Sandblasting Advice needed ASAP please..

[xpackken]

hey guys, im a compleate newbie to sandblasting, i currently run a mobile alloy wheel repair business.. Im sick of wheels that could really do with sandblasting taking forever or not doing them atall so i have decided to give blasting a whirl, me being me i went all out spent a few hours making my alloy wheel prep booth into a foldown cabinet and my setup is listed below..

The problem seemed to be spluttering.. a load of media at times then would seem to clear and i would get a loud hiss (air noise) out the gun and it worked great but then would go back to crap.. i tried 4 different nozzle sized but made no difference, it wasnt working properly enough of the time..

Only thing i do know now i have read instructions lol is i had media control all way out if that matters





Blaster
clarke cpsb100 preasurised blaster..





compressor
Clarke 100ltr 3hp

media ..

 

[rtbcomp]

Try reducing the pressure feed to the pot. Too much can stop the media dropping down the pot uniformly. Make sure the media and air are dry, moisture can cause the media to stick.

When the grit supply fails, close the valve at the side of the pot. If air continues to flow the media isn't dropping down, if you get a thick stream of media it's sticking at the bottom the pot.

 

[xpackken]

there is 3 controls..

1 were the air line goes in, i assume thats preasure to the pot .

2. at the bottom is the media conrol..

3 what is this??

 

[xpackken]

its more like a solid stream of media like far to much..

why would it stick to the bottom of the pot?

 

[Wendelspanswick]

Try reducing the pressure feed to the pot. Too much can stop the media dropping down the pot uniformly. Make sure the media and air are dry, moisture can cause the media to stick.

When the grit supply fails, close the valve at the side of the pot. If air continues to flow the media isn't dropping down, if you get a thick stream of media it's sticking at the bottom the pot.

It sounds like he had the media lever all the way open so the media would have been clogging the delivery hose.
I normally start with the media valve halfway open and then adjust from there, never opened it much more than about 75% and that is when the media is clogging.

 

[brightspark]

if your refurbing wheels u cant realy expect to get far with one of those pots using a 3hp compressor .i used to blast them on weekends as a business and had a 90cfm comp using a 6mm nozzle @ 90 psi and i classes that as a minimum . i have another home made pot i use that runs @ 28cfm with a 3mm nozzle and that is adequate for home use on most itemsbut i wouldnt fancy doing it for anyone as a business it takes 2 long and times money

 

[Wendelspanswick]

You want a constant stream of air coming through the bypass hose with a steady trickle of media joining it at the T piece, if you have the media valve fully open the T piece fills with media and blocks the air!

 

[xpackken]

fair enough, but its only something i will uses every so often and the job will be priced as extra accordingly.. It costs more to reject work and it certainly wont take longer than mini da sanding them and hand finishing..

 

[RA Dunk]

if your refurbing wheels u cant realy expect to get far with one of those pots using a 3hp compressor .i used to blast them on weekends as a business and had a 90cfm comp using a 6mm nozzle @ 90 psi and i classes that as a minimum . i have another home made pot i use that runs @ 28cfm with a 3mm nozzle and that is adequate for home use on most itemsbut i wouldnt fancy doing it for anyone as a business it takes 2 long and times money

What size of compressor and nozzle would you think would be needed to do this on a more professional level then if 90 CFM was minimum?

 

[brightspark]

its the minimum for doing steel wheels for most cars. land rover wheels take longer .a 150cfm comp with larger jet than a 6mm on the pot would be fine.its down to cost and time depending on how many u doing

 

[RA Dunk]

a 150 CFM comp with a suitable pressure pot would be a bit pricey TBH, I'm guessing a 150 CFM comp would be one of those ones that's on wheels and towable.

 

[captain-destructo]

next time you change your van why not look at an ex water / gas van with a built in compressor?

 

[rtbcomp]

It sounds like he had the media lever all the way open so the media would have been clogging the delivery hose.
I normally start with the media valve halfway open and then adjust from there, never opened it much more than about 75% and that is when the media is clogging.

Yeah. I start with the media valve closed but it's pretty much the same idea. I sometimes have to to tweak it as the pot empties. It takes a few seconds for the pot to settle down after making an adjustment and a very small adjustment makes a significant difference.

The media can clog above the bottom valve, so a quick close of the side valve will clear it (and most likely block the nozzle!)

I use very fine media (almost like flour) and this is reluctant to drop down into the mixer so I close the side valve slightly to encourage it.

Re the original post, I've used 2x 16cfm compressors to do steel wheels, it's not too bad with with new media and a worn 3mm nozzle. I think 90 cfm and a 6mm nozzle would be a challenge in the OP's cabinet.

I built a turntable for blasting wheels which saves a lot of time http://www.mig-welding.co.uk/forum/threads/rotary-jig-for-ac-tig-tubing.53028/#post-617169 (Post #7)

Stripping wheels in a stripping bath before blasting saves a lot of time.

 

[cobcorsa]

rtbcomp what do you use in the stripping bath if u dont mind me asking , sounds like the right idea

 

[rtbcomp]

I use neat dichloromethane for paint, but it's getting a bit tricky to buy (EU and all that). There's a product called Atlas-T that's formulated for powder coat, but it's very nasty stuff

http://www.paintstrip.com/cold.htm

http://www.eurochem-northern.com/paintshop_powdercoaters.html

 

[SmartWerks]

Just out of chance, do you know chris jeffries?

 

[rtbcomp]

No

 

[SmartWerks]

No

Not you!!! The op