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-   -   Help?Redid my Mustang Fastback roof (with filler). This is where I always get stuck! (http://www.hotrodders.com/forum/help-redid-my-mustang-fastback-roof-filler-where-i-always-202674.html)

JohnnyK81 07-26-2011 12:07 AM

Help?Redid my Mustang Fastback roof (with filler). This is where I always get stuck!
 
So I had tried to fill it before, but it was still too oil canny.. So I stripped it of filler, and banged and shrunk the dents as best I could (She was bad.. Had many a body man tell me).. I'm no metal worker, but it seems decent now for a giant roof with no support..

So, I smeared it with filler, and this is what one side looks like after 40 grit.

now my question is, do I switch to 80 and a durablock and call it a day (except for the obvious low spots). Seems like an awful lot of filler.

OR, do I try to tap down those high spots (unless the rest of the roof is low). She's a VERY finicky roof though. I'd be terribly upset if tapping one of those down caused the oil canning to come back. I also don't want to crack the filler.


On a side note, what is the correct 'way' to sand this roof? From the sides, I'm doing it towards the middle.. On the front and back, and I'm doing it towards the front and back (x patterns, obviously, but it's a pain to sand in a specific pattern, especially due to the body line down the center).

Secondly, I will be block sanding again with 2k high build (Or, SPI regular build, I guess). What is the advantage for going for a second coat of filler (except to get those low spots)?

But yeah, my main question is, the metal showing through. There is more filler than metal poking through.. I assume that's bad?

http://www3.sympatico.ca/gkrikorian/...28Large%29.jpg
http://www3.sympatico.ca/gkrikorian/...28Large%29.jpg

Thanks guys, as always, it's appreciated! (I'm getting somewhere.. I think I might almost be ready to jamb it.. Yippee.. 9 years later).

On another side note, I'm not sure if I'm digging this epoxy under the filler.. Doesn't seem as solid to me. Seems the epoxy itself scrapes off easier than the filler would to bare metal.. But that's for a different thread!)

deadbodyman 07-26-2011 06:54 AM

The passenger side looks really good,this is where I start with poly putty (EZ sand) and move up to 80 grit....BTW, Epoxies grip gets stronger the longer it sits...

swvalcon 07-26-2011 07:01 AM

As dbm said now go with the poly putty and block sand with a long hand broad and sand toward center but at a slight angle. I've also used sprayable poly primer at this point. Just be sure to put on a little more that normal so you have enough to block sand. then go with 2-k primer.

jeremyb 07-26-2011 07:02 AM

How long has the epoxy set before applying filler?

The passenger side looks good. You might want to consider buzzing over it with some 80 grit and then apply some poly primer like slick sand. A couple coats over that and you should be able to block it smooth. This is where poly primer plays and extremely important role in my book. Spray it on even and block it out letting ONLY the pressure of the block do the work. You dont have to worry about trying to glaze that entire large aread and blocking out your spreader marks on an already weakened surface. Can be difficult and challenging to a novice to say the least.

That's how i do most roofs that are in this shape. A rough fill with filler..the rest is done with poly.

66SSImp454 07-26-2011 10:08 AM

I am learning how to work with filler myself. I came across this (as well as many other great links on this site)

http://www.roddingroundtable.com/tec.../sanding1.html

I think block sanding with a guide coat would be my next step to help get it straight. In the link, it is talked about how to determine if there is a high spot and what to do with it.

JohnnyK81 07-26-2011 10:40 AM

Thanks for the quick replies guys.

So it's not a big problem that there is so much filler, and not too much metal showing? You wouldn't bother trying to bang down those high spots and keep going (And risk oil canning)?

The epoxy set for about 5 days.. I then scuffed it with a red scotchbrite, and 180/220 where i could (A lot of low spots.. Hard to get the paper in there). I tried 80 but it just grabbed the epoxy and that was all she wrote.

JohnnyK81 07-26-2011 10:59 AM

Ooh I forgot to mention.. So there are still a few low spots (Mostly on the side.. That one will require filler).

And on the rear you can see in the first picture.. Now, would you guys skim the entire roof again (I fear screwing it up if I do that),

OR just apply it to those low spots in the rear?

OR just go right to a putty right now (Is putty even necessary? Can't this platinum plus be used as a putty?) Since the low spots on the rear aren't really that low.. Just low enough the paper didn't touch them?

Thanks again guys!

ogre 07-26-2011 11:09 AM

one thing to mention: once you hit metal you really need to apply more filler or you risk getting a low spot. if you sanded with 40 and change to 80 now, you will get low spots. that's why dbm says to go with more filler (if i read him right). get it right before you apply primer will save you a bunch of work block sanding the primer.

JohnnyK81 07-26-2011 11:28 AM

Yup, that's one mistake I always make.. But recently I've been tapping down the metal when I hit high spots. But sometimes that leads to oil canning. And on this roof, I'm dreading it doing that.

But, when I go to apply more filler now, should it just be putty (except for the obvious low spot near the door), or more platinum plus.. I am running out of platinum plus though. :D

(On another side note, is it ok to go over those bare metal patches with putty? I know it is with filler (obviously) but I've never really used putty).

swvalcon 07-26-2011 01:16 PM

Just fill your low spots along the edge with more filler going out far enough to make it easy to work filler and block sand down as best you can. Then I would coat the whole side with poly putty and hand board down with 80 grit.And then go with your 2-k primer or a good coat of sprayable poly primer.Do not tap down high spots unless there's something that's way to high. Sometimes it can mess thinks up.

milo 07-26-2011 01:47 PM

1 Attachment(s)
Now that there is filler it will hold the panel from oil canning..

It looks really good now. The word bang is to harsh, Tap tap is what those obvious high spots need to help them down easy, then re float one more time with a tight skim coat.

It is a mistake to believe primer will "take care" of what needs more metal/filler work...

http://www.hotrodders.com/gallery/da...enterpunch.JPG

http://youtu.be/G9ux6abzW1M

http://www.hotrodders.com/forum/atta...chmentid=57124

Yes , a 2 part putty like *Iceing would be a good skim coat...

JohnnyK81 07-26-2011 01:53 PM

Aha, so you're recommending I do tap those down?.. Now, would you use the round side of a hammer, or the pick side? It still oil cans with pressure now, but waaay better than the last time I had applied filler to it (Since it was bad enough for me to DA all the filler off and start over).

Now what is the correct way to apply the putty I just bought? (USC Blaze Glaze.. It was on sale. :D Hope it's decent). Surely I don't have to epoxy the bare metal?

Do I actually lay a thickish (1/8) coat down.. Or can I just push it really hard into the scratches?

milo 07-26-2011 01:57 PM

fast forward to 26:53
http://youtu.be/G9ux6abzW1M

JohnnyK81 07-26-2011 02:39 PM

Hmm, if you're suggesting I use my center punch on my roof, I think that may spell disaster on this flimsy thing!

milo 07-26-2011 02:44 PM

tap tap with the pointy side :thumbup:


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