The Stovebolt Site Forums The Shop Area Paint and Body Shop sandblasting problem

Man, this sucks! Ok, let me start from the beginning.

I have my fenders, doors, hood and grille off of my truck and they're ready for sandblasting. Well, I went and bought a $285 compressor from Home Depot the other day. 5.5HP and a 26 gallon tank. I'm not sure what the CFM output was, but ANYWAYS, I also went to Pepboys and bought a Syphon blaster ($30) and I hooked it up and it didn't work really well. I mean, it kept seeming like it was getting clogged up or something. Well after waiting a few seconds for the sand to start coming back through, the PSI would drop on the compressor and it woulnd't take the rust off... THIS IS VERY FRUSTRATING! I was told the $150 sandblaster's wouldn't do any better than that syphon blaster (I've been told that by several people). What should I do? I don't want to buy an $1800 compressor and I sure as heck don't wanna pay $1000+ for my pieces to get sandblasted.

Is there any other way to take rust off or ANYYYYYY alternative??? I'm frustrated and would like to start doing my body work, but I can't because nothing is sandblasted.

Thanks!

First of all, be very careful when sandblasting a flat surface like a door, even a fender but to a lesser extent, as you do not want to deal with a warped panel. I have never used a syphon blaster, so I cannot tell you how good it will work. Working properly, it should take the rust off though. At work, using a small pot blaster we have two 80 gallon 5 horse each compressors. Just enough air. At home for my own projects, I have the exact same small pot blaster, a 20 gallon-5 horse compressor. Can only blast constantly for a minute or so.

Next, alternatives to sandblasting. Is it mainly light surface rust? If so, find someone with an electric 8 inch orbital sander (or buy one). (I say electric because I doubt your compressor could run a pneumatic sander. I also say 8 inch because it just makes quicker work of the rust/paint). Electric works fine, at the body shop we use it over the pneumatic 8 inch ones. To strip down to bare metal, use 60 grit discs. It will strip your whole truck down without to much effort.

Hope this helps a little bit.
Good Luck!
Colin

I'd bet your compressor is to small, sand blasting takes alot of air, my dad and I did the fire wall and front clip of his 56, we got a syphon gun and compressor from a local rental place, the gun and tank set on the floor in the cab, the compressor was pulled behind on a trailer, when we asked why that big a compressor they said thats what it takes to sand blast. our local parts store has a small parts sand blasting cabinet that runs his 100 gl tank and compressor empty in a few minutes. they us a lot of air fast!!!!

Well I did what you said, Colin.. I went and bought a Skil orbital sander.. I got some of the 60 grit discs and it is working really good!! I spent about 20 minutes and got about half of 1 of my fenders done. It's allll the way down to the metal. Works VERY nice. I wish I would have known about this sooner.. Thanks Colin!!

Sunday I experiment with a wire cup brush, and a cheapo Die grinder on my doors sills and other spots on the driver's side cab. Worked out really good, considering the coats of paint were not the best "pro" job.It took the sills down to bare metal. You can also experiment with the chemical strippers, such as the ones mentioned on the board here. Good Luck!

You have to have an inline drier for sandblasting, or all you're going to do is end up with wet media.

BTW, DON'T USE CHEAP SAND!!!

they are wrong i now have a pressure blaster you still have to fine tune them have a good water trap and i have someone man the feed rate they open the valve that lets the sand out if they open it to far it will plug the nozzle but its so much better and cleaner then sanding its not even funny you can do a lot real fast sounds like your compessor is a little small

As stated above, it is important to use water seperators. Also, pour the sand through a screen whose mesh is smaller than the tip of the gun.

Sand could be too large. Use #4 or fine sand. (Use respirator!)
Siphon blaster $30! Got mine for $10 at Wallymart.
I have used the same set you are describing and it is not going to be a fast process. I found the siphon blaster good for the nooks and crannies but used other methods (knotted wire wheel on grinder, DA sander with 80 grit paper)for removal of larger areas)
You might call around to local equipment rental outfits as some may have a pressure pot and all should have 175 CFM towable compressors. Compressors rent for $75 a day here and blasting pot rigs about $100. If you do go this route be careful as the sheetmetal WILL warp if you are NOT CAREFUL. That will leave you in a worse spot than where you are now.

The sanding is going really well. The orbital sander I bought is doing wonders.. I bought 2 packs of 60 grit discs, but I'm almost out after completely sanding 1 of the doors and 1 of the fenders.. I may try a 40 grit to take it off faster.. its coming along. Yesterday I finished sanding the seat frame and shot 2 coats of primer on it.. looks nice!

I'll be getting all of my other pieces ready for primer as well (window frames, hoodliner frames, side vent frames, etc) - I'll probably go ahead and finish sanding EVERYTHING first and then shoot epoxy on everything at once.. I hate having to mix all the paint and then CLEANING THE PAINT GUN.. that really sucks, but I'll have pics soon! Wish me luck!

Glad to hear its working!

As mentioned above, if you can get your sandblasting working a little bit, it could make it easier for in the door frames and such(awkward places to sand).

If your time is valuable, sandpaper is cheap. Don't be worried to use it up.

Good Luck!

Colin

Try electrolytic rust removal, it works great I did my 1940 truck and it took all the paint off too.All you need is a tank bigger than your parts {kids pool} soda ash-aka sodium carbonate- from pool store and a battery charger. I made a big tank 8 foot square 6 feet high with plywood and rubber roofing held 2500+ gal and used a welder for the cab.

