Homemade Spray Booth

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    Well, time to start sanding down the top edges of the booth panels.  Glue has set and all of the tape “clamps” have been removed.

    Taking a three foot long length of a straight edged 1 x 4, I glued a 12 inch long piece of 100 grit sandpaper to opposite ends of that boards’ edge.  The center portion was covered with a section of heavy manila envelope approximately equal in thickness to the sandpaper.  Then resting the center section on the top of the baffle panel and the sandpaper on the two raised panels, I just kept sliding the center across the baffle until the sandpaper ground the rear and right side panels down to equal heights.  That was the area with the most to even out, the rest was simply using a sanding block and a straight edge to check on the progress until it was all evened out.  This whole sanding operation only took about an hour to do, so I was happy that I decided to do it this way.

    Tipping the booth upright, the top panel was mounted by ripping several narrow pieces of 1/8” thick hardboard to use as spacers and I set them on the top edges of the panels.  The top panel was then placed on top and clamped down with a bar clamp to secure it.

    Using the hinges as templates, the new locations for the bolts were marked with an awl and the holes were drilled.  The  holes were counter sunk on the inside of the booth with an overlong 3/8” drill bit as the new brace and the filter channels made it too difficult to get my drill in position to use my counter sink bit.

    The booth was unclamped and top panel was then removed.  All of the unpainted parts of the booth were then given two quick coats of paint and left to dry overnight.

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    I sense that the completion of this project is finally in sight.  Since I already had the booth on its backside, I wiped down the top edges of the panels and the self-adhesive backed foam weather-strip was applied.  One thing to keep in mind while applying the weather-strip is to keep the backing tape on  until just before it is pressed down because everything sticks to it, much like fly paper.  Any dust or even oil from your fingers will reduce the effectiveness of the adhesive.

    When I applied it, a small portion of one end was exposed and pressed in place.  Then with one hand used to lightly press it in place and keep it aligned with the edge, the other hand keeps pulling the backing tape off as you go along.  After it’s in place I go along the entire tape length with a smooth tool handle, the foam is firmly pressed in place.  The method works quite well for me.

    The top vinyl filter channel was given a double strip to keep it from twisting when installed.

     Since the foam needed to be compressed to half its thickness, the stove bolts would be under a bit of stress, I thought I would give the slotted end of the bolts a little more purchase with a washer.  However, since this end of the bolt went into a countersunk hole, a flat washer wouldn’t work.    The washer was fairly thin, so I made a sort of tool and die arrangement to make the washer conform to the hole.  Drilling a matching hole into a ¾” piece of oak complete with the countersink for the die, a matching bolt was set into the die hole with the flat washer in place.  Taking a one handed sledge hammer, I simply pounded the bolt down into the die until it conformed to the shape of the countersink.  Seven more washers were made up similarly.

    Eight of the bolts, complete with washers were now placed in the booth with the threaded ends projecting from the backside of the booth.  Tipping the booth back upright, a difficult job for one person to handle, reattaching the top panel, began.  First off, the foam needed to be compressed to half its thickness to allow the projecting ends of the bolts to align with the hinge holes.  Placing the bar clamp next to the hinge on the end, I tightened the clamp until the two bolts aligned with the hinge holes.

    The next step had me puzzled for a bit, namely how to tighten the bolt when I could only reach one end of the bolt at a time by myself.  I solved this by clamping the nut in the jaws of a small pair of vise grip pliers.

    Now I was able to reach inside the booth with a straight slot screw driver.  With the resistance provided by the weight of the pliers, I was able to tighten the bolt. 

    This method was repeated for three hinges, but the last hinge was a slightly more difficult problem, in that the plenum framing would not allow me to reach through the booth to reach the bolt with the screw driver.  Once again I used the bar clamp to align the bolts with the hinge and loosely installed the washer and nut to keep the foam compressed.  Tilting the booth down on its backside once again, the top panel was allowed to drop down leaving me access to the inside of the booth and the slotted end of the last two bolts.

    I tried several methods of doing these last two bolts but was unable to keep the bolt from turning with the nut until I sort of discovered by accident an easy way to do it.  Inserting a nut driver in my impact driver, I set it on the nut and kind of goosed the trigger several times.  To my surprise, it actually worked. 

    Apparently the combination of the twisting motion when combined with the impact motion kept the bolt from turning in place and it tightened it down quite solid.  I could have saved a bit of hassle if I had realized it would do that with all the bolts!  Oh well, live and learn.

    Tilting the booth upright again, I took a photo of its current status.

 

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    I have a pair of draw catches to install that will pull the top panel down to compress the foam weather-strip and seal the plenum.  Unfortunately installing anything with screws into the edge of particle board simply splits it when pressure is applied (I tried that already), so I’ll need to come up with another method of attaching the catches.

    Today I took the Plexiglas window upstairs to my desk/bird playground to install the tear-off tapes. I cleared off a space to lay the window down flat and since you need both hands to apply the tape I used a piece of double sided tape under each end to keep it from shifting around.  Because my window is wider than the tape, I had to use two pieces of tape overlapping each other roughly one inch down the center.

