Sandblasting + compressor?

[dhr.vdw]

Hey guys,

 

So I am for nearly a month by now the happy owner of a 02 racer. It's rot af and I'd like to start blasting the rust off. My old compressor is not strong enough so I am thinking about getting myself a new one. Can someone help me advice on a low-budget fine compressor that can handle sandblasting and painting the car anyhwere near properly..

I was thinking about this one: https://www.compressorcenter.nl/product/457871/category-212083/airpress-hl-425-50.html combined with this thing: https://www.datona.nl/mobiele-zandstraler.html

What are your thought?

 

Kind regards,

JP

[joysterm]

Sorry but my Dutch is very weak, but what is the CFM (cubic ft per minute) output of the compressor and what size is the tank?

 

[dhr.vdw]

27 minutes ago, joysterm said:

Sorry but my Dutch is very weak, but what is the CFM (cubic ft per minute) output of the compressor and what size is the tank?

 

No problemo haha, I am not familiar with CFM but it can handle 8 bar, it has a suction capacity of 425 liters per minute and the tank is 50 liters.

 

[Simeon]

I got 425 litres per minute which is about 15cfm and a 50 litre tank. Looking at the design of the compressor (direct drive, oiless(?), relatively small receiver) I would say that it would not be good for blasting which will use a lot of air. The compressor would be running all the time to keep up and I would then be worried about duty cycle (whether it is designed to run constantly or it assumes it will spend so much time on and off). 

 

Blasting also needs really dry air dry air so you will need to think up a way of condensing out and trapping the water from the compressed air. 

[dhr.vdw]

I got 425 litres per minute which is about 15cfm and a 50 litre tank. Looking at the design of the compressor (direct drive, oiless(?), relatively small receiver) I would say that it would not be good for blasting which will use a lot of air. The compressor would be running all the time to keep up and I would then be worried about duty cycle (whether it is designed to run constantly or it assumes it will spend so much time on and off). 
 
Blasting also needs really dry air dry air so you will need to think up a way of condensing out and trapping the water from the compressed air. 

I think it's bigger than on the pictures (longer), and it is oil filled btw. They say it can be used for blasting and painting etc.. but I did not find that very believable either..do you suggest anything else? Thanks, JP


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[joysterm]

I think you will need a tank greater than 250 litres( 80 gallons) putting out at least 5 HP. otherwise your compressor will not be able to keep up with the demand while sandblasting. I know your electrical system over there is rated quit differently from NA standards  but I think you will need something higher than the standard voltage if you run a higher volume tank.  I could be totally wrong on this point.. 

 

As for painting, shooting primer, etc  these portable type compressors are great for smaller low volume jobs but not so much for the bigger ones.  IMHO

 

My suggestion is to simply get it done by a professional or friend that has the proper setup, it might save you some money in the long run, providing its done properly which is another topic on its own.

 

good luck  

[TobyB]

So I've painted and blasted with a compressor that was too small.

 

It's not the end of the world for blasting- it just takes some patience,

and you get good at using as little air as you can get away with.

 

Painting really sucks.  At first, the tank's full, and it takes a while to

get into the flow.  And then, you start to realize your pattern control's

starting to go squiffy, and the texture's way up.  So you stop, wait,

and the edge of whatever you were working on starts to flash.  So you

melt it in, paint some more, and do it all over again.  It absolutely blows,

no 2 ways about it.

 

So yes, if it doesn't draw 10a+ at 220v, it's not going to be good for painting.

Ideally, you'd like something quite a bit bigger than that- I currently have

3 (yes, 3) 3 hp compressors in parallel.  That just about keeps up...

I really miss the scroll compressor t the old body shop...

 

t

 

[dhr.vdw]

Thanks guy, I will find myself a bigger one hearing all this..I kinda wanna learn and blast my entire car but not pay like 2,5k...And then spray it with epoxy primer. Btw how do u guys run the big compressors that are not over the normal 220V.

Cheers, JP

[Brandon]

In the United States 120 volt is normal residential house current, although 220 is used for larger appliances like clothes dryers, air conditioners, etc.

 

If you've never sandblasted a car before, be sure to research how to do it or find someone with experience to help you.  If you don't know what you're doing you can easily warp the sheet metal.  This is especially true with 2002's because of the thin sheet metal BMW used on these cars.

[joysterm]

3 hours ago, Brandon said:

 

If you've never sandblasted a car before, be sure to research how to do it or find someone with experience to help you.  If you don't know what you're doing you can easily warp the sheet metal.  This is especially true with 2002's because of the thin sheet metal BMW used on these cars.

