sand blasting...

[paulob1]

Okay I have never done any, never seen it done and there is no one locallty to tell me how it is done...

 

I have a good ish compressor or do i need one of those road side ones...i have a small grit blasting gun but guess that will be too small for doing my 432...

 

So can anyone give me a bit of advice on what to get and how to use it etc etc...what about the grit getting into the engine things like this...I need some advice...

[G506]

Okay I have never done any, never seen it done and there is no one locallty to tell me how it is done...

 

I have a good ish compressor or do i need one of those road side ones...i have a small grit blasting gun but guess that will be too small for doing my 432...

 

So can anyone give me a bit of advice on what to get and how to use it etc etc...what about the grit getting into the engine things like this...I need some advice...

 

 

Paulob,

are you in northern or southern Hampshire? The reason I ask is that Woodfield Metals are just north of Portsmouth, and offer blasting services at reasonable rates, they blasted my Chevy chassis, and did a great job. He is on this forum as Bodger Baz, send him a PM.

 

If you want to have a go yourself, you are going to need a very large compressor, because you will get through a massive volume of air.

 

You dont want ANY grit getting into the engine, or any bearings etc, and it doesnt matter how well you mask everything off some always seems to get through!

 

Needle guns have been used on the hulls of armoured vehicles with a fair amount of success, could be worth considering?

[sirhc]

A needle gun is the way to go for your 432. It might not be as quick, but it's definitley a lot cleaner. You will still need a good compressor with a large tank. Once the hull is needle gunned you can run an angle grinder with a cup brush or sanding disc over it to get it nice and smooth before painting it. I've done a Ferret and a Sabre like this, both have come out nice.

 

Chris

[Stormin]

You'll need over 100cfm of air to get decent progress on sand blasting. Nothing to beat it for speed and a clean metal finish in all the nooks and crannies you can't get with any other tool.

If it's large realtively flat panels (432) other methods may be nearly as good.

 

Down side is dust and noise, but you get that with any other method of rust removal. Be careful around bearings and oil seals. Blast media will find it's way past even good seals into bearings.

 

My past experience with getting someone else to do blasting is they always missed bits. I assembled my own kit so when I miss bits I've only myself to blame and it's easy to catch them again later.

[Rick W]

I tried grit blasting with a small compressor in the garage at home. Complete waste of time unless you have something like a twin cylinder and a big tank. Even with our comps at work it takes time. So if you have a big job it pays to find a pro.

[Lauren Child]

Second vote for the needle guns in preference. Loud and hard work, but definitely better. Sandblast the small unboltable/detachable bits and needlegun the hull and big beefy bits. The small bits should fit in a sandblasting cabinet that will keep the grit from going everywhere.

[LarryH57]

Perhaps an explanation of a needle gun is required here in case it is confused with something in a tattoo parlour. So how is it different from sand blasting?

[john fox]

Perhaps an explanation of a needle gun is required here

 

needle gun

 

the difference to sandblasting should therefore be self evident, one hits paint with sand particles, the other with needles :yay:

 

You will always get a better finish sand (ie grit) blasting.

I have a blasting cabinet at home. SLOW but great for small parts.

Anything bigger forget it unless you have a road grade compressor and a proper blast kit. I used such as that at Duxford and its a dream, the kit I have at home I used once and gave up (petrol powered 20cfm compressor but its still too small, clears about 1 sq inch at a time compared to one pass across the whole plate with the Duxford set up)

IMHO Needle gun is fine for removing paint and rust scale but will never do anything to surface rust so not the solution if you are trying to properly de-rust

[G506]

Perhaps an explanation of a needle gun is required here in case it is confused with something in a tattoo parlour. So how is it different from sand blasting?

 

A needle gun basically looks like a large pistol, but with a much fatter 'barrel'. It has a handle one end, and at the barrel end has 30 or 40 toughened steel rods poking out by a few inches. It is generally powered by compressed air, which makes the steel rods 'rattle' vigourously.

Probably not the best discription ever!

I think Machine Mart sell them.

[sirhc]

Needle guns are only suitable for cleaning thick walled components or vehicles. Do not try removing the paint from your Land Rover or Jeep with one!

 

I use a needle gun to clean up hulls of armoured vehicles, for anything made from sheet metal, such as the wings or bins, or bits from soft skin vehicles I use a blast cleaning company.

[paulob1]

hmm okay

 

to do it properly I need a big road side compressor.

It will get into the bearings...bugger...

Needles guns slowly but harder work, but not if it gets into the bearings it isnt...

I have a needle gun and twin cylinder compressor on 2hp though so only 10cfm...hmm maybe will try needle gun first...

