Hi - I would ask the instructor first. As I recall, when I took a similar
class at my local community college, the final coat was not regular bondo,
but more of a glazing. Very fine material - created a much more
smooth/finished feel/look. In fact, in some places, where there was only a
slight indentation, I only used the glazing. I believe the glazing material
entirely covered the bondo, when I did use bondo. If some of the bondo
shows, after the glazing material is sanded, then the primer may attach to
each substance differently, thereby creating your difference
Good luck!
David Gunn
54 TR2 TS3388L
Chico, CA
>From: FGFO1@aol.com
>Reply-To: FGFO1@aol.com
>To: triumphs@autox.team.net
>Subject: [TR] primer paint problems
>Date: Mon, 1 May 2006 17:26:13 EDT
>
>i have never been really good or fast at body repair. but iv done a bunch
>of
>it over the years.
>so in the fall of 2004 i took a body class at the local community college.
>learned a lot of good stuff and i feel IM getting fairly good at it. so IM
>kinda
>foxed at this problem.
>
>i have been working the rear of the car "B" pillar and back. took all the
>old
>paint off and back to bare metal. laid down thin layers of bondo (3M brand)
>as needed. flat it our with sanding block. used guide coat to show the low
>spots. added bondo to the low spots. repeat many times until guide coat
>comes off
>all even. ever notice how the second application of bondo has a slightly
>different color from the first so that you can still see its outline but
>cant feel
>it. and the guide coat says there is no low spot?
>so i put 2 coats of PPG primer on it. (DP40LF) all those 2nd applications
>to
>fill the low spots showed through like you just had drawn a line round em.
>i
>thought they were really feathered and perfect. i was so bummed out.
>so after 4 weeks i guide coat the primer and block it with a 8" long block
>sander. add a little more bondo (evercoat metal glaze) in a few spots.
>guide
>coat. block. oh so light bondo. feather it out. guide coat. block sand.
>this time
>i know it is feathered out sooo nice. in some places the feathered bondo
>was
>so thin it was almost transparent. 2 coats of primer (NCP280)
>again...........same results!!!!!!!
>its as if the primer is almost too thin or too clear. always i put 2 coats
>of
>primer on.
>any ideas on what IM doing wrong? or is it always like this?
>is this not a problem? i have not never worked with this HVLP paint before.
>will the color coat hide it all? because it looks and feels great, other
>than
>looking like a topographical map.
>thanks
>Frank Fisher
>58 TR3 TS41366L
>Temecula
>California
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