 

+1...... be careful if you lack the experience, you may just end up spending more on body work than you  will save on the cost of getting it blasted by an experienced shop. 

 

I am curious though,  what is the rate for media blasting there? 2,5K seems a little high.

[dhr.vdw]

28 minutes ago, joysterm said:

 

+1...... be careful if you lack the experience, you may just end up spending more on body work than you  will save on the cost of getting it blasted by an experienced shop. 

 

I am curious though,  what is the rate for media blasting there? 2,5K seems a little high.

Yeah, will do got some useful friends haha. When I take my car to a random shop does not really matter wheather it's just a garage or a classical cars spezialised shop it will cost me at least 2000 euros, but mostly around 2500.. That's why I wanna do it myself lol. I just began my restoration and I'm a poor student Cheers JP

[Oldtimerfahrer]

When I lived in the US, I had a gas engine powered compressor because I was renting and didn't want to invest in a 220v setup. Check first what size sand blaster you intend to buy. I had a vertical pressure tank type from TIP (?),  that needed a lot of air....litres per minute is crucial. To effectively blast, good to have a compressor that can deliver that flow for a longer period. Don't bother with the small sand blaster with a little pot to hold the sand. Get appropriate quality blasting medium. That compressor will handle painting too, but after I painted my 02, I swore I would never take the risk of painting again. It was thoroughly unhealthy at the time, requiring an expensive external air supply. The masks, regardless of grade, are a bit of a risk if you are in a small room with little ventilation for a long time....even if you are not using iso-cyanate paints any more. You can put one or two water separators on to keep the air dry, but it has been very damp in NL the last few days....

Andrew

[dhr.vdw]

When I lived in the US, I had a gas engine powered compressor because I was renting and didn't want to invest in a 220v setup. Check first what size sand blaster you intend to buy. I had a vertical pressure tank type from TIP (?),  that needed a lot of air....litres per minute is crucial. To effectively blast, good to have a compressor that can deliver that flow for a longer period. Don't bother with the small sand blaster with a little pot to hold the sand. Get appropriate quality blasting medium. That compressor will handle painting too, but after I painted my 02, I swore I would never take the risk of painting again. It was thoroughly unhealthy at the time, requiring an expensive external air supply. The masks, regardless of grade, are a bit of a risk if you are in a small room with little ventilation for a long time....even if you are not using iso-cyanate paints any more. You can put one or two water separators on to keep the air dry, but it has been very damp in NL the last few days....
Andrew

Alright, I see. I will let my car paint but I meant more like painting with primer (2K epoxy primer). But what would you recommend at least as minimum litres per minute ? Thank you for your respons.
JP


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[Simeon]

2K epoxy will need a larger air cap on the gun (probably 2mm) so work back from there. Pick your epoxy, pick your cap, pick your gun and size compressor from there. 

 

I would say, I shot my own epoxy and found that coverage was more critical than surface texture since it saw a lot of sanding before it got near paint. Obviously less sanding the smoother you can lay it down but your main trick is to get the steel evenly covered. Choose a direct to metal, sandable primer to make your life easier. 

[Oldtimerfahrer]

Hi,

As I said, pick the SAND BLASTER first. A sears sand blaster like this

http://www.sears.com/stark-usa-20-gallon-hd-air-sand-blaster/p-SPM7435492622?plpSellerId=RVTravelMats&prdNo=5&blockNo=5&blockType=G5

 

needs between 180 and 750L per minute based on the nozzle size you use. With the smaller nozzle it will take longer. Sears shows the following for this compressor

6 CFM = 170l/ min (2.4 mm nozzle)

25 CFM = 708L/min (3.6 mm nozzle)

It will vary a bit based on pressure, but people smarter than me will tell you how much sand can be pushed through the thick hose to the nozzle at a time. I always had problems with moisture, so keeping the blasting medium dry before you blast in Holland may be a challenge. You may need to do what people do with welding rods, put them in an oven at a very low temperature to dry them before use.

The manufacturer will give you guidance on how much air it needs with a certain nozzle. Make sure they are ceramic, I think that is still the  right material.

The spray gun is usually not the issue, you can use a High Volume Low Pressure spray gun, which will not place extreme demands on the compressor. Just ensure you have thick hoses, none of the spiral thin nonsense and have a pressure valve on the gun.

A.