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Author Topic: Issue with Sem trim black?  (Read 503 times)

NY81TTASE

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Issue with Sem trim black?
« on: April 03, 2020, 06:44:16 PM »
This happened when I painted my window molding a while ago,,now...the same can and it's happening to the headlight trim rings.  I washed them real well with soap and water and every time I use the sem trim black it doesnt stay on,,it seems to pull away in spots.  What am i doing  wrong?
 
« Last Edit: April 03, 2020, 07:07:24 PM by NY81TTASE »
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Maxthe222

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Re: Issue with Sem trim black?
« Reply #1 on: April 03, 2020, 06:57:10 PM »
The headliner trim rings are a metal, right? Aluminium or something? You're not using SEM interior trim paint are you? Not the vinyl one? I think it will have a hard time sticking to metal. I first hand have seen it as the interior paint I used on the metal A-trim pillar pieces has deteroirated in certain spots, I think I need to properly strip those metal parts to bare metal, use some form of primer at the very least, possibly adhesion promoter if you really want to use SEM, and then try again very lightly.

I don't think SEM paint is best for exterior metal applications, on plastic it works ok, but on all the metal parts of the interior I have had issues with it.
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NY81TTASE

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Re: Issue with Sem trim black?
« Reply #2 on: April 03, 2020, 07:03:45 PM »
I'm going crazy trying to get the image to show, but it won't.
Yes they are some sort of pot metal or something. I'm pretty sure it is exterior trim black,,I'm going to go back and read the can.  Most sites I was on recommended this for outside window trim and headlight bezels so i do think it is correct.
Yes...it says exterior
« Last Edit: April 03, 2020, 07:10:25 PM by NY81TTASE »
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NOT A TA

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Re: Issue with Sem trim black?
« Reply #3 on: April 03, 2020, 08:31:14 PM »
At a minimum, you need to wipe (wet) and dry (with a separate cloth) with wax & grease remover. Then use light - medium coats. Looks like you're putting on to thick of a coat although the pic is tough to see.
John Paige
Lab-14.com

NY81TTASE

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Re: Issue with Sem trim black?
« Reply #4 on: April 03, 2020, 08:53:41 PM »
I'll give it a shot...I ordered 2 cans of paint. This one is basically done.  Hopefully the second can with more cleaning will give better results.
1981 turbo trans am se

Wallington

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Re: Issue with Sem trim black?
« Reply #5 on: April 03, 2020, 10:56:05 PM »
Just sounds like an oily surface. You also need to remove whatever removes the oil. Light dusting coats will show up problem before you get into it thick enough to ruin.

NY81TTASE

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Re: Issue with Sem trim black?
« Reply #6 on: April 04, 2020, 10:49:29 AM »
I guess I need to handle them with rubber gloves after cleaning
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squirrel

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Re: Issue with Sem trim black?
« Reply #7 on: April 04, 2020, 01:10:14 PM »
I usually scuff the surface with sandpaper, lightly where needed and wipe clean with lacquer thinner then spray SEM.  Have done hundreds of projects this way.
Dan from Cincinnati Ohio

1978 TA W72/WS6 Brown/Black
1974 GTO Pinemist Green

Nexus

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Re: Issue with Sem trim black?
« Reply #8 on: April 04, 2020, 01:27:29 PM »
I guess I need to handle them with rubber gloves after cleaning

Anytime you grab a part with your bare hands, oils from your skin transfer over and a potential bad spot can occur. As mention above, wipe clean with wax/grease remover or a lacquer thinner. I would personally use self etching primer on the bare metal then follow that with colour. The self etching primer will grab the surface of the metal far better than paint alone. Use fresh clean gloves too before you go and grab the part again after it's clean.

My 2 cents sir!!
« Last Edit: April 05, 2020, 07:04:55 AM by Nexus »
Charlie

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(19 years and counting but still have her)

NY81TTASE

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Re: Issue with Sem trim black?
« Reply #9 on: April 04, 2020, 05:57:33 PM »
Yeah...back to sanding them again.  Ugh
1981 turbo trans am se

Nexus

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Re: Issue with Sem trim black?
« Reply #10 on: April 05, 2020, 07:07:11 AM »
Yeah...back to sanding them again.  Ugh

lol...My father always said, "education is always costly and time consuming"

think of the valuable education you are getting!!!!

btw...some updated pics of the final, you're happy with it part is a must!!
Charlie

79 Esprit but like many, it will be a T/A clone
(19 years and counting but still have her)

Grand73Am

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Re: Issue with Sem trim black?
« Reply #11 on: April 05, 2020, 07:59:40 AM »
Looks like fish-eyes from contamination, basically what the other guys said. For the one you have painted, I highly suggest that you wash the old paint completely off the bezel with lacquer thinner. Once it's bare, wash it again with lacquer thinner. Just sanding it won't help, as the contamination will still be there and fish-eyes will still come back.

