Time to build a Blast Cabinet

[Sagebrush Steve]

I’ve decided I need a blast cabinet to help me prep things like Green River fish and various invertebrates.  I have a few questions I’d like to post for feedback.  First, I have a stereomicroscope with a Barlow lens, so I want a cabinet with a flat top.  Even with the Barlow lens the working distance between my microscope and the specimen is only about 6”, so a cabinet with an angled window won’t work.  I will primarily be using this with an air eraser and a Dremel engraver tool.  I don’t expect to pick up any kind of serious pneumatic air scribe, and I recognize what I will be trading off by not doing so.

 

@Malcolmt gave a design for a blast cabinet here: http://www.thefossilforum.com/index.php?/topic/76546-affordable-trilobite-preparation-setup/  Also, in September I visited Fossil Butte National Monument.  At their visitor center they had a ranger demonstrating how to prep fish under a blast cabinet.  I didn’t take photos but the FBNM website has a video showing their blast cabinet in use.  I liked that design.  Here are a couple of screen shots I clipped from the video:

 

 

Here are my questions:

1.       The FBNM blast cabinet opens from the front.  I’ve seen other designs that open from the top.  Opening from the front would seem to be nicer because I wouldn’t have to move the microscope out of the way every time I want to reach in.  Am I missing anything here?

2.       I plan to use it with a shop vac and dust collector (see below for my ideas there).  A lot of people say you need to seal every joint in the blast cabinet securely to prevent dust from getting out and all over the place.  But if you look at the photos above, the FBNM blast cabinet has three large holes on the side, presumably to help with airflow to the shop vac.  Should I be drilling holes like this or not?  I don’t expect to use sealed gloves on the armholes, just some sort of fabric I can reach through, so that should be another path for airflow.

3.       I’m a bit limited on space.  While 20x24 inches would be a nice size, I think I may only be able to do 16x20 inches.  That would also let me use a 16x20 piece of glass from a picture frame for the top.  Do you think that would be a sufficient size (I don’t expect to be prepping any large vertebrate fossils)?

4.       For dust collection I have two choices.   @Peat Burns uses the Dust Deputy: http://www.thefossilforum.com/index.php?/topic/79131-what-is-your-microscopeair-blaster-setup/&tab=comments#comment-871944, and @Ptychodus04 designed a Water Trap system: http://www.thefossilforum.com/index.php?/topic/79125-water-trap-dust-collector/&tab=comments#comment-834634. That one is cheaper and seems like it is less likely to let really fine dust escape so I will probably try that.  Anyone have any recommendations here?

 

 

[caldigger]

Do you think you can build one of these Steve? 

I mean seriously, what kind of technical experience can an engineer really have if you're driving those trains around all day?!  

[KimTexan]

8 minutes ago, caldigger said:

Do you think you can build one of these Steve?  I mean seriously, what kind of technical experience can an engineer really have driving those trains around all day?!  

Always the comedian.  I think I recall a previous engineering marvel of exquisite craftsmanship designed and produced by Steve in the form of a fossil storage cabinet. 

Meanwhile I’m at the beginners, kindergarten level of building useful devices. I bought a piece of lumber today to build a sifter screen to go sift for bison feet bones and fragments in the collapsed bank material. It will probably look like the product of a 5 yr old, but will work.

 

Steve I plan to follow this thread and see what you come up with. I’ve been wanting to build something along this line. Prepping outdoors can only be done a few months of the year. I need to be able to prep indoors.

[Kane]

Going 16 x 20 is doable, but you might find it a bit cramped unless you want the arm ports on the sides rather than the front. That might make it more awkward.

 

I can see the convenience of front end loading compared to from the top, but sometimes you can get the piece in through the arm port. If you think about how much time each prep piece takes, swinging the scope to load from the top may only be an occasional inconvenience.

 

I’m using a Malcolm-made, Malcolm original, and definitely swear by it. 

[Sagebrush Steve]

25 minutes ago, caldigger said:

Do you think you can build one of these Steve? 

I mean seriously, what kind of technical experience can an engineer really have if you're driving those trains around all day?!  

I’m great at building things.  It's digging up fossils I’m terrible at.  

