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Really big sand blast booth


Barry Wolk
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I've used a number of sand-blast cabinets and they all have the same problem. They are built for a shorter, narrower person, which puts the glove holes too close to the floor and too close together. Also, anything over 4-feet wide gets pricey.

I've seen a number of home-made blast cabinets made from plywood and that's the route I chose. The materials were inexpensive and woodworking is a skill set that I still need to exercise every once in a while. My HVAC guy will be making the funnel so my work is just in wood.

I wanted to avoid the pitfalls of a suction feed sand blast rig so I've opted to use my pressure vessel blaster, which will fit neatly under the cabinet. I'll leave the bottom of the funnel open with a 5 gallon pail underneath the opening. On top of the rail that the funnel attaches to will be a grate that's 36" x 96". I havent decided what material to use. Expanded metal is cheap, but weak. Actual grating would probably work better, but be heavier. It'll be stationary, so that won't matter.

The object of this project was to do the least amount of cutting so I used standard measurement materials. The housing is made of vintage G2S 1/2" plywood that I've had lying around since 1999.

I used full 8' 2x4s for the uprights and horizontal braces. Using a full sheet of plywood allowed me to make the cabinet perfectly square.

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This use of lumber makes for taller legs than normal, but could easily be trimmed to match the user. I used the squared up back panel to precisely make a matching front assembly.

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Using the remaining pieces from the center uprights and cutting two new ones I made the legs stronger by adding a corner support.

The brake made a handy plywood holder as I cut a beveled 14" piece to serve as the front panel.

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Front and rear panels standing on their own.

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The rest of the space above the window area will be shelved to house all of the things associated with sand blasting. There will be 4 F96T-12/HO lamps in the ceiling of the booth on two switches for adjustable light levels.

More to progress pictures to come.

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Barry,

You will have to protect the lights from the sand that will bounce on them and put a small hole into them.

Take my word for it! I spent 30 minutes replacing bulbs before noticing the very small holes in them.

You will also have to protect the plywood on the back of the cabinet. You will blast through it in a very short time and have splinters in your return abrasive.

I couldn’t view your pictures so I don’t know what you are going to use for a vent but you need a very large one to keep the dust down. Don’t rely on a shop vacuum, it will plug up real quick with the fine dust. I once tried to sand blast a truck in a large room (20 X 35’) with a 3 Hp exhaust fan running. The dust was so bad I couldn’t see what I was doing. I do all my blasting outside now, even the little stuff.

One problem that you will encounter is re-using the abrasive’ is that in a short time it will have as much dust in it as abrasive, cutting down the efficiency to less than 50%.

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From experience, the plywood won't blow though very quick, BUT the splinters that were mentioned are a real problem because some will pass through a screen filter.

I use a heavy duty outdoor floodlight bulb in mine and I've yet to replace it in quite a few years.

Yes, the dust is a problem, and even more so with a pressure blaster. Some sort of high flow squirrel blower would be better than a vacuum system. IMO. smile.gif

I also do stuff outdoors like bigger parts that can still fit in the cabinet, because a bigger part is hard to move around for better vision when the dust blows around.

It sure is nice to have any size/type cabinet for small parts and it saves so much time versus trying to drag your blaster outside for just a simple part.

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Barry, my comments:

1. The sheet metal liner in the back wall should be fine.

2. Suggest using several flood lights from differant angles like in the corners. Multiple lights prevents shadows and "punches through" the dust so you can see. As your cabinet is so large, plan on a way to replace the bulbs like the ones on the far end or just have double doors. Wait, don't you specialize in "replacing bulbs"..... smile.gif

3. The glass window should have a protection layer on the inside that can be easily replaced. The bouncing media will frost the window so just admit defeat and include a replaceable clear covering on the inside. Plan on replacing every 20-25 hours of use. Use the 1/4 inch glass, held using a step or offset channel screwed using hex screws for easy removal using a drill/driver. Don't forget a thin seal around the perimeter of the viewing hole between the cabinet and the glass.

4. Large air intake, preferably on the top with a metal deflector on the inside so blast media doesn't fly out.

5. Attach gloves to the front holes so they can be easily replaced. Invariably you or someone will blast through the glove finger tip or other part necessitating their replacement.