Also, I would not spray the SEM directly over the bare metal. The adhesion won't be good enough to last. The best way is to prime the bezel first with a coat of black epoxy primer. It sticks much better to the metal, and the paint sticks better to the epoxy. Wait about 30 minutes and then spray your SEM directly over it, using light coats.
Steve F.

roadking77

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Re: Issue with Sem trim black?
« Reply #12 on: April 05, 2020, 08:52:25 AM »
I would agree with all the above advice and I try to follow it myself when painting. But I had that same problem with some rustoleum a couple of months ago. I had the parts sanded well, and cleaned thoroughly with paint prep. I try to never touch any surface I am going to paint. The paint still bubbled terribly. I sanded and cleaned again and it still did it. I finally gave up, sanded to bare and sprayed with the auto paint I had and it came out fine. I used the same rustoleum a couple of days ago on another small part and the same thing happened. I cant help but think there is something wrong with the paint im using.

Charlie, I like what your Pop said, Dad would say something similar, only his was 'If I keep learning from my mistakes I cant afford to learn anything else', LOL
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Wallington

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Re: Issue with Sem trim black?
« Reply #13 on: April 05, 2020, 05:42:16 PM »
And of course, some castings like pot metal can be full of tiny pinholes that hold onto oils until you've added a layer of paint before letting them go.

squirrel

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Re: Issue with Sem trim black?
« Reply #14 on: April 05, 2020, 08:38:54 PM »
I have detailed hundreds of engine bays and used duplicolor for the last 5-7 years almost exclusively and over the last 6 months or so the product is not the same and get a lot of fish eyes and the paint does not dry sometimes as it used to.  They had to change something and stopped using them and now use krylon or SEM, no problems with either of those products.
Dan from Cincinnati Ohio

1978 TA W72/WS6 Brown/Black
1974 GTO Pinemist Green

Re: Issue with Sem trim black?
« Reply #14 on: April 05, 2020, 08:38:54 PM »


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NY81TTASE

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Re: Issue with Sem trim black?
« Reply #15 on: April 06, 2020, 02:12:49 PM »
I wish I was able to go somewhere and get better primer as mentioned. I ran out of laquer thinner and denatured alcohol.  Inwas also painting part of a guitar with rustoleum black and had to give up,,,different issue, it went on looking like 400 grit black sandpaper.
I cant find krylon in the stores,,i used to like it.
I'll update when I figure out what to do.  Right now I'm taking a break.   I'm thinking...I have the front metal bumper  out and was going to have it sandblasted until this quarantine crap came.  Maybe I'll send the bumper and the bezels to the guy and he can powder coat them.  Might be easier
1981 turbo trans am se

Nexus

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Re: Issue with Sem trim black?
« Reply #16 on: April 06, 2020, 04:31:39 PM »
Powder coating looks nice but is obviously not the budget build route but it does yield great results when finished
Charlie

79 Esprit but like many, it will be a T/A clone
(19 years and counting but still have her)

roadking77

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Re: Issue with Sem trim black?
« Reply #17 on: April 07, 2020, 08:07:05 AM »
I have a couple of powder coating places within an easy distance and neither are overly expensive. In fact when considering your own time of prep and materials involved they are quite reasonable. And you cant beat the finish.
Finished!
77 T/A - I will Call this one DONE!
79 TATA 4sp-Next Project?
79 TATA - Lost to Fire!
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82 Firebird - Sold
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NY81TTASE

