Media Blasting Questions

[cobramike33]

My 69 Charger project is going to require a lot of sheet metal and the only potentially outer body panels being saved is going to be the roof, hood, and decklid. I would hate to spend the money for a professional media blast when most of the panels are getting replaced anyways. The frame looks solid with the factory undercoat in place.

I am leaning towards doing blasting in my backyard with glass bead or something similar and strip the few outer body parts to bare metal with a wire wheel, neutralize the metal, and then epoxy prime all parts.

I am looking for suggestions, this is going to be a driver quality that I will hopefully never sell.

Another thought I had was to start replacing/repairing from front to back in different stages by blasting, repairing/replacing and then epoxy priming as I go. Breaking it up into front/floor pan/quarters&trunk pan.

It is a big project, will take lots of time...looking for input from the much wiser

[Patronus]

Gonna come down to pressure, air pressure. What size compressor ya got? An 80 gallon version would be best. 

[tan top]

 plan on  getting  the highest  CFM rating compressor you can afford , depending on if this is just a one off job or not & space permitting.  ,  alternatively  look at the air consumption of the tools / equipment  , your going to be using ,  look for at least 13cfm minimum    , 13 cfm will do almost everything & the bigger the tank the better ,   having said  this  a 13 cfm compressor  is  not enough to run a airfed mask & a paint gun at same time  

[Mike DC]

 

Cut away the roof & quarters that you aren't saving and then have it professionally blasted.  It's smart to weld some metal bracing into the unibody to hold it square with all that metal removed.  


Then buy the biggest compressor you can afford anyway.  

And be prepared to epoxy prime the car immediately after blasting.  Have all the materials sitting in your garage, the compressor already wired up & fired up, done a few practice sprays, etc.  You DO NOT want to end up waiting a couple weeks for some unexpected reason.  

[Troy]

Doing it in your back yard sounds like you won't be recycling the media.

Glass beads will take you forever (especially for any heavy rust) and will cost a lot. I have them in my cabinet right now and it's painfully slow - but great for delicate stuff like aluminum and carburetors. It took over two hours to strip paint and slight surface rust off a set of bumper brackets though. Sand would have done it in 10 minutes.

If you're doing frames, floors, engine compartment, and mechanical parts (rear axle, cross member, etc.) then it's ok to use sand as the metal is thick and/or reinforced. I use stuff called "black beauty" and it's like $9 for 50 pounds. You may end up using 20 bags (depending on how much of the car is left). If you can do the work over a tarp then sift the media through a screen you can reuse it a few times and save some money (but not effort so it depends on what your time is worth). Don't use play ground sand! Definitely wear protective clothing and a respirator. A normal dusk mask won't stop nearly enough and silica is really bad for your lungs. Do NOT use sand on large areas of unsupported sheet metal body panels (roof, hood, trunk, quarters, doors, etc.) because it's really easy to heat up the metal and warp it. Sounds like you won't have that problem.

Blasting uses a LOT of air. I have an 80 gallon compressor with a pump that is capable of 100% duty cycle - and it will run the entire time I'm blasting. A small compressor will probably only be good for a couple minutes of blasting then 10-15 minutes to "catch up". Make sure you have a good water removal system. Most media is useless once you get it wet.

A while back a local mobile soda blast operator had a deal with our car club for $700 per car. If I only had one car there's no way I'd have ever bought any of my equipment or done it myself. Even now, I wonder why I even bother! The only place I can get to come to me right now wants about $2,200 for a whole car. It may still be worth it. I can have it dipped or plastic media blasted cheaper if I want to haul it somewhere. To do that you want as much removed as possible beforehand. Your option of doing it in small chunks is a smart idea. You can use a Harbor Freight "spot blaster" and smaller compressor for little jobs.

If you don't have a giant compressor the 3M Clean and Strip disks are pretty great. They're about $7 each for the double ones and will get you through a couple panels before they wear out. I also use assorted sizes of wire wheels to get into tight spots. Both of these work on paint and rust. Make sure you're wearing eye protection!

For paint on outside body panels I use an 8" pad with 80 grit sandpaper on a buffer/polisher. Goes fast, doesn't heat the metal, and only makes half the mess of blasting but doesn't fill the air with silica. I also use chemical stripper around body lines and anything that's not flat enough for the big sander or too delicate for abrasives. I use a scraper to get the bulk of the paint off then a steel brush or wire wheel after to get all the way down to the metal.

Troy

[Lennard]

Cut away the roof & quarters that you aren't saving and then have it professionally blasted.  It's smart to weld some metal bracing into the unibody to hold it square with all that metal removed.  
Then buy the biggest compressor you can afford anyway.  
And be prepared to epoxy prime the car immediately after blasting.  Have all the materials sitting in your garage, the compressor already wired up & fired up, done a few practice sprays, etc.  You DO NOT want to end up waiting a couple weeks for some unexpected reason.  

  By the time you have everything bought and set up, you could have paid a professional business to do the work for you.

