Replacing your Hohner Basso Melodica bladder

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This topic contains 4 replies, has 3 voices, and was last updated by  Melodica-Me 1 month ago.

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  • #5446

    Melodica-Me
    Participant

    Bladder Replacement for Hohner Basso Melodica
    By Oscar Verdugo

    We recently discussed on Melodicaworld.com the topic of Bass Melodica bladders and the material needed to replace existing worn-out deteriorating bladders. I would like to offer a “Step by Step” DIY how to on replacing your basso bladder. That was a mouth full. Take your time and read this article completely and make sure you have everything you need before you get started. As noted above, I will be replacing a Hohner Basso bladder, but the principle should apply to the Suzuki and Hammond Bass Melodica’s as well.

    The following materials will be needed:

    A flat surface with open ventilation to work in
    Small flat head screw driver
    Clean rag to apply acetone and cleaners
    Citrus cleaner (goo gone)
    Pure acetone (your wife’s nail remover will work fine)
    Contact cement (see pictured)
    lue masking tape
    White sheet of paper
    Pencil or crayon
    Skewer / rochettes
    Exacto knife or a razor blade
    Rubber neoprene sheet, available at (www.zorocanada.com)
    You will need the 1/64 in T, 12×36 inch; sorry this is the smallest they offer.
    Cost is about $8.00 plus shipping.

    Hohner Basso Melodica

    Step 1
    Removing the bladder
    Remove your moisture cap and mouthpiece and cover them in blue masking tape. Before removing the back, place a piece of tape on one side of the back cover and on the side of the melodica to know what side the holes will align too since they will not be visible once the new bladder is installed.

    Remove the (7) screws from the back.

    With the Exacto knife cut around the non-removable bolts leaving the existing rubber if it is not worn out or deteriorating.
    Remove all the worn out rubber (see picture) to not over remove.

    Remove the (4) screws with washers

    src=”http://i355.photobucket.com/albums/r445/BigPwr/Hohner%20Bladder%20replacement%20pictures/195c3e28-2b68-4659-8db8-ab165808cfd9.jpg” alt=”” />

    Cover the (3) sound holes with blue tape prior cleaning off the glue so nothing drops in.

    Trim around the fixed bolts leaving the old rubber in place

    Step 2
    Removing the existing glue
    Cover the edges of the melodica as not to damage the plastic when removing the old glue on the metal back. VERY IMPORTANT!!! If your bass melodica has a plastic back below the rubber bladder DO NOT use acetone. Use a citrus cleaner. This will take a bit longer to remove where as the acetone works very fast on metal.

    Remove all the existing contact cement completely so there is nothing left on the
    surface and it is flat and clean.

    Step 3
    Prepping the melodica and bladder
    With blue tape cover the center portion of the melodica back, the two areas of rubber not removed. Once you have placed the blue tape as needed you will need to cut your rubber bladder about a 1/4 to 3/8 of an inch bigger than your melodica.

    Make sure that once you have cut your rubber that you clean it with warm water and soap. Dry it completely and lay it over your melodica to get use to its position. Once you are confortable wit the position remove your bladder an mirror the blue tape on your melodica. Making sure that they both align with eac other.
    Practice laying your bladder over your melodica back to get use to the position.

    Melodica back prepped for gluing

    Melodica back and bladder prepped for gluing

    Step 4
    Gluing your bladder material
    Once you have made sure that your bladder and melodica back mirror. Lay your bladder next to your melodica and with a brush paint a thin cost of contact cement on the non-taped surface areas.

    Contact Cement

    Applying contact cement on Melodica

    Applying contact cement on the Bladder

    Do not put to much as it can clunk up and get messy. Do not place more than (1) layer of glue on your back and bladder.
    Once the glue has dried (read the instructions on the contact cement bottle label for the suggested drying time) remove the blue tape from the bladder and the melodica leaving only the blue tape on the sides of the melodica for protection.

