Lotus Elan

Home media blasting kits

PostPost by: nigelrbfurness » Sat Feb 17, 2018 10:58 pm

Opinions sought. I'm considering buying a soda blasting pot - see http://www.millarsodablasting.com/index ... icle&id=59 - and I note from the advert that the pot requires a compressor capable of supplying a minimum of 8cfm. I have two compressors, a 125litre and a 50litre, both capable of supplying a maximum of 8cfm at around 100psi. This sounds a bit marginal to me so does anyone have any experience of using these small blasting pots with low-volume compressors? if so, is it worth the bother? I have a fair bit of blasting to do on a number of ongoing projects and soda appears to be the only safe medium for blasting Elan bodies and farming it out is getting expensive. Doing it at home would save time and money but if I have to buy another compressor then it's starting to look non-cost effective. Anyone have any thoughts?

Thanks in advance.
Nigel F.
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PostPost by: rgh0 » Sun Feb 18, 2018 3:31 am

Hook up both compressors in parallel

cheers
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PostPost by: 661 » Sun Feb 18, 2018 9:10 am

Nigel,
I have one of those pots.
I bought it to soda blast my son's classic mini shell.
Fundamentally, it's a good bit of kit. It can take a little bit of getting used to as to which valves do what and how best to achieve the right flow of power and mass of media flowing through it. Additionally, with soda, it gets clogged from time to time and you need to use the purge valve.
I'm not sure of my compressor, it's 100L , 3Hp, one phase and was pretty much on all the time.
The main issues I think you'll experience for a shell are twofold. It became very quickly apparent to me that this equipment is only useful at stripping a thin band effectively, perhaps 5mm strips. If you can imagine having to cover your shell with a 5mm broad bladed marker pen, you get the patience you'll need to do a shell. It would take a maddening amount of time. ( but probably gentle enough and safe)
Secondly, mess.
You'll get through loads of media which will end up on your drive/neighbours drive/thousand acre horse paddock.
Yes, soda dissolves in water, but it's still a mess.
I've actually ditched the soda (mini done) and am using one of the Al+++ medias they sell which I've found brilliant at cleaning up small bits and components. That said , you still have mess, this time less of it but not dissolvable, so given time again I'd probably get a blast cabinet and give the large soda blasting bits to a company that specialises in it. Albeit, you'd have to watch them like a hawk stripping a fibre glass shell, which I'd preferentially do in the Miles W way, stripping and sanding.


PPS, Have you been in the loft yet for those documents for 26/5538?
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PostPost by: Bud English » Sun Feb 18, 2018 3:49 pm

+1 on Graeme's post. I purchased a 40lb capacity blast rig and found that neither it nor my compressor were up to finishing the task in my lifetime. It was back to scraping and sanding for the +2.

On the plus side, it's so controllable I was able to remove pin striping on my Jeep pickup by masking around it and blasting down to the original paint without damaging the paint. Just a quick polish and there was no trace that the pin striping had been there.
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PostPost by: nigelrbfurness » Sun Feb 18, 2018 8:52 pm

Thanks chaps, that's what I needed to know I think. Rohan's answer made me chuckle as I considered the plumbing necessary to run both compressors in parallel without one pump fighting the other - like two batteries in parallel. I'm still not sure if you're serious, Rohan!

Stripping a 5cm strip at a time is clearly not a working proposition so the setup as described is only likely to be useful for small items, in which case it is simply not cost effective. I have a fibreglass hard top I wanted to soda blast so I will get that contracted out probably. The review suggested that an engine bay could be blasted in 2 hours! Two days would seem nearer the truth if only 5cms can be blasted at a time, unless the engine was made by Triang and the motor an X03 :?

Many thanks once again.

Nigel F.
1970 S4SE/1760cc big valve/SA-AX block, L2s, 45DCOEs, 1978 Jensen GT, 1962 AH Sprite, Alfa-Romeo 159, 1966 Bristol Bus, 1947 AEC Regal bus.
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PostPost by: nmauduit » Sun Feb 18, 2018 10:01 pm

nigelrbfurness wrote:Thanks chaps, that's what I needed to know I think. Rohan's answer made me chuckle as I considered the plumbing necessary to run both compressors in parallel without one pump fighting the other - like two batteries in parallel. I'm still not sure if you're serious, Rohan!


