The Thrifty Gadgeteer

OK you mashers, let us harken back to a time in the dim past (last year) when Thrifty taught you how to make your very own brewpot out of a stainless half keg. You may recall that I alluded to the fact that the basic design for the brewpot would serve as the foundation for a mash tun, and that I would be covering the necessary accessories in future issues. Well, I guess it's time I finally got around to it, so, this issue we'll talk about making a screen plate to separate the solid mash residue from the liquid runoff. You will, of course, have to build a second brewpot assembly first, and then use the accessories we'll be discussing over the next few issues to convert the second brewpot into a mash tun. By the way, for those who tuned in late, or weren't paying attention (shame!), or lost those precious earlier articles (double shame!!) and have not yet built the basic brewpot, reprints can be obtained by contacting our fearless leader, Editor Bill Metzger at the Great Lakes Brewing News. Bill will, in exchange for a nominal fee and a confession of guilt or plea of temporary insanity, provide the requisite text (ask for Volume 1, Numbers 2, 3, & 4).

You have probably seen screen plates advertised in the various homebrew mags, where they go for up to fifty bucks, sometimes more. If you don't have the time, or the tools, or the patience, or are all thumbs, or just can't be bothered, then I suppose it might be worth the fifty bucks. But if you happen to be an industrious and stubbornly cheap SOB like me, then making your own for less than ten dollars is the only way to go.

Making the screen plate is a relatively simple but labor intensive project. Basically, you will have to cut out a circular piece of stainless steel sheet metal to fit the bottom of the converted keg brewpot, then drill a seemingly endless number of small holes in it, and finish up by fabricating and attaching a small lifting handle. To do this you will need a 16" square piece of 3/64" thick (you can use 1/32" or 1/16" as well) stainless steel sheet metal, a hammer, a center punch, a power drill with a 3/32" titanium coated or cobalt alloy drill bit, a 3/8" drill bit, a 9/64" drill bit, a sabre saw with 18 or 24 tooth per inch bimetal blades, two #6-32 X 1/4" (or 3/8") stainless steel screws with nuts, a fine half-round file that will fit into a 1/2" diameter hole, a 16" or longer metal rule with 1/32" divisions, a small square rule, a large drawing compass, a pair of diagonal cutting pliers, a spray bottle of water, work gloves, safety glasses, a bench vise, and a scratch awl or scribe. The stainless screws and nuts will cost about ten cents each, and the stainless sheet metal can be got at almost any scrap yard for the cost of a good six pack (you might even be able to barter with a six pack of your own brews, if you can bear to part with 'em).

Start out by placing the stainless sheet metal on a flat surface, measure and mark several widely spaced points 5/8" in from one side, then use a straight edge to draw a straight line through those points so as to define a 5/8" wide strip along the entire length of one side of the 16" square. Now put on your safety glasses and work gloves and use the sabre saw to remove the 5/8" strip, which you should set aside for later use. Stop sawing every inch or so and use the spray bottle to cool both the saw blade and the work piece. Next, use the straight edge to draw connecting lines from corner to opposite corner diagonally across the resulting 15-3/8" X 16" rectangle. Use the center punch and hammer to mark the center point of the rectangle at the point where the two diagonal lines cross.

Next, set the compass to a 7-1/2" radius and draw a 15" diameter circle around the center point. Repeat this with the compass set to a 7" radius to form a 14" circle. Measure the width of the drain tube on the brewpot assembly and set the compass to draw another circle just big enough to accept the drain tube with no more than 1/16" clearance (the hole diameter should be just slightly over 3/8" for a 3/8" drain tube, or just over 1/2" for a 1/2" drain tube), then set the compass to a 1/8" larger radius and draw a final circle. The layout should look like Illustration "A".

With that done, put on your protective gear and use the power drill with the titanium coated or cobalt alloy bit to drill a series of holes around the inside of the smaller drain tube circle, with the outside of each hole just touching the inside of the circle. Drill the holes as close as possible to each other without actually touching, and remember to pause frequently to cool both the drill bit and work piece with water. Now use the cutting pliers to snip the thin strips of material between holes, leaving a single roughly circular hole in the center of the rectangle. Finish the hole by using the half round file to remove the irregular material around the inside of the drain tube circle, leaving a uniformly circular hole just big enough for the drain tube to pass through freely.

