Sandblasting reference?

Just thinking into the future at the moment.

I know nothing about sandblasting except you can apparently use
different abrasive material i.e. glass beads, sand, nut shells (?)

An aircraft I'm looking at has some rust at the tail cone. If I
purchase it, I'd like to remove the rust and prime it.

Assume my A&P says the tubing is structurally intact, but pits are
evident.

Can someone point me to a reference that talks about what I need to
sandblast the area, what abrasive to use, or if the area is small,
some other method of rust removal? Other considerations?

Sorry, but I know only enough to ask a general question at this point
- Mike

In article ,
Michael Horowitz wrote:

Just thinking into the future at the moment.

I know nothing about sandblasting except you can apparently use
different abrasive material i.e. glass beads, sand, nut shells (?)

An aircraft I'm looking at has some rust at the tail cone. If I
purchase it, I'd like to remove the rust and prime it.

Assume my A&P says the tubing is structurally intact, but pits are
evident.

Can someone point me to a reference that talks about what I need to
sandblast the area, what abrasive to use, or if the area is small,
some other method of rust removal? Other considerations?

Sorry, but I know only enough to ask a general question at this point
- Mike

Sandblasters do not typically use sand. The most commonly used "media"
is aluminum oxide, which is the same stuff used to make sandpaper. Like
sandpaper, it comes in various grits. You'd want to choose a grit based
on common sense, just like you would when choosing sandpaper. Since it's
propelled by compressed air, adjusting the air pressure will vary the
speed with which you remove rust (and metal) from the surface, with any
given grit.

Once you've used a sandblaster to refinish irregularly shaped objects,
you'll be frustrated with the inadequacy of other techniques. But, it's
unlikely that you're going to remove your tailcone to put it into an
enclosed sandblast cabinet, which means you're going to have to find
someone with a portable unit in your area. Look in the yellow pages.
Glass beads, incidentally, are great for removing very very thin layers
of paint from very smooth surfaces without dulling the finish of the
substrate, but for this job you're going to want aluminum oxide.

Now, I'm going to leave it to you and others more knowledgeable about
airplanes to say whether you ought to be blasting abrasives into your
airplane. If I were to take a wild guess, I'd say you'd want to keep it
away from control surface hinges and linkages.

You can also use White masons sand for large projects in the open. Works
very well and doesn't cost very much.


"Smitty Two" wrote in message
news
In article ,
Michael Horowitz wrote:

Just thinking into the future at the moment.

I know nothing about sandblasting except you can apparently use
different abrasive material i.e. glass beads, sand, nut shells (?)

An aircraft I'm looking at has some rust at the tail cone. If I
purchase it, I'd like to remove the rust and prime it.

Assume my A&P says the tubing is structurally intact, but pits are
evident.

Can someone point me to a reference that talks about what I need to
sandblast the area, what abrasive to use, or if the area is small,
some other method of rust removal? Other considerations?

Sorry, but I know only enough to ask a general question at this point
- Mike

Sandblasters do not typically use sand. The most commonly used "media"
is aluminum oxide, which is the same stuff used to make sandpaper. Like
sandpaper, it comes in various grits. You'd want to choose a grit based
on common sense, just like you would when choosing sandpaper. Since it's
propelled by compressed air, adjusting the air pressure will vary the
speed with which you remove rust (and metal) from the surface, with any
given grit.

Once you've used a sandblaster to refinish irregularly shaped objects,
you'll be frustrated with the inadequacy of other techniques. But, it's
unlikely that you're going to remove your tailcone to put it into an
enclosed sandblast cabinet, which means you're going to have to find
someone with a portable unit in your area. Look in the yellow pages.
Glass beads, incidentally, are great for removing very very thin layers
of paint from very smooth surfaces without dulling the finish of the
substrate, but for this job you're going to want aluminum oxide.