 

9 minutes ago, KimTexan said:

Meanwhile I’m at the beginners, kindergarten level of building useful devices. I bought a piece of lumber today to build a sifter screen to go sift for bison feet bones and fragments in the collapsed bank material. It will probably look like the product of a 5 yr old, but will work.

If it works, that’s all that matters. 

[Peat Burns]

1 hour ago, Sagebrush Steve said:

Should I be drilling holes like this or not?

If you are using a shop vac to draw out dust from the cabinet, vent holes are a must.  I didn't think about that and nearly imploded the window in my cabinet in a matter of seconds.  So, I drilled holes in the side of the cabinet.

[Sagebrush Steve]

3 minutes ago, Kane said:

Going 16 x 20 is doable, but you might find it a bit cramped unless you want the arm ports on the sides rather than the front. That might make it more awkward.

 

Good point, thanks.  I don’t want the arm holes on the side so I will shove enough stuff out of the way to make it fit.

 

5 minutes ago, Kane said:

I’m using a Malcolm-made, Malcolm original, and definitely swear by it.

I think his design only uses an 11x14” sheet of glass.  Is that sufficient or do you wish the whole top was glass?

[Kane]

2 minutes ago, Sagebrush Steve said:

Good point, thanks.  I don’t want the arm holes on the side so I will shove enough stuff out of the way to make it fit.

 

I think his design only uses an 11x14” sheet of glass.  Is that sufficient or do you wish the whole top was glass?

I find it is more than enough room to accommodate the scope on top, plus enough to let light through with an adjustable neck lamp that sits on the plywood corner. I also find having some non-glass space above is handy for holding stuff in my prep queue and some prep materials/tools ready to hand outside of the box (such as the duct tape to keep the hose on my Paasche from popping off!). With the prep queue, sometimes I switch projects when I feel that the current one is getting a bit grind-y and I need to put it aside for a bit, but still want to keep prepping something.

[Kane]

And I should add about the lighting and glass...

 

I have a built-in ring light on my scope, but that alone is not bright enough. The closer you zoom, the darker it gets, so it is important to have a secondary directed light source. Putting bulbs in the box is not a good idea as it will eventually shatter with the blasting that goes on in there. 

 

When it comes to glass, it's usually the bigger it is, the more expensive it is. Malcolm's design accommodates standard picture frame glass that you can probably get cheap when it goes on sale. If you do a lot of blasting, you will need to replace it from time to time as it gets frosted by the blast medium. Much easier and cheaper to go with the picture frame glass than with a large glass top!

[Ptychodus04]

@Sagebrush Steve If you build a water trap, one modification to my design would be to add a 90 and a short piece of pipe to the inside of the can where the shop vac attaches. Also, consider perforating the pipe. I’ve found that a straight outlet allows my super powerful shop vac to evacuate some of the water. This reduces the effectiveness of the trap and allows some of the fines to escape. 

[SailingAlongToo]

Some reasonably priced units here if you are more impulsive or require instant gratification. 

 

https://www.harborfreight.com/catalogsearch/result/index/?dir=asc&order=EAScore%2Cf%2CEAFeatured+Weight%2Cf%2CSale+Rank%2Cf&q=blast+cabinet

 

[Malcolmt]

I too have a Malcolm original serial # 1... Kane's box is actually identical to mine but 1 inch taller. I would recommend the extra inch be added to my plans. One of these days I will redo the plans non hand written. They were originally done for another friend who was making one. .

 

I normally use a .5 barlow but if I switch to my .75 then that extra inch would be nice. I have never really needed anything bigger than the 11 * 14 glass for use with a scope. The box as per my plans has only ever not been able to fit one piece of matrix which I eventually cut so that it would fit in the blast box...  11*14 was chosen because I can get glass frames from Michael's when on sale for $6 or slightly thinner glass frames from the dollar store for $1.25. I now pretty much go with the $1,25 frames and rotate the glass at about 10 hours and swap out at about 20 hours. This way I basically always have crystal clear glass. The FBNM cabinet is much too shallow for air abrasion, it needs to be a lot taller'

 

Do not put a light in the cabinet... they get covered in dust very quickly and you loose tons of lumens. They also break when you hit them. My previous smaller box had a light inside and that was eliminated when I built the bigger box. Definitely use white enameled particle board for the box. It reflects the light inside the box and makes everything brighter. You can never have too much light.

