Body filler problems

[ed1380]

The previous owner thought it would be fun to take a hammer to the hump on the hood. Stupid I know.
Anyways I popped it out, sanded, and filled it with bondo. That all worked out fine. Now I've having problems with little bubbles appearing when sanding it down. I keep trying to fill then in with putty, but for some reason the holes don't want to fill. They're 1mm wide and smaller. I'm hoping someone with more experience can chime in.
Thanks

To mods- I know this is the newbie forum, but its the only forum with an appearance subforum.

 

[dsmornothing]

They are little air pockets. you can get them by using cheap bondo. Although they are pretty common in body filler anyways. Go over it with metal glaze and then sand it down again with something fine.

 

[re-rx7]

Wouldnt it be cheaper to find a hood out of the salvage yard?

 

[Boostinsideways]

No most salvage yards will charge 75$+ for anything on the front of a vehicle because the most common wrecks are people running into shit (light posts, curbs, trees, mailboxes, etc). Then you still have to paint match it.

The bubbles are air pockets. You need to put glaze on there, and then sand it down.

 

[cola]

you need to bondo, let it harden, sand and repeat a few times to get a completely flat surface...as it dries the bubbles will rise, and eventually after repeating you will get a smooth surface ready to be primed.

 

[ed1380]

That's the problem I'm having. The glaze/spot putty doesnt cover them. I've done the glaze 3 times and got half of the bubbles. What grit should I be using. I'm using 220 on a da

 

[cola]

I got a smooth surface that didnt bubble up by using a 320 grit wheel on my angle grinder..then hand buffing it with a slightly smoother grit..400 i think. Ive read wetsanding works even better but I have not tried it.

 

[NWHTanK]

Here are some of the issues with pin holes. The use of to much hardner, improper mixing, and a cheap filler. When it is hot either the out side temp or the panel its self u need to use less hardner, colder more hardner. Mixing bodyfiller is sorta a art because u cant trap air in the filler and combined with to much hadner will cause the air to become trapped. Cheap body filler have cheap ingreediants, and how they are mixed. Finnaly look for a experation date if it dont have one dont buy it. Last dont forget to mix the filer in the can before using. In other words while siting on the self the resins will seperate over time, mix with a stir stick, then take out the amount u need and mix with hardner. Mixing can be done buy using a figure 8 motion while keeping the spreader in contact with the board. As far as ## current pinholes it would be nice to have a pick. Some ones pin holes can be another persons crators.

 

[Boostinsideways]

If your not wet sanding your doing it wrong.

I don't understand how anyone can get a perfect feathered edge without wet sanding....

 

[NWHTanK]

Wet sand body filler?

 

[lglracer]

Ya I wouldn't wet sand the bondo. That doesn't do anything. But I did have this problem and I learned its easier to go buy a good hood and not fight with the bondo.

 

[ed1380]

I could have, but I just wanted to learn.

great post tank

 

[bastarddsm]

Oh man...

1. Don't sand bondo with a da.
2. Don't wet sand bondo, it absorbs water!
3. Start with 36, then 80, then 180.
4. The repair area with be lots larger than the bondo, keep the feather edge way out so you don't put 36 grit scratches in it.
5. Use a da with 180 on it to feather in the paint.
6. Use a razor blade to spread bondo or spot putty in the pin holes.
7. Don't just spread little spots of bondo, cover the whole area. Different batches of bondo sands at different rates, its hard to get it straight like that.
8. Use sharp paper, worn sandpaper doesn't cut straight, and it makes it hard to get it straight.
9. Make sure you have nothing corse than 180 scratches before you prime it.
10. Use a quality high build primer. Preferably a 2k, but a laquer primer will do, just let it sit for a few days to shrink up. Don't use spray can primer.
11. Block it with 180, then reprime.
12. Wet sand with 400, then your ready for sealer and paint.

 

[drewj]

Have you tried using air to blow off the bondo when your done laying. also go over it with some seal skin , or a top coat of polyester filler. the bubbles will go away. 2k High build primer after that. Block her down and shoot!

 

[Boostinsideways]

I've literally never had an issue wet sanding body filler once it has hardened and been glazed. Never had a problem with getting paint to adhere to it after wet sanding it either. I guess if you haven't properly glazed it, you might have some issues wet sanding it.

 

[NWHTanK]

Oh man...

