Westwood T1200

[bertsmobile1]

Well if you can make a telescope like that , a soda blasting gun should not stretch your abilities.
BE careful with the glass as it will embed into the aluminium if you get too close.
For that price I would be using it myself although I would normally used crushed net shells or soda as I do my blasting outside.

 

[clicon357]

Off down another rabbit hole.....prompted by @bertsmobile1 ?

As aforementioned I ran out of blasting media for my cheapo Lidl Parkside sandblaster. It's OK but you have to give it a shake now and then.

Then the suggestion here I search out "pop bottle soda blaster" builds on YouTube.

I tried at first putting soda crystals through the Parkside gun but it clogged/didn't work.



So...after a rummage in the garage and delve into the collected scrap and I came up with:

- a cheapo blow gun
- a copper tap connector, 15 down to 10mm
- an airline connector
- the plastic bottle the blasting grit came in from Lidl



I found if I unscrewed the end of the blow gun then an airline adapter screws in being the same thread.



I cut the tap connector down roughly at where it narrows down and found that slotted over pretty well, the airline connector.



I figured if I heated up the copper flare with the MAPP torch I could tap the airline connector into it.....and that's where it all went wrong! The copper bent like a banana!



Plan B!

Another rummage came up with some heavy wall chrome steel tube.



The airline connector taps home nicely into the end of the steel tube. This junction mind is NOT airtight but we have a solution to that I think!



More later!

 

[bertsmobile1]

Some people just have to build a better mouse trap don't they
Sorry I did not mention that a conventional open bucket sand blaster won't work.
The soda is not heavy enough and cloggs the feed line but I see you have already worked that one out for yourself.
The cheapskate soda bottle works because it is essentially gravity fed but the slight pressurization of the bottle aids in clog prevention.
I am guessing that real blast soda will flow a lot better but I won't know that for a couple of years yet till I empty the bag of feed soda
Because the soda is not very agressive you can get away with plain old mechanics rubber gloves remembering that compressed air should never ever be blown onto bare skin.

 

[clicon357]

compressed air should never ever be blown onto bare skin.

I remember the lectures as an apprentice about "gas gangrene" from dirt and grease pushed in through cuts or bodily orifices etc by compressed air ?

 

[clicon357]

Just read you said sodium bicarbonate! It's washing soda crystals I have here bought for electrolysis derusting. Someone else pointed out that might not be the best blasting medium

I drew up the assembled gun/adapter/pipe junction in CAD and had my lad 3D print me two halves to clamp the lot together and mount the h.duty bottle the blasting grit came in with my cheapo sand blasting gun from Lidl:









Got to lop the top off the bottle and drill through into the pipe.

Problems might be the internal diameter of the "barrel" is too big and I'll use up media like there's no tomorrow. Also the fact the barrel isn't not secured to the compressor attachment overly other than by the clamping action. A blockage might see it fire off the end!

SWMBO creating a bit over the height of the grass so I've had to put the box back on pre blasting. All bolts new and/or greased up so it should be easy to take off again. I'll test the blaster on the old box before I bench strip that to see what's wrong inside.

 

[tom3]

I might be missing something here, probably. But what's to stop the compressed air from blowing back up into the feed bottle? Would need an ejector or something to draw the medium into the air stream. Pretty neat to 'print' out that adapter for sure!

 

[clicon357]

But what's to stop the compressed air from blowing back up into the feed bottle?

Won't the mass of medium above in the "hopper" mean that the main, horizontal air flow through the bigger diameter barrel strips the medium as it drops into the barrel?

One way to find out!

 

[clicon357]

As aforementioned I've put the gearbox back on (pre grit blasting / painting it). As much to test it out as get SWMBO off my back!

Brake assembly swapped from my mower to the new gearbox.

Drives forward and back aok. 1,2,3,4,5 and reverse all there after some playing with the gear linkage rod adjuster.

(It even cuts grass but some rattles I need to sort. Might be blade balancing...tba).

The pto wasn't working so the grass flail wasn't rotating. Traced to a plastic tension pulley having seized then the belt having worn a groove in the pulley.



Around £25 plus VAT plus p&p for a new one from a cursory search.

Went back to the two donor mowers and on one was the same tensioner pulley albeit in steel and one big lump of rust. Knocked the loose rust off and into the citric acid bath for a loosen up. Guess the steel one was an earlier incarnation?

 

[bertsmobile1]

If there is nothing inside the air tube to deflect the air stream then it will follow the path of least resistance , ie:- go out the end.
The air rushing past the hole in the bottle will draw soda ot of the bottle according to the venturi effect, exactly the same as air rushing through a carb draws fuel out of the float bowl.
The bottle does slightly pressurize and when you stop the air flow this pressure causes a lot of soda to be pushed out the tube which is why I invert it so the excess air just leaves the bottle.
?
It is virtually the same as those cheap sand blasters where you get a gun with a tube that you place into a bucket of sand.
Cliccon has done a bang up job. I am very impressed
When can we buy one at Wallys ?

 

[bertsmobile1]

As aforementioned I've put the gearbox back on (pre grit blasting / painting it). As much to test it out as get SWMBO off my back!

Brake assembly swapped from my mower to the new gearbox.

Drives forward and back aok. 1,2,3,4,5 and reverse all there after some playing with the gear linkage rod adjuster.

(It even cuts grass but some rattles I need to sort. Might be blade balancing...tba).

The pto wasn't working so the grass flail wasn't rotating. Traced to a plastic tension pulley having seized then the belt having worn a groove in the pulley.

View attachment 52490View attachment 52491

Around £25 plus VAT plus p&p for a new one from a cursory search.

Went back to the two donor mowers and on one was the same tensioner pulley albeit in steel and one big lump of rust. Knocked the loose rust off and into the citric acid bath for a loosen up. Guess the steel one was an earlier incarnation?

Well the plastic ones would be a lot cheaper than the steel ones to make and it is all about cutting cost not making the mower better.
By the time I get to buy them there is very little difference in price and that would indicate that the logistical costs are a bigger percentage of the final cost than the manufacturing costs,
Rule of thumb is new idlers every 2nd or 3rd belt & change the lot