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Runs still show after wet sanding down..

PostPosted: Tue May 07, 2019 8:39 pm
by GRAYAUTO
Getting run completly flat on a black paint job is virtually impossible to me can someone give me some help here I'm wet sanding it down with 1500 but at a certain point u can still see a wavey reflection still in the parts I got flat where the run was.

Re: Runs still show after wet sanding down..

PostPosted: Tue May 07, 2019 9:44 pm
by '68 Coronet R/T
I would use a block of wood and sand just the runs until they are almost level with the surrounding surfaces.

They will sand out, just be careful not to sand on the surrounding areas, only on the run.

Check this out:
P1010004.JPG


Finished:
Runs Gone.JPG

Re: Runs still show after wet sanding down..

PostPosted: Tue May 07, 2019 10:48 pm
by GRAYAUTO
What's best grit to use I'm using 1500 right now wet

Re: Runs still show after wet sanding down..

PostPosted: Wed May 08, 2019 12:43 am
by '68 Coronet R/T
Using a narrow block of wood and 600 grit sand very gently until almost level, then 1000 grit until level with surrounding area, then 1500 with a soft pad to remove the 1000 grit scratches and 2000 to remove the 1500 scratches. At that point a rotary buffer and Meguair's M-100 with a wool pad should give you a scratch free finish to continue polishing.

Re: Runs still show after wet sanding down..

PostPosted: Wed May 08, 2019 3:09 am
by NFT5
Jeez '68, that's the mother of all curtains. Nice job getting it out, though.

Grayauto, if you're inexperienced at taking out runs then the polyester filler method is very effective and fairly safe. This video explains it fairly well. Note that the key is to use a coarser grit to start, which will get it flat. The P1500 you're using now won't do that and you'll end up rubbing through next to the run.

Re: Runs still show after wet sanding down..

PostPosted: Wed May 08, 2019 6:44 am
by GRAYAUTO
Yeah cant say I'm not experience I done painted a few cars but I just try to paint without getting a run.. but still sometimes with my best effort I still get small tags which seem more headache to get out than anything.. I done tried different methods even the putty method but I usually only put 2 heavy coats on a car and if I do notice any runs while drying I would normally just spray 1-2 extra coats on top of the run on like 1x1 area so it would have build up around the clear espicially of it's just a sag it really helps. But I have tried it with as course as 600 and I notice it cuts the run down fast but usually but the time i get to buffing i find the buffer burning threw the clear because it's so thing then.

Re: Runs still show after wet sanding down..

PostPosted: Wed May 08, 2019 6:50 am
by tomsteve
the method NFT mentioned has worked pretty great for me. however, i start at 800 grit on a block. take it down until the filler is just about gone- as in theres more paint showing than body filler- then switch to higher grit

Re: Runs still show after wet sanding down..

PostPosted: Wed May 08, 2019 8:02 am
by PainterDave
cut it down with 500/800 and reclear the panel. if you cut down that surrounding clear to under 2 mils it will likely fail.

Re: Runs still show after wet sanding down..

PostPosted: Wed May 08, 2019 9:50 am
by '68 Coronet R/T
All of the above are why I stated "just sand the runs."
The block will give you control of the area. Use the edge of a paint stick if necessary.
It's sanding the surrounding areas that will do you in.

The shiny spots next to the run are the thinnest layer of clear and you have to ultimately get down to that level. This is where how many coats of clear come into play. If those lower areas have at least 3 coats you should be fine. If not then follow Painter Dave's advice to be on the safe side.

Re: Runs still show after wet sanding down..

PostPosted: Wed May 08, 2019 3:09 pm
by PainterDave
i use the side of a stick as well. good advice