Sunday, July 22, 2012

Blasting Off

There was a break in the temperatures this week...if you call a predicted high of 89F degrees on Saturday a break.  This summer heat wave has definitely hampered progress on the fastback.  I much prefer colder weather since you can always put on more clothes.  When it's hot, there's only so much you can take off...legally.

But weather aside, I've been pondering the next step on the car...finishing up the driver's side floor, or start work on the trunk drain lip or start on the rusty toe board...some part of the car that I could stand a chance of work in this heat.  So what did I decide to do was to jump into the fire and media blast the bottom of the car.  I already got a small start when I did my little "test" last week and made a nice mess in the garage.   I would be more prepared this time around.

For starters, I followed Sven's advice for personal protection equipment.  I somehow misplaced my respirator.  So a trip to Lowes snagged a nice 3M tekk respirator with the P100 cartridges.  These are good for, paints and toxic gasses including acid.   It may be overkill, but I have only one set of lungs I'd like to see finish this project.

Then, from my last experience I posted previously, I didn't want to be covered in a mess of blasting media.  So I also picked up a "monkey suit" to keep me as media free as possible.  It has a hood and "booties" along with elastic at the wrists.

To be sure that my blasting wouldn't allow media to get in places that I didn't want, I obviously moved the fastback into the driveway.

I moved all the vehicles to the end of the driveway hoping that the blasting force and the breeze wouldn't carry it onto the cars.   Hopefully they would be out of harms way....

Then after getting all the equipment and media staged, it was time to suit up.   I definitely won't win any beauty contests but it's about function, not form.

Now it's on to the work.   I got the Mustang rolled on its side.  I started on the driver's side rear seat floor and moved right towards the firewall.  Then I did the area over the rear axle and moved to the rear of the car.  I started on the passenger side and worked my way forward to the firewall again.  The top and bottom of the car on the rotisserie is a good "before" and "after" view.

This all sounds so nice and easy, but it was anything but.   First of all, my media blaster held only 20 pounds at a time.  That was good for maybe--maybe 4-5 minutes of blast time.  Then I would have to purge the air, load it up, re-pressurise, and blast away.   I had put in my last load that emptied the first 100 pound bag of media.  When I got done, I could have broken out the other bag, but there was, for all practical purposes, 100 pounds of media in my driveway, minus the losses from the wind, what was in the car, and what ended up in the yard.   After sweeping the media into a pile, I noticed there was a lot of foreign debris.  I had a screen in the garage I put over my media pail. 

Then I scooped up some of the media and poured it onto the screen, shaking it back and forth to sift it through.

When I got done, the debris was visible.   I dumped it off the side of the drive.  I took the sifted media and put it in the blaster.  It worked with no problems.

So this is the process that took four and a half hours.  I got the bottom of the car done and did do the front frame rails and the lower part of the firewall.   I did do some of the fender aprons where there was surface rust.   I had to take breaks to re-hydrate and move the car into position as the sun progressed to get the best visibility.   By 4 PM, I was hot, I had finished dumping the third round of media recycle, and the temperature decided to go north of 90F degrees.

Of course, not all was sunshine and roses.  I did find during the process some more of that wonderful iron oxide deposits called rust.   The passenger side trunk drop-off definitely showed it's true colors.

There are rust holes in the lower 2 inches.  The rest looks good along with the trunk floor, which is a relief.  So I'll need to order that part and add that to the list of rust repairs.  (Any suggestions on vendors would be appreciated)   The rough looking metal at the top of the picture is actually undercoating that needs to be removed.

Then I found some pin holes in the passenger side rear floor.  This isn't to bad and can be easily patched.   There's a small one on the floor just inside the right rear fender well that will also be an easy fix....or I hope all of these will.

When my wife asked how it was going, I mentioned the rust I found and the extra work needed.  She rather stoically says, "Better to find it now than later."   I guess that's true, especially after what Alex found late in the bodywork and paint process.  I took the 3" square tubing off the rotisserie so I could spin the car 360 degrees and blow the media out of it.  That took several turns to get most of it out.  The rest will have to be by shop vac.  I'm not sure what I'm going to do about the factory undercoating in the rear wheel wells.  It was not budging much, even with repeated passes.  The body color paint came off, but that was about it.

This was all I got done.  I was tired, hot, and had a mess to clean up.   I got some help from my better half getting the car back into the garage since my back was getting pretty stiff.   So the fastback is back where it started the day, and in much cleaner condition.  It may not be a "professional" job, but it's better than manning a whirly-bird and sander.

I think at this point I'm going to call this quits on media blasting since I can get the rest of the car, particularly the inside,  cleaned up with the braided wire brush. 

Reflecting on this exhausting and demanding task, I will say it was worth the effort.  I was able to get some nooks and crannies cleaned out that would have been difficult any other way.   I identified a couple  more areas of rust repair.  and the cleanliness of the metal is better than using a whirly-bird.   Messy?  Yes.  Demanding?  You betcha.   Would I do it again?  In a heartbeat.

Now it's on to ordering the trunk drop off and getting back to the underside of the floor work.  With family coming in for the Brickyard races this weekend and the continuing 90+  temperatures in the forecast this coming week again,  it may be better than a week or so before I get back on the Mustang.  But at least it's ready to go whenever I am.


  1. Dennis,

    Well done on all that blasting. Have I ever mentioned how much I hate sandblasting? But you sure have to admit it works well for the kind of work you are tackling.

    The indercoating removal is no big deal. I have a technique that works great and you can get it done with tools you may already have. Check it wout here:

    Careful with that heat!

    1. Hey Sven, Thanks for the tip on undercoating. I never would have though of using my air chisel/hammer. I'll need to see if I can get a wide blade for it. I have a hand-held chisel that's 4" wide, but I don't think it would work as well as the air powered one. I'll definitely check into it!

  2. I don't know Dennis. I'm thinking that anything is better than the wire wheel of death. Refilling the pressure pot every 5 minutes can't be much fun but I really hate using the angle grinder. I guess the only difference between your setup and what I might consider if I had a better working area would be a fresh air hood so's the media doesn't ping me to death but I certainly would have liked to try my hand at blasting the rear floor to trunk transition hump, the engine compartment, and under the dash (if a fresh air hood could fit under there). Nice work though. I think you saved a LOT of time and self-abuse doing it the way you did.

  3. Alex, for some reason, I got the email of your post but it didn't show up here. You may want to try again.

    1. That explains a lot. I too have received blog comment emails from Google only to go to my blog and not see them. I think that Google has some kind of over-zealous spam filter running.

      The media blast job looks great and I think you've saved yourself a lot of time and hassle (with the exception of the mess) by blasting instead of wire wheel. I wish I could have done the same with the underside of the rear of my car as well as the engine compartment (and possibly under the dash if possible). I've read that a fresh air hood helps deal with much of the discomfort of media blasting and protects your entire face from ricochets. Nice work though, I'm jealous! :-)

    2. Actually, the "bounce back" of media was pretty minimal. I was careful to note which way I was pointing the nozzle and did have a full face shield for the tight places where the media did rebound. I'm thinking about having another blasting session and do the inside from the rear passenger area to the back of the trunk. I'm weighing the wire wheel vs. going through the mess again since it's not that big of an area.

      I did get the trunk drop off ordered from CJ Pony Parts. How convenient they had 20% off to the end of the month! : )