June 29th, 2009

Fiberglass Practice

Today I worked on a piece that has absolutely nothing to do with my truck. I went to a neighbors garage sale last weekend, and my friend Erik who lives next door to him put a banged up Porsche fender in the back of my truck, just to get rid of it. It's from a rather nice '83 Porsche 944, which he is now trying to sell. I was originally going to sneak into his back porch while he was at work and leave the thing in his grill or something, but I decided instead to use it for some bodywork practice, since nobody really cares about it. Besides, I think he locks the screen door, anyway.


Right, so here's the piece in question. Now, you may wonder why I would try to work on this piece. It's thinner than anything on the truck, and instead of rust holes, its problem is serious deformation. If you asked the question, go take a hike. Any practice is good practice, right? I figured that Bondo work can't really be all THAT difficult. I mean, I've met some of the people that do it. I will now share some of the learning experiences I had during this attempt.

For those of you not familiar with Bondo, it is this two part fiberglass goop that you mix together into a paste, and then apply onto metal (or wood or plastic), and then when it hardens, you can sand it into shape rather easily. It hardens quickly enough that you can shape it, sand it, and paint it all within a few hours.

I removed the paint with my new grinding pad. If you've never used one of these, they look kind of like a coarse sponge but are stiff. I haven't decided whether I like it yet, but as you can see, the wire wheel was quickly reaching retirement age. I started banging it out to what I thought was the original shape.

Lesson 1. Check your work often against a known pattern. If you can attempt to fit your piece to the car, do it often. Unfortunately, this was a luxury I did not have, since it was not actually a piece of a car I own. I went over to Erik's house to look at the new fender he had installed, so I was able to get a feel for what the original body line was supposed to look like. I must have gotten it close, but I'm sure it's not going to be a perfect fit. Fortunately, as already mentioned, no one really cares about the fate of this fender.

I then mixed up a heaping dollop of Bondo out of an old quart-sized can I had in the garage and began to apply it.

Lesson 2. Don't mix up too much Bondo. It only has a working time of a few minutes, much shorter than what I was expecting. Maybe it actually was the three or four minutes as shown in the directions on the can, but it certainly felt much shorter than that.

This was directly related to lessons 3 and 4.

Lesson 3. Don't put it on after it has started to harden. It stops going on like toothpaste and instead starts to look like you're attempting to spread stale bread. This, of course, was not much fun to shape, and wound up getting almost entirely ground back off.

Lesson 4. Don't put too much on. It's better to do it in multiple thin layers. I wound up grinding a vast majority of the first layer off. Interestingly, the chemical reaction between the two parts made it warm up noticeably.

All right, this was turning out to be more difficult than I thought.

Lesson 5. Clean up your mixing surface as soon as the Bondo starts to harden. If you catch it early, it's really quite easy to scrape off. Now, if you're using something flexible, it's easy to remove after it hardens. If you're using something disposable, no worries, just throw it away. But if you're using a scrap of plywood that you were planning to reuse, you really should scrape it off with a putty knife as soon as you can. Oh, and speaking of putty knives . . .

Lesson 6. Use the right applicator. You can pick up a nice set of applicators at any auto parts store for three to five dollars. They're really useful, you can kind of shape the material as you're applying it, and being flexible, they're also easy to clean up. I recommend these. I used a putty knife.
(Side note- I bought some today, and amazingly enough, they're the same pink color as the Bondo should be when it's mixed properly!)

Lesson 7. Rough shaping can start right away. As soon as it hardens, I found that I could scrape the ridges left by my putty knife could be scraped off rather easily with the same putty knife, saving tedious shaping later. Just be careful not to go overboard with it.

Lesson 8. Use the right tools for shaping. They make these cheese grater looking things which are excellent for shaping while the material is still soft. Not having one of those, I used a coarse metal file. It worked all right, but would have been better if it was wider. It is better to use these tools more and sandpaper less, as sandpaper tends to clog up rather quickly. I was using 120 and 220 grit paper, and I did purchase a flexible sanding block, which I also recommend. Feather the edges with a 400 grit sandpaper, per the directions on the can. If you do mess up per lesson 4, that grinding disk is effective at removing large amounts of material quickly, but keep in mind- no matter what attachment you put on an angle grinder, it was never designed to be a precision instrument.

Lesson 9. Wear your dust mask when sanding (or grinding). I forgot ONCE and I've been coughing ever since. Take the time to put one of these on.