Considering each compressor system already having a non return valve embedded at the air tank connection, a simple Y connection would work : two operating conditions my then present themselves, either you don't need more flow at the requested pressure than 1 can provide, then chances are you'll be running on the one set the lowest, or if you need more flow then both will try to push as much air as they can, which still may or may not be enough... just make sure there is oil in both and they don't overheat, media blasting tend to require a lot of air.
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PostPost by: billwill » Mon Feb 19, 2018 12:28 pm

nmauduit wrote:
nigelrbfurness wrote:Thanks chaps, that's what I needed to know I think. Rohan's answer made me chuckle as I considered the plumbing necessary to run both compressors in parallel without one pump fighting the other - like two batteries in parallel. I'm still not sure if you're serious, Rohan!


Considering each compressor system already having a non return valve embedded at the air tank connection, a simple Y connection would work : two operating conditions my then present themselves, either you don't need more flow at the requested pressure than 1 can provide, then chances are you'll be running on the one set the lowest, or if you need more flow then both will try to push as much air as they can, which still may or may not be enough... just make sure there is oil in both and they don't overheat, media blasting tend to require a lot of air.



Possibly better if you can feed both compressors into one storage reservoir ??
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PostPost by: Orsom Weels » Mon Feb 19, 2018 4:43 pm

I have borrowed a similar blast pot in the past & ran it off a clarke 28 cfm compressor, which is essentially two 3HP 14 cfm pumps sitting on one air receiver, similar to this https://www.ebay.co.uk/i/111041622052?c ... 912&crdt=0. Even with that amount of air, the compressor was running constantly & gradually lost pressure so I had to wait for it to catch up now & then when I had something stubborn to shift. The guy I borrowed the pot from runs it on a bl**dy great hydrovane shoving out something like 100 cfm & it works much better & quickly on that, suggesting it needs something like that to be efficient.
Two compressors will work quite happily in tandem as long as they are both set to cut out at the same pressure, if they're not, the one set to the lower pressure will not cut back in until the pressure drops sufficiently, so you'll potentially be running on one compressor a lot of the time. Linked together, the pressure will equalise between the two receivers, but you will have double the volume of air, (or cfm if you prefer :) ) to replenish what you're using.

Regards, Tim
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PostPost by: AHM » Tue Feb 20, 2018 4:49 pm

As above - I have done a whole car with a 3hp compressor.
+

Lots of air and lots of media

Use both compressors, if you are doing a body you will still be waiting for them to catch up. They won't 'fight each other' but make sure they both have the same switch off pressure

Check your power supply is it up to running 2 compressors.

Get a larger bore hose = more air

Youll soon bin the pot and go for one with a hose into a bucket of media.

The media will be reappearing for years it gets everywhere no amount of cleaning will get rid of it.

It's a horrible job but doable.
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PostPost by: mikealdren » Sun Apr 01, 2018 12:44 pm

Be careful on an Elan body. I've heard that the infamous Jerry Thurston Classics Monthly Plus 2 was actually a bit of a disaster and the body ended up paper thin, not sure how true that is though.

The people who strip cars regularly (like Option 1) don't use blasting so it probably isn't quick/cost effective commercially.
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PostPost by: Elanintheforest » Thu Apr 19, 2018 1:44 pm

Soda is the exception and it's quire safe to use on Fibreglass. It's used extensively for cleaning timbers in listed buildings, removing graffiti from old stone walls / timbers, etc.

It is time consuming even with a large pot and a big compressor. I blasted a fair bit of fibreglass with this setup (below) with fantastic results. It was adjustable enough to clean my oily hands after blasting some engine components, and it's the only media I know that will do that without blood stains!

One other advantage with soda is that you can blast with the glass and chrome still on the car...it will polish those, and brings up old rubber seals like new.

As you can see though, my compressor was rather large; one of the old diesel compressors that could run two road drills at the same time. Around 120 CFM I believe.

In the end I didn't have much use for it so did a deal with Spyder Cars, who now have this setup and use it for their body restorations....or at least, that was their intention.

If I had to strip another fibreglass or aluminium car, I would definitely only use soda.
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blaster-pot.jpg and
compressor-1.jpg and
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PostPost by: Bud English » Thu Apr 19, 2018 2:26 pm

That's as close to a "Home media blast kit" as this
s-l640.jpg and
Home Robotic Welder
is to my wire welder. :lol:
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PostPost by: Elanintheforest » Thu Apr 19, 2018 8:03 pm

I used it at home!
Anything smaller won't really touch stripping paint from a shell, but could be used for small areas of stripping I guess. The 'hobby' soda kits will really only be useful for components.

The pots and compressors used to strip boats do make my setup look like a hobby kit!
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