DIY Micro Pencil blaster?

[angelo909]

Hi everyone, am new here and although am not a welder or car body artist the tools you guys use are pretty similar to mine for use in rock etching/deep cutting. I have been reading on diy blasters and hope someone else can help me please.

Basically, am looking to diy a sandblaster that can shoot 240 grit soda/dolomite/aloxide from a small maybe 2 litre or so pressured container down a fine 0.06 carbide nozzle with minimal air consumption. There are plans to mod propane tanks but would these eat up loads of air? What affects the air consumption of these things? Airline diameter? Nozzle width? Tank size? Crikey this is really tough!

Ive come across the grit meter/flow valve...seems a really important part and am prepared to shell out if required but am having real trouble finding a pressure vessel or sand pot on my own.

Can anyone suggest something to suit what I might need? Would a soda blaster be a good start to mod?Am having real trouble searching online and can only find top end dental stuff like comco, guyson and swamblast that cost a fortune. There is something called a PAB blaster but even that is £600.

Any help would be greatly appreciated.

 

[rtbcomp]

I've been looking for something similar.

The airflow depends on the nozzle size and the size of the grit you use, IMHO that's the least of the problems.

The ones I've seen on Ebay seem to use a suction gun rather than a pressurised pot, a bit like an airbrush.

Do you have a source for the small nozzles?

The metering valve is probably the most critical item.

 

[brightspark]

Hi everyone, am new here and although am not a welder or car body artist the tools you guys use are pretty similar to mine for use in rock etching/deep cutting. I have been reading on diy blasters and hope someone else can help me please.

Basically, am looking to diy a sandblaster that can shoot 240 grit soda/dolomite/aloxide from a small maybe 2 litre or so pressured container down a fine 0.06 carbide nozzle with minimal air consumption. There are plans to mod propane tanks but would these eat up loads of air? What affects the air consumption of these things? Airline diameter? Nozzle width? Tank size? Crikey this is really tough!

Ive come across the grit meter/flow valve...seems a really important part and am prepared to shell out if required but am having real trouble finding a pressure vessel or sand pot on my own.

Can anyone suggest something to suit what I might need? Would a soda blaster be a good start to mod?Am having real trouble searching online and can only find top end dental stuff like comco, guyson and swamblast that cost a fortune. There is something called a PAB blaster but even that is £600.

Any help would be greatly appreciated.

the size of the pot is irelavant for the air consumption its down to the size of the blast nozzle and compressor to suit . a cheapo blast pot for 95 quid would be a starting point if u didnt want to make your own then buy a carbide blast nozzle for it or if u have all the gear make your own including a decent grit regulator in stead of the crap ball valves that are supplied but are adequate id u are doing small amounts and dont want to shell out a lot of money or time making

 

[angelo909]

Hi thanks for your prompt replies everyone am starting to relax a little!...am pleased that tank size is not an issue...I have seen small coleman tanks that a friend could weld a few bits on for me and there is a carbide grit meter (mini one not a ball type) for about £130?

RTB comp yea those suction things dont have much grunt for the amount of grit consumed...The nozzles can be bought from epak electronics or from guyson (both UK) they may be expensive but the actual real deal can hit £3000 for a pressurised pencil blaster! ouch. Does anyone know about fluidising the grit in the vessell to improve grit flow or will a lot of this be done in the regulator/meter valve?

 

[rtbcomp]

What sort of things are you using it for? I use a decent suction gun to spot blast the bits I've missed with the pot blaster (Scooter frames &c).

I find very fine grit doesn't feed from the pot very well, it tends to stick. I was wondering if it would be possible to divert the main airflow to the nozzle through the pot to prevent the grit sticking.

 

[angelo909]

Its for rock etching? Ill need to be able to decrease powder flow and increase air flow for precision cutting around areas of the rock I need to preserve. At times, the cutting speed needs to be quite aggressive to smooth off the very hard rock am working on. Really would love it to be a constant smooth flow for sure!

 

[rtbcomp]

The mixer valve will allow you to alter the air/grit ratio. Would it be feasible to have an extra air jet to weaken the mixture?

Would this system be useful for glass etching, either freehand or with a stencil?

 

[angelo909]

rtbcomp cheers for helping out matey, do you mean run another air jet in to the sand tank keeping it agitated? sorry if im asking silly questions, does this dilute the mixture so as to kind of give the grit more fluid dynamic making it a more consitent route to the mixer valve?

 

[rtbcomp]

I was thinking of using an extra jet at the nozzle.

As for keeping the stuff in the pot fluid, break the air feed to the mixer, connect it to the pot about 1/2 way down and then take the air feed to the mixer from the top of the pot.

 

[angelo909]

im forcing my understanding at the mo prob need some time to think how this all fits together! am glad I joined now, as id really like to get this thing : attached and reliably smooth

http://www.pabblaster.com/store/pab-pencil-gun

 

[dannyp]

lot smaller than what i'm used to dealing with but a couple of ideas for you.


A 1ltr disposable mig gas bottel would probaly make a good pressure pot. with a 1" or bigger hydralic fitting weled on for filling, ether a ball valve or blanking cap.

simalar to rtbcomp to fluidies the grit, my first thoughts were to feed the tank with air from near the bottom close the grit takeoff, possobly with a small bleed valve at the top of the tank so a small quantity of air is constantly flowing up through the grit to agitate it. tho it may be a bit heavy on air or it may not be. to i cant see a pencil blaster needing much air.

i guess you want to run a fairly high pressure to chew the rock off a bit quick, i found with my blasting setup a bit more pressure makes a huge differance in how agressive it is

 

[angelo909]

some grand ideas guys thank you so much. I can see how the bleed valve will help the grit flow to mix, would this decrease pressure in the hopper? how would this affect flow rate/cutting speed at the nozzle or is this dependent on the carrier flow? sooo many questions but you are really helping me out!

 

[rtbcomp]

It's a bit difficult to predict what happens with these pots! - trial and error with setting it up works best.

It's a case of spending time and a bit of money experimenting with prototypes or forking out six grand on something that works.

The speed and hence cutting force of the grit depends on its speed and the mixture, running too rich will not cut, it's got to be just right.

 

[angelo909]

got you rtbcomp. am mulling over two designs at the mo now thanks to all your help? am proper truly grateful! thank you .

 

[brightspark]

80 prcent air and 20 percent media is about the ratio more grit than that = less velocity

 

[rtbcomp]

How do you measure it though?

 

[brightspark]

How do you measure it though?

u dont thats what the manafacturers recomend for optimum cutting . practice makes perfect and as u know do enough of it and u will soon get the idea

 

[dannyp]

you soon get a feel for when its working right. just have to play with and tweek things untill your happy.