Lesson 10. You CAN mix up too little. I was just filling in a few little nicks and pits, so I decided to be conservative, based on lesson 4. By the time I had it mixed, it had spread it mostly around my mixing board, and almost didn't have enough to reload onto my putty knife. a non-absorbent surface like a plastic or metal mixing board may alleviate this somewhat.

Lesson 11. Bondo has a shelf life. By now, I had mixed up four batches of fiberglass and was getting near the bottom of the can. Now, I bought this can for work a little over three years ago. On the top it looked normal, but when I got down to the bottom few inches of the can, it looked kind of like greasy cottage cheese.

 I was now running low on Bondo, sandpaper, time, and patience. I really did learn a lot, but the fender isn't anywhere near being finished. But who cares? I got in some practice, learned some pitfalls, and hopefully have been able to pass something useful onto my readers. I may try to finish it another time, but for now, my curiosity on this subject has been satisfied. And it's not like anyone needs the fender. However, if any of you want to buy it...

June 27th, 2009

Fiberglass Practice

Today I worked on a piece that has absolutely nothing to do with my truck. I went to a neighbors garage sale last weekend, and my friend Erik who lives next door to him put a banged up Porsche fender in the back of my truck, just to get rid of it. It's from a rather nice '83 Porsche 944, which he is now trying to sell. I was originally going to sneak into his back porch while he was at work and leave the thing in his grill or something, but I decided instead to use it for some bodywork practice, since nobody really cares about it. Besides, I think he locks the screen door, anyway.


Right, so here's the piece in question. Now, you may wonder why I would try to work on this piece. It's thinner than anything on the truck, and instead of rust holes, its problem is serious deformation. If you asked the question, go take a hike. Any practice is good practice, right? I figured that Bondo work can't really be all THAT difficult. I mean, I've met some of the people that do it. I will now share some of the learning experiences I had during this attempt.

For those of you not familiar with Bondo, it is this two part fiberglass goop that you mix together into a paste, and then apply onto metal (or wood or plastic), and then when it hardens, you can sand it into shape rather easily. It hardens quickly enough that you can shape it, sand it, and paint it all within a few hours.

I removed the paint with my new grinding pad. If you've never used one of these, they look kind of like a coarse sponge but are stiff. I haven't decided whether I like it yet, but as you can see, the wire wheel was quickly reaching retirement age. I started banging it out to what I thought was the original shape.

Lesson 1. Check your work often against a known pattern. If you can attempt to fit your piece to the car, do it often. Unfortunately, this was a luxury I did not have, since it was not actually a piece of a car I own. I went over to Erik's house to look at the new fender he had installed, so I was able to get a feel for what the original body line was supposed to look like. I must have gotten it close, but I'm sure it's not going to be a perfect fit. Fortunately, as already mentioned, no one really cares about the fate of this fender.

I then mixed up a heaping dollop of Bondo out of an old quart-sized can I had in the garage and began to apply it.

Lesson 2. Don't mix up too much Bondo. It only has a working time of a few minutes, much shorter than what I was expecting. Maybe it actually was the three or four minutes as shown in the directions on the can, but it certainly felt much shorter than that.

This was directly related to lessons 3 and 4.

Lesson 3. Don't put it on after it has started to harden. It stops going on like toothpaste and instead starts to look like you're attempting to spread stale bread. This, of course, was not much fun to shape, and wound up getting almost entirely ground back off.

Lesson 4. Don't put too much on. It's better to do it in multiple thin layers. I wound up grinding a vast majority of the first layer off. Interestingly, the chemical reaction between the two parts made it warm up noticeably.

All right, this was turning out to be more difficult than I thought.

Lesson 5. Clean up your mixing surface as soon as the Bondo starts to harden. If you catch it early, it's really quite easy to scrape off. Now, if you're using something flexible, it's easy to remove after it hardens. If you're using something disposable, no worries, just throw it away. But if you're using a scrap of plywood that you were planning to reuse, you really should scrape it off with a putty knife as soon as you can. Oh, and speaking of putty knives . . .

Lesson 6. Use the right applicator. You can pick up a nice set of applicators at any auto parts store for three to five dollars. They're really useful, you can kind of shape the material as you're applying it, and being flexible, they're also easy to clean up. I recommend these. I used a putty knife.
(Side note- I bought some today, and amazingly enough, they're the same pink color as the Bondo should be when it's mixed properly!)

Lesson 7. Rough shaping can start right away. As soon as it hardens, I found that I could scrape the ridges left by my putty knife could be scraped off rather easily with the same putty knife, saving tedious shaping later. Just be careful not to go overboard with it.

