Hohner Gola... broken

[Sebastian Bravo]

Hi forum! long time not posting something. I hope everyone is ok. I've been doing my jobs with accordions as usual (Tuning, mechanic repairs, air leaks and things like that) but i've never had to repair celluloid... until now.

I recieved a Hohner Gola, that fell and broke. It has signs of been broken in the past in the same part (grill corners) and had an epoxy and celluloid repair job (which can be noticed because the new celluloid is darker than the original black, the corners looks darker, but only when pointed with a bright light)
It also broke in the top corner of the box, and had glue marks. Now every repaired part has broken again. Even some black keys had to be glued again.

I repaired the wooden corner with epoxy, now the air leaks are ok, then i made the same with the grill corners (Gotta paint that epoxy with black paint)

But it's time to work with the celluloid, to make it looks like nothing happened. Most of the celluloid in the corners of the grill is trying to separate from the aluminum, 2mm gap. There's also missing parts that broke.

It also has a 1/4 jack hole in the front of the grill and i would like to seal that too.

I have a broken Weltmeister with black celluloid. I want to try and test my technique with that one first, and then try it with the Gola.
Any tips?

 

[Dingo40]

Hi Sebastian,
Nice to hear from you again!?
Although I have no suggestions to offer, am very curious to hear any that may be made as this topic interests me too, but doesn't often arise !??

 

[debra]

Ouch! This repair is a tough one. I cannot help you on the aluminium repair. Obviously the "epoxy job" has proven to not be strong enough. There are some glues for metal. What you need to do first and foremost is to get the aluminium of the grille back in shape and glued together very strongly, and that only on the inside of the grille.
Once the grille is structurally solid you can start work on the Celluloid. If wooden parts are also in need of repair. Use the green labeled Titebond wood glue for that.
Working with celluloid isn't as daunting as you seem to think. You need to first of all have a clean surface, broken parts removed, missing bits are not a problem. Then, you need black celluloid. I don't know where you can source a relatively small piece of celluloid. Maybe from an accordion repair shop? I got mine from Carini in Castelfidardo, but in order to get a cheap usable piece you have to be there and browse through their stock of scrap pieces.
Celluloid dissolves in acetone. You soak a piece of celluloid in acetone for about 3 minutes until it becomes very soft (but not yet dissolves into a paste. Put the celluloid on the missing parts, making sure everything is covered. It is normal to put too much celluloid on, that will be sanded away later.
Wait for the celluloid to dry, which takes 24 hours. Then you can sand away all the excess, creating a smooth surface in the right shape. Sand manually and in circular motions. Note that celluloid is flammable and when you sand too vigorously it will self-ignite. Use finer and finer grain (100, 200, 400, 600 or 800). Often you will have sanded too much. Reapply celluloid (if you dissolve it more you can use it as a paste). Again wait for 24 hours, then sand again. After sanding you end up with a smooth but dull surface. Now you start polishing, with increasingly softer types of "soap". I start with a coarse (brown) one, then move to a soft/fine one (light beige). There are about 5 different levels of coarseness but I just use 2. You end up with a nice gloss in the end.
It takes practice, but the good part is that if you are not fully satisfied with the final result you can sand again, apply more celluloid, etc. So it's not a problem that your first celluloid job is on a Gola.

Good luck!

 

[Sebastian Bravo]

Thanks for your response, Debra.

The epoxy job was made in Germany, but after a fall, it obviously broke again.
Now the aluminium part was repaired by me. I used the hairdryer to heat the aluminium, then i shaped it back with hammer and other tools. Then, i used epoxy made for metal by "pegatanke" (Which is an epoxy that proves to resist 400kg of force and 700°C heat) but it's gray. Thats why i said i have to paint it black. It's very resistant, i applied a gentle coat of epoxy and it worked perfectly.

(The grill corner repaired)

(The epoxy glue made for metal)

Can i use a piece of black celluloid removed from the Weltmeister box? I'm sure i can cover every needed parts with a small piece of celluloid from that old abandoned accordion.

 

[debra]

In principle celluloid is celluloid, all the same. But of course you never know, especially with a very old Weltmeister box...

 

[nagant27]

This sounds pretty good and exciting. Celluloid repairs I thought were nearly impossible and I never tried it. I have a perfect accordion to test it on that I fixed a fracture, but you can see the line in the celluloid. Functionally it’s perfect but you can see the line that bothers me.
I may give this a try myself. What are the “soaps “/ polishers that you use specifically so I can buy them? At my job I’ve polished precious metal ending with a rouge, and acrylics with Tripoli.

 

[debra]

This sounds pretty good and exciting. Celluloid repairs I thought were nearly impossible and I never tried it. I have a perfect accordion to test it on that I fixed a fracture, but you can see the line in the celluloid. Functionally it’s perfect but you can see the line that bothers me.
I may give this a try myself. What are the “soaps “/ polishers that you use specifically so I can buy them? At my job I’ve polished precious metal ending with a rouge, and acrylics with Tripoli.

I got the polishing "soap" from Carini (when I was there, in Castelfidardo). They have 5 levels of "grain".
See http://www.carinidena.it/MS5ECOMMERCE60/jsp/eco_cc_home_bs_portlet.jsp?p=searcharti&w_ricgruppo='10FISA'&w_ricsgruppo='80LU'&w_riccateg='8030LU'
I do not believe these products are really specific to polishing celluloid. Other products should work as well.
In order to obtain a perfect result on the crack you need a little bit of black celluloid to work with (assuming the accordion is black). Most accordion parts that look like they are plastic are actually celluloid. So is you have some parts from an old scrap accordion you probably have a source of celluloid. Not only are celluloid repairs not "nearly impossible", I find them the easiest repairs on a material that looks like plastic.

 

[Sebastian Bravo]

Finished!


Thanks to everyone the results were 8/10. Pretty sure i will get better results with more practice.

 

[Corinto]

¡Muy bien Sebastian, enhorabuena, eres jóven y seguro que estás en el buen camino para convertirte un maestro importante!