Pin wholes in bondo work?

HollywoodMX

HollywoodMX

Coast to Coast
So I have been battling with my tank modification/restore as the tank had a lot of dents and I extended portions and welded new metal, etc. I have the bondo smooth everywhere its ready for paint except I have a bunch of pin wholes in the bondo but only on certain sections. So I bondo'd over them, sand again. uncover more wholes, rinse-repeat. Man I hate bodywork.

I'm not sure filler primer will fill the pin holes or not. I have mixed luck with filler primer in the past.

I'm not a bondo expert, maybe I am using too much hardener? I'm using the gold edition premium bondo.
 
All regular filler is a consistency where it has pinholes. The air just gets trapped from mixing, and when you sand down to a bubble BOOM pinhole. The rougher the filler (like, longstrand fiberglass filler > shortstrand fiberglass filler > lightweight filler) the more likely there will be pinholes.

The fix is to shape your filler to pretty much perfect, sand to 220-400, blow it off extremely well (this is important, because a pinhole filled with dust looks like there's no pinhole, but the dust blows out as soon as you try to spray over it), and then use "icing" or spot putty to fill in the pinholes. It has a much thinner consistency filler, but works exactly the same and usually uses the same hardener. I recommend a 2 part one, and not the old style single stage.

If you try to high build over pinholes you'll probably end up with little craters around the pinhole, without filling it. If you prime, and come upon a pinhole (they'll either show as a crater, or as a bubble) just mark the spot, scuff it and fill with icing.

I recently built a 6'x10' fiberglass plug from 2 part polyurethane foam and bondo. You can imagine how much pinhole chasing that was!
 
mathil said:
All regular filler is a consistency where it has pinholes. The air just gets trapped from mixing, and when you sand down to a bubble BOOM pinhole. The rougher the filler (like, longstrand fiberglass filler > shortstrand fiberglass filler > lightweight filler) the more likely there will be pinholes.

The fix is to shape your filler to pretty much perfect, sand to 220-400, blow it off extremely well (this is important, because a pinhole filled with dust looks like there's no pinhole, but the dust blows out as soon as you try to spray over it), and then use "icing" or spot putty to fill in the pinholes. It has a much thinner consistency filler, but works exactly the same and usually uses the same hardener. I recommend a 2 part one, and not the old style single stage.

If you try to high build over pinholes you'll probably end up with little craters around the pinhole, without filling it. If you prime, and come upon a pinhole (they'll either show as a crater, or as a bubble) just mark the spot, scuff it and fill with icing.

I recently built a 6'x10' fiberglass plug from 2 part polyurethane foam and bondo. You can imagine how much pinhole chasing that was!
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I have icing but i find its softer than bondo (when cured) and more prone to imperfections than this gold bondo.

xb33bsa said:
I like how you spelld hoels ;)
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Doh! Not sure why I spelt it that way.. I was multi tasking the girlfriend was trying to talk to me while i was typing..
 
You could use a 2k glaze, but the problem is that it sands differently than bondo. The icing sanding slightly easier is actually good, since only an extremely small amount is left when sanded, and you can flatten it back to the filler without changing the fillers shape.
 
mathil said:
You could use a 2k glaze, but the problem is that it sands differently than bondo. The icing sanding slightly easier is actually good, since only an extremely small amount is left when sanded, and you can flatten it back to the filler without changing the fillers shape.
Click to expand...

Ya thats true.
 
Pinholes in bonds can be easily filled and smoothed with glazing putty. It would seem logical that the one part glazing putty is easier to use, but it's not. I prefer the two part glazing putty because it dries faster and sands easier. And as mathil stated, blowing the smoothed out bonds with compressed are is important to expose these pinholes.
 
Scratcher09 said:
Pinholes in bonds can be easily filled and smoothed with glazing putty. It would seem logical that the one part glazing putty is easier to use, but it's not. I prefer the two part glazing putty because it dries faster and sands easier. And as mathil stated, blowing the smoothed out bonds with compressed are is important to expose these pinholes.
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Ya 2 part only. That single stage is garbage.

Well my icing was a little dry in the tube so i mixed up a small batch of bondo and new spreader and pushed really hard then scraped the surface so very little bondo was left. Seemed to work.
 
Pin "holes" gone.. :-)

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Another thing of note is pinholes are more apparent in lower quality brands of body filler. "Bondo" brand is notorious for pinholes, I myself have fallen in love with Evercoat RAGE extreme lightweight filler.....its such a nice consistency to work with when applying, sands out easier, and leaves nearly no pinholes when you've sanded your part into proper shape. I almost NEVER need glazing putty/icing with the evercoat product.
 
focusinprogress said:
Another thing of note is pinholes are more apparent in lower quality brands of body filler. "Bondo" brand is notorious for pinholes, I myself have fallen in love with Evercoat RAGE extreme lightweight filler.....its such a nice consistency to work with when applying, sands out easier, and leaves nearly no pinholes when you've sanded your part into proper shape. I almost NEVER need glazing putty/icing with the evercoat product.
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Yeah, a big part of it is how someone mixes their bondo. Always fold and wipe out, fold and wipe out. Don't drop it in a tub and stir with a stick...that'll just create a bubbly mess.
 
focusinprogress said:
Another thing of note is pinholes are more apparent in lower quality brands of body filler. "Bondo" brand is notorious for pinholes, I myself have fallen in love with Evercoat RAGE extreme lightweight filler.....its such a nice consistency to work with when applying, sands out easier, and leaves nearly no pinholes when you've sanded your part into proper shape. I almost NEVER need glazing putty/icing with the evercoat product.
Click to expand...

Ya I will try that next time. I did use their premium gold edition and it was notably better than their standard one.
 
focusinprogress said:
Another thing of note is pinholes are more apparent in lower quality brands of body filler. "Bondo" brand is notorious for pinholes, I myself have fallen in love with Evercoat RAGE extreme lightweight filler.....its such a nice consistency to work with when applying, sands out easier, and leaves nearly no pinholes when you've sanded your part into proper shape. I almost NEVER need glazing putty/icing with the evercoat product.
Click to expand...

+1
 
Bondo is garbage. Sure it will fill your dents, but only God knows how long it will stick to the metal. Evercoat Rage and Z-Grip are the best fillers on the market (as far as bang for your buck vs performance), I use the Z-Grip and have good luck with it. Evercoat also makes a variety of different glazes, Metal Glaze being my favoite. The proper way for doing this type of thing is to get your body work shaped to where it is near perfect and then force glaze into the pinholes and smooth the glaze very thinly over the entire surface and block it again. And a word to the wise, if you are NOT using high build primer on top of your filler, you're doing it all wrong. High build is what gets rid of all of your imperfection and sand scratches and will show you where you screwed up and need more attention. And high build will get rid of pinholes too, you just need to know what you're doing. There all different kinds of ways to do body work, but your final preparations will make or break the paint job.

Scottie J
 
I ran out of the good filler and had to buy some from Crappy Tire, paid the price for the Bondo gold and it ruined my work, it is crap. I won't buy that again, I now have to basically start over when I can get to the body shop supplier and get real filler again. So if you can get good results with Bondo crap, wait until you try a real filler like mentioned above, you will wonder how you ever lived without it.
 
Maritime said:
I ran out of the good filler and had to buy some from Crappy Tire, paid the price for the Bondo gold and it ruined my work, it is crap. I won't buy that again, I now have to basically start over when I can get to the body shop supplier and get real filler again. So if you can get good results with Bondo crap, wait until you try a real filler like mentioned above, you will wonder how you ever lived without it.
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That good hey? I look forward to it then.
 
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