Lesson 8. Use the right tools for shaping. They make these cheese grater looking things which are excellent for shaping while the material is still soft. Not having one of those, I used a coarse metal file. It worked all right, but would have been better if it was wider. It is better to use these tools more and sandpaper less, as sandpaper tends to clog up rather quickly. I was using 120 and 220 grit paper, and I did purchase a flexible sanding block, which I also recommend. Feather the edges with a 400 grit sandpaper, per the directions on the can. If you do mess up per lesson 4, that grinding disk is effective at removing large amounts of material quickly, but keep in mind- no matter what attachment you put on an angle grinder, it was never designed to be a precision instrument.

Lesson 9. Wear your dust mask when sanding (or grinding). I forgot ONCE and I've been coughing ever since. Take the time to put one of these on.

Lesson 10. You CAN mix up too little. I was just filling in a few little nicks and pits, so I decided to be conservative, based on lesson 4. By the time I had it mixed, it had spread it mostly around my mixing board, and almost didn't have enough to reload onto my putty knife. a non-absorbent surface like a plastic or metal mixing board may alleviate this somewhat.

Lesson 11. Bondo has a shelf life. By now, I had mixed up four batches of fiberglass and was getting near the bottom of the can. Now, I bought this can for work a little over three years ago. On the top it looked normal, but when I got down to the bottom few inches of the can, it looked kind of like greasy cottage cheese.

I was now running low on Bondo, sandpaper, time, and patience. I really did learn a lot, but the fender isn't anywhere near being finished. But who cares? I got in some practice, learned some pitfalls, and hopefully have been able to pass something useful onto my readers. I may try to finish it another time, but for now, my curiosity on this subject has been satisfied. And it's not like anyone needs the fender. However, if any of you want to buy it...

June 26th, 2009

My time in South Florida has ended! I am now back in the Sanford area full time! I now have plenty of time, in between looking for a job, to play my favorite truck-related game- Just How Bad Is It, Anyway?

Okay, so it was Friday afternoon, my girlfriend was going to be tied up several hours in the evening, and I'd had enough housecleaning to last me a while. So I decided to go after my truck with my wire brush.

I started on the passenger side door. Yes, that disgusting orange thing off the parts truck that was partially spraypainted a distant blue with wirewheel marks on the window. The surface featured, among the traditional surface rust, this amazing textured paint job. It appears that someone in that trucks past had applied a paint incompatible to what was already there, or simply decided that sanding was unnecessary before painting. If the surface already looked like that, then I guess I can see where anything would have been an improvement, sanding or no.

I started just behind the window and brushed down a small spot, then moved below the window to some particularly grievous looking surface rust. And so, "Just How Bad Was It?" Surprisingly, not bad. I was actually able to expose bare metal easily enough, and the offending mostly orange paint gave way to smooth steel underneath. Even the surface rust had only minimally pitted the surface.

Encouraged by these results, I covered up the bare metal I had uncovered with sanding primer to protect it from rusting, and moved on to the rear corner of the hood on the passenger side. There were some rust holes visible and the surface was bubbling, a classic indication of a poorly done repair job. After some liberal application of the wire wheel, I uncovered the ugly truth. So, "How bad was it, Anyway?" The original rust hole had formed where two pieces of metal joined and were spot welded. This created a water trap, and both pieces rusted through. Our would-be restorer (recall that this hood came from a different parts truck) filled up the holes with fiberglass and smoothed it over. After some time, no less than ten years, rust started bubbling up the paint and glass and it became obvious that a better repair job was in order. I also covered this up with sanding primer and left it for later, when I really start in on the hood and weld in some new metal.

Quit while I'm ahead? Never! I moved onto another spot, this one on top of the hood on the drivers side. Now this one looked easy. It looks like a dent had been repaired at one time, but the fiberglass had bubbled and popped away from the center, leaving a hole about 6" long and 3" wide, revealing the metal underneath, which featured some surface rust. No problem, right? Simply remove the fiberglass back to metal, remove the rust, and bang out the dent. "Just How Bad Was It?" Well, getting back to the norm, the answer with this spot was the usual "worse than I thought." I chipped back some of the Bondo with a screwdriver and started attacking the rest with the wire wheel. As it turned out, it was more than a simple dent- it was a scratch that ran almost the whole length of the hood. The cracked out part was just the deepest part. I took out the Bondo forward of there I started and some backward. I removed as much surface rust as I could with the wire wheel (which was starting to look pretty sad at this point) and treated the area with this rust converter stuff. Available at many auto parts stores, this his chemical converts iron oxide to "iron chromo-phosphate" and leaves a sealed surface. I'll get back with you on how it works. I covered this too with primer to ward off rust and that was a day.