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Rusty Bumper Practice Run

  #1  
Old 03-15-2017, 02:32 PM
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Default Rusty Bumper Practice Run

Well, now that summer is coming along I figured the next repair I'll do for my blazer will be the body. The poor thing is covered in Michigan rust and I'd like to conquer it. The spot I'd like to try first is the bumper which has a nice gaping hole where the license plate light used to be and a even bigger hole on the left flat side.

Way I see it I could just go get a new bumper if I screw this up, but if I can fix this then the rest should be comparatively down hill. I have no welding equipment and no power tools. What I've heard many people do is sand away the rust to bear metal and then use layers of fiber glass to fill in the holes left behind. How hard is this to do and what are the ideal weather conditions (ie low humidity required, hot or cold, sunny or cloudy, in garage or outside)?

I'll potentially remove the bumper entirely in order to make sure all the rust is removed and the paint has a complete coat. This doesn't look too hard and will line me up for simply replacing this if I screw up too bad or figure it isn't worth it. Either way I want to at least get some practice before touching an irreplaceable part.

I've heard others use Bondo for smaller spots that are not yet holes or just small dime sized holes. Does this work better? I'm pretty sure my hole is much too big for Bondo but there are a few small ones scattered throughout.

The blazer is that classic red that every other blazer I've seen is colored (it is the one in signature), does anyone have any idea what that is called so I can get the correct shade of paint. Speaking of which is there preferred brands of primer and paint, I've had fairly good luck with Rustoleum in the past. Are spray paints better or should I get a bucket and a brush?

I'm on collage budget so I defiantly can't afford a professional body shop. Besides, so far I've enjoyed fixing this poor thing up and it has rewarded me with safe driving in an icy winter and some fun trips down uncharted roads .

Any advice is welcome, I plan to start this come May when at home and I have an income again.
 

Last edited by LuckyAce; 03-15-2017 at 02:41 PM.
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Old 03-15-2017, 02:47 PM
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Bondo does not fix rust. If you Bondo over rust and paint it you are just wasting your time, energy, and money. The ONLY way to fix a rust hole is to cut out the rusted section of metal, and weld in new steel. Anything short of that, or replacing the bumper is like putting a bandaid on a broken arm.

I would recommend replacing it. However, if you have access to a welder- repairing it would be a great learning experience.

As far as getting paint to match, Napa sells a good quality paint that is made by Sherwin Williams, and rebranded as 'martin senour". it's affordable and a good quality product, and even better Napa will mix it to match your car by your paint code.
 
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Old 03-15-2017, 03:01 PM
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I did plan to remove all the rust with sand paper for sure, but unless there is a cheap way to get welding equipment I can't replace the rust with metal. Best I got is a propane torch which won't melt let alone weld metal.
 
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Old 03-15-2017, 03:29 PM
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Harbor freight has fluxcore welders you can find onsale for around 100 bucks, that would be good enough​ to learn with. By the time you buy the welder and a grinder it would probably cost about as much as a new bumper....But you get the learning experience and still have a welder for your next project!

Cheapest/easiest route is definitely to replace. I'm all about helping people learn bodywork though (I was raised in a body/restoration shop) and will help walk you through the right way to do it if you want to repair.

I'd just hate to see you waste your time trying to Bondo up a rust hole(or any hole for that matter, its not made to fill holes) it might look good for a tiny bit, but it will show back up in no time, and look worse than it did to begin with
 
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Old 03-15-2017, 03:46 PM
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I was told buying welding gear from harbor freight was suicide... Assuming I did, how much does new metal run and where do you get it? What about fuel? Welding safety gear (helmet, gloves)? Is welding similar to soldering (closest thing I can think of that I've done)?

I was certainly not planning to use the Bondo on the bumper, kinda figured that would be near impossible. Would like to use it however at the point were the bumper end meets the wheel well (small rust mark making paint bubble and peel) and on the tailgate by the wiper blade.

I was hoping I could layer on fiberglass to replace the lost metal on the bumper and was told this was a decent fix, however since the two materials expand and contract at different heats it won't last forever.
 