6. The vaccuum system probably should be a good dust collector. I don't think a shop Vac will be enough, but try it. Can't hurt to try.

7. Like the idea of using a pressure system rather than syphon version. Should work well.

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I plan on using 2 sets of 8-foot high-output lamps for two sets of light levels. 4 HO lamps would be the equivalent of one 400-watt metal halide lamp.

Someone elsewhere recommended using fiberglass window screen in front of the sacrificial plastic. They said it greatly extends the life of the sacrificial sheet as it acts as a deflector.

Instead of a vac system I'm going to use a squirrel-cage blower to simply blow the air outside. The air intake will be the opening in the chute at the bottom. As deflected material drops into the chute the flow of air into the opening should remove small particles, effectively removing debris and particles of blast media too small to be effective. On the outside of the building I'll have some type of rudimentary sack of cloth to catch any particles that get out. That's all theory, but I believe it will work. I don't see where it's any different than blasting outdoors.

Gloves are a problem. I want dexterity but I want longevity, too. I'd like to find long rubber gloves or rubber reinforced cloth gloves but I'm having trouble finding gloves to fit these mitts. XXL gloves are too tight.

Siphon systems are enormously frustrating. I'll live with repeated refills. Pressure feed moves tons more material.

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<span style="font-style: italic">EDIT---got rid of the stuff since its fixed now</span> I make that mistake CONSTANTLY with photobucket haha. Youre viewing the image but with their frame deal so putting that in IMG tags means nothing to the forum. View the whole album, then move your mouse over the thumbnail to see the little drop down menu that shows up with "Direct Link" "IMG code" etc... so use those and it'll be linking right to the file itself. In fact the only issue was, after ".JPG" youll notice the ? and then garbage after that, I guess that's for the frame or something. Little annoying but photobucket is still awesome!!!! And that's definitely a great idea. Plenty of stuff you can't fit in a normal cabinet.

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Barry,

Only concern about intake vent on the bottom is that air will take the shortest route, from the bottom and along the side to the vac source. Ideally air should draw across the work area. For the Gloves, try the ussual places like McMaster & MSC. I know TIP in Ohio sells individual components. Maybe someplace that sells the media for blasting bridges. One trade name for slag based media is Black Beauty.

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I built a wood box sandblaster years ago. It worked well. Wood splinters were not a problem. Don't aim the gun at the wooden sides.I used a Sears siphon unit. It worked fine for what I was doing. I used a shop vac. Totally useless. I had two floodlights in ceramic fixtures. Had no problems with them. I "po' boyed" it together, so I had my wife sew a pair of work gloves to the legs of an old pair of Levis. After a few years, I blasted through the gloves, but it was a simple matter to sew in a new pair

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I use the Black Beauty blasting media exclusively. The only problem with it lies in the fact that the FINE grit may be too aggressive for many delicate parts.

The reason that I don't use sand is because it causes a disease called Silicosis of the lungs.

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Unfortunately, they didn't list gloves to fit me. I downloaded a hand size chart and I am a XXXL or size 13.5, whatever the .5 means.

Today I cut the window openings. I've saved tempered glass lenses for commercial light fixtures. These were off of some 1000-watt mercury vapor floodlights that were enormous by today's standards. The lenses are 14" x 33" and are 1/4" thick.

I laid them on the angled face and positioned them with screws around the edges. I drew a line around their perimeter. I removed the glass and used my circular saw to cut an opening 1/2" smaller, all the way around. Using a rabbit to creating a 5/8" wide by 1/4" deep recess, so the glass can sit flush. I'll hold it in place with storm window clips. I used a 3/16" router bit to square up the corners to match the glass.

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I decided to make two return funnels instead of one. This allowed the sides to be at a steeper angle on the sides. A single funnel 8 feet wide would have trapped a lot of material on its surface. Adding the center support significantly stabilized the structure.

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I installed the rest of the full depth shelf at the top of the chamber and installed a shallower shelf right above the windows. I installed some spacers on the inside of the chamber so that the high-output fixtures can breath. The manufacturer recommends that there be 6" of air space above but that distance won't be necessary with the amount of air circulating through this chamber. The fan will be on the same switch as the lights. so the fixtures will always be ventilated while in use.

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The top of the framework will get some horizontal bracing and another layer of shelving. I've had to give up some storage space to put this monster in my shop but the extra shelving makes up for the loss.