Now, I'm going to leave it to you and others more knowledgeable about
airplanes to say whether you ought to be blasting abrasives into your
airplane. If I were to take a wild guess, I'd say you'd want to keep it
away from control surface hinges and linkages.

Here is a reference for you from The Eastwood Company:
http://tinyurl.com/d5vkd

The Eastwood Company also sells a variety of other rust removal tools
and chemicals.


Michael Horowitz wrote:
Just thinking into the future at the moment.

I know nothing about sandblasting except you can apparently use
different abrasive material i.e. glass beads, sand, nut shells (?)

An aircraft I'm looking at has some rust at the tail cone. If I
purchase it, I'd like to remove the rust and prime it.

Assume my A&P says the tubing is structurally intact, but pits are
evident.

Can someone point me to a reference that talks about what I need to
sandblast the area, what abrasive to use, or if the area is small,
some other method of rust removal? Other considerations?

Sorry, but I know only enough to ask a general question at this point
- Mike



--
John Kimmel


"To announce that there must be no criticism of the President,
or that we are to stand by the President, right or wrong, is
not only unpatriotic and servile, but is morally treasonable
to the American public."

Theodore Roosevelt

On Mon, 15 Aug 2005 18:03:46 -0400, Michael Horowitz
wrote:

Just thinking into the future at the moment.

I know nothing about sandblasting except you can apparently use
different abrasive material i.e. glass beads, sand, nut shells (?)

An aircraft I'm looking at has some rust at the tail cone. If I
purchase it, I'd like to remove the rust and prime it.

Assume my A&P says the tubing is structurally intact, but pits are
evident.

Can someone point me to a reference that talks about what I need to
sandblast the area, what abrasive to use, or if the area is small,
some other method of rust removal? Other considerations?

Sorry, but I know only enough to ask a general question at this point
- Mike

Mike I have beadblasted the rust from my Auster J1B fuselage
successfully.

of the rust removal techniques beadblasting is by far and away the
fastest. it is acceptable for aircraft use because it hammers the
surface minutely and puts it into compression which is good for
fatigue resistance.

I used a cheap modified taiwanese beadblasting handle from an
automotive discount house. as you use the handle it will wear from the
passage of beads and all the worn off particles get blasted onto your
aeroplane. this is not so critical if it is a steel tube fuselage but
is vitally important if you are treating aluminium. my mod was to
replace the nozzle with either one made from teflon rod or stainless
steel rod which was machined on my lathe.(basically bought in the
diameter required and drilled 5/16")

ballotini (glass beads) are inert and have rounded surfaces which make
them perfect for aviation use. the rounded hammering is perfect for
fatigue resistance. I have used one 25lb bag of beads for the last 4
years. I just keep on sweeping them up, pass them through a trash
sieve made from flywire and stick them back in the bucket.

the handle will use, I estimate, 60 cubic feet per minute of air. on
my 13cufm compressor I spend probably 2/3rds of the time waiting for a
pump up. hiring a commercial trailer mounted diesel compressor in
australia works out to be $aus120 a day. it is worth it since you get
continuous pressure air and can get the job done in a day.

most people go overboard on the beadblasting cabinet. a drape of the
flimsiest plastic painting drop sheet is entirely adequate as a bead
stopping backdrop. I've used one sheet, which would be shopping bag
thickness, for so many years that uv deterioration is now making it
tear. a 6ft x 6ft plastic tube frame hung from the ceiling with paint
drop sheets taped on to it and a plastic tarp on the floor is what I
use. you just position the job, then walk around twisting up the seams
to seal them and then clip them. a few 5.00x5 tyres to weight down the
bottom edges and you are away.

protective gear is needed. my face mask is an arc welding head mask
with the glass replaced by a piece of perspex which has some
transparent plastic sheet over it. the sheet will go cloudy from the
bounceback of the beads and it is easy to replace it every few hours.
overalls, and a head cover made from teeshirt material. I wear safety
glasses and breathing protection under the mask. (the beadblasted off
crud becomes a very fine airborne powder)
and some vinyl gauntlet gloves. all very agricultural but it works for
me.

