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| Dustless/Wet/Vapor Blasting https://www.rypn.org/forums/viewtopic.php?f=1&t=45314 |
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| Author: | warren032 [ Wed Mar 03, 2021 6:15 pm ] |
| Post subject: | Dustless/Wet/Vapor Blasting |
Does anyone have any experience using a dustless/wet/vapor blasting system? I have a 60' RR car to blast. Have used dry blasting and it is waaaayyyyy to dusty/messy. The dustless/wet/vapor blasting systems promise 90%+ less dust, better blasting, less media usage, etc. I have been looking at two vendors Graco/Ecoquip and MMLJ for either rental or potential longer term purchase. Any experience shares greatly appreciated. Warren Milw Rd Dynamometer Car X-5000 Curator Illinois Railway Museum |
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| Author: | Doug Debs 2472 [ Wed Mar 03, 2021 6:58 pm ] |
| Post subject: | Re: Dustless/Wet/Vapor Blasting |
I'd be very interested in your experience with low-dust wet or vapor blasting. Please keep us posted! The old ways: Disposing of lots of blast media contaminated with lead paint dust can get expensive fast. Disposal of only the lead-based paint chips, on the other hand, is relatively cheap. Here is our experience on heavyweight lounge car Southern Pacific 2979 (75' long): The car had several layers of SP-applied paint, plus a thick coat of 1960s house paint on top. We chose to needle-gun off the thick total paint accumulation. This generates a surprisingly small amount of paint chips (filled about half a 55-gallon drum), so the hazwaste disposal was cheap. Significant expenses included needle gun parts (even the Ingersoll-Rand guns need the pounding parts replaced frequently), special vibration-absorbent gloves to protect the gun operators, and labor hours. Relatively little sanding was needed to prep the surface after needle-gunning. We got down to the earlier layer(s) of paint, which still adhered well. Needle-gunning can also remove heavy layers of rust, but it cannot generate a clean bare steel surface ("clean to white metal"). - Doug Debs |
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| Author: | EWrice [ Wed Mar 03, 2021 7:17 pm ] |
| Post subject: | Re: Dustless/Wet/Vapor Blasting |
Dustless or water blasting is the way to go. I have personally used it on multiple projects. Last fall I had the bottom of my boat stripped to bare aluminum. 2.5 hrs to do a 32ft boat. Mess gets rolled up in plastic and thrown out. There is a contractor out of Ohio (I can't find their contact info right now) that does blasting and painting and specializes in locomotives and rail cars. I got to see the work they did on a G&W SW1200 over a period of 3 or 4 days. Top notch work. I will have to see if I can find their card. |
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| Author: | PMC [ Wed Mar 03, 2021 9:11 pm ] | ||||
| Post subject: | Re: Dustless/Wet/Vapor Blasting | ||||
Pueblo Railroad Museum used water mixed what I believe was garnet to remove the paint from AT&SF #2912, I recall seeing an article about it in the Pueblo Chieftan around five years ago. https://pueblorailway.org/roster/atsf-2912/
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| Author: | Rollerman [ Thu Mar 04, 2021 3:27 am ] |
| Post subject: | Re: Dustless/Wet/Vapor Blasting |
Look into pelletized CO2 blasting, it will remove paint, not sure about rust. CO2 evaporates leaving nothing except paint to dispose of. |
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| Author: | whodom [ Thu Mar 04, 2021 8:27 am ] |
| Post subject: | Re: Dustless/Wet/Vapor Blasting |
Wet sodium carbonate (baking soda) is a pretty widely used process. I spec’ed a system for a project some years ago. I don’t believe it will remove heavy rust; IIRC it’s typically used for paint removal and lighter gauge metal. One good thing about this process is the metal is not prone to immediate flash rusting as occurs with conventional sand blasting. The very light residue left from the process provides some short-term corrosion protection until you get paint on it. |
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| Author: | Doug Debs 2472 [ Thu Mar 04, 2021 12:04 pm ] |
| Post subject: | Re: Dustless/Wet/Vapor Blasting |