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I used a 7" hole saw to cut a hole in the top of the cabinet to mount the squirrel cage blower. I secured the blower housing directly to the top of the blast cabinet. This will draw air across the high-output fixtures, keeping them cool.

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I used tow double pole switches to control the lights and the fan. The way I wired it the fan will come on with either light. I used metal jacketed cable that should withstand years of deflected particles hitting it.

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With the lights in the room turned off you can see how intensely bright 2 HO lamps really are!

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Next, I'll be building the doors. I may fab those out of metal.

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I am not a doctor ,but any fine dust will cause irreperable damage as in black lung from coal, brown lung from cotton ,sillicosis from sand , and on and on.If you have ever noticed how sand will settle to the bottom of a bucket of water ,or how body filler dust sticks to a wet floor, so to will it settle in your lungs. Have fun but please be carefull. Happy New Year

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Words of wisdon from some who has been there and done that!

A long time ago I made a wooden sand blasting cabinet.

I used Tip gloves and window and a cheap Harbor Freight blaster.

The blaster was crap and clogged all the time so I started using my Tip 99 pressure feed blaster in the cabinet. First it destroyed the plywood back in no time at all. I eventually I put a self healing drafting board cover rubber we were replacing at work on the back and it helped a lot.

But the thing still was what I call a disposable, use a few times a throw away or rebuild it.

As far as air movement, move as much as you can otherwise you cannot see what you’re blasting. I tried the shop vac, not enough, I even tried a few 3-4 inch squirrel cage blowers I had not enough. Be sure to use an air filter before the blower or the sand and dust trashes the blower.

Lights I first tried some plain light bulbs because I had some ceramic sockets I could use.

I kept breaking them; my next attempt was florescent tubes. Much better light but with all the sandblasting the sand sandblasted the tubes and they became thin and broke easily. It is very awkward turning large pieces inside the cabinet and easy to hit the bulbs.

To make the glass window last longer I read about putting nylon screen wire in front of it..

Problem is if it is fixed you cannot clean the glass.

So much for my failures now for what worked.

About 10 year ago I started over.

I went to the local heating air-conditioning supply place and bought a couple of sheets of galvanize steel 5’x10’. I had them sheered to 40 inches because that is what my break is. If I had a wider break I would have left it wider.

I made the entire thing out of galvanized sheet metal it it was very cheap, cheaper that plywood at the time. At the time it was like $22 a sheet.

I reused the gloves and window I had from before. I took a large 14 inch squirrel cage fan from an old furnace, I cut a round hole in the end and bolted it up, I put some old 16 inch (old but new, I had bought them for something I had long since sold.) round automotive air filers I had over the hole and made a lid just like and old air cleaner and wing nutted it over the hole. Really fine dust still got though so I put and old laundry bag I had in college over the output of the fan to catch the dust the filers missed.

As far as light I still used florescent .but I got an OSHA plastic cover that slides over the tubes the one I got was 8 foot but I cut it in half to fit the 4 foot tubes.

I made the entire end open so the door would fit anything that would fit in the cabinets. I flanged the metal on the cabinet ends for strength without shrinking the opening any morethan I had to.

As far as the screen helping prolong the glass life it works great just put it on a removable frame so it can be removed to wipe off the glass. I also put the window on with wing nuts to make the easily removed to cleaning crawling the cabinet to clean the glass sucked.

I put and small door on the other end so I could get my blasting gun in and out without taking anything apart.

All that works well.

The only real mistake I made was since I was still planning on using my 99 to blast with. I decide why not make the height so I could filter the media and let it drain back in to the hopper directly. To do that I had to make the bottom of the cabinet at a light slop, not the heavy slope of the ones you buy. Well I didn’t put enough slope for the sand to flow well, it allways has media stuck in the corners, and to change media I have to remove the floor/grate made of expanded metal and sweep the sand to the center hole. And the floor/grate is a pain to remove to do tight clearances and sharp edges. If I would have made the floor with more slope and still have the blaster fit under it the cabinet would have been too high to reach, I should have just planned on a bucket transfer.

I find that even at 40 inches by 25 inches by 25 inches it is too far for me to reach to the extremes inside so anything bigger wouldn’t be very useful so I just do large things in the driveway.