1. Don't sand bondo with a da.
2. Don't wet sand bondo, it absorbs water!
3. Start with 36, then 80, then 180.
4. The repair area with be lots larger than the bondo, keep the feather edge way out so you don't put 36 grit scratches in it.
5. Use a da with 180 on it to feather in the paint.
6. Use a razor blade to spread bondo or spot putty in the pin holes.
7. Don't just spread little spots of bondo, cover the whole area. Different batches of bondo sands at different rates, its hard to get it straight like that.
8. Use sharp paper, worn sandpaper doesn't cut straight, and it makes it hard to get it straight.
9. Make sure you have nothing corse than 180 scratches before you prime it.
10. Use a quality high build primer. Preferably a 2k, but a laquer primer will do, just let it sit for a few days to shrink up. Don't use spray can primer.
11. Block it with 180, then reprime.
12. Wet sand with 400, then your ready for sealer and paint.

Good post im good at doing bodywork, but its hard to put it in type.

I could have, but


I just wanted to learn.

great post tank

NP
Thier is a new body filler out and its good stuff. Its a epoxy based filler, it has the fill like regular filler and the easy sanding of a polyester filler. I got forced into it when the shop was trying new stuff out. After a year of use absulty love it. The corses grit u use is 80 and then 180. It cuts down on matirals and time. But is trickier than regular filllars becuse u use way more hardner. The benifits easyer sanding, good fill, and since its is epoxy based it dosent absorb moisture. The brand is by evercoat they make quality fillars.

I could have, but I just wanted to learn.

great post tank

I've literally never had an issue wet sanding body filler once it has hardened and been glazed. Never had a problem with getting paint to adhere to it after wet sanding it either. I guess if you haven't properly glazed it, you might have some issues wet sanding it.

To each his own, but the problem i have with it is that regular filler has taulk in it when dried on the panel then exposed with sandpaper will absorb moisture and cause issuse later down the road.

 

[ed1380]

I have 80 and 220 grit for the DA. It's 3m bondo body filler and the red 3m bondo glazing/spot putty.
I'll be trying to finish it tomorrow. Hopefully it'll turn out good. I'm looking to get a harbor freight HVLP gun. I know it's not the best, but for primer it should be fine. I just don't know where to buy paint/primer in bulk(not rattle cans)

 

[NWHTanK]

U need a sanding blocks,or air file when sanding filler not a da

 

[bastarddsm]

It's 3m bondo body filler and the red 3m bondo glazing/spot putty.

Don't use that red glazing putty, its junk. It's laquer based and it will shrink up. You'd be best off just using bondo. Use a razor blade to spread it and keep it super thin.

Also, don't stir the bondo when you mix it. Fold it with the spreader. That will help keep air out of it.

That harbor frieght gun will probably be ok, the only thing it will lack over a good gun is good pattern control. That will mostly effect you when spraying metallics.

Overall the bodywork and the primer blocking will be more important than the gun you use. Use a rag between your hand and the hood to "feel" if its straight or not. The Rag lets you feel things better. Once you have primer on it, you can wet the hood down so it will be "glossy" and you can see if its straight or not.

 

[bryanwheat]

U need a sanding blocks,or air file when sanding filler not a da

It kind of depends on where you are sanding. On something that is relatively flat and convex like the hood a block will work the best. On something that is concave i prefer a da with thick foam pad on it.

 

[92AWDHX40]

Ive used that hb gun its pretty good, especially for a primer, i painted my car with one turned out pretty good, not as good as the sata i used before.

 

[bastarddsm]

It kind of depends on where you are sanding. On something that is relatively flat and convex like the hood a block will work the best. On something that is concave i prefer a da with thick foam pad on it.

No. Do not use a da to sand bondo. If your really really good you can use a Hutchinson Speed sander to sand it, but it won't be as good as done be hand.

Also, an air file can give you railroad tracks if your not careful.

 

[bryanwheat]

Ive used that hb gun its pretty good, especially for a primer, i painted my car with one turned out pretty good, not as good as the sata i used before.

I've got a few harbor freight guns also. Never had any problems with them. I've found that if you have it clean, and have your pressure right and gun adjusted properly it will do what you want it to.

 

[ed1380]

That's good. I might get one today. Where would I buy the paint and primer?

 

[Boostinsideways]

That's good. I might get one today. Where would I buy the paint and primer?

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