 

You do not need vent holes if the arm holes are open (ie the gloves are not attached to the box). The size of the arm holes in my plans is sufficient to allow plenty of air into the box. Also the picture frame glass at the top is only loosely fitted and is help in ,ostly by the negative pressure in the box. I just tack a couple of spots with masking tape. It takes me all of 2 minutes to change out my glass.

 

Get a dust cyclone off online that you place between the cabinet and the vac. 90%-95%  of your abrasive will be trapped in the cyclone . I got the cheapest plastic one from China with free shipping and it works perfectly.You fit the cyclone on top of a home depot  bucket with lid. This makes for easier reuse of more abrasive (after sieving) . It also significantly extends the life of your shop vac and reduce the expense of expensive drywall dust bags. I do a lot of fossil prep ........before the cyclone a $99 shop vac would last me 6- 9 months now they last about 2 years.

 

I always tell people build your own box to meet your own needs you will be far happier with it than any box you can buy that does not cost mega dollars (Comco, Crystal-Mark etc...)

[Sagebrush Steve]

2 hours ago, Malcolmt said:

I too have a Malcolm original serial # 1... Kane's box is actually identical to mine but 1 inch taller. I would recommend the extra inch be added to my plans. One of these days I will redo the plans non hand written. They were originally done for another friend who was making one. .

 

I normally use a .5 barlow but if I switch to my .75 then that extra inch would be nice. I have never really needed anything bigger than the 11 * 14 glass for use with a scope. The box as per my plans has only ever not been able to fit one piece of matrix which I eventually cut so that it would fit in the blast box...  11*14 was chosen because I can get glass frames from Michael's when on sale for $6 or slightly thinner glass frames from the dollar store for $1.25. I now pretty much go with the $1,25 frames and rotate the glass at about 10 hours and swap out at about 20 hours. This way I basically always have crystal clear glass. The FBNM cabinet is much too shallow for air abrasion, it needs to be a lot taller'

 

Do not put a light in the cabinet... they get covered in dust very quickly and you loose tons of lumens. They also break when you hit them. My previous smaller box had a light inside and that was eliminated when I built the bigger box. Definitely use white enameled particle board for the box. It reflects the light inside the box and makes everything brighter. You can never have too much light.

 

You do not need vent holes if the arm holes are open (ie the gloves are not attached to the box). The size of the arm holes in my plans is sufficient to allow plenty of air into the box. Also the picture frame glass at the top is only loosely fitted and is help in ,ostly by the negative pressure in the box. I just tack a couple of spots with masking tape. It takes me all of 2 minutes to change out my glass.

 

Get a dust cyclone off online that you place between the cabinet and the vac. 90%-95%  of your abrasive will be trapped in the cyclone . I got the cheapest plastic one from China with free shipping and it works perfectly.You fit the cyclone on top of a home depot  bucket with lid. This makes for easier reuse of more abrasive (after sieving) . It also significantly extends the life of your shop vac and reduce the expense of expensive drywall dust bags. I do a lot of fossil prep ........before the cyclone a $99 shop vac would last me 6- 9 months now they last about 2 years.

 

I always tell people build your own box to meet your own needs you will be far happier with it than any box you can buy that does not cost mega dollars (Comco, Crystal-Mark etc...)

 

Thanks, Malcom, lots of useful information here.  I will keep everyone informed of my progress, which may be a little slow for the moment, as I'm helping my wife as she recovers from some major surgery right now.

[Sagebrush Steve]

Well, I decided to conduct a little more research before I finished designing my blast cabinet.  So I emailed the contact at Fossil Butte National Monument to find out more about their design.  I got a really nice reply from Arvid Aase, their museum curator.  As a reminder, here is a photo of their blast cabinet snipped from a video they have on their website:

 

 

Here is the reply I got from Arvid:

 

Stephen,

 

Unfortunately when we made our fossil preparation box it was hand written dimensions on scratch paper, so I don't have plans to share. I can give you dimensions and suggestions for improving the design.