[Stormin]

You can try to reduce the chances of grit getting past seals by taping over them a being careful with the direction and quantity of blasting in vulnerable areas. Get someone else doing it and that won't happen.

Better still is to remove wheels propshafts etc completely to protect bearings. If grit can get in there's a good chance paint can get in as well when spraying, lower pressure but finer media and nearly as destructive in some cases.

[Lauren Child]

Having tried a couple of different needle guns, I can recommend the Trelawny pistol grip ones. You can also load different types of needles with different characteristics.

[Davie]

I have seen needle guns mentioned a fair bit over the last few months, but nothing about one of the physical side effects. Vibration white finger.

Vibration white finger is a nasty condition where the fingers and hands tingle, and become numb after using vibrating tools. The more you use the tools the worse it becomes. It is irreversible. Worst case scenario,you may lose the use of your hands and be unable to work or play again.

Needle guns are one of the worst offenders. I recently used mine for three hours, it took three weeks till my fingers felt normal again.

This prompted me to do a bit of research, I found that the recommended amont of time a needle gun should be used for in an eight hour period is about twenty minutes.

 

Just a wee warning, lets take care of ourselves whilst enjoying our hobby.

[Stormin]

This prompted me to do a bit of research, I found that the recommended amont of time a needle gun should be used for in an eight hour period is about twenty minutes.

 

 

You'd need an army of friends to needle gun a 432 or a few years doing it yourself at twenty mins a time.

[antar]

I would go for the sandblasting, it produced a superb finish in the hands of a professional, here is a picture of my M578 being done last year.

[antarmike]

It appears that your M578 is being Sand balsted rather than grit blasted. The use of sand is illegal. it causes silicosis. It you are going to blast an MV then you should, by law be using a safer blast media, such as copper slag. The trouble is that Copper slag, does not give as good results as using dry Paviour sand, it costs more and the work is slower.

 

When I say use of sand is illegal, that has implications for professional/industrial users, and all the local builders merchants refuse to sell Paviour sand for sand blasting, so you have to declare to them that is not going to be used for sand blasting.

 

If you are getting a professional to blast for you you should be asking the question "what medium will you be using" Some Blasters still deliberately break the law because sand is cheaper than Copper Slag, and it works better. But if we are to be seen as reponsible in our hobby, we should not be giving trade to blasted, who deliberately break the law to save themselves time and money.

 

 

The problem is that for months after a strong wind will whip up and carry of the finer particles, and these in the air do cause serious, permanent injuury to the respiratory system, so be very aware in todays"where there is a blame, there is a claim" society that you are doing something that is recognised as damaging health and is illegal.

 

Every one, even amatuer users, has under health and Safety regs "A duty of Care" to those around them who may be put at risk by their actions. Sand should not be used.

Edited August 10, 2009 by antarmike

[Marmite!!]

so you have to declare to them that is not going to be used for sand blasting.

 

 

 

 

I've been in the building game for 30 years & I have never been asked to make a declaration for kiln dried sand... you can buy it anywhere without stating it's uses & I know blasters who still buy & use it although illegal, one I know has an account with a major builders merchant & gets regular deliveries & they know what he is using it for...

[Stormin]

There's no problem using sand for blasting. It's the object that is being blasted that makes it illegal. Generally buildings, bridges and inanimate objects are fine. Things termed as articles, i.e. components and vehicles are illegal if sand blasted in an open space.

 

There are many other alternative blast media besides copper slag which can do a better job than sand.

 

http://www.centurywise.co.uk/content/pdf/Guidetoblastcleaning.PDF

 

http://www.hse.gov.uk/foi/internalops/fod/oc/200-299/273_18.pdf

[Ed Batchelor]

I have heard of allsorts of media being used, ground coconut shells being one example. I think some kind of bicarb of soda is used for delicate stuff.

Glass is another I hear of, anyone know what application this is suitable for? Also as glass contains silica is there any of the associated dangers attached to using sand? Obviously correct PPE and working environment are required whatever is being used.

[antarmike]

There's no problem using sand for blasting. It's the object that is being blasted that makes it illegal. Generally buildings, bridges and inanimate objects are fine. Things termed as articles, i.e. components and vehicles are illegal if sand blasted in an open space.

 

There are many other alternative blast media besides copper slag which can do a better job than sand.

 

http://www.centurywise.co.uk/content/pdf/Guidetoblastcleaning.PDF

 

http://www.hse.gov.uk/foi/internalops/fod/oc/200-299/273_18.pdf

 

I was trying to keep the comments applicable to blasting the hulls of AFV, this being the original question. My comments related paricularly to the image that appears to show an MV, an M578 (which is an article as covered by these regulations) being (APPARENTLY) blasted with silica sand, IN THE OPEN. (I WILL GO INTO THIS FURTHER IN MY) NEXT POST.

