Why Do I Keep Sanding Through To Metal When Block Sanding Primer?

Why Do I Keep Sanding Through To Metal When Block Sanding Primer?

– In this video, we’re gonna talk about why you may be block sanding your primer but you keep sanding through to metal. So, I had a question on YouTube. Fred Jones asks, “Thanks
brother. Great video, as usual. “My issue is I have a small
area where I sanded through. “You told me to use etch
primer, then primer surfacer, “then block with 320. “Every time I block sand with 320, “it takes the primer surfacer
and the edge primer off again. “I use three coats of primer surfacer “and a light coat of etch primer. “I do have Epoxy primer, beige color. “Should I try that over the bare metal “and then primer surfacer,
and then block with 320 “to see if I get different results? “This is new to me and I’m
not giving up, please help.” So, the problem you’re having
is you’re block sanding and metal keeps showing up. And I don’t think it’s the type of primer. I mean, you do want to
use either etch primer on bare metal, Epoxy,
you know, either one, your preference, or you
know, a primer surfacer that is direct to metal, that
is designed to go to metal. If you just put primer
surfacer on top of metal and it’s not a DTM, direct to metal, you’re not gonna have
the corrosion protection that you should have. But I don’t think this is
your problem right now, the type of primer. Reading this, I think
you’re having a problem with the high spot, there’s
a high in the metal. And I think this, just
to back up a little, I’ll give you how you
might fix this for now, but to back up a little, I
think this is the problem. Whenever doing your metal work, there’s probably a dent there. And anytime there’s a
dent, and there’s a low and then there’s a high,
just like if you laid down on an air mattress, you
know how when you lay down, it pushes up somewhere else? Or like water, you know,
something splashes in the water, it usually makes ripples or waves? Well, metal’s the same way. When something causes it to go down, there’s usually a high somewhere. And that high is kind of
your secondary damage. It’s not real noticeable,
it’s a little harder to find than the direct damage, which is the dent. You know, you can see
that and a lot of times, and I’ve seen this a lot, where you try to raise that low out and you do. And here’s your high and here’s your low. You raise the low out, but then you just raise that high up, too, and it’s still, you know, effecting the surface. And it’s easy to miss because
it’s not real noticeable, but when you go to do
your body filler work, you know, that spot’s gonna keep hitting, or, you know, going to bare metal again. And then whenever you start
doing your priming and blocking, that high spot’s just
gonna keep sanding off and there’s really no way to fix that unless you go back to
straightening your metal. Now, what you may do for
right now, to see if it works, if it’s just a very minor high area there, get, like a pick hammer and
use this part right here and just lightly tap on that metal that keeps sanding through every time. And you don’t want to hit it hard. You’re just wanting to try
to lower that a little bit, so when the next time
you prime and block it, maybe it won’t sand through again. But I think, after reading this, I think that is the problem
you’re having is maybe you’re not paying attention
to that secondary dent and this is a common mistake, I mean a lot of people do this. You have a tendency just to
raise that direct damage out. But the way to do this when
you’re straightening your metal, as you’re trying to raise
that low out, you know, feel the metal with your bare hand, make sure it’s the flat of
your hand, not your fingertips. And kind of find, identify
where that high’s at. And as you’re trying to raise that low, tap down on that high, so that way as you’re raising the dent,
you’re moving the high at the same time and
that will eliminate you from having that problem. So, that’s a common
problem, a great question because I do see that quite often. And it’s just something
you have to get used to is trying to find that indirect damage, to locate it and work the highs down as you raise that metal. So, give that some thought as you’re doing any more metal work. Like I said, that is, the indirect damage, the highs are a lot harder to find, they’re not visible to you
like the direct damage, you know, like the dent. But if you’ll concentrate on that. Now, it’s actually more important because like this problem you’re having, if you don’t raise that down, it’s just gonna keep popping out on ya. Now, if it’s a little bit low, you know, that’s gonna fill in. So, that won’t give you problems. But the highs are just
gonna keep reappearing. And if this is not the
issue you’re having, if I didn’t read that correctly and maybe it’s something
a little different than I thought, you know, be sure and leave another comment below and I’ll try to further
answer that question. But I’m pretty sure, and
I’ve seen it, you know, I’ve seen that happen a lot,
that that is your problem. So, hopefully that helps. If you like this video, be
sure and give us a thumbs up. Subscribe to this channel. If you have any questions,
leave a comment below or on any of my other videos and I’ll try to answer
them, either by typing or, you know, if it’s too,
like this would be too hard to really discuss or explain, you know, in a comment, so I’ll make a video in it. But anyway, thanks for watching. Take care and we’ll see
you in the next video.

About the Author: Michael Flood


  1. Excellent again brother thanks for getting back to me!!! The area is pretty flat, mabe I just need to use a little filler, I put apoxy primer I’m gonna see if it happens again then I’ll use the hammer… but thanks again!!!

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