Sand blasting media to use for surface prep

[tavo1765]

I know alot of us have had problems/questions in the past wondering which is the best to use so I am going to break it down:

1. aluminum oxide is used by professional coaters (best surface prep)90psi

2. Glass beads 60psi, is also used by the professionals. Why? because mosy places are using chrome base coats and metalic powders are relfective, what give a reflection a polished piece of metal, polishing is basically getting the metal flat so it reflects light, thats why it shines so if you use alot of chrome or aluminum powder, make sure you have a really smooth surface.

3.Black Magnum: Provides an etch which acts as an achor for the powder to adhere to. Great stuff and its cheap get it in either meduim of fine grade and it is recommended that when using this stuff you sand down the piece with 220 grit sand paper, it knocks down the profile a bit and gives you a better inspection of what you will be coating

Thats really it, I am sure people use others but these are the medias that come up more often.

What do I use? I mix a 50lb bag of fine black magnum with a 60/120 bag of glass beads and a 15lb bar of walnut.

Why do I do this? Because I still get the achor effect, and the smoothing effect of the glass beads, it also keeps down the dust and if you have parts like aluminum this mix will not eat the metal and create pits.

I would recommend using a pressure blaster at 80 with the mix if you try it and dont blast close, give a good distance like your painting the part your stripping, slowly fading the surface and blending the profile evenly.

[trsick]

Re: Sand blasting media to use for surface prep

Hey Tavo:
I read your post on Sand blasting & media. I have a couple of questions
A: Pressure blaster... what brand are you using?
B: Pressure blaster... How much CFM @ 80 psi are you pushing?
C: Blasting time... With your mix of media how long are you able to blast with out having to stop to refill the pot & are you screeenig & reusing the spent media?
D: Blasting time.... how long does it take you to clean (example) fairly rusty 15" steel rim (both sides)?
I ask, as I spend way too much time (in my opinion) on sandblasting. I have a compressor that will push 27 cfm @ 100 psi, a 60" wide cabinet & just ordered a pressure pot to do stuff that won't fit in my cabinet
Thanks
Bob

[tavo1765]

Hello,

To answer your ?'s

1. I have 3 pressure blasters, central machine blasters. 100gal/40gal/20gal

2. I have about 12-13 cfm at 80 psi

3. Blasting will last about 1hr with the 100gal, when that runs out I have already ripped through an entire atv frame, set of rims, railing, and brackets. When that runs out I already have the 40 gal ready to go and refill the 100 so I can use that once the 40 is out.

4. I can use this mix for about 4 weeks of reusing.

5. Only use the cabinet for aluminum parts, and keep glass beads in it, fine grade.

6. Best advice I can give you is build a room out of wood and seal it up, get a 2hp dust collector with 2.5 micron bag, make duct work giving it a exhaust gate to allow the dust to suck into, then accross from that make a intake and a fan blowing fresh air in. Get a Bullard air hood system for breathing for your protection and only use a pot blaster with the mix I use, your life will be so much easier and blasting will be quick and cleaner. What falls on the floor can be sucked into the dust collector which goes into a container and collects the media for you.


In all honesty, I work for many serious big name dealer ships and in one day I can bang out all the work as far as blasting goes with this set up"time is money and blasting can kill your time", next day I sand every part down with 220 grit, degrease with simple green full strength and rinse, preheat then coat.

The only cabinets that work fast is pressure but for that money I can build a blast room the size of 2 of my shops, the one I have built is 14ft L, 10ft H, 10ft in width.
5.

[trsick]

Re: Sand blasting media to use for surface prep

Thanks Tavo:
WOW! Sounds like you are getting better results than I!! As I said, I just ordered a pressure pot (holds 100# of media) should be at my shop next week. I have a 8'W x 8'H x 20'D Ocean storage container I plan to use as a blast room (closes up nice & tight).
I planned to design a air supply & dust removal system similar to what you described. I will try your custom blend of media. I have plenty of cfm. I only hope it works as well as what you described, boy would my job be easier & more cost effective.
One more question... What size nozzle are you using on your pressure pot?
Thanks & sorry for some many questions.
Bob

[tavo1765]

the pots come with 3 different tips, I use the medium size nozel.

the over seas container will work good as a blast room.

you will definitley like the mix, it can be used so many times over.

I only buy 4x 50lbs bags and 2x 50lb glass bags and it lasts about a month 1/2, only make a 100 pound batch and use it by 50lbs not 100

figure over 200-300 pieces a month including frames, wheels etc...

[trsick]

Re: Sandbalsting & media

Thanks Tavo:
I have heard of Walnut shell for media, but you mentioned "Walnut Bar" What is that, how much do you put in your custom blend & where do you buy it? I will be PUMPED if this works better than what I am doing
Thanks
Bob

[trsick]

Re Sandblasting & Media

Hi Tavo:
Just to confirm.. you said "Black Magnum" same as "Black Beauty" aka coal slag?
Bob

[tavo1765]

Typo, it was shell, you dont really need to add that in the mix

[tavo1765]

What were you using that isnt giving you the results you want.[/url]

[trsick]

Re: Sand blasting & Media

Thanks Again:
I only been using my syphon cabinet (Cyclone brand) 60" wide, with both black Beauty & sometimes glass bead depending on what I am tryng to clean. But it is painfully slow, even with my big air compressor (27 cfm). I have the 20' Ocean container & ordered a pressure blaster to do items that won't fit in my cabinet & hoped it would be quicker. In the mean time, I borrowed a (OLD) snap-on brand pressure blaster from a buddy. It has a big nozzle (maybe 1/4")?? I also think the valves are worn, because the media (Black Beauty) was coming out too fast. It only ran for about 10 -15 minutes before it either ran out of media (100# hopper) and or clogged. Very disapointing... I'm hoping it was a worn out pressure system & my new one will be much better If so, like you, I will only use the cabinet for Glass bead & use the walk-in for everything else. I am spending way to much time on prep.
Hoping
Bob

[tavo1765]

Problem is the wrong nozel is being used and you maybe had the settings set with the media and air at high flow, trick with the pot you ordered is to close the valve on the bottom half open to give you more pressure either way will can controll air and media rate, you can give the stream more air, less media and vise versa.

[tavo1765]

Do you own a hobby or pro gun?

[trsick]

Re: Sandblasting & Media

I own several Hobby guns, makes it nice & fast to change colors, But I am considering a pro gun soon I just spent my spare cash on a 2 hsp. buffing machine, pads & compounds.
On the Pressure pot... I fiddled & fiddled trying to ge the air & media flow better, no go. Like you said, I'm sure it was the nozzle being to big. I also think the valves are all worn out.
Thanks for all your help, I will let you know how it goes when the new pressure pot comes in next week.

[tavo1765]

No problem, here to help at anytime, I myself had found this forum to be very informative.

Some advice about pro-guns, get a ITW Gema. I got mine off Ebay for $2500.00, best money I could of spent. Hobby guns are good but very weak, after you use a pro your life is much more easier, like what it is going to be when you get the blasting set up your talking about. But what a pain in the ass at first to figure out.

The Caswell unit looks like a good gun for the price. Good luck and keep us posted about your business.