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What stops the air pressure just blowing all the media out of the top in a big cloud?...
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brightspark
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rtbcomp
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The best pots are fitted with a pop-up valve under the hopper which closes when pressure builds up
brightspark
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Same for us, used various people, quality a bit hit and miss, and hardly ever done when they say it will be!
rtbcomp
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the msv metering valve on that pot looks verry much like the ones ive made on my pots
or vice-versa
normspanners
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If I was doing it I would lay the beams flat touching each other side to side and make a 'floor' , then you could blast them together, to maximise the use of grit, put 8x2 ply on edge around the beams to form a box, so you could stand inside, then you could collect a lot of the medium and re-use.
SmartWerks
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Get them blasted, the less we expose ourselves to those sort of chemicals the better.
Why remove the galvanising, just trying to learn something not questioning judgement?
SmartWerks
Why remove the galvanising, just trying to learn something not questioning judgement?
SmartWerks
brightspark
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if your going to cut and weld something up u need to remove the galv . its ok to do it with stick welder and just burn it off if its not a critical weld
but not realy recomended
SmartWerks
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if your going to cut and weld something up u need to remove the galv . its ok to do it with stick welder and just burn it off if its not a critical weld
Thank you, does the galvanising stop good penatration so your literally only attached to the coating?
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Its for a suspended car park steelwork; large podium deck. The steel needs to have shear studs site welded (resistance welded) on site once the composite floor deck is laid. For more than a handful of reasons the shear studs cannot be shop welded onto the beams before galv.
The shear studs can't be welded onto the beam with a galv coating - we have tried various ways to mask off the galv but all have failed. So, plan Z.
Not ideal, especially now there are more beams to treat in this way than originally
normspanners
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Second idea
Could you not use an end mill in a mag rotabroach and just take the bit off where the studs need to be, it would leave perfect clean metal for the stud weld.
Could you not use an end mill in a mag rotabroach and just take the bit off where the studs need to be, it would leave perfect clean metal for the stud weld.
mike 109444
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So you only need to spot blast rather than blast the whole beam(s) ?May therefor be doable with a smallish compressor and a spot blaster on site ?
Windy Miller
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Liquid Metal
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1. Shot blasting with Nickel grit wont do much damage to hot dip galv, let alone copper grit. Tried it myself few times at various employers yards, using proper industrial shotblast units
2. Hydrochloric acid??? Think you'll find any chlorine residue left behind from the reaction will turn into phosgene gas if expose to welding type temperatures, arc or resistance.
If your working outside anyway, mark out the areas you need to remove galv from, then 9"grinder, grinding disk, followed up by a 3m softpad ------->
http://www.3mdirect.co.uk/cubitron-fibre-disc-988c.html
I think it sounds as if whoever engineered the project didnt quite think it through properly if you ask me. Specifies Hot galved steel, then has studs/mounts welded to it on site??
Can you not use stud bars into drilled&tapped holes rather than welding the studs in place?? Will be much less agro and much faster/less labour intensive.
2. Hydrochloric acid??? Think you'll find any chlorine residue left behind from the reaction will turn into phosgene gas if expose to welding type temperatures, arc or resistance.
If your working outside anyway, mark out the areas you need to remove galv from, then 9"grinder, grinding disk, followed up by a 3m softpad ------->
http://www.3mdirect.co.uk/cubitron-fibre-disc-988c.html
I think it sounds as if whoever engineered the project didnt quite think it through properly if you ask me. Specifies Hot galved steel, then has studs/mounts welded to it on site??
Can you not use stud bars into drilled&tapped holes rather than welding the studs in place?? Will be much less agro and much faster/less labour intensive.
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Welcome to my world!
Stud welding isnt a precision art, plus they are in pairs so the whole lot needs to come off the top flanges. The studs sit in the trough of the deck so there is no way of establishing where the troughs will end up on the steel.
Stud welding will knacker the galv on the underside of the top flanges, but we've put all this in writing so they know it will rust. Stupid.
I've bought 5L of hydrochloric acid so we can try it on a bit of galvd steel to see what happens. A couple of people have said today that blasting might not take the galv off so im dubious about buying the kit.
I'm hoping that if the acid does work, beams can then be laid on the side, acid put on, let it do its work then jet wash clean. Plenty of PPE and do in an empty yard on a Saturday. Looks like everyone who has tried it has dipped the stuff in acid which i would imagine would do a better job than brushing it on. Hmmmm.
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Wonder if one of them weld planers would be any quicker......or hows about one of them gert push along linishers... 24g belt....
Youve got a 'Grit' linisher havnt you? Wouldnt take much to knock one of these trolleys up.....?
Youve got a 'Grit' linisher havnt you? Wouldnt take much to knock one of these trolleys up.....?
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Weld planer?
Some bit of kit that push along linisher isn't it. Wonder how long the belts would last and if they would clog?
Need one of these...
Joking apart, i've looked at hand held concrete planers...either have diamond or carborundum cutter drums. Don't think either would take kindly to being used on steel.
Some bit of kit that push along linisher isn't it. Wonder how long the belts would last and if they would clog?
Need one of these...
Joking apart, i've looked at hand held concrete planers...either have diamond or carborundum cutter drums. Don't think either would take kindly to being used on steel. 