Body Filler and Skim Coat for My Hood

[sick472]

I have read through several recent posts regarding fillers and skim coats only to be left feeling "special".

I have a hood for a 72 C10 that has a few dings where the backside cannot be accessed with a dolly/hammer. I plan to fill the dings with fiber strand filler because that’s what I've been doing, but the overall hood is a bit wavy and I cannot get it all worked out with spacers between the braces and the underside of the hood. In my mind a 1/16" or so of filler is needed on 40% of the top surface. The fiber glass filler would be a real buggar to sand at that kind of coverage.

I started this project more years ago than I will admit and have been using Lacquer Primer so that is what I am finishing it with. I'm not switching on the last panel. The hood is in primer (self-etching then lacquer) ...

What type of filler is best to use for the "wave"?

Can it be applied over/under the lacquer primer?

Thanks in advance for helping!

[mongocanfly]

The wave is stretched metal... a shrinking disc can help on stuff like this...1/16" filler isn't bad....I'm using evercoat filler on mine...I started with bondo but the evercoat seems to work much better...I've used fiberglass yrs ago..never again
Dont know about laquer...

[bs46488]

As a beginner/amateur I've used a few different types of filler (mainly because of waste). I'm currently using an off brand Premium Gold Bodyfiller. I've noticed no difference than when I spent the $$ on the name brand stuff.

My C10 was the first vehicle I painted. I didn't skim coat any of the panels trying to keep filler to a minimum. Now that I'm working on my second project and I did skim these panels....I can see tons of imperfections in the trucks panels.

I also think once you start to block sand your 1/16" of filler on 40% of the panel, you will find that most of that got sanded off. But it will be worth it for the final product!

[MARTINSR]

Originally Posted by mongocanfly

The wave is stretched metal... a shrinking disc can help on stuff like this...1/16" filler isn't bad....I'm using evercoat filler on mine...I started with bondo but the evercoat seems to work much better...I've used fiberglass yrs ago..never again
Dont know about laquer...

It doesn't mean something is "stretched" it could simply mean an inner structure isn't holding it firm or it got bent down and a "Crown" has formed on the edge of the dent.

Brian

[MARTINSR]

Originally Posted by sick472

I have read through several recent posts regarding fillers and skim coats only to be left feeling "special".

I have a hood for a 72 C10 that has a few dings where the backside cannot be accessed with a dolly/hammer. I plan to fill the dings with fiber strand filler because that’s what I've been doing, but the overall hood is a bit wavy and I cannot get it all worked out with spacers between the braces and the underside of the hood. In my mind a 1/16" or so of filler is needed on 40% of the top surface. The fiber glass filler would be a real buggar to sand at that kind of coverage.

I started this project more years ago than I will admit and have been using Lacquer Primer so that is what I am finishing it with. I'm not switching on the last panel. The hood is in primer (self-etching then lacquer) ...

What type of filler is best to use for the "wave"?

Can it be applied over/under the lacquer primer?

Thanks in advance for helping!

Forget about the fiberglass filler, that is for specific repairs and not your typical dent. FORGET applying filler over that lacquer primer. You need to post some photos showing what you are working with. This could be something totally different, a little crown as mentioned in the last post, search around for a crown. You can run some sand paper in a block over it and look for high spots where the sand paper sands it more than the surrounding area, that would be because it's sticking up, that may be a crown. If it is you can push up the low area and tap on that crown moving it back into shape to hole the low spot up where it belongs.
You also mention no access to inside, well, that could be the problem too, and it could be because the panel is "flopping" over the top of the inner structure because of sealer or foam that has rotten and fallen out.

Bondoing 40% of the hood to bring it up 1/16" may be a serious overkill, can you really see it over that large of an area, if so it's probably more than a 1/16".

If it is just a 1/16" then spraying a few coats of polyester primer may be a better choice. It's MUCH easier to sand than the filler being it doesn't have all the spreader stripes, you know what I mean? I did a test with polyester primer once where three coats got me 21 mils, that is about 8 times the thickness of a new cars paint job, primer, paint, clear, all of it, that is quite a bit! We are talking lay a dime on it and bury it under primer!

So that may be an option.

But post some photos, showing the whole low area with it marked with tape or something so we can see it. Plus the other damage, show us what you are talking about.

Brian

[sick472]

Thanks for the replies folks!
I'll explain the situation: The outer-most high parts (OUTER BLUE LINES) of the waves are directly above the two supports that run front to back on either side. As if the hood was once supported well with the foam spacer pads at the metal supports (I removed the foam pads and they were loose as you would expect, but not by much). It appears as if the center section (with the front-to-back ridge) and the outermost sections have "flopped in the wind” long enough to stretch the metal. The ridge is high, like it's supposed to be, then it dips down (RED AREAS), then back up (over the supports), then back down (OUTER RED AREAS) until it evens out and approaches the side of the hood where it bends down to make the sides. Most of the wave is towards the front. Using a straight edge, (and my imagination because its all curved one direction or another) it appears to only need that 1/16” of fill maybe a bit more.

I would love to try the shrinking disks or other methods of hammer/dolly to fix this, but I’m not very experienced with metal shrinking and I would hate to make this litte wave worse.