    While trying to do this operation, I have one suggestion on how not to do this.  If your tape is on one of these useless dispensers, get rid of it and just use the tape directly from the roll.  It may work on taping packages, but it just got in the way here.

    I stretched out the first piece of tape aligning it by eye just inside the holes on the edge.  Securing the left end of the tape an inch or so beyond the end of the window, I stretched the tape while still on the roll about an inch or so beyond the other end being careful not to touch it down on the window yet.  With my left hand I smoothed the tape down onto the window from left to right trying to eliminate any air bubbles as I went. (Not as easy as you think!)  Once I had the whole length pressed down beyond the right end, the tape was folded back on itself forming about a one inch tab at the end.

    I repeated the steps above with the overlapping piece of tape, but the end of this tab was wrapped around the previous tab at the end.  This will allow me to pull just one tab to remove both pieces at the same time.  I placed three more layers similarly over the first one and trimmed the ends of the tape off on the left with a box cutter.

 

    To make it easier to separate the different pull tabs I decided to cut some different colored pieces of post it notes and tape it to the various tabs.

    Oh, and one more suggestion.  Once you have removed the window from the booth, make sure that you are putting the tape on the correct face of the Plexiglas or your screw holes will not line up properly when you reattach it to the booth. (Don't ask how I know this!) 

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     I think that I have come up with a solution now on how to install the draw catches.  Since the particle board is  so prone to splitting, I will need to reinforce the edge of the top panel to mount the hook portion of the catch.  A search ensued for some metal angle to use as a mounting plate.  I found a suitable piece of aluminum in my scrap pile that would need quite a bit of trimming.  However, since the admiral just bought this new coping saw with a special hack saw blade for me that I was anxious to try out anyway, I decided to use it.

    Here is the section of aluminum angle that the component was cut from.  The first step was to cut a 1 ¼” long section off of the angle.  As there was only one inch of clearance for the top of the plate on the left end, this latch was done first to test out my solution.  The two irregular edges were then cut off to give the angle two flat surfaces.

    Once the angle was cut and filed smooth I needed to drill two holes in the vertical legs to match the holes in the hook piece for some small bolts. (I don’t have any tools to tap holes in metal so I had to use the bolts instead.)  Then one larger hole in the horizontal leg was drilled for a heavy ½“ long screw.  Here is the angle with the needed bolts, flat washers, lock washers and nuts along with the screw for the top and the hook.

    Once the hook component was assembled it had the nuts and bolts projecting from the backside. So now they needed some clearance holes bored into the edge of the top panel.  Once the clearance holes were bored, the component was held in position and I drilled through the hole in the top of the angle into the particle board.  The heavy screw was then driven in to complete mounting the upper component of the draw catch.

    

    Now all that remained was to install the lower component of the catch.  As I mentioned earlier, the foam weather-strip has to be compressed to half its thickness so the top panel will seal it evenly.  So, before I could locate the screw holes for this part I used a C-clamp to pull it down.  Setting the bottom component in the latched position, a piece of tape was stretched over the mounting plate to hold it in place.  The catch was taped up out of the way and the locations for those screws were marked.

    Once the mounting plate was secured, all the tape was removed and the latch was tested to confirm that, it would in fact work as planned.

 

    Since my experiment worked out so well, I made a duplicate for the right end.  Since I had plenty of clearance on this end I mounted it on the front face of the booth.

    So here is the booth as it stands now.

 

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   I got back in the shop today to work on the booth once more.  First off, I tipped it down onto its back once again with the catches locked, being very careful this time since it is getting a bit top heavy now.  Unlatching the top panel, I tipped the top panel open and reattached the Plexiglas window. All the screws were driven in tightly and then backed off about a quarter turn so it could still expand if it had to.

   The top panel was latched closed now.   As I said, the booth is a little tippy in this position, so I placed a board across the far side with a half-gallon container of paint for a counter weight since the added weight of the light would make it more so.  Once safely balanced, the light fixture was reattached.   

     

    So, at this point I thought it was time for the acid test.  I tipped the booth upright again, routing the light chord around to the side and plugged it into the power strip.  The power strip was plugged in and crossing my fingers, I turned it on. Eureka!! It all worked.  There was ample light to work with (as you can see here) and as the fans amped up, the draw proved to be quite satisfactory.

 

    So I guess that all that remains to be done now is to decide which rolling cart will be used.  I will try using it to see if the height above the floor needs to be lowered for me or not.  The cart that it is sitting on right now has the advantage of having storage drawers on one side, but it will be harder to shorten the legs than the other one which has no drawers.  I think that I may also need to work out an exhaust duct system, although I plan on wheeling it outside on the driveway to use it.  Of course if it’s too cold or raining out that might prove to be a little inconvenient.

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     As per Murphy's Law, after being unable to locate my jig saw blades when I needed them (way back on post #2) for this project,  I found them today while looking for something else.