chromatic

Hohner made three different models of 10-hole chromatic, all out of production as of 2013. Their smaller size can often mean a nice airtight instrument.

The #260 was Hohner's first chromatic and came in two versions, one tuned like a diatonic with a slide and the other tuned like a standard chromatic.

The Koch 980 was inherited when Hohner took over Koch around 1930. It was tuned like a diatonic and had no valves. Valves make a chromatic far less leaky but prevent blow and draw reeds from interacting during bends.

The Slide Harp was like the Koch but with valves, and was produced for awhile in the 1990s.

All three models have reedplates nailed to pearwood combs like the Marine Band.

FIRST STEPS

You can remove the covers and disassembled the mouthpiece/slide assembly and clean those in warm, soapy water. You may have to scrub off accumulated crud.

When disassembling the mouthpiece assembly, make sure to keep the bumpers, the two short plastic tubes that protect the cover screws from impact with the slide. These both reduce slide noise and keep the slide from damaging the screw threads. If you lsoe these or they have disintegrated, you can replace them with material clipped from the end of a ball point pen refill.

When cleaning the slide, lay it on a flat surface with the button hanging off the edge so that the slide stays flat when any pressure is applied.

The white powder you mentioned is probably Barkeeper's Friend, an abrasive scrubbing powder that is fine enough not to leave visible scratches. Harmonica players do use it to clean reedplates.

The comb/reedplate sandwich is the most problematic part when cleaning. You don't want to get the wood wet and risk swelling, warping, and shrinkage when it dries. (This includes ultrasonic cleaners, which require immersion in liquid - dangerous for wood combs.) Cleaning can follow two paths:

PATH 1 (easy)

Get an ozone sanitizer, which uses ozone gas to disinfect the reedblock. This won't remove crud but will sterilize whatever's in there and may take care of odors as well. Here's one marketed especially to harmonica players:

https://www.turboharp.com/harmonica-bug-blaster/

PATH 2 (detailed)

You can pry the reedplates off the comb with a broad-handled knife that's at least as long as the harmonica, and then clean the reedplates and comb individually.

Before you start, prepare two strips of adhesive tape (one for each reedplate), with the adhesive side up, to receive and store the reedplate nails.

With the covers and mouthpiece assembly removed, inset the knife under one of the ends of the reedplate.

When you use a knife to pry up reedplates, you don't want to dig the blade edge into the wood. To avoid doing this, rotate the knife handle to push the edge of the blade up into the reedplate, pushing the reedplate up and pushing the knife blade away from the comb.

If the nails come loose, place them on the tape in a sequence that will allow you to replace each nail in its original hole, as nails often are slightly bent just below the head and will seat best when placed back in their original hole.

Pry up both ends, then insert the knife along the back of the comb (i.e., not the side with the holes) and pry up the back, again storing any nails on the adhesive tape.

Once you have the reedplates disassembled from the comb, you can treat both the comb and the reedplates.

The Comb

The comb, if it is very old, may split into right and left parts. Combs were commonly glued together from two pieces of wood, and can usually be re-glued, taking care to keep a completely level surface on the top and bottom where the reedplates are seated, and along the front, where the mouthpiece assembly is mounted.

I've had very old pre-war combs simply disintegrate during disassembly. You can buy replacement combs from Hohner. I'm not aware of anybody making aftermarket combs at the present time.

You can brush any accumulated gunk off the comb, and even scrape it provided you don't dig into the wood.

Optionally, you can flatten and seal the comb.

• You can flat sand the top and bottom comb surfaces if they show saw marks or signs of unevenness

• You can seal the comb by hanging it up from a thread looped through the coverplate holes, and spray it with acrylic spray, using a light application to avoid drips, and applying tow or three coats at the time intervals recommended by the manufacturer.

The Reedplates

If the reedplate is valved and you don't want to replace any valves, a light application of Barkeeper's Friend or fine metal polish such as MAAS will serve to clean the surrounding surface of the reedplates, using a cloth and finger pressure while holding the reedplate between thumb and forefinger.

As chromatics have reeds on both sides of the reedplate, I don' recommend applying pressure to the reedplate while it is laid on a flat surface, as the pressure may change the profile of the reeds on the downward facing side.

If the harmonica is valved, check for any loose valves that may need to be re-glued. Also check for any valves that appear twisted or that don't lie flat, as these may cause unwanted noise during playing and should probably be replaced.

REASSEMBLY

When reassembling the reedblock, place one of the reedplates on the comb. Make sure it’s the right one, top or bottom, and that the reed lengths match the lengths of the slots in the comb. (Sounds basic, but you’d be surprised how easy it is to get this wrong!)

Insert the nails into their holes, and use pliers to press them into their holes. You can also use a nail punch with a flat head to gently tap them down with a small hammer.

With the second reedplate, you can follow the same procedure, but be careful not to affect the reed profiles on the first plate, which is now no the bottom.

Check the front edge of the reedblock to make sure that the front edges of the reedplates are flush with the front edge of the comb. If they’re not, that can be a major source of air loss. Not sure I want to go into that topic right now, so fingers crossed.

Lay the backing plate on the reedblock, followed by the slide.

On these models you can play the slide upside down so that instead of a C harp that goes up to C#, it’s a C# harp that goes down to C when the slide is pressed. Some players prefer this setup, which is known as flat-slide. Lay the slide on the comb and look at which set of holes are revealed, top or bottom with the slide at rest. If it’s the top set, that’s what you want for standard slide placement.

Make sure the slide spiring is engaged with the hole in the side before proceeding.

Place the U-channel over the slide, making sure that its locking tabs engage with the notches in the backing plate.

Insert the mouthpiece screws in their holes in the mouthpiece and slide the bumpers onto the screws.

With the back of the harp laid on a level surface, guide the screws into their holes in the comb. You may have to press the slide in slightly to uncover the right hole, which can get a bit fussy.

Tighten the mouthpiece screws gently, making sure that all layers are in alignment.

For final tightening, first tighten one of the screws until the slide binds (doesn’t move freely) and then back off a quarter turn, or until it moves freely. Do the same for each screw in turn until you get a satisfactory combination of slide movement and airtightness.

This may seem like a huge amount of detail, but there is much more.