Next, use the sabre saw to cut out the 15" diameter circle, then use the file to remove any burrs and sharp edges. Now comes the "fun" part. Use the metal rule and scratch awl or scribe tool to lay out a uniform grid of 5/32" squares across the entire surface of one side of the work piece. Then use the center punch to set a drilling point at each grid intersection, avoiding the area outside of the 14" diameter circle and inside of the 1/8" larger circle around the drain tube hole. Drill a 3/32" hole at each drilling point, pausing frequently to cool the drill bit and work piece. After every ten holes or so, use the 3/8" drill bit to remove the burr on both sides of each 3/32" hole. I won't lie to you, this is gonna take a lot of time and will be extremely boring (no pun intended), so it might be a good idea to split each task (layout, point setting, drilling, and deburring) into several sessions so you don't go bonkers or get sloppy and careless.

The final part of this project is to fabricate and attach the lifting handle. Get the 5/8" wide strip of stainless material and cut off a 5-3/4" length (save the rest for future projects). Use the file to remove all burrs and sharp edges. Starting at one end of the 5-3/4" strip, mark the strip at the following intervals: 3/4", 1-3/4", 4", and 5". Use the square rule to draw a perpendicular line across the strip at each mark. Also draw a center line, 5/16" from each side, down the entire length of the strip. Mount the strip in a bench vise so that the line at the 1-3/4" mark is exactly parallel to and just barely visible above the top of the vise jaws. Now carefully bend the strip to a 90 degree angle. You might need to use a hammer to coax the strip into the proper position. Now remount the strip at the 4" line, and make another 90 degree bend so that the strip is now formed into a squared "U" shape. Make two more 90 degree bends at the 3/4" and 5" marks respectively so that a "foot" points outward from each "leg" of the "U" (see Illustration "B"). The lifting handle should now be about 3-1/4" long from the tip of one "foot" to the tip of the opposite "foot".

Next, measure 1/4" in from the end of one "foot" and set a drilling point on the center line, then drill a 9/64" hole at that point and deburr the hole on both sides. Now place the handle on the screen plate with the "feet" down so that the hole in the one "foot" is aligned with one of the holes in the screen, as close as possible to the outer edge of the screen without any part of the "foot" touching the edge of the screen. Slide a 3/32" drill bit through the aligned holes, then pivot the handle until the opposite "foot" is also positioned over a screen hole, approximately 1/4" from the end of the "foot", as close as possible to the outer edge of the screen without any part of the "foot" touching the edge of the screen. Use the scratch awl to mark the position of the screen hole onto the "foot", and to clearly identify the two screen holes, then remove the handle from the screen plate. At the mark on the remaining undrilled "foot", set a drilling point on the center line, drill a 9/64" hole at that point and deburr the hole on both sides. Also run the 9/64" drill through each of the two marked screen holes and deburr. Now reposition the holes in the handle over the corresponding holes in the screen plate and fasten securely in place with the #6 stainless screws and nuts.

To mount the screen plate in the mash tun, remove the drain tube assembly and insert the shorter leg of the drain tube through the center hole in the screen plate from the handle side. Grasp the handle in one hand and lower the screen plate into the mash tun until the edge opposite the handle touches bottom. Using your other hand to guide the long leg of the drain tube, slide the screen into place while guiding the drain tube into its fitting on the side of the pot. Thread the compression nut on by hand, then tighten the nut with a wrench until just snug - do not over tighten. Reverse this procedure to dismount the plate for cleaning.

OK, that does it for this time around. Next issue we'll talk about through-the-wall mounts for two different styles of dial type thermometers. Until then, happy drilling!

Your crusader for cost containment,

The Thrifty Gadgeteer

Copyright 1997, Great Lakes Brewing News. No material herein may be reprinted without permission of the Great Lakes Brewing News Distributed On the W3 For personal, non-commercial enjoyment and use only. Cheers!