 

The outside dimensions of the box are 26" wide x 26" deep x 8" tall.   

 

The clear top is tempered glass set into a dado. We chose tempered glass for resistance to scratching and less static than Lexan or Plexiglass. To prevent it from accidentally falling out when moved it has been taped in place.

 

The holes for hands have cut off sweatshirt sleeves tacked (or stapled) to the inside. This keeps the dust off your arms. The front panel with arm holes is attached by a piano hinge along the full length screwed to the bottom board in the box. A hook and eye on each end keep the box face closed while working.

 

The box is made from 3/4 inch baltic birch plywood. Since building this box, I have used pocket screws to build cabinet boxes at home. I like the pocket screw technology to build a box like this. The bottom of the box is fully enclosed with plywood thus making recycling iron powder abrasive easier and prevents abrading your counter top. 

 

To the rear of the box, on the side of your dust collector, use a hole drill to cut exhaust hole of a size to fit your dust collector hose. We placed a sliding damper into the hole and attached the hose to that. The sliding damper allows you to reduce air flow if desired. 

 

Along the top edge of the side opposite the exhaust hole we drilled seven evenly spaced 7/8-inch holes. We placed a 1/4 piece of plywood on the inside and spaced out from those holes about 3/4 inch such that the incoming air is directed downward. 

 

We drilled two holes in the right side close to the front. One hole allows our largest scribe to slide through, the other hole is smaller so the air abrasion stylus can fit. In this way we can have two tools in the box and quickly switch between them as we work. 

 

The height of the box was selected to optimize our use of a microscope while working on flat slabs of fossil fish from the Green River Formation. We have a lens that extends the focal distance. But our air scribes cannot stand fully upright when working which is on occasion a problem. Making the box two inches taller would resolve this issue, but then we would need to purchase another focus extending lens. Making the box taller would also raise the eye pieces on the microscope which may cause problems with ergonomics for shorter people. 

 

Well, I think that's all the information. The only concern is whether I stated it clearly.

 

Good luck,

Arvid

[steelhead9]

The bigger you build it the better. I have had to rebuild my cabinet so many times. Every time I think I will never be prepping anything that won't fit in my new cabinet, guess what happens! I have similar holes in the sides of my cabinet which also serve as ports for the various tools I use. I guess the size of your box may be dependent on the force of your vacuum. I have a large, industrial dust collector that would pull a golf ball through a garden hose so I just keep makin' em bigger.

[Sagebrush Steve]

On 2/10/2019 at 12:20 PM, Sagebrush Steve said:

Well, I decided to conduct a little more research before I finished designing my blast cabinet.  So I emailed the contact at Fossil Butte National Monument to find out more about their design.  I got a really nice reply from Arvid Aase, their museum curator.  As a reminder, here is a photo of their blast cabinet snipped from a video they have on their website:

 

 

Here is the reply I got from Arvid:

 

Stephen,

 

Unfortunately when we made our fossil preparation box it was hand written dimensions on scratch paper, so I don't have plans to share. I can give you dimensions and suggestions for improving the design.

 

The outside dimensions of the box are 26" wide x 26" deep x 8" tall.   

 

The clear top is tempered glass set into a dado. We chose tempered glass for resistance to scratching and less static than Lexan or Plexiglass. To prevent it from accidentally falling out when moved it has been taped in place.

 

The holes for hands have cut off sweatshirt sleeves tacked (or stapled) to the inside. This keeps the dust off your arms. The front panel with arm holes is attached by a piano hinge along the full length screwed to the bottom board in the box. A hook and eye on each end keep the box face closed while working.

 

The box is made from 3/4 inch baltic birch plywood. Since building this box, I have used pocket screws to build cabinet boxes at home. I like the pocket screw technology to build a box like this. The bottom of the box is fully enclosed with plywood thus making recycling iron powder abrasive easier and prevents abrading your counter top. 

 

To the rear of the box, on the side of your dust collector, use a hole drill to cut exhaust hole of a size to fit your dust collector hose. We placed a sliding damper into the hole and attached the hose to that. The sliding damper allows you to reduce air flow if desired. 

