
 

EPfiffner

Member
Ok, thanks everyone. I was trying to follow the Perfect Paint Job as much as I could, and I don't recall it advising anything about UV exposure.
So I guess for you guys that do high end jobs, it's part of your SOP to put them out in the sun?
I painted and buffed the car, then immediately began restoring the suspension (unibody car) so it was immobilized at that point.
I now see the need for products like speed clear, as obviously collision shops don't have time to wait for Universal to cure.
 

orangejuiced86

Garage hack at night.....
I learned this when I have to place freshely painted parts on stands to do reassembly. I'd see some light marks and think, ok Ill buff that when its all assembled, then I would go back a week later and be like "WTF I know they were here." Now I dont even freak out when dumb stuff like that happens.

If its not a scratch, hole or bubble....it can be easily fixed...
 

jcclark

Oldtimer
obviously collision shops don't have time to wait for Universal to cure.
Most shops use a clear that doesn't stay soft like Universal,
and not a "speed" or "spot" clear either.
I used Nasson for a while and it would get rock hard in two days, if you didn't buff it
by the very next day it was like sanding concrete.
You can also add some "accelerator" to your clear to harden it up faster,
but it's not recommended during hot weather.
but you can get away with a little.
 
Top