dry compressed air is essential to prevent rust being set off again.
there are filters available which do a good trapping job. a friend
uses two filters with a hoselength between them and gets better
results than I do with one filter.
when you have the surface beaded off degrease it with a solvent then
prime it straight away.(within an hour)

pressures used vary from 60psi for a *very* mild action to 150psi
which will clean off the heaviest rust in a millionth of a second and
will erode surfaces if you arent careful. 100-120psi is a good
starting pressure range.
soft stuff like a stray smear of silicone can be beaded for hours
without a shred of effect. I found that a pocket knife with a
reasonably blunt blade was of great assistance in scraping this sort
of crud off.

I think that that is a reasonable synopsis. I have probably left out
mountains but it isnt hard. just remember that you are working with
aircraft and sharp grit is a no no because of fatigue considerations.
I have used dry water washed rounded quartz sand that was cleaned by
rainfall quite effectively as well.

have a shot at it on a piece of spring first.
Stealth Pilot

On Tue, 16 Aug 2005 02:59:39 GMT, "Cy Galley"
wrote:

You can also use White masons sand for large projects in the open. Works
very well and doesn't cost very much.



I'm aware of the discussion concerning health and using sand.
If I go shopping for a respirator what qualities should I look for?
I plan on buying one for when I start spraying coatings, but I"m
thinking I"d want something else to keep small sand out of my lungs
- Mike

Michael Horowitz wrote:
On Tue, 16 Aug 2005 02:59:39 GMT, "Cy Galley"
wrote:


You can also use White masons sand for large projects in the open. Works
very well and doesn't cost very much.




I'm aware of the discussion concerning health and using sand.
If I go shopping for a respirator what qualities should I look for?
I plan on buying one for when I start spraying coatings, but I"m
thinking I"d want something else to keep small sand out of my lungs
- Mike


Sand: Particulate filters/ HEPA

Paints: Organic Vapors + HEPA - MAKE SURE you read the instructions on
the paints and ensure you dont need supplied air. some paints are toxic
and are not stopped by filters. This can be a deadly mistake.

You should look for one with a wide silicone or soft rubber seal that
fits your face comfortably. You should be clean shaven in the seal area
and do a fit test. You should be able to take a cartridge mask with the
covers still on it (sealed) and be able to hold the mask to your face by
inhaling/suction alone. If not, you have a mask seal leak or a mask
leak. Once you find one that fits and seals well, then you can adjust
the straps to your head and strap it on

One caveat - wearing a respirator increases the work of breathing. If
you are a healthy person, this is a non-issue, but when i performed fit
testing and sprirometry tests on construction workers, we had a handful
who were not able to qualify for wearing a respirator in dangerous
environments continuously. Some were limited to 2 hrs/day and others
were limited to escape use only. These guys were bad smokers or had
heart conditions. I'm guessing its not as pertinent if you can hold a
3rd class or better FAA medical.

On Sun, 12 Aug 2007 22:49:59 -0500, Dave S
wrote:

Michael Horowitz wrote:
On Tue, 16 Aug 2005 02:59:39 GMT, "Cy Galley"
wrote:


You can also use White masons sand for large projects in the open. Works
very well and doesn't cost very much.




I'm aware of the discussion concerning health and using sand.
If I go shopping for a respirator what qualities should I look for?
I plan on buying one for when I start spraying coatings, but I"m
thinking I"d want something else to keep small sand out of my lungs
- Mike

#1 Do not use sand- period. Use glass beads, coal slag, etc that has
little or no crystalline silica.
#2 Look at the MSDS for whatever you decide to use. It will normally
list permissible exposure levels. (Outside with a well fitted P100
respirator is probably ok - Sold at most welding stores)
#3 If you're doing this in an enclosed space or often look into a
supplied air system.

Spray coatings - if they contain isocynates, you will need a supplied
air system.

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