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From behind or Flush? Filler or welding?


RedFive

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Hey, I've got two questions and I couldn't really find a straight answer by searching.

 

1) I'm "rolling" the rear pan on my 280z and filling in all the holes. I've filled in one of the bumper shock holes already and I tried to cut a piece of sheet metal to fit the hole exactly. With the tools I have, this is hard to make it exact. So the question is...should I just put square plates of sheet metal on the back of the hole and tack them in and then fill all of that gap? Or should I do my best to fit the piece into the hole so that filler will be minimal? I'm using "All metal" and supposedly that will reduce cracking...but I don't want to deal with cracking at all...so which route should I take?

 

2.) I'm getting rid of the side trim and I've drilled out the rivits that hold it in. A body shop owner told me I should make a small dent around the area of my hole and then put filler in there. But online I've seen guys just welding the holes shut. Which way should I go??

 

Thanks!

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Hmm, i suppose I should get my digital camera out there. I really am not great at this welding thing. Although it seems to be easier when I got the piece cut out to fit exactly.

 

But even when I got it to fit perfectly (for the most part), I still ended up burning a couple holes. And it seems to be harder to weld on the bottom...

 

Is it imperative that I have a solid connection all the way around my piece, or is it more important that it feels solid when I push on it...and then the putty filler will take care of the rest even if I have holes here and there?

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Guest 1972_240z

i just used a grinder and every few grinds, i would check it against the hole or whatever you are covering.

 

here are some pics of the process.....

 

ef34b527.jpg

 

ef34b4e1.jpg

 

ef34b48e.jpg

 

ef34b457.jpg

 

Trust me, you want to try and make it as flush as possible. then you don't have to worry about crazy stress cracks with bondo and bondo glass.

 

bondo glass --- what the other guy used --- is only ment for small pin holes, not for a huge job like he was using. "Read the Directions"

 

Cut to size and weld, you will be much happier.

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Guest 1972_240z

if you get solid tack welds on there, then "lightly" bead the rest and you are good to go. Whenever i got a hole, i would just weld the hole right back up. not a huge deal. working with thin metal will do that to you.

 

p.s.-- i pound with my fist on my panels that i have welded and they are as solid as the rest of the body, if not more solid.

 

o, and i used 22 gauge. usually easier to grind down, yet does like to blow through with the mig welder.

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Yeah, I saw your photos in the other post from the guy whose rear is damaged. But my welding doesn't seem anywhere near as clean as yours. In some parts it is, but in other parts I have holes and crap. I'm having a little trouble fixing them.

 

I'd like to have it solid all the way around, but...somehow I don't think that's going to happen.

 

I think that if I posted a picture of my welding you guys would laugh at me. I dunno, at least it feels solid...

 

Do you have any tips on the technique? Today the piece I made fit the hole perfectly, so that wasn't the problem. It's my welding. I know this because nobody has ever taught me anything about it, lol

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i found that globular(i think thats what they call it) works realy well on sheet metal. turn the heat and wire speed way down untill it balls up at the tip, then push the moten ball onto the metal. it'll take a bit of tinkering to get it set right, and it'll be slow work, but it won't burn thru if done right. but this is more for making strings than it is tacks. has anyone tryed lead filler instead of bondo?

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Guest 1972_240z
Yeah' date=' I saw your photos in the other post from the guy whose rear is damaged. But my welding doesn't seem anywhere near as clean as yours. In some parts it is, but in other parts I have holes and crap. I'm having a little trouble fixing them.

 

I'd like to have it solid all the way around, but...somehow I don't think that's going to happen.

 

I think that if I posted a picture of my welding you guys would laugh at me. I dunno, at least it feels solid...

 

Do you have any tips on the technique? Today the piece I made fit the hole perfectly, so that wasn't the problem. It's my welding. I know this because nobody has ever taught me anything about it, lol[/quote']

 

I was self taught to, and to be honest, i have about 4 total working hours with the mig welder. its not very diffucult, i still blow holes alot too. you just fix them, that's all. remember, the grinder is your best friend.