 

 

Firstly to answer Lee. Whilst I agree that generally you do not have to make a declaration regarding the end use of Silica Sand, the comment related to a person I know, now retired from mobile sand-blasting, who was buying sand under his business name, (Buc******r blast cleaning) and as far as all the local builders merchants were concerned, they would not sell to a company with Blast cleaning as part of the company name, without a declaration of end use.

 

I think any of the companies you now buy Sand from might adopt this attitude towards you if they suspected that you would sand blast with the product they had sold you.

 

I hope this clarifies things. I am trying to help people stay clear of litigation, and although, yes, there are some exeptions, the objects most of us are going to get blasted, in the areas where they are likely to be blasted would make it illegal if sand were to be used.

Edited August 3, 2009 by antarmike

[antarmike]

There's no problem using sand for blasting. It's the object that is being blasted that makes it illegal. Generally buildings, bridges and inanimate objects are fine. Things termed as articles, i.e. components and vehicles are illegal if sand blasted in an open space.

 

There are many other alternative blast media besides copper slag which can do a better job than sand.

 

http://www.centurywise.co.uk/content/pdf/Guidetoblastcleaning.PDF

 

http://www.hse.gov.uk/foi/internalops/fod/oc/200-299/273_18.pdf

 

Having re-read these two links are I confused(.com)

 

The first link indicates that sand cannot be used to blast articles.

The second use says that it is illegal for blasting Articles. but you add the priviso in your comment on these articles that it illegal to use sand for blasting articles "in an open space." You seem to imply that sand can be used in circumstances other than in "an open space" ie "in the open".

 

I cannot see the second link, the official advice, makes exeption to allow the use of sand indoors, in a blast chamber or even in a blasting cabinet (the sort were small parts are put in a closed box with a window, and the part and the blastgun are manipulated from outside wiith long sleeved rubber gloves.)

 

I cannot at the moment see how you reach your analysis of the law. Unless I am missing something the use of Silica sand for blasting articles is an outright ban, and does not allow its use even in dedicated blast cleaning booths, or in enclosed blasting cabinets. The actual wording appears to be a ban probiting the use of sand for "Use as an abrasive for blasting articles in any blasting apparatus."

 

If the use of sand for blasting articles in dedicated blast booths is acceptable, maybe someone would be good enough to post a link to an official goverment site that indicates that this is so, but at the moment I can't see it is.

Edited August 3, 2009 by antarmike

[Stormin]

I know of three very large stone properties within a mile of my home have recently been sand blasted all by the same company, no sheeting or attempts to contain dust.

 

Yet if I decide to use sand to blast a small component of my vehicle it is deemed illegal!

[antarmike]

It is not deemed illegal, it is illegal to Sand blast any MV or MV component using sand, which is what I had try to convey in my earlier post, untill we got sidetracked into how to or how not to paint the Forth Railway Bridge.

 

And when it comes to outdoor blasting of buildings and bridges, I disagree with you, there may well be a problem using sand, not as a direct result of the ban on silica sand for blasting,, which as you so rightly say does not apply in this situation, but because the sand breaks up into a very fine dust, (unlike mineral slags,) and other aspects of safety regulations may prevent its use because general dust regulations may not be able to be met when using sand as a blasting medium.

 

Depending on the actual circumstances at the time, ( ie the amount of dust actually being produced) the respirable airborne dust limit of 4mg/cubic metre in 8 hour average, set in COSHH Regs may itself make blasting buildings and bridges with silica sand illegal.

Edited August 10, 2009 by antarmike

[listerdiesel]

FWIW:

 

Over the past 10 or so years we have had a lot of items shot-blasted and then Zinc Sprayed.

 

The two need to be done one after the other, and then it is almost rustproof once painted or powder coated.

 

It is a pro job, not the sort of thing you can do at home, but almost all of our engine trolleys and trailer chassis get processed, usually powder coated afterwards.

 

Cast iron goes rusty almost as you watch it after shot-blasting, mild steel is not quite as bad but all ferrous stuff will rust very quickly once you are down to bare metal.

 

If you look at the bottom two pictures on this page:

 

http://www.stationary-engine.co.uk/Trailer/trailer3.htm

 

you'll see the finish before powder coating was done.

 

Peter

[Glynn]

I used one of the little air chisels with a flat chisel in it great for taking off

200 layers of paint when i had a ferret.Dont use them on thin stuff though.