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Old 03-15-2017, 04:23 PM
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I`ve been using a harbor freight welder for years with no issues. I have their 220volt one that uses argon gas
 
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Old 03-15-2017, 04:29 PM
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Ok, I see what you were going to use Bondo for now. Where the metal is pitted from rust, but not thru the steel, Bondo is the right thing to use to smooth that out.(after the rust fully is ground/sanded off)

The fiberglass and steel expanding and contracting at different rates is correct, but again it's not so much a fix, as it is a way to temporarily hide the rust. Will it last longer than Bondo over a rust hole? Yes, but still not very long.

Harbor freight welders are definitely lower​ quality, but you'd be spending 500-1000 for a decent used welder. The harbor freight one is a low cost way to start learning. And it is capable of welding the thin steel the bumpers are made from on these.
EDIT: nice to see newguy has had good luck with his also! Though I'm sure his was a little more costly than the one I was talking about
With the fluxcore welders, there is no gas, all you need is fluxcore mig wire(they might even come with a spool) helmet and gloves could be had for less than 50 bucks at harbor freight too.(surprisingly their autodarkening helmets are pretty good, and last a while). The small amount of metal you'd need would be super cheap, like next to nothing. Home Depot or Lowe's would probably have it, other than that you can usually find a metal shop locally.

As far as it being like soldering...It is in theory, but not in practice. A mig welder feeds the welding wire for you
 
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Old 03-15-2017, 08:17 PM
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what about small holes... like a pin hole to dime in size? Would Bondo be ok on these (rust and paint removed of course)?

I have one whole in the rear wheel well that I'm kinda scarred to remove the rust on just because of the curvature.

I've never welded before so have no idea where to start if I were to do it. You mentioned it feeds the metal to you. So I just slowly build in around the hole until the gap is closed again, or get a metal plate and bind it over the hole like a patch?

I'll be graduating next year and hopefully will have a nice full time job lined up, with it I'll be more likely to be able to invest into the Blazer. Will fiberglass at least hold a year, and be easy to remove when I'm ready to properly fix it?
 

Last edited by LuckyAce; 03-15-2017 at 08:53 PM.
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Old 03-15-2017, 09:03 PM
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I wouldn't recommend using Bondo to cover any hole, not even a small one. It's just asking for problems down the road. Something like an 1/8th inch hole would probably last a while before you had an issue, but I personally wouldn't​ do it.

This is the only example I could find on my phone right now, what you're doing would probably be a much smaller, flat patch, but the process is basically the same:

Make the patch for the area that's rusted out, hold the patch to the panel, mark around it and cut out the old metal






Weld new patch in place, welder feeds a thick wire and melts it as you go, it won't fill giant holes, but anything up to half inch is pretty well doable I'm sheet metal. Watch a few YouTube videos on mig welding to get a general idea of how it works.



Grind the weld down, and bam! Like nothing happened. Now is when you'd use Bondo, just to smooth out the rough/wavy area from the welds.




Sorry to load your thread up with pics, but I hope it helps explain the process a lil better
 
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Old 04-09-2017, 03:04 PM
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Well, I got confirmation from my summer internship, looks like I get to go back again . This gives me the green light to buy the needed materials for welding. I looked up fluxcore welders on harbor freight and found four different ones varying on amperage. Which one will get the job done? Does anyone have experience with one of them? Also how far does the welding wire go and are there any differences in quality I should know of? How messy will this be (ie am I going to **** off my parents by doing this in their garage?)?

I heard from a friend that there is a strong acid I can use to remove the rust instead of cutting it, but I have to be careful with it since if it is left on too long it will eat the metal as well.

Is there an easy way to remove paint with hand tools short of taking a razor blade to it and slowly chiseling away?

Found new rust spots coming through paint, thanks a lot Michigan winter. How difficult is it to weld new metal onto the wheel wells? Both rear ones are rusted through on that curved piece inside the door.

Also how did you get the new metal to bend to the same shape as the old part? Did you just whack at it with a hammer till it looked good?

Short of primmer and paint do I need to add anything to the metal to make sure it doesn't rust any time soon? How many coats of primmer and paint are required? How does the welder keep oxygen out during the heating phase? I know argon welders flood the area with the noble gas to make sure the metal doesn't rust when heat is added in to the equation. Do I just need to be quick before the metal literally rust before my eyes?

Sorry about all the questions, just want to get this right the first time. Never have done body work before and this is my first car and therefore very special to me.
 

Last edited by LuckyAce; 04-09-2017 at 03:17 PM.

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