We tried CO2 (dry ice) blasting on 4-6-2 SP 2472's boiler shell exterior during the 2004-2005 retubing and firebox work. CO2 blasting removes paint OK - not too quickly - but doesn't remove surface rust. It could not produce a clean "white metal" surface, or anything close, on slightly rusty steel. - Doug Debs |
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| Author: | jayrod [ Fri Mar 05, 2021 11:18 am ] |
| Post subject: | Re: Dustless/Wet/Vapor Blasting |
Some thoughts assuming you’re painting outdoors.... Soda blasting works well to bring the luster back to stainless fluting however it’ll take a month of Sundays and a lot of soda to remove multiple paint layers on steel. But it does so without damaging the substrate. If the rust isn’t too severe, after blasting you can use a rust converter on any remaining spots before priming. Then you don’t have to go to full white metal. For a smooth surface, a skim coat of body filler over rough spots with some sanding before priming works. If wet grit blasting is used, you may get flash rust so clean and dry as fast as possible and get primer on it even if you have to work in smaller sections. The mobile paint companies build a “booth” around the equipment and just have at it until it’s done and painted. Makes cleanup easier and keeps any mess and overspray contained. You’ll likely be removing lead paint so precautions are necessary. |
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| Author: | warren032 [ Mon Mar 08, 2021 12:50 pm ] |
| Post subject: | Re: Dustless/Wet/Vapor Blasting |
Thank you EVERYONE for such a wealth of experience!!! I will post what what we end up doing with blasting... Warren |
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| Author: | Nova55 [ Mon Mar 08, 2021 3:40 pm ] |
| Post subject: | Re: Dustless/Wet/Vapor Blasting |
Most shipyards these days have switched over to some form of waterblasting, as it is so much easier to control the dust (there is none!). The ones I have seen were all inhouse built rigs, very basic gravity feed sandblasting rigs tied into a water line. Simple, and very effective. We did not even use sand, it was a very course recycled glass product. |
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| Author: | Dennis Storzek [ Mon Mar 08, 2021 4:22 pm ] |
| Post subject: | Re: Dustless/Wet/Vapor Blasting |
Comment about flash rust. Someone else mentioned that blasting with baking soda yields a bit of rust resistance, which is what we have found with some steel stampings we have tumble deburred where I work. Would it be possible to add baking soda to the blast water carrying a more aggressive grit, such as crushed glass, or alternately, wipe the bare steel down with baking soda solution from a bucket before it dries? I would imagine the baking soda needs to be wiped off with thinner before the primer coat is applied for best adhesion. |
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| Author: | crij [ Wed Mar 10, 2021 1:52 pm ] |
| Post subject: | Re: Dustless/Wet/Vapor Blasting |
Problem Ive seen with wet blasting is the sand/mud gets driven deep into the machine. Bag and tarp everything you are leaving connected to the machine, unless you don't mind grit and crap driven into every crevice. Make sure to duct tape every overlap and hole in the bags/tarps including the underside. Also create plastic sheet walls to protect electrical compartments. One place I know of tried wet blasting on a Center Cab Diesel locomotive, after the vendor left the outside looked great, but every cavity under the hoods were plastered with mud. The vendor never covered or cleaned beyond the metal they were blasting or warned the customer it might happen. It seemed like the water jet and media went through every gap and bounced off 6 surfaces before stopping. An engine that submerged in a flood would probably had less grit inside. At least with Dry Blasting you could come through with an air hose and blow the dust out into an air filtration system to capture it, the mud from wet blasting turns to concrete on everything. My opinion would be use a Dry Ice Blaster to remove paint, then sand blast, wire wheel or needle gun the remaining rusty areas. Then if you need to gently remove paint or restore scorched or painted wood, use a soda blaster. |
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