Hi Blake... I have a craftsman compressor about the same size as the one you have. It can power just about any pneumatic tool out there. Generally, what I have seen is a need of about 90 psi to run those tools. Those compressors go well above that. I also have a small sandblaster kit that I also got from Sears. The first time I used it was around Christmas. It worked for about 1 minute and then nothing would come out. I was ready to chuck the thing in the woods. I had a fair amount of hose connecting it to the tank and though it was a big pressure drop by the time it reached the gun. I horsed around with the thing for an hour or so. I took the gun apart several times and couldn't find any clog. Eventually I figured out what was going on. The gun would freeze up inside after a real sort time of use. By the time I had gotten the gun taken apart, the ice would have melted and show no signs of any problem. Your not going to have this problem down in Georgia, but it could be a water issue inside the gun. Secondly, it could be the design of the hopper. The cheap hoppers have the hose attached to the side and work well when their full. The weight of the sand above closes the voids created by the hose. Once they get even 3/4 to 1/2 full, you have to constantly shake or kick the thing to shift the sand and close those voids. Lastly, everyone is right, don't use the really cheap sand. It can work ok the first time through, but don't expect to try and reuse it. Hope this may help. Later

Winky,

Give more details. Sounds intresting

I bought 50 lbs of sand and got a plastic storage box from wally world. Cut out part of the lid, made a wooden frame to hold some door screen in the lid. Now when I sand blast I put down plasic underneath, scoop up the sand, sift it, and re-use it. So far I've needed 100 lbs and re-used it lots of times!

Try 80 grit paper and a D/A sander in strip mode, it might go quicker than orbital.

Houston54, I am sure you mean a 175 psi compressor.

But anyway, when looking at compressors, forget psi and horsepower. Those numbers are all worthless. Interesting how most compressors have psi and horsepower promintly displayed, but CFM is hidden. And it is CFM that is important, and you probably need about 20 CFM to do sandblasting. Which is usually a 2 stage compressor running on 220 volts. And also expensive.

no he prolly did mean CFM - the rental towable commpressors are designed for running jack hammers and commonly can push up to 200CFM!! but yer right, using 175 CFM w/ a sandblaster would put holes thru 1/4" plate I think run-of-the-mill home blasting guns are rated about 8-15 CFM, and the size of the tank is more relevent as long as the HP and PSI can keep it full

Bill

Honestly, the failure of your sandblasting may have saved your panels from destruction. As mentioned, sand blasting can warp panels FAST. So stripping it your DA is much safer. And in the ORBITING mode, the "grinder mode" can create a lot of heat and warp as well.

Buy QUALITY paper. Those retail packs it sounds as if you are using (10 or 20 discs) are usually JUNK. Go to an AUTO paint store and buy a roll or box of quality paper. Carborundum Red or 3M yellow will cut MUCH better than most of the junk retail packs at the McHome or WallyWorld stores. Get to know the REAL auto paint store in your area that services the body shops. BELIEVE ME, the products a shop uses are more money, but WELL WORTH the difference in price. There are shops that use cheap junk, I am just talking about the quality products that most shops who really want to make money use. They take less energy and less time to get the job done. They are WELL WORTH IT.

And the wire brush wheel, they don't work nearly as good as a "Surface conditioning disc" or a "Clean-n-strip" disc by 3M. They make a wire wheel look like a fingernail polisher.

Brian

Hello guys,

Just thought I would add a few points to this discussion although it is several weeks old....

YOU ABSOLUTELY, POSITIVELY, SHOULD NEVER USE REGULAR SAND TO SANDBLAST ANYTHING!!! Most people aren't aware that most sand contains silica which is a known carcinogen. You need to purchase sand which has NO silica for sandblasting.

You also should always have a respirator made specifically for sandblasting. Any old respirator will not do. They allow particles to bypass the filter and enter your airway and lungs. I hope I don't need to elaborate on the effects of inhaling dust, dirt, paint, rust, and other chemicals. It may seem fine to do it today but beware of what can happen to you tomorrow. In case your wondering what can happen, take a look at a friend or neighbor who suffers from emphysema or lung cancer. THAT COULD BE YOU! What you do to protect yourself now may help you more than you realize later on in life. Be safe when you sandblast.

John

I'm confused...sand is basically small particles of rock that used to be larger rocks. They've just been crushed over time. One of the things I see regularly at work are x-ray defraction and sieve analysis reports from various sand samples and I can't remember one of them that didn't contain some silica, mica, and various other minerals. Your safety topic is DEFINITELY well founded, but I would suggest that it should include ALL small particulate matter from grinding dust to paint to sand blasting media. There's no way that you could sand blast a panel without creating particles small enough to work their way into your lungs. By the way, iron (rust dust) may actually be worse. Iron inhibits the blood's ability to carry oxygen...get enough iron in your blood stream and you could actually suffocate. I seem to remember reading somewhere that this is the reason that most children's vitamins no longer contain an iron supplement. Whether you suffocate today or die of cancer tomorrow...neither one is a good option...wear a respirator!

I built a kind of homemade sandblaster called the PA Sandblaster... Try to google that and get the plans and you can convert a cheap bought blaster or make one from scratch.The guy has a website with good directions. It works pretty good & I don't think that it is too overpowering that would damage your panels. Has anyone tried this ?