Cheap Sandblaster for Frame Reno's

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WyvernRH
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Cheap Sandblaster for Frame Reno's

Postby WyvernRH » Fri Feb 09, 2018 6:28 pm

I've had a fairly large compressor in the workshop for well, ever really, but it never seemed to be able to drive the 'suck up' sandblasting attachment that came with it to any effect. For Christmas this year I was given a sandblaster gun attachment for the compressor that has a small tank for the sand as part of the gun. Came from 'SpeedyAuto' or the like. We I have to say it works as advertised. It runs at 90 psi and although it needs refilling on a regular basis it really strips off the paint and rust with the coarse sand grit.
Image
Image
(The headset was taped up by the way...)
Uses up the grit but if (unlike me on my first test) you have a good catching system you should be able to re-use the grit no problem.

Not something you would use if you did lots of blasting on a daily basis but for bicycle reno's it is doing pretty well so far.

Richard

PS And of course wear all the protective gear, especially a facemask to cover mouth and nose and something for the eyes. I had my leather welding apron, a facemask, welding visor over a reversed cap, long sleeves and pants, welding gloves and the blasting grit still got everywhere that wasn't covered (the beard for example :P ), down the gloves, inside the boots....

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AUbicycles
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Re: Cheap Sandblaster for Frame Reno's

Postby AUbicycles » Fri Feb 09, 2018 7:58 pm

After sand blasting - what are your next steps before priming? Any other surface treatments?

For the sand, could you go for a finer grade? (This is just a question out of curiosity whether you still get the cutting power but a 'finer' finish on the frame).
Cycling is in my BNA

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find_bruce
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Re: Cheap Sandblaster for Frame Reno's

Postby find_bruce » Fri Feb 09, 2018 8:12 pm

Bicarb soda is often used as a softer blasting medium. Wonder if your gun will use it.

One thing to be aware of is that at least the blasting gun I had, the sand would wear out the nozzles fairly quickly with an associated drop in performance

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WyvernRH
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Re: Cheap Sandblaster for Frame Reno's

Postby WyvernRH » Sat Feb 10, 2018 5:04 pm

AUbicycles wrote:After sand blasting - what are your next steps before priming? Any other surface treatments?
For the sand, could you go for a finer grade? (This is just a question out of curiosity whether you still get the cutting power but a 'finer' finish on the frame).
Hmm dunno, still a beginner at this lark. I used a rough grade sand and it cleared away the paint very well. It leaves the surface of the metal with a slightly matt finish as you can see. It is meant for paint removal from steel, not cleaning rust off of cast iron or anything drastic like that :P .
I also have some fine grade sand left over from my father in law's stash and some micro bead type stuff that came with the gun that is meant to achieve a finer finish. I will try these out on the remaining paint and see what happens. I suspect from past experience that the cutting power will be much reduced and much more time and sand will be needed to achieve the same results.
Still, I am pretty happy with the finish on the tubing from the rough sand as it will act as a 'key' for the primer coat. It has not affected or removed any of the softer brazing medium at all (unlike some sand blasted frames I have seen) Where there were brass patches on the tubes they are still there and no smaller. Although I might think twice about using the course stuff on Reynolds 753 or the ultra thin Japanese tubing maybe?

I will also try going over some of the blasted surface with the micro bead sand to see if that achieves a smoother finish but I don't think it is necessary to get a good paint finish.

I have an idea that in future I will be using paint stripper to break down the paint and remove the majority of the paint coverage and then use the blaster to clean all the remainder away, especially in the tricky bits around the lugs.

Richard

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Nate
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Re: Cheap Sandblaster for Frame Reno's

Postby Nate » Mon Feb 12, 2018 1:24 pm

dont worry about finer grades, the paint & prep should cover that.

You can use proper grit - which is finer and takes off more, as its a better shape for the job. Sand - well it can be cheap & plentiful!