[cobramike33]

Cut away the roof & quarters that you aren't saving and then have it professionally blasted.  It's smart to weld some metal bracing into the unibody to hold it square with all that metal removed. 
Then buy the biggest compressor you can afford anyway. 
And be prepared to epoxy prime the car immediately after blasting.  Have all the materials sitting in your garage, the compressor already wired up & fired up, done a few practice sprays, etc.  You DO NOT want to end up waiting a couple weeks for some unexpected reason. 

  By the time you have everything bought and set up, you could have paid a professional business to do the work for you.

I think you hit it on the head, the few bucks I saved can be outweighed by the supporting items like a good respirator and a beefed up compressor (my 1.5hp 60gallon doesn't sound like it will do the trick).

[Lennard]

I think you hit it on the head, the few bucks I saved can be outweighed by the supporting items like a good respirator and a beefed up compressor (my 1.5hp 60gallon doesn't sound like it will do the trick).

I have a Husky 60 gallon 3.2 horsepower compressor and that's just big enough for my Skat media blasting cabinet.
To media blast a car you'll need a huge commercial compressor, which will cost you thousands.

[cobramike33]

Doing it in your back yard sounds like you won't be recycling the media.

Glass beads will take you forever (especially for any heavy rust) and will cost a lot. I have them in my cabinet right now and it's painfully slow - but great for delicate stuff like aluminum and carburetors. It took over two hours to strip paint and slight surface rust off a set of bumper brackets though. Sand would have done it in 10 minutes.

If you're doing frames, floors, engine compartment, and mechanical parts (rear axle, cross member, etc.) then it's ok to use sand as the metal is thick and/or reinforced. I use stuff called "black beauty" and it's like $9 for 50 pounds. You may end up using 20 bags (depending on how much of the car is left). If you can do the work over a tarp then sift the media through a screen you can reuse it a few times and save some money (but not effort so it depends on what your time is worth). Don't use play ground sand! Definitely wear protective clothing and a respirator. A normal dusk mask won't stop nearly enough and silica is really bad for your lungs. Do NOT use sand on large areas of unsupported sheet metal body panels (roof, hood, trunk, quarters, doors, etc.) because it's really easy to heat up the metal and warp it. Sounds like you won't have that problem.

Blasting uses a LOT of air. I have an 80 gallon compressor with a pump that is capable of 100% duty cycle - and it will run the entire time I'm blasting. A small compressor will probably only be good for a couple minutes of blasting then 10-15 minutes to "catch up". Make sure you have a good water removal system. Most media is useless once you get it wet.

A while back a local mobile soda blast operator had a deal with our car club for $700 per car. If I only had one car there's no way I'd have ever bought any of my equipment or done it myself. Even now, I wonder why I even bother! The only place I can get to come to me right now wants about $2,200 for a whole car. It may still be worth it. I can have it dipped or plastic media blasted cheaper if I want to haul it somewhere. To do that you want as much removed as possible beforehand. Your option of doing it in small chunks is a smart idea. You can use a Harbor Freight "spot blaster" and smaller compressor for little jobs.

If you don't have a giant compressor the 3M Clean and Strip disks are pretty great. They're about $7 each for the double ones and will get you through a couple panels before they wear out. I also use assorted sizes of wire wheels to get into tight spots. Both of these work on paint and rust. Make sure you're wearing eye protection!

For paint on outside body panels I use an 8" pad with 80 grit sandpaper on a buffer/polisher. Goes fast, doesn't heat the metal, and only makes half the mess of blasting but doesn't fill the air with silica. I also use chemical stripper around body lines and anything that's not flat enough for the big sander or too delicate for abrasives. I use a scraper to get the bulk of the paint off then a steel brush or wire wheel after to get all the way down to the metal.

Troy

Thanks for the thought out options Troy. Definitely a lot to chew on. I would ideally like to do as much work as I can do myself. Become one with the car lol. I had the opportunity to buy my first car back and look forward for many weekends spent on this.

[astjp2]

I have a 15 cfm ingersol 5 hp 60 gallon compressor and it's not enough to do a proper media blast, you need about 30 cfm! My blaster's compressor is 100 cfm and he uses a mix of plastic and glass beads, and doesn't do the flat panels because blasting warps the panels.

[Dreamcar]

Blasting makes such an incredible mess that I would lean towards just getting it done professionally rather than buying the necessary equipment. I removed most of what I was replacing then had the rest professionally blasted. It was just under 1K including the tow to and from the blaster. Blasting was about 600. They did it in a few hours, then I started coating the bare metal when I got it home that evening.

See my posts from December 21st 2015 in this thread...

http://www.dodgecharger.com/forum/index.php/topic,110598.0.html

[67Charger440]

Dreamcar,

Update that build thread!


I'm getting mine blasted next week or the week following.  No sense in fooling around with doing anything less...

[Dreamcar]

Dreamcar,

Update that build thread!


I'm getting mine blasted next week or the week following.  No sense in fooling around with doing anything less...

I know I know...the thread needs updating. I've got new quarters to test fit in the next few weeks, so an update is coming. Good call on getting it done by a pro.