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Re: Issue with Sem trim black?
« Reply #18 on: April 08, 2020, 08:58:43 AM »
Powder coating looks nice but is obviously not the budget build route but it does yield great results when finished
I totally agree.  My car is in such poor shape, to me, I cant justify doing any "real" work to it.  The guys on this forum could probably see a gem but I'm not that good of a diy'er to do the work myself.  I wish I could weld panels on like I've seen people do here,,and any paint or body work would have to be like an earl scheib job ("I'll paint any car for $99.95")
But....I figure the powder coat would be better than I could do,,,stop the rust on the bumper piece, and I wouldnt be buying metal brushes, sanding discs, rust converter, primer, spray paint, and I can get time to move to something else.   I mentioned somewhere that they charge $65 an hr to sandblast by me and they dont do it under an hour.  I think that's a little much.
1981 turbo trans am se

nUcLeArEnVoY

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Re: Issue with Sem trim black?
« Reply #19 on: April 08, 2020, 12:25:05 PM »
Powder coating looks nice but is obviously not the budget build route but it does yield great results when finished
I totally agree.  My car is in such poor shape, to me, I cant justify doing any "real" work to it.  The guys on this forum could probably see a gem but I'm not that good of a diy'er to do the work myself.  I wish I could weld panels on like I've seen people do here,,and any paint or body work would have to be like an earl scheib job ("I'll paint any car for $99.95")
But....I figure the powder coat would be better than I could do,,,stop the rust on the bumper piece, and I wouldnt be buying metal brushes, sanding discs, rust converter, primer, spray paint, and I can get time to move to something else.   I mentioned somewhere that they charge $65 an hr to sandblast by me and they dont do it under an hour.  I think that's a little much.

I second the powdercoating, man. You'll never have to worry about your trim pieces again. Besides, it can't cost TOO much to powdercoat some trim pieces. Maybe while you're at it, you can go back and do the window moldings, too.

NY81TTASE

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Re: Issue with Sem trim black?
« Reply #20 on: April 08, 2020, 01:55:05 PM »
That's actually a good idea since I need to do the front mouldings anyway. I can pop all of them off so they all match
1981 turbo trans am se

TATurbo

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Re: Issue with Sem trim black?
« Reply #21 on: April 29, 2020, 09:42:18 PM »
This is a little late, but thought I'd share...
 I had problems with SEM and/or VHT trim paints not sticking to certain pieces of metal exterior trim.  If I remember correctly it was the trim around the edge of the T-Top Glass and headlight rings which wouldn't hold paint in spots after multiple sandings/cleanings and repaints. Similar to your pics.  Ultimately, what worked for me was to scuff them up, clean with wax/grease remover, then set them outside in a sunny spot for 2-3 sunny days.   After they sat in the sun I dusted them off with a clean, dry, lint free cloth before applying the paint (or primer).  Sitting in the sun a couple days did the trick and the paint took OK after that. 
My guess is that maybe stuff can get into pores in the metal and reacts to the chemicals in the paint, or maybe it's solvent in the paint that can't evaporate properly or evenly because of tiny pores in the metal?

Whatever it was, a couple days in the sun corrected the problem for me more than once. 

Tom
King of Prussia, PA

1981 Turbo Trans-Am
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FormTA

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Re: Issue with Sem trim black?
« Reply #22 on: April 30, 2020, 06:21:12 AM »
Since I think folks will find this thread when looking for SEM help, I'll tell you what worked for me. I had issues with the headlight trim rings. I ended up using SEMs self etching primer and then their trim Black. Came out great.





I only did one as a test (so I wouldn't have to sand down 4 if it didn't work again).

« Last Edit: April 30, 2020, 09:34:50 AM by FormTA »
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See the recurring theme???

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roadking77

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Re: Issue with Sem trim black?
« Reply #23 on: April 30, 2020, 07:42:16 AM »
Tom that is a great tip on the sun. I still havent got my taillights right and had given up with the thought of just biting the bullet and getting new. I think I will try your tip for one last chance. I also have some headlight trims to paint but I was just going  to use rustoleum.
Finished!
77 T/A - I will Call this one DONE!
79 TATA 4sp-Next Project?
79 TATA - Lost to Fire!
86 Grand Prix - Sold
85 T/A - Sold
85 Fiero - Sold
82 Firebird - Sold
'38-CZ 250
'39-BSA Gold Star
'49-Triumph 350
'52-Ariel Red Hunter
'66-BSA Lightning
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Nexus

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Re: Issue with Sem trim black?
« Reply #24 on: April 30, 2020, 12:33:42 PM »
Self etching primer is what (to my understanding from the past) is used on aluminum aircraft before they go to paint. I helped my dad a couple times as he has painted several airplanes when he worked on them.

Clean, oil and dust free followed by self etching primer. I have always done this with any bare metal surface and don't recall having any issues with paint there after. Granted they have all been small jobs on a multitude of items but the process has remained the same.
Charlie

79 Esprit but like many, it will be a T/A clone
(19 years and counting but still have her)

Re: Issue with Sem trim black?
« Reply #24 on: April 30, 2020, 12:33:42 PM »
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