I am interested in the polyester primer as I have done that with multiple
coats of fill primer in smaller areas. Can that be put over lacquer primer?

The fiber filler would be for the dime-sized dings that reside above some of the understructure that does not allow for hammer access.

I think will be adding a front-to-back support under the ridge so that it can be shimmed upward just a bit which should take some of the inner wave out. And, I have contemplated adding wide strips of aluminum (0.05” thick or so by about 6” wide) above the side supports and pads to spread out the support area prior to fill putty and sanding.

[MARTINSR]

How was the old paint removed?

Brian

[sick472]

A varety of methods...

Wire Wheels,
Palm Sander,
and sandblasting at 100 psi (craftsman gun).

[nsb29]

Originally Posted by sick472

A varety of methods...

Wire Wheels,
Palm Sander,
and sandblasting at 100 psi (craftsman gun).

Sand blasting at 100 psi was your mistake I can tell by where the lower areas in your hood are at I have also found using plastic fillers over large areas like hood or a door 1/16 turns into 3/8 because as the filler hardens it shrinks bowing the metal inword it almost seems as the more you put on the worse it gets

[mongocanfly]

(and sandblasting at 100 psi (craftsman gun).

This may very well be what caused your issues...read MP&C sandblast repair post....
http://67-72chevytrucks.com/vboard/s...d.php?t=647269....

nsb out typed me on this one...

[sick472]

Well, sandblasting may be the cause. I have done several pieces like this with my sandblasting equipment...I guess it jumped out and bit me this time.

I am still uncomforatble trying to shrink things back. I will start to brace the hood as decribed above and regroup when if/when that improves things. The bracing needs to be done anyhow just to make the panel more stable for sanding. Meanwhile I will try to digest the thread that mongo supplied.

[mongocanfly]

Bracing under hood may be needed anyway...but it won't fix stretched metal..if that's what you have...I never used a shrinking disc before my current truck build...sandblasting ruined my doors....I spent many hrs with hammer and dolley...never could get it right...got the disc and it was like holy cow!!...this thing works...but if your uncomfortable with using a disc..take it to a body shop and have them fix it for you....may be money well spent...
Look on utube...theres several vids on shrinking discs
And if you do decide to get you one,,then get the small one.....its much easier to handle....

[mongocanfly]

And I dont think I'd be using alum or any metal to shim between hood skin and bracing...I think itd be better with something pliable....think about if when it goes from hot sun to winter temps...that hood skin will expand and contract...when I was hammer/dolley working my doors I was in the shop...I could take my door outside in the sun and after a few minutes the door panel would pop when the metal got hot and expanded...I finally got that out of it with the disc...
btw...I've got hundreds of hrs invested in my doors....it was a real learning experience

[bs46488]

Check out this hood bracing upgrade. It might help your problem a little:

http://67-72chevytrucks.com/vboard/s...d.php?t=524652

[72HuggerK20]

Definitely try the shrinking disc. If you're really comfortable, a small propane torch and a wet rag works really well to shrink metal. You could easily end up screwing up the hood that way though. Like MARTINSR said, that fiberglass filler is not a good idea for large skim coats. Regular filler followed by a skim coat of polyester glazing putty over the entire hood would be the easiest way to make it straight. You'll need a pretty long block too; like 17+ inches. It helps to cut the filler down first with very sharp, rough paper (80 grit). This way you can cut the filler without putting much pressure on the block, causing the block and the hood to both warp under the pressure. Once it's straight, then you can focus on getting rid of the 80 grit scratches. Make sure you put enough filler on to be able to do this in one shot. If you have to add into low spots after your final skim coat, you'll end up chasing your tail to get it all flat. Also, trust your block. If there's a low spot that the sandpaper can't get to, don't force it.

[sick472]

Thanks for all the input folks!

I am contemplating and researching the shrinking discs. I have to figure out if they work by heating up the highs, or if they are effective when used in the lows too. This would determine which side of the hood I would be using the disc on - Meanwhile, I will be adding the bracing and supports materials to stabilize the skin.

The nice thing is that I will be wet sanding the final paint (Acrylic Enamel) to give the whole truck a flat finish, not a fake patina, but an oxidized look is my goal. My truck will be gray and white so the results will be like and old faded truck with a primer aspect to it. This will hide what is currently going on with the hood (and other areas), but I am into it for the learning experience. I started this project as a tool to teach myself restoration techniques. I have learned alot, but the ole' girl was really beat up and rusted to begin with and my lack of ability would stick out like a sore thumb if the paint was shiny.

I'll post my efforts as they occur.

[MARTINSR]

Personally, I am thinking BONDO it. Shrinking is something that takes a bunch of lessons learned, and that mutha would be a BIG job even for someone with some experience under their belt. The shrinking disc is like magic, I get that, but you need a "high spot" to shrink down, so the low spots between the braces would have to be held up to do it, honestly, this is a BIGGIE and I think it would likely be made worse. ESPECIALLY if a torch or something was used.

I have a shrinking disc, I get it, but that sucker would take someone with some time under their belt with stuff like this.