 

Along the top edge of the side opposite the exhaust hole we drilled seven evenly spaced 7/8-inch holes. We placed a 1/4 piece of plywood on the inside and spaced out from those holes about 3/4 inch such that the incoming air is directed downward. 

 

We drilled two holes in the right side close to the front. One hole allows our largest scribe to slide through, the other hole is smaller so the air abrasion stylus can fit. In this way we can have two tools in the box and quickly switch between them as we work. 

 

The height of the box was selected to optimize our use of a microscope while working on flat slabs of fossil fish from the Green River Formation. We have a lens that extends the focal distance. But our air scribes cannot stand fully upright when working which is on occasion a problem. Making the box two inches taller would resolve this issue, but then we would need to purchase another focus extending lens. Making the box taller would also raise the eye pieces on the microscope which may cause problems with ergonomics for shorter people. 

 

Well, I think that's all the information. The only concern is whether I stated it clearly.

 

Good luck,

Arvid

 

I had one more question for Arvid.  I wanted to know whether they used any sort of weatherstripping seal between the folding front door and the front of the cabinet to keep abrasive from leaving the cabinet.  I've read plenty of complaints online that blast cabinets frequently don't seal very well and the abrasive gets all over the place.  I figured that with open armholes and air vents on the side it must not be too much of a problem, but I wanted to be sure.  Here is his reply.  He also confirms that iron powder is their abrasive of choice, which is what they told me when I visited the monument back in September:

Steve,

 

We have no weather stripping. We have found no need for it because the negative air pressure from the dust collector sucks air into the box at all possible points. When using iron powder abrasive we don't use the dust collector continuously, and even then we do not have problems leaking dust .

 

Good luck with your box!

Arvid

 

[steelhead9]

21 hours ago, Sagebrush Steve said:

 

I had one more question for Arvid.  I wanted to know whether they used any sort of weatherstripping seal between the folding front door and the front of the cabinet to keep abrasive from leaving the cabinet.  I've read plenty of complaints online that blast cabinets frequently don't seal very well and the abrasive gets all over the place.  I figured that with open armholes and air vents on the side it must not be too much of a problem, but I wanted to be sure.  Here is his reply.  He also confirms that iron powder is their abrasive of choice, which is what they told me when I visited the monument back in September:

Steve,

 

We have no weather stripping. We have found no need for it because the negative air pressure from the dust collector sucks air into the box at all possible points. When using iron powder abrasive we don't use the dust collector continuously, and even then we do not have problems leaking dust .

 

Good luck with your box!

Arvid

 

If your vacuum is sufficient, no powder should escape anywhere. Iron powder is a good all around abrasive,  not the best for some applications. It’s big advantage is you can recover it all over and over with a simple electro magnet. In my experience don’t try carrying it on a plane. It’s uncanny similarity to gunpowder and the fact that the label says “weapon grade” (and it must be to function as an air abrasive. Don’t try using the common iron powder sold on sites like online) make for an interesting experience at airports. After Homeland Security lowered their weapons, my strip search was completed, and countless tests were performed, they actually did let me on the plane with my two 10 lb canisters of iron powder. Outside of Europe, the only place I can find that sells suitable quality iron powder is Paleotools. It ain’t cheap, but as I said, is completely recoverable. 

[Sagebrush Steve]

1 hour ago, steelhead9 said:

If your vacuum is sufficient, no powder should escape anywhere. Iron powder is a good all around abrasive,  not the best for some applications. It’s big advantage is you can recover it all over and over with a simple electro magnet. In my experience don’t try carrying it on a plane. It’s uncanny similarity to gunpowder and the fact that the label says “weapon grade” (and it must be to function as an air abrasive. Don’t try using the common iron powder sold on sites like online) make for an interesting experience at airports. After Homeland Security lowered their weapons, my strip search was completed, and countless tests were performed, they actually did let me on the plane with my two 10 lb canisters of iron powder. Outside of Europe, the only place I can find that sells suitable quality iron powder is Paleotools. It ain’t cheap, but as I said, is completely recoverable. 

Very useful information, thanks.  I just looked on the Paleotools website but didn’t see any kind of abrasive powder for sale.  Is there another source?

