Mike´s Gon Bops project

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Mike´s Gon Bops project

Postby Mike » Thu May 07, 2009 2:29 pm

Hola a todos!

Every man needs a goal and a task in life :wink: - so do I, which is why I am going to restore a 1970s Gon Bops mahogany set (conga and tumba) that I have acquired recently.
Their beauty is hidden under a layer of ugly paint, and the ladies have scratches and cracks all over their body...
Conga.JPG
CONGA 10.75"

Tumba.JPG
TUMBA 11.5"

Being a novice in Gon Bops, I have to rely on some of your expertise and advice, guys.

Here are some questions of mine:

1.
Reparing the cracks: TITEBOND III, Gorilla glue or even epoxy - what would U recommend?
And what about the black layer inside the drums: What is that, should it remain there?
I have got a bunch of cracks to fix that run through the whole shell. Fortunately, they are not all too long.

2.
Next step would be removing the reddish brown varnish - what is the best method that does
not harm the wood? Sanding?

3.
The bearing edge, which is pretty steep, should I leave it as it is?
Tumba bearing edge closeup.JPG

4.
Which new skins would U recommend? The old ones are pretty worn out. BTW they are not too thick,
ab. 2 - 2.5mm, maybe because the hardware cannot take thicker skins? The sideplates are alright, the hooks too, but the backing plates and the bolts look a bit on the weak side.

5. To regain the original mahogany wood color, what finish is best? Varnish, tung oil etc.?

Anyway, there is plenty to do.
BTW there is no Gon Bops badge whatsoever, but allegedly they are GBs

So, please take a look at the photos and bombard me with constructive suggestions, keeping in mind that I am not that much used to brittle old ladies like these two :)
Last edited by Mike on Thu May 07, 2009 5:32 pm, edited 5 times in total.
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Re: Mike´s Gon Bops project

Postby Mike » Thu May 07, 2009 2:34 pm

Here are some pics of the conga´s wounds:



Other crack in conga.JPG
Conga crack.JPG
Conga crack at bottom.JPG
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Re: Mike´s Gon Bops project

Postby akdom » Thu May 07, 2009 3:02 pm

Hi

Nice project.

Sanding is fine, no problem. I suggest to fix the cracks after sanding...

The edge should be 45° so do not hesitate to sand it too. You can apply wax to it also so that the skin suffers less the tuning.

I prefer polyurethane marine varnish (not gloss) applied in several coats with fine sanding in between.

Good luck.


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Re: Mike´s Gon Bops project

Postby Mike » Thu May 07, 2009 3:08 pm

And here is the tumba at a closer look.
I wonder how I remove the foot ring if I repair this one:
Crack in Tumba.JPG
Crack Tumba bottom.JPG
Tumba bearing edge + interior.JPG


So these are the major wounds, not to mention the numerous little cracks, especially at the bottom.
The footring does not cover all of the wood!
The other minor chips and scratches should be tackled with wood filler I guess?
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Re: Mike´s Gon Bops project

Postby vinnieL » Thu May 07, 2009 3:13 pm

I personally would not mess with the bearing edge unless your absolutely sure you know what to do and what the end result will be.
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Re: Mike´s Gon Bops project

Postby deadhead » Thu May 07, 2009 3:18 pm

The foot ring should only be held on by 3 tacks. I'm doing a resto on my super tumba and had no problems at all getting the foot ring off last night. Use a flat head screw driver and lightly tap it with a rubber mallet in a sort of criss-cross pattern around the foot ring, shouldn't be very hard to do. I'd suggest gluing the cracks at the bottom first, they will open up a lot more when you take the ring off.
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Re: Mike´s Gon Bops project

Postby vinnieL » Thu May 07, 2009 3:26 pm

Mike good luck with the congas i look foward to seeing the end result titebond III is probably your best bet and i'm sure most here would agree. They should end up being a gorgeous set. I would contact SalseroBoricua as far as finish his work refinishing congas is nothing short of spectacular.
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Re: Mike´s Gon Bops project

Postby deadhead » Thu May 07, 2009 3:29 pm

As for the bearing edges, there are alot of misconceptions when it comes to this subject. You should not be worried about the degree of cut. The only thing you need to worry about is that it is level. Put it on a flat level serface and shine a flashlight into the shell. If you see light comming out anywhere on the bottom then you have a problem. A good bearing edge has little to do with the degree, but whether or not you are getting a 100% even seal around the drum. Do the flashlight test and if you don't see any light, don't touch the bearing edge.
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Re: Mike´s Gon Bops project

Postby Mike » Thu May 07, 2009 3:33 pm

vinnieL wrote: They should end up being a gorgeous set.
I would contact SalseroBoricua as far as finish his work refinishing congas is nothing short of spectacular.


Thanks so far, your advice really has helped me already!

As to the bearing edge, I think I´ll leave it as it is. The sound of the two drums was quite promising considering the skins were old, no ringing, a really wooden and round tone.
Conga bearing edge.JPG


I guess after sanding I will glue all cracks, like this one:attachment=0]Crack at bottom.JPG[/attachment]
Which grain would you recommend to remove the varnish? I am a bit anxious to take away too much of the original GB substance.

Yes, Steven is da restoration man, no doubt, I remember the thread about the LP congas - most amazing
Let´s not forget the terrific job Bongosnotbombs has done on his oak Gon Bops either!
Geordie, you have already given me some highly useful input when I still did not have the set, thanks again.