Brian

[72HuggerK20]

Originally Posted by MARTINSR

Personally, I am thinking BONDO it. Shrinking is something that takes a bunch of lessons learned, and that mutha would be a BIG job even for someone with some experience under their belt. The shrinking disc is like magic, I get that, but you need a "high spot" to shrink down, so the low spots between the braces would have to be held up to do it, honestly, this is a BIGGIE and I think it would likely be made worse. ESPECIALLY if a torch or something was used.

I have a shrinking disc, I get it, but that sucker would take someone with some time under their belt with stuff like this.

Brian

100% agree here. There's no reason to completely mess up a hood, especially if all of the warping is within the 1/8" that you can do with filler. Remember, the bodywork on those trucks was never perfect from the factory either. It is highly possible that your hood was slightly high where the bracing is right from the factory. My truck had a factory hood in almost perfect condition and it still had the exact same warp pattern that yours does. Now, that doesn't mean leave it alone. I also wanted to make it right to the best of my ability, so I skim coated it to take most of the warp out, but it is still not perfect. Guess what, nobody but you will ever notice. It's all about how much time and money you want to spend to get the results you want.

*EDIT*
Also, thought I'd add, if your hood is going to be flat white/grey, you can practically get away with murder in the bodywork. Now I'm not saying to do a bad job, but your rime may be better spent elsewhere on the truck. Body and paint is 90% about how well you can trick the human eye, hence why people do blend panels when repairing paint.

[sick472]

Originally Posted by MARTINSR

Personally, I am thinking BONDO it...

Brian

We have come full circle to where this thread started...enjoying the ride, at any rate...When the hood gets skim puttied which it will need some even if I attempt shrinking it....

Is there a preferred bondo-like substance that can be applied over lacquer primer that would be easier to sand when compared to fiber strand style fillers?

If lacquer primer is the problem, I will remove it from the needed areas and start with bare steel...recommendations from there??? I suspect options are numerous (evercoat, premium Gold, Rage, etc) and I will have to research what primers to use as I have always dealt with lacquer primer.

[72HuggerK20]

Originally Posted by sick472

We have come full circle to where this thread started...enjoying the ride, at any rate...When the hood gets skim puttied which it will need some even if I attempt shrinking it....

Is there a preferred bondo-like substance that can be applied over lacquer primer that would be easier to sand when compared to fiber strand style fillers?

If lacquer primer is the problem, I will remove it from the needed areas and start with bare steel...recommendations from there??? I suspect options are numerous (evercoat, premium Gold, Rage, etc) and I will have to research what primers to use as I have always dealt with lacquer primer.

Lacquer products have a tendency to do funky things when solvents touch them. That means anything with solvent in it, which includes filler. Your best bet is to take it off (which can be done with a rag and lacquer thinner to prove my point). Then give it a coat of EPOXY primer, doesn't matter what brand. Even the cheap stuff is better than lacquer primer.

As for fillers, evercoat rage gold would be great for the first fill to repair the damage, followed by a skim coat over the entire hood with their polyester glazing putty. If you don't want to use evercoat, 3M makes great products. There is no reason to use fiberglass reinforced filler on a repair like this. It sucks to sand, doesn't featheredge nicely, and I don't think it adheres as well either. You won't have a problem with rage gold adhering to epoxy primer prepped with 120 grit.

[mongocanfly]

agree...take it to metal,,,,epoxy prime it,,,,,evercoat rage followed by evercoat glaze,,,epoxy prime over that...then a high build primer.....this is what I did based on a lot of recommendation from this section...results have been great....as im no pro by any means

[72HuggerK20]

Originally Posted by mongocanfly

agree...take it to metal,,,,epoxy prime it,,,,,evercoat rage followed by evercoat glaze,,,epoxy prime over that...then a high build primer.....this is what I did based on a lot of recommendation from this section...results have been great....as im no pro by any means

The epoxy between the filler and the high build primer is unnecessary unless you sand through to metal when doing bodywork. Even then, all you need to do is hit the bare metal spots with a quick coat of something. Most body shops actually use a spray-can etch primer to hit these small spots. Spot priming with epoxy before the high-build would be absolutely fine too. But high-build primer will adhere perfectly fine to filler that has been finished out to 150 or 220 grit.

[mongocanfly]

Like I said, I'm no pro,,,by any means,,,,but that is what was recommended to me when I asked about the bare metal I had around my repairs...and I did have bare metal around my filler areas...always learning though...

[nsb29]

Evercoat is good but it’s pricey UPOL GOLD is a great filler have been using it for over 16 years on the high-end cars without issues I finish it off with evercoat slick sand Which is a high build polyester primer with zero shrinkag forget the glaze except on miner flaws that’s my 2 cents PS never use raddel can under your paint the shops just want it done

[nsb29]

Originally Posted by 72HuggerK20

Lacquer products have a tendency to do funky things when solvents touch them. That means anything with solvent in it, which includes filler. Your best bet is to take it off (which can be done with a rag and lacquer thinner to prove my point).

I wouldn’t leave the lacquer but just because lacquer thiner will take it off don’t mean much when it will remove ppg DP90 epoxy its $500 a gallon lol