[steelhead9]

57 minutes ago, Sagebrush Steve said:

Very useful information, thanks.  I just looked on the Paleotools website but didn’t see any kind of abrasive powder for sale.  Is there another source?

Try calling and asking for it specifically. It's distributed by Crystal Mark, but they have (at least last year they did) a deal with Paleotools to not sell it retail to fossil preppers. I have not found another source of abrasive quality iron powder in the USA.

[Sagebrush Steve]

 

I’ve started building my blast cabinet and thought I would share with you my progress.  First, I had to decide exactly what I wanted to build.  Commercial blast cabinets come in all sizes from large freestanding models all the way down to small cabinets for dental work.  Here are the factors that went into my decision:

 

1.       I will primarily be collecting smaller fossils such as trilobites from Nevada and Utah as well as fossil fish from the Green River.  I don’t plan to collect any large vertebrate fossils.

2.       The amount of space I have available is somewhat limited, so a large cabinet is out of the question.

3.       I have wood left over from the storage cabinet I built last year (described here: http://www.thefossilforum.com/index.php?/topic/79670-homemade-fossil-storage-cabinet/&tab=comments#comment-841071) and wanted to be able to use as much of that as possible.

 

4.       I will not be using this with an air scribe.  I have a Dremel engraver and plan to purchase an air abrasive system (either the Paasche with remote canister or, if I win third place in the lottery, a Vaniman).  If I decide to invest in an air scribe in the future, I will build a new blast cabinet if necessary.

 

After reviewing everyone’s feedback I decided to make it 24” wide by 20” deep by 12.5” high (61 cm x 51 cm x 32 cm for those of you who haven’t yet abandoned the metric system and adopted English units).  The height was decided by the fact I have some leftover plywood that is 12” high for the side and back walls. This isn’t quite as tall as some people recommend but it’s 3.5” taller than the blast cabinet they use at Fossil Butte National Monument, so I figured it would be good enough.  I also decided to make the cabinet with a drop-down front panel rather than a top that lifts up.  This makes it easier to slide in the adjustable shelf described below.

 

Another consideration was my stereomicroscope.  The 0.5x Barlow lens I recently acquired gives me a working distance of about 5” between the bottom of the Barlow lens and the focal plane of the fossil.  So with a cabinet that is 12” tall on the inside, if the fossil is flat like a Green River fish, I would need to raise it about 7” above the floor of the cabinet for it to be in focus.  Not every fossil will be thin like that, so I designed a removable shelf that can be adjusted to two different heights.  And I might eventually acquire a 0.3x Barlow lens for greater working distance.

 

As usual, my first step was to design the cabinet in Visio.  Here’s one view of what it looks like. 

The top view shows the 11x14” cutout for the glass window.  I was hesitant to use ordinary glass because of the danger of sharp edges if it breaks.  So I went online and found a cheap source of tempered glass.  It comes as part of an 11x14 picture frame, and they use tempered glass so it doesn’t break during shipment.  I took it out of the frame and just use the glass.

 

Here’s a photo of the cabinet starting to come together.  Notice the top.  I don’t have a miter saw so rather than trying to cut exact 45-degree angles for the four pieces to come together like a picture frame, I made straight cuts.  I used my router table (I’m not completely devoid of power tools) to cut a shelf for the glass to sit in and another lip on the underside for the pieces to fit together snugly.

 

 

Here’s a photo with the shelf installed.  Note the underside edges of the shelf.  I attached strips of 1x1.5” wood.  When oriented as shown, these strips raise the shelf 1.5" higher up from the floor.  If you turn the shelf upside down, it drops down by 1.5”, giving me room for thicker fossils.  Or I can take the shelf out entirely for large fossil blocks to sit on the floor.

 

 

Here’s a photo with the top temporarily installed.  I will take it off so I can paint the entire inside white.

