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Sandblasting pressure.


alexideways

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Here is a quick question, I'm about to sandblast the shell in the next few days and I was wondering what pressure you guys in the know would recommend for the exterior body panels? Tey are all incredibly straight and I don't whant to mess 'em up doing something wrong.

 

Thanks.

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:icon14::icon14:Cool! I have a friend who knows a farmer (same farmer who gave us an allmost mint 49 roadmaster we found in the back of one of his fields.) who have heavyduty sandblasting equipement to clean his farm machinery.

He's kinde enough to let me blast the car at his place FOR FREE!!!!!!

 

RacerX! :icon5: What medium would you recommend, I'd go with wallnut shell as I'm going to be doing this outside and I'm environementally aware so, I whant something biodegradable. I think glass beads would'nt be to harmfull either in a huge gravel driveway.

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What Ernie Said! Use the lowest pressure (determined by experimentation) that will accomplish what you want.

 

Another suggestion would be to chemically strip as much as you can, and reserve abrasives for those spots too built up for chemical stripping, or to treat corrosion you find after the stripping.

 

I blasted my engine bay in 1985. To this day, I still have media coming in from the air tubes in the front fender. Once it gets in, it's impossible to get out. Were I to do it again, I'd chem strip the whole schebang, and then blast the corroded areas, or where I was going to be doing welding.

 

I got a nice case of "Silicosis" which Ernie alludes to above, as well. You do NOT want to breathe that dust. The feeling of breathing in to feel a million microscopic dust particles abrading your lung tissue is one you can do without... I know I can...

 

Incidentally, the lower pressure you use, the less dust you produce. Depending one the media you use, some will fractionate and become unusable after one pass through the system. Most medias that are low-dusting will actually break apart and dust like crazy if you run them at too high a pressure. A little pressure goes a long way. And if you can recover the media through a seive and re-use it becasue you didn't blast it into oblivion, you save $$$ in the process...

 

IMO, the suction blasters are far inferior to Pressure-Post Style blasters when doing large projects. I used an ALC Sandy-Jet back in 85, and recently (like 2002) did the entire undercarrige of a Sport Fury Hemi using a Pressure Pot (100# Model from Harbor Freight), and the difference in material removed versus air pressure needed, and air consumed was like night and day!

 

For the cost of the HF Pressure Pot on sale, we saved that in media. I don't think it took me four hours to strip the bottom of that Fury start to finish. The Engine bay, on the other hand took hoppers and hoppers of dusty coral infested beach sand..... NOT RECOMENDED!

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Hope this helps!RacerX

 

It helps quite a lot.:2thumbs:

 

So, chemical stripping & orbital sander it'll be for the shell. You have any product names you'd recomend?

 

For sanders, I heard good coments on the Harbor Freight & Porter Cable units, wich one do you guys use? Am I better off with air or electric?

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i am in the middle of sand blasting. i have tired the suction one, read suck. i borrowed a pressurized one from dave at azcar. kicks ass. i have used glass in my blast cabinet and a little out side. the alum oxide works good too. but at $20 for a 20# box at hf, i can get 5 bags of play sand at hd and go nuts. i have a portable garage thing on the side of the house to HELP maintain the mess. i layed a tarp down so it is easier to harvest the used sand to reuse. i have the pressure in the tank maxed at 100-110 psi and the blow by valve at 1/3 open and adjust the sand outlet to maintain an even flow. i have not noticed any warpage. i have the nozzel 18" away at all times and keep it moving. the sand needs to be replaced now after 5-6 times through. still cheaper than glass or walnut. if i were to do it again, i will pay someone to do it.

 

jim

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Alex,

 

 

Please don't use sand as the abrasive because you can easily "heat warp" and at the same time that happens you'll "temper" the metal and won't be able to repair the warpage!!!

 

 

I agree.. don't use sand.. I made that mistake... I got lucky and didn't warp anything but I'm still finding sand in that car 4 years later! I'm going to try soda blasting on it next time.

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You shouldn't use sand most importantly because of the above mentioned silicosis. Its extremely harmful to your health.

 

I use black beauty or black diamond coal slag. If you have a northern tool near you, its about $8 for a 50lb. bag and works great.

 

 

For paint stripper, I like the Kleen Strip in an orange can from home depot. Brush it on liberally and then put a plastic trash bag over the body panel to keep it from drying up. It needs to stay wet to work.

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proper protection is key with whatever medium you use. having sandblasted for a living, i do not mess around with saftey equip. my job was to clean the concrete off of the forms used for sidwalks and gutters. the contractors would not use the release agent on the forms. i would have to blast it off with the blaster or even more fun, hcl. that crap there is no room for error. media blasting is ok if done right, no matter the material. take precautions for the object and yourself.

 

jimbo

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Thanks again, the more I look at it, the more I think I'll go with chemical stripping, I tought about blasting cause I could get access to equipement and "SAND" for free but, now that I see the prices of more suitable medias and the many downfalls, I think it'll be less trouble scraping the paint of and sanding smooth what's left.

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