Anyway, I will need further assistance, that is pretty sure, so please let the ideas come pouring in, hermanos!

Edit: Can anyone guess how old these congas are? The seller was way younger than me and did not know :wink:
Attachments
Crack at bottom.JPG
Last edited by Mike on Thu May 07, 2009 7:15 pm, edited 1 time in total.
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Re: Mike´s Gon Bops project

Postby bongosnotbombs » Thu May 07, 2009 4:02 pm

Mike,
Nice set of drums, it's going to be a fun project. Those are certainly Gon Bops drums. Philipine Mahogany.
The look like early 80's or late 70's drums to me.
The bearing edge you are showing in the pictures is the factory bearing edge these drums were made with.
Gon Bops edges are pretty flat. You can use a sanding sponge to smooth it out with though, it looks a little rough.

The black stuff on the inside I would leave it there, only because I know what kind of hard work
it would be to get rid of it all. I can't see how it is hurting the drums being there.

For the finish on the outside, just sand it the old fashioned way. Do not use an orbital sander, this wood is soft
and the orbital sander will leave round swirls. Those swirls were all over my GB. Just do it by hand, it's an easy object
to sand, just set it down and sand up and down, rough to fine sandpaper. Start of with 100 grit paper. 80 is probably too rough.
I don't like wood filler, I just smooth out the dents and scratches as best I can. It depends on what you finish the drum with.
I used oil, which is transparent, and you can never get the filler to match 100%. If painting then it doesn't matter.

Either Titebond or Gorilla glue. I used both on my drum. The thing is, it can be difficult to get into a
tight crack to get enough Titebond inside of it, the Gorilla glue will expand and get into the tight little
spots and actually create a better bond. Whatever glue you use, get a plastic syringe so you can squirt
it into the really tight spots.
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DSCF8887.JPG
an original Gon Bops bearing edge on the left.
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Re: Mike´s Gon Bops project

Postby Mike » Thu May 07, 2009 4:43 pm

bongosnotbombs wrote:The bearing edge you are showing in the pictures is the factory bearing edge these drums were made with. Gon Bops edges are pretty flat. You can use a sanding sponge to smooth it out with though, it looks a little rough.
(...)
For the finish on the outside, just sand it the old fashioned way. Do not use an orbital sander, this wood is soft
and the orbital sander will leave round swirls. Those swirls were all over my GB. Just do it by hand, it's an easy object to sand, just set it down and sand up and down, rough to fine sandpaper. Start of with 100 grit paper. 80 is probably too rough.


Thank you so far for all the details, BnB,
next thing I will do is gather all the materials and maybe start at the weekend.

The bearing edge is has really become a bit rough, but with a little smoothing it should be fine.
I remember the thread about your Gon Bop restoration now when everyone hotly debated the shape of GB bearing edges...

OK, I surely want to avoid round swirls produced by orbital sanders, so some elbow grease will be needed for sanding, but that will be some fun on a nice spring weekend on my roof terrace :)

Depending on my progress, I will post more pics.
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Re: Mike´s Gon Bops project

Postby bongosnotbombs » Thu May 07, 2009 5:14 pm

Other%20crack%20in%20conga.JPG
Your lugplate looks upside down.

In this pic you posted, it looks like the lug plat is upside down.
Because of the shape of the plate it's harder to tell which side is
up. The other pics seem right.

The two peices of metal that are riveted to the plate should be flush on
the bottom.

When I got that quinto all the plates were installed upside down, and I put
it back the exact way it came to me, wrong! I found out the right way later on.
post-14-78877-DSCF8754.JPG
Mine were also upside down.

DSCF0694.JPG
These plates are right side up.
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Re: Mike´s Gon Bops project

Postby Mike » Thu May 07, 2009 5:22 pm

Uh-huh! That is good to know.
Thank you, that is all highly useful information, so when I remount the sideplates
that I am going to number on each drum, I will be able to put them the right way up.
Great, I would have never known about that at all :D

One further question: As you can see in one of the pics, some of the bolts´n´nuts in the inside
have a really tiny washer. Finding a bigger one is no problem, but: Would it be more useful to use a
backing plate instead of the washers - just like may LP Congas have? That would add to stability perhaps, but also to the weight. I love the lightness of the drum very much.

On the hand I like the idea of keeping as much of the original Gon Bops stuff as such,
but on the other hand sometimes it is "safety first" :wink:
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Re: Mike´s Gon Bops project

Postby bongosnotbombs » Thu May 07, 2009 5:38 pm

On the hand I like the idea of keeping as much of the original Gon Bops stuff as such,
but on the other hand sometimes it is "safety first"

I kept the original hardware, except I added the handle of course. Bigger washers would be
cool. A backing plate might be good to, but I'm not sure it would be worth the extra effort to make one, as
opposed to just getting a few new washers for a couple pennies at the store.
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Re: Mike´s Gon Bops project

Postby Mike » Thu May 07, 2009 6:13 pm

For my vintage 1980s Supercussion bongos I made some backing plates on my own
and, by placing pieces of a thin and foamy mousepad behind it, protected the somewhat brittle
shell made of fir, ("Douglasie" or some other wood).

Because you also mentioned the brittleness of the mahogany wood, I will consider the idea of backing plates,
as they they spred the tension more evenly.

Still another thought (and it is really fun, this project): You have got cow skins on your Gon Bops congas, do you?
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