 

 

The other thing I needed to do was to build a stand for my microscope.  Since I don’t have an extra few hundred dollars lying around to buy a commercial boom stand, I decided to make my own using material I bought at Home Depot or had lying around.  For the vertical stand, I bought some 1” diameter steel pipe and two flanges.  I mounted the bottom flange to an old piece of aluminum plate I had lying around.  The top flange holds the square aluminum tubing I bought and cut to length.  I decided to make this an articulated arm so I could move the microscope anywhere around over the glass.  Here are a couple of photos of the result.  It's pretty stable although a commercial boom stand might be a little better.  The 48” ruler lying across the top of the cabinet is what I used to determine how far apart I want the holes in the front cover to be.  I found that with my arms resting comfortably while holding the Dremel tool, the optimal distance between them is 12.5 inches.  This photo also shows the holes I drilled on the left side for incoming airflow.  I live in California’s wine country so wine corks are plentiful.  If I need to restrict airflow I will plug individual holes with corks.  You can also see part of the 2.5” diameter hole on the right side, which is where I will connect the shop vac.

 

 

Notice the vertical post holding the microscope.  I had to machine an aluminum rod to 20 mm diameter for this post using my Harbor Freight 7x10 mini-lathe.  This is about the longest piece I could machine on this lathe.  Projects like this allow me to justify my investment in power tools to my wife.

 

 

That’s a far as I’ve gotten with the cabinet, I will post more pictures as I go along. Next step is to caulk all the seams and then paint the entire inside white.  I also need to finish the front panel and attach it to the cabinet using a piano hinge on the bottom and two latches, one on either side near the top, to hold it in place.

 

 

 

 

[Ptychodus04]

That looks great! You’ve given me some inspiration to build a boom for my microscope. I’ve been wanting one and the desire to purchase one for several hundred dollars hasn’t fallen upon me yet.

[RJB]

Nicely done Steve.

 

RB

[Sagebrush Steve]

12 hours ago, Ptychodus04 said:

That looks great! You’ve given me some inspiration to build a boom for my microscope. I’ve been wanting one and the desire to purchase one for several hundred dollars hasn’t fallen upon me yet.

 

Here's a closeup photo of the hinge.  Notice I put a spacer inside the tubing where the bolt goes through.  That prevents the tubing from being crushed when you tighten down the bolt.  The spacer should be just slightly shorter than the inside dimension of the tubing so it slides in easily, but not too short so the tubing doesn't crush when the bolt is tightened.  I bought 1" long spacers at my local Ace Hardware store and used my lathe to turn them down to about 0.85" length.  If you don't have a lathe you can cut them with a hacksaw.  Or you could even build up the necessary height just by stacking ordinary washers.  I'm using a thumbscrew to tighten the bolt but you could just use an ordinary bolt.  I've found that even when pretty tight you can still move the microscope around to position it and it won't move on its own.  The white spacer between the two tubes was a washer I picked up at Ace Hardware.  Ditto for the black end cap.

 

[Malcolmt]

Nicely done. 

[Sagebrush Steve]

I'm making slow but steady progress on the blast cabinet.  Here's what it looks like now, with the front closed and open.  I decided to use window weatherstripping where the front closes, primarily because the cheap oak boards I bought at Home Depot aren't perfectly flat and don't seal tightly to the box.  The weatherstripping does a good job of sealing.  I made the arm holes 5" in diameter because that's the largest size hole saw I own.  It was also the right size to fit a 4" ABS straight coupler, which I cut in half and use for the arm holes.  The part that extends into the cabinet is where I may decide to attach gloves (or cut-off sweatshirt arms).  But I'm not sure I like or need the ABS so I may take it out.  On the right you see the black adapter that lets me mount my shop vac, which right now has a 1.25" hose diameter.  When I eventually get a better shop vac, make a water dust trap, and move to a 2.5" diameter hose I can reverse the adapter, which gives me a fitting for 2.5" hoses.  You can also see the removable shelf in the center that elevates thin fossils to a height that let's my microscope focus on them.  Last major things I need to do are to make a removable cover to protect the glass during storage and a plastic plug for the hole you see on the left where I will run the power cord for my Dremel engraver and at some point, tubing for a Paasche AECR air abrasive system I have on my wish list for later this year.  I may also add a couple of handles to make transport easier.  I'll start using it to prep some Green River fish I have from the 18" layer once everything is ready.  Total cost about $75 but I had some of the wood already on hand.