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Generally, the stopping up of the siphon blaster is caused by moisture in the air. If you've ever noticed, when you hold the nozzle close to the piece you are cleaning, you will see water droplets develope on the part. Two cures ,wait for a day with no humidity, or ocaasionally hold your gloved finger over the nozzel, then pull the trigger, this will back blow the sand and clear the nozzle. Humidity will also stop up large pressure blasters.Pressure blasters will clear themselves, but very anoyingly,they will slow down a lot,then will suddenly blow clean,then repeat the cycle.Hope this helps, I have had cheap siphon blasters and supposedly good ones,and big commercial pressure blasters and they all work the same, and have the same problems.Hope this helps, Fiddler

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I agree with Jay Wolf, I have an 8 foot wood cabinet with metal doors on each end and sheet metal funnel collector. It is real hard to blast objects at each end of the cabinet since it is so long. Maybe your arms are longer. I also have an old dryer blower motor and exhaust dust outdoors thru a duct pipe. It works pretty good. I use a pickup tube sold by tips and foot pedal control so I don't have to keep moving media. It just recyles inside of the cabinet. We use glass beads. They can last for alot of parts. Good luck on your project.

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<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> the stopping up of the siphon blaster is caused by moisture in the air</div></div>

Actually there is a third and better cure for air line moisture. I hassled with the problem for years before finaly buying a refrigerated air dryer. They are plentiful and fairly cheap on EBay. I bought a used commercial 50 CFM unit for $50 that works great. It's about 24" square, takes up little space and uses no more electricity than a mini fridge. Now I have dry air on the most humid of days......Bob

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I built the cabinet in the building next door where I am setting up one of the front offices as a wood shop. I picked it up with the hi-lo and moved it into my shop. It's huge.

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I considered making the doors out of wood but discovered that plywood would not lay flat enough to keep a tight seal against escaping dust and sand. I then considered making my own doors out of steel but soon realized that the 10 foot brake is not a box brake. I wouldn't have been able to bend the tabs at the edges, necessary for stability. I had mirror image doors fabricated out of 14 gauge steel. They have been, by far, the biggest expense in this build. I had all the lumber except 18 8' 2x4s. I had the fixtures and the lamps. I also had the tempered glass windows and the ventilation fan. I had the switches and the electrical supplies and all the fasteners. So far, I have about $300 in it. $260 of it was for the doors. They did do a nice job, though. No sharp edges and welded and rounded corners.

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I had some commercial door hinges with bearings. The sand should play havoc with them but they're cheap to replace.

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I spaced the door far enough out to take a compressible EPDM gasket that will help keep sand in the cabinet. No sense in painting the insides of these.

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The largest gloves I could find are not big enough. They are a size 12 1/2. The fingers are plenty long. I just can't bend my fingers very comfortably. The manufacturer is getting some gloves in that are "ambidextrous" and have room for bigger fingers. Told me to keep these. I figured I'd try to stretch them out. Until he sends the new ones I'll suffer.

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Most sand blast cabinets I've seen have 6" portals. The commercial gloves are designed for 10" diameter portals. They fit perfectly on a 10" ductwork take-off. I positioned them where they are comfortable for me. I simply held a pencil in each hand at a comfortable height to mark the center. They're about 8" further apart than a standard blast booth. Since my shoulders are 24" across I now understand why it was so uncomfortable and awkward to use a standard cabinet.

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Added some handles for the side doors. They sit on rests to keep the doors aligned and need to be lifted slightly, so leftover handles from another project fit the bill.

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My tinknocker friend came by and built the funnels and bent a flange for the back wall metal.

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I needed a means to get the sand from the pressure pot to the blast chamber. I had some fittings left over from the soda-blast conversion so I devised a bulkhead fitting the would get the sand where I want it. By passing it through the wall in the center I can use it in either bay. The fitting swivels as it passes through the wall so there will be more flexibility. I used reinforced 1/2" heater hose on the inside of the booth. By loosenng two clamps I can return the blaster nozzle to the tank when I want to use it outdoors. That's not going to happen any time soon as it was -10° yesterday.

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I installed a shut off so that I can quickly shut off the blast nozzle if a hose ruptures or comes loose.

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Gloves, funnels and back wall metal installed.

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Sacrificial mylar sheet. It attaches with double stick tape. Prevents etching tempered glass window. Simple to peel and replace.