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Re: Cheap Sandblaster for Frame Reno's

Postby twowheels » Mon Feb 12, 2018 7:22 pm

But don't use sand!
http://www.gritco.com/can-i-use-just-an ... r-blasting
Nowadays, it's clear that exposure to respirable crystalline silica during sandblasting can cause a serious or even fatal respiratory disease, called Silicosis, a scarring and hardening of the lungs.
In most countries, it is now forbidden to use abrasives which contain more than 1% free silica. Silica sand contains 90% or more! During blasting the sand particles break down into very small particles. These particles, smaller than 5 microns, are inhaled and become embedded in the lung, causing respiratory problems, pulmonary silicosis (also called 'dust-lungs'), and eventually even death.

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Re: Cheap Sandblaster for Frame Reno's

Postby WyvernRH » Wed Feb 14, 2018 4:26 pm

twowheels wrote:But don't use sand!
http://www.gritco.com/can-i-use-just-an ... r-blasting
Nowadays, it's clear that exposure to respirable crystalline silica during sandblasting can cause a serious or even fatal respiratory disease, called Silicosis, a scarring and hardening of the lungs.
In most countries, it is now forbidden to use abrasives which contain more than 1% free silica. Silica sand contains 90% or more! During blasting the sand particles break down into very small particles. These particles, smaller than 5 microns, are inhaled and become embedded in the lung, causing respiratory problems, pulmonary silicosis (also called 'dust-lungs'), and eventually even death.
A bit scary but +1 lots.
I still use the term 'sand' cos that what was used as a generic term to describe the various blasting mediums when I was a junior engineer working on marine structures back in the day.
You should only use an approved blasting medium various sorts of which are easily available from most hardware and car superstore places. BUT still ALWAYS wear protective equipment including a good facemask cos remember, you are blasting crap off something so even if the blasting medium is reasonably safe you have no idea what is happening to the paint dust and other crap.
Sealed blasting booths with sleeves for access are obviously best as they keep all the crap contained, I may build one if I get into this properly but for the minute I will rely on the good quality disposable facemask and welding helmet (oh yeah, don't be cheap and reuse facemasks/filters).

I must admit, it did make me wonder that none of this safety stuff was printed on any of the equipment or blasting medium containers that I bought from the car store.

Richard

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Re: Cheap Sandblaster for Frame Reno's

Postby twowheels » Wed Feb 14, 2018 7:45 pm

WyvernRH wrote: BUT still ALWAYS wear protective equipment including a good facemask cos remember, you are blasting crap off something so even if the blasting medium is reasonably safe you have no idea what is happening to the paint dust and other crap.
Such as Lead etc. Yes, take precautions and use PPE.

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Re: Cheap Sandblaster for Frame Reno's

Postby QuangVuong » Sun Feb 25, 2018 7:36 pm

AUbicycles wrote:After sand blasting - what are your next steps before priming? Any other surface treatments?

For the sand, could you go for a finer grade? (This is just a question out of curiosity whether you still get the cutting power but a 'finer' finish on the frame).
I have access to an industrial blasting cabinet at work which I've used to blast many frames and parts.
ImageIMG_7702 by VillaVelo, on Flickr

It is loaded up normally with brown aluminium oxide powder thats 46 grit mixed together with white aluminium oxide powder thats 80 grit. This gives quite a fine finish on the frame without destroying finer details or threads, but whilst still going through paint and rust without a problem. Depending on how thick/hard the old paint is, I could spend anywhere from 15 minutes to an hour on a frameset on blasting. Beats using paint stripper any day, and I definitely wouldn't go back to doing it that way again.

With what I'm using now, it's quite good as I don't need to mask up threads or other areas which are delicate. There is also a 180 grit pink alox powder for really fine work, but I've never needed to use it. This is the Columbus dove logo which is still visible even after a blast.
ImageIMG_7716 by VillaVelo, on Flickr

And any stamped drop outs come out with no loss in detail.
ImageIMG_7710 by VillaVelo, on Flickr

Straight after blasting, I just dust the frame off by giving it blow with some air before some etch primer goes on. No need to contaminate the frame any further.
VillaVelo, by the Vuong brothers

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Re: Cheap Sandblaster for Frame Reno's

Postby AUbicycles » Mon Feb 26, 2018 7:00 pm

Ok... I am asking the wife if I can have a sand blaster.
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