 

tips --

cut out as best as possible. cut/grind, then put up to hole, then cut/regrind, then put up to hole, etc....

 

once you have the piece cut to a good size/fitment, tape it up sturdy enough so you don't have to hold it. Then make a few tack welds approx. .5 - 1" apart (or wherever the tape is not).

 

once the tack welds are nice and in place. strip the tape, then tack weld where the tape was. Next, slowly try and bead yourself around the piece and go from there. You will get holes and shallow welds, but don't get down on yourself, just fill them in with small welds and go from there.

 

REMEMBER --> Newbs to welding like us like GRINDERS !!! The grinder is your best friend !!!

 

let me know if you got any more q's.

 

Late

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Okay, so I've already done pretty much exactly what you described. Except for the last part -- the bead. After my inital tacks and removing the tape, I just kept tacking all over the place.

 

I attempted to run a bead, but it just melts all over the place. I've already turned the voltage down......*shrug*

 

Can you describe the beading process?

 

And what should I do to the back side of all my welds when I get to that stage? Some primer spray paint? Or some other sort of sealer? And should I do it before or after I put the body filler in?

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Guest 1972_240z

hmm...describing the beading process....you make short quick circular motion to produce a "puddle" and move away from it so it hardens into a circular hard blob. and you just continue until it forms a steady "beading" type action. If that doesn't work, tack weld large beeds and just continue doing that instead of beading. It a little longer process but works just as well.

 

Make sure to have voltage AS LOW AS IT GOES and WIRE SPEED (if using Mig) AS FAST AS IT GOES. As soon as the puddle starts, you want that wire to fill it up immediately so it doesn't burn a hole.

 

another suggestion, try staying about .75 - 1" away from where u are welding. This also allows for a cooler weld and I noticed that I didn't burn through as much when I was at that distance.

 

Backside and front side should be filled with a welding silicone seam seeler. works good and keep moisture out. Then grind/sand down and primer and you are good to go.

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As fast as it goes? Really? Okay, I'll try it.

 

Do you have pictures of the silicone after it has been applied? Do I just gob it up on the back side and then leave it? Obviously I'm not going to be grinding down the back side and such...

 

Thanks for all the help so far.

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Guest 1972_240z

yeah,

 

i suppose you can do that. just goop it up in the seam. if you weld to the point where there is no seam, then you don't need seam seeler. just put it where it needs to be. try and make it somewhat flush so it looks halfway decent and go from there.

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Well, turning up the speed helped a lot. I still burn holes once in a while, but I seem to be doing better. I think with the two holes I've been working on (read: learning on), that I should stop pretty soon, even if they aren't 100% filled. I'm worried about grinding through the metal.

 

So...where my "seam" is...just fill in the holes with the sealer? I thought that was the filler's job? Does it dry? Do I have to do anything to the sealer before I put the filler over it? Or in the case of the back side, the paint?

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Guest 1972_240z

hey bud, sorry it has taken me so long to reply. broke up with the girlfriend of almost 3 years, and my whole life has been turned upside down. anywayz.... although it may not look like there are any holes, there are. even the tiniest of holes...seam sealer gets into those little rivets and holes and blocks moisture and other junk from getting in. before you put sealer on, you should definately wipe it down with some acytone/paint thinner to get all the microscopic **** out of the way.nope, just sand flush as possible before filler, paint, and primer, and u are good to go.

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Hey no problem. Obviously I don't know what happened, but after 3 years, it might be worth saving. Maybe just take a break for a little bit or something.

 

Anyways, so I fill it with the seam sealer, both sides, and then sand down the front side after the sealer has dried. Then put some regular filler over that and finish the process like normal. And on the back side, I can just spray paint the dried seam sealer...Right?

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Guest 1972_240z

yup !!! u got it

 

3 years --> i wanted to get married, she didn't, and wanted to travel the world ALONE. There really isn't anything to save. O well.

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So I went to the hardware store and they didn't have any welding sealer. I even went so far as to ask two different people after my own thorough search, but they said they didn't have it.

 

Are you sure I have to use this stuff?

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