home made blastpot

brightspark · Mar 14, 2010

another gas bottle pot :laughing:

this ones simlar to most others that are either bought or made . the only improvements are the quick release filler neck which ive used on the last 3 that ive made and the quick release couplings on the underside of the pot . any blockages can soon be cleared/ it has 6mm carbide jet and runs on a 90cfm comp at 90psi . all the fittings and pipes are new total cost £130.00

rtbcomp · Mar 14, 2010

I was thinking of using those quick relaease fittings on mine - how long do they last?

brightspark · Mar 14, 2010

the brass blast hose couplings last forever as long as u dont let the rubber inserts wear out and it lets the grit through

rtbcomp · Mar 14, 2010

So they're specials - I thought they were just quick release air couplings - where do you get them from?

brightspark · Mar 14, 2010

yes they suit the blastpipe size. the hose just pushes in to the sleeve and is held in by 4 small screws into the pipe the presure keeps it airtight i got mine from a blasting suply firm just up the road but hodge clemco sell them there used on there minipots

eil · Mar 14, 2010

How do you do things if you get a blockage in say the bottom 'T', you shut off the air supply at the red ball valve and then what?. how do you vent the pressure still in the pot.

brightspark · Mar 14, 2010

eil said:
How do you do things if you get a blockage in say the bottom 'T', you shut off the air supply at the red ball valve and then what?. how do you vent the pressure still in the pot.

if its running on the mobile comp
and blocks just stop the comp and the line and pot decompress .if it.was on an electric comp with tank and did happen to block which is verry rare just turn the comp off and vent the tank which will empty the pot as well i have double outlet on mine

eil · Mar 14, 2010

Just wondering if you might have a valve to vent the pot only, I have one of them ones made from a pipe which I bought years ago from Practical classics and at the time was using sand, the damn thing kept blocking, because of moisture of course which didn't occur to me at the time , chucked it to the back of the shed somewhere and that was the end of that.

brightspark · Mar 14, 2010

the one in the picture uses c fittings on 3 quarter hose.verry rarely give bother my other on the electric comp uses eurofittings so if it blocks which can be quite frequent using a 3mm jet .shut the main tap off on the pot. disconect the coupling. then open tap on pot and it will back feed into freshair recomended . NOT JUST UNCOUPLE WHILST FULL :ashamed:

eil · Mar 14, 2010

brightspark said:
. NOT JUST UNCOUPLE WHILST FULL

You would have to be a pretty silly person to do that wouldn't you :whistle:

brightspark · Mar 14, 2010

heres the small one .the most problem is blockages at the jet with it been as small .grit and sand need sieving to be consistent and dont overfeed the blast pipe with media

rtbcomp · Mar 14, 2010

eil said:
Just wondering if you might have a valve to vent the pot only...........

This is what I did on mine

http://www.mig-welding.co.uk/forum/showthread.php?t=8921

brightspark · Mar 14, 2010

rtbcomp said:
This is what I did on mine

http://www.mig-welding.co.uk/forum/showthread.php?t=8921

a safety device is good realy as u can get complacent

gordon stephenson · Jun 20, 2010

the originals of those quick couplings were called "macDonald couplings"

rtbcomp · Jun 20, 2010

I've fitted one to my Ebay blastpot. The 1/2 inch one for the blast hose is fitted with a 1/2" BSP thread if anyone wants to know, so you need a 3/8 - 1/2 adaptor.

Ho55 · Sep 5, 2020

Is that just a T at the bottom, or a venturi?

brightspark · Sep 5, 2020

Ho55 said:
Is that just a T at the bottom, or a venturi?

just a plain tee piece. the only thing ive altered is the cheap ball valve to a proper regulator one I make

Ho55 · Sep 23, 2020

Well i tested mine out and not great on the first attempt. It blasts for a few seconds then dries up.
Mine pretty similar to yours, large fire extinguisher. Only difference is that the feed to the top has a regulator, the plans i saw said put less pressure up there. I assume yours is feed pressure?
So i perhaps have some moisture in there, the blasting hose was full of water initially (must have been used for that before) I've tried to dry it out by feeding air for a while.
Or
Its my media ball valve, think its a 10mm hole, and eventually had it full open but not getting consistent feed.
Any ideas?

brightspark · Sep 23, 2020

the pot supply at the top in to tank is the same pressure at the bottom out to the blast jet at about 90 psi

home made blastpot

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