    Melodica back

    Bladder

    The next step did not get photographed so pay attention. Lay 5-6 pieces of woo skewers on the back of the melodica, placed gently with equal spacing (Not shown)

    Flip the bladder over the back of the melodica laying the bladder on the skewers gently. Once the bladder is aligned with the back of the melodica, remove the center skewer pushing the bladder on to the back of the melodica making contact. Working your way from the center to the left and from center to the right,
    removing a skewer slowly then pushing down the bladder after each skewer removed until all the skewers are out. Gently press the entire surface carefull with your fingers, making sure you do not gauge the new rubber bladder. The bladder is now attached to the back of the melodica.

    Step 5
    Trimming the bladder.
    Once the bladder has been installed with a sharp Exacto knife or razor blade tri the excess rubber from the bladder.

    Tip: There is a slight grove between the back and the sides of the melodica where you can gently palace the tip of the blade and use it as a guide. Once all the rubber has been trimmed you can remove the rest of the blue tape.

    Gently cleaning the melodica with citrus cleaner to remove any excess glue on your melodica, clean and prepare to trace out the screw holes under the bladder.

    Step 6
    Re-installing the screws and metal back.
    Now that your bladder is installed you need to install the (4) screws with washers through the bladder to the back. The best method for this is to get a white piece of paper and place it over the bladder and tape it down.

    With a pencil or crayon rub the back of the melodica to see where the holes are. Take your time here and make sure you are placing the screws in the right place If you rush this part you can wind up putting a hole in the bladder and you will then have to start all over again. You can measure the screw holes for placemen but the paper and pencil/crayon trick works every time. Now that you have found all your screw holes gently push the screw through the rubber checking for depth, proceed with the installation of the screw with the washer all the way in until set. Do not over tighten; this can cause the screw to strip the thread or crack the screw base.

    Once you have installed the (4) screws with washers, your melodica is ready for
    its back cover. Before screwing check to make sure you have the melodica back
    in the right position (position the tapes as originally placed at the beginning)

    Once you position the back cover in its proper location, screw the (7) screws back in place. Replace your moisture cap and mouthpiece. You are now ready to play your basso.

    When possible apply a rubber treatment on your bladder to keep it soft and
    prevent it from drying out and becoming brittle.

    Oscar Verdugo
    Monsters of Melodica

    #5447

    Alan Brinton
    Participant

    Too marvelous for words! This is an incredibly valuable tutorial, Melodica-Me. I don’t know whether I’ll outlive my bladder or not (B-24 bladder, that is), but there’s no place else where any of us could get this information. This is what Melodica World is all about. I may try replacing my bladder with a thicker one, or blocking one or two of those holes, to see if I can make it playable for me. The sound is so good. Fine looking Basso.

    #5449

    Melodica-Me
    Participant

    Thanks Alan, the 1/64 thick bladder is about double of the Hohner and about the same as the Hammond bass melodion which is thick. there is a 1/32 you can try as well from the same supplier. If you would like to try the 1/64 I would be more than happy to send you a piece so you don’t have to buy a whole role.
    Melodica-Me

    #9434

    Dan Leary
    Participant

    Melodica-Me, thanks for the write up. I’m about to replace the bladder on my basso and this helps a lot.

    There’s a wide range of neoprene sheets available from McMaster-Carr. Several options for hardness, strength, food grade, thickness seems to start at 1/64 inch.

    You report on the another thread thread that playability improved after your replacement. Perhaps the hardness rating of the material is also a factor, softer being “springier” (but perhaps also more delicate).

    Your procedure also appears to have resulted in a larger air volume under the sheet than was there originally, you seem to include the 4 felt washer backed rivets in the air space. Any idea what the function is of those 4 rivets? Adds mass to the backing plate which might affect resonance, but I can’t see any other purpose.

    #9435

    Melodica-Me
    Participant

    Hello Dan, If you are on Facebook, go to our Monsters of Melodica page and send me a message with your mailing address and I will send you a small piece of neoprene that will be enough for your replacement project, just pay for the shipping. The original material that was removed seam actually thiner but I did not have a way to measure the thickness so the closes I could fine was 1/64″ I do not have an answer for the (4) rivets since there was no need to replace open the melodica. You just need to put contact cement around them so the seal can be made. Also make sure you use a sharp exact to cut the neoprene, make sure you take your time in cutting the neoprene if you cut in the wrong place you will need to start over. Please take pictures and post and share with other Melodican’s here.
    Thanks and I hope this helps you
    Melodica-me

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