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It's pretty close to complete. All that's left to do is the grating above the funnels and hooking up the ventilation.

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I have a diamond grit hole saw that I use for installing recessed lighting in plaster ceilings. It's 6 3/8" diameter, perfect size for 6" ductwork. The outlet of the fan motor is 4" x 6" or 24 square inches. I'll modify a 6" ductwork boot to transition to 6"round. I picked a position in the 12" thick block wall where I would only have to cut through one of the webs. I drilled a 1/4" pilot hole and drilled until the saw bottomed out.

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It had cut through the side of the block, but no deeper before it bottomed out. Repeated deepening of the pilot hole allowed me to remove just the material necessary to get the pipe through.

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It might have been a little easier to do some of this from the outside, but then, I didn't have to deal with this.

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Finished. I'm amazed at how well it actually works.

I ducted the fan to the outside. I gad to alter a stock transition boot to go from 6" round pipe to the 4" x 6" opening on the fan. On the outside I'll use an air intake hood that's screened against critters getting into the building. Hate to start blasting and have a red squirrel go nuts on me.

By adjusting the dampers at the bottom of each funnel there is a significant updraft of fresh air coming through the openings. This updraft carries huge amounts of dust out of the building leaving me with only larger particles of paint and debris to filter out of the media after it falls into retrieval bins below.

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The booth is large enough to easily sandblast one of the huge doors off of my Lincoln limo. The beautiful thing about an 8-foot sand blast booth is that I can blast the ends of the doors by simply sliding them over to gain access.

Anyone that has a siphon feed sand blast rig would quickly convert it to pressure feed if they saw how fast rust and paint is stripped off of metal. The only thing left to do is find an appropriate drying system so that moisture doesn't clump up the media.

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Total cost, under $500. Ability to blast metal clean without bothering my friends to use their equipment, priceless.

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We all collect rolling art; that's why we're here. The difference is that we share and show ours at AACA Meets, regardless of what class they're in. HPOF, DPC, Class Judging, etc.,

...there's room at the inn for all.

We also know that you enjoy concours beauty pageants, where everyone gushes enthusiastically over your Continentals. When are you gonna step up to the plate

and let AACA judges get a load of yours?

Just curious,

TG

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You asked,

I don't think it's a matter of stepping up. While I completely understand why you like to be judged in the manner you are, I prefer the beauty pageant aspect of Concours. I really like people telling me what they like about my toys, not what's wrong with them. To each his own.

I believe West told me that my Mark II was ineligible for AACA events due to the fact that it's modified from it original coupe configuration and further modified in '66, adding the metal boot that completes the sculptural look. Actually, the car was modified once more in '94 when the fiberglass top bow covers replaced the canvas flaps installed when the metal boot was installed.

I suppose I could show it in some type of exhibition class, but I like trophies.grin.gif

I have the same problem with showing my '55 Cabrio in a club event. Everyone's so critical, and everyone's an expert. That's very disheartening, sometimes. Another problem with that car is that it was only marginally changed in its 17 years of production. To me, it boring to participate in marque shows. I guess I've found a home doing beauty shows.

I have a great idea. How about you all come and see me in the next Concours? I'll have the Mark II at Keels and Wheels in early May. Texas is lovely in May. I was sent a generic invitation that they send to all past participants so I applied with the '55 Porsche. They asked if I still had the Mark II. They disinvited the Porsche and insisted I bring the Continental.

Come to think of it, no one from AACA has ever invited the Mark II to a show. Every other Concours we've participated in has always been by invitation. The invitations usually come from recruiters attending the shows. The only time I've made application to a Concours is to this years' Pebble. My fingers are crossed. It's the only major show that I know of that we haven't participated in.

There's another reason that we participate in Concours. All of them are benefits for either the historic venue or some form of charity, or both. Some of the shows have raised huge sums, in the past. As such, they are 501©(3) charitable organizations. Some of my expenses related to transportation, travel and lodging are tax deductible, within reason. Without the car, there is no show. Without the owner, or their representative, there is no car. The black-tie events, in good times, were paid for by the sponsors. The gate for the events went to charity. I get to do good while doing well. Does that make sense?

I like Concours because you get to rub elbows with the rich and famous, without being either. smile.gif

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