Questions about bass making tools

M_A_T_T · #1 10-22-2005, 11:55 AM

I'm nearing the varnishing stage of my violin, and am starting to think about my next instrument. I think an upright would be the ultimate challenge to make, and I'd love to try one. I have a few questions regarding tools & processes:

Bending iron - Did you buy a commercially availabe one, or make one? If you made one, is it the propane torch/aluminum pipe design?

Body clamps - Did you buy or make these? I made them for my violin, based on the German Herdim design.

Gluing tables to ribs - Do you let the hide glue gel, then clamp the table on, and then go around re-activating the glue with heat and/or steam? Do you also size the area first? I did something like this on my violin.

Amount of glue - How much glue do you generally cook up when gluing on a table, for instance? I think make around a teaspoon when working on my violin.

I will be getting 'So, you want to make a double bass' by Peter Chandler with all the plans, as well as Harry Wake's bass making book, and I was just talking with a local supplier of spruce and figured maple that does custom cutting, so I'm set for wood.

Thanks for your help.

nicklloyd · #2 10-24-2005, 11:21 AM

Hey M A T T, I think I'm in your neck of the woods this week... are you in Vancouver? What's yer phone #? PM me if you get a chance...

I built a bending iron with a heating 500 watt heating cartridge set into a 8 1/2" curved block of aluminum. All you need to control the heat is a 600 watt dimmer switch. However, you also have to make a wood pattern of the desired iron, take the pattern to a foundry, have the thing cast, then take the piece to a machinist and get a hole drilled out for the 6" x 1/2" heating cartridge to go into the iron. This is pretty much a copy of a GEWA-style bending iron, but it's much cheaper than paying the Germans to make it for me. You could build something simpler and with less work, but this iron will last me a lifetime.

Glueing tops and backs to ribs is done a number of ways. I prefer to first size the endgrain in the body blocks, dry clamp the plate to the rib structure, then proceed to glue the top on in similar fashion to closing an open seam. You do one section at a time, and it's much easier to control how you work and insure the top/back is properly lined up at all times.

g/l.

M_A_T_T · #3 10-24-2005, 07:39 PM

I'm in Langley.

Your method got me thinking. I already have one the the 'violin/guitar' bending irons, so I ws thinking I could just replace the aluminum casting unit. Here is a shot of my iron with the cast off:

Here is a plan for the new cast:

I have the means at work to build this, from solid stock I'd machine on a lathe. What do you think?

Ken McKay · #4 10-24-2005, 10:35 PM

I have a 2 inch diameter galvanized pipe with a squashed charcoal lighter element inside. I am not sure but I believe the galvanized metal is toxic when burned, but mine seems fine. I have bent a lot of wood with this and it works just fine. But I don't like the cylinder, preferring an egg shaped iron. I would like one of Nicks!

I have an Idea for a cheap bending iron made from a silicon blanket over shaped wood. Kinda like this (one on the right)

http://www.olsonguitars.com/shop_bodyAssem2.html.

Look at the photos in Olson's shop, he is the jig meister. Olson made James Taylors guitar and is backloged forever.

I make guitars too and have adapted the heating blanket to my side bending for making basses also. The bending jig is known as the Fox bender after Charles Fox who invented it.

The silicon blankets are not that expensive. I believe a 10 by 24 inch one would be less than $100 USD.

arnoldschnitzer · #5 10-25-2005, 06:22 AM

Quote:

Originally Posted by M_A_T_T

I'm in Langley.

Your method got me thinking. I already have one the the 'violin/guitar' bending irons, so I ws thinking I could just replace the aluminum casting unit. Here is a shot of my iron with the cast off:

Here is a plan for the new cast:

I have the means at work to build this, from solid stock I'd machine on a lathe. What do you think?

I think that the round profile is not what you want for bending bass ribs. That said, I love your idea of placing a smaller cylinder on top for linings and purflings. By the way, do you keep the alcohol handy in case of flare-ups?

Eric Jackson · #6 10-25-2005, 08:40 AM

MATT, when you say "body clamps" do you mean spool clamps like these ? If so, you can make them far cheaper than you can buy them. Check out page two of this thread, it details how I made mine. They work great.

Eric Jackson · #7 10-25-2005, 08:56 AM

Quote:

Originally Posted by Ken McKay

...I believe the galvanized metal is toxic when burned, but mine seems fine...

Galvanizing is a plating process whereby a zinc coating is applied to a steel part. If the zinc is burned it produces a gas and a yellow-white ash, both of which are toxic. Welding a zinc plated part will do this, I doubt an electric heating element would get it hot enough. Zinc doesn't melt till it hits 400 degrees C, I think it has to get to something around 700 C to burn.

M_A_T_T · #8 10-25-2005, 01:15 PM

Quote:

I think that the round profile is not what you want for bending bass ribs. That said, I love your idea of placing a smaller cylinder on top for linings and purflings.

Yeah, I was just going to turn down that smaller portion with a lathe if I make it.

Quote:

By the way, do you keep the alcohol handy in case of flare-ups?

Hehe, the alchohal is actually for the spirit varnish of my violin. Everything on my bench is setup for making varnish samples, I just pulled out the bending iron because I was thinking about it....it was never plugged in.

Eric Jackson · #9 10-26-2005, 10:53 AM

MATT, what do you use to clean brushes after applying spirit varnish?

M_A_T_T · #10 10-26-2005, 01:11 PM

Quote:

Originally Posted by Eric Jackson

MATT, what do you use to clean brushes after applying spirit varnish?

Not totally sure. I'm going to be applying it to sample pieces for the first time today. I think you can use the solvent that you dissolve the shellac flakes with, which is some kind of denatured alcohol in my case.

Eric Jackson · #11 10-27-2005, 08:06 AM

Thanks MATT.
Anyone else?

Jeff Bollbach · #12 10-27-2005, 09:06 AM

Eric-
I have always used denatured alcohol with no problem.

Silversorcerer · #13 10-27-2005, 09:17 AM

Many alcohols would work, but I just use the denatured ethanol that you get at the hardware store. Protect your hands when using raw ethanol, it can cause some irritation. You certainly want to steer clear of rubbing alcohol which is really mostly water.

Eric Jackson · #14 10-27-2005, 10:06 AM

Thanks, gents.

nicklloyd · #15 10-30-2005, 08:35 PM

...as a little .02 about spirit brush cleaning... keep a fine tooth plastic comb handy when you are cleaning out your varnish brush. little bits of shellac like to cling on way up in the bristles, and combing with denatured will keep the brush nice and clean.

arnoldschnitzer · #16 10-31-2005, 06:08 AM

An interesting aside about spirit varnish brushes: I was at Michael Krahmer's shop in Mittenwald. Mike opens a closet, pulls out a handled bowl with a stiff-as-a-board varnish brush stuck to the bottom. He fills the bowl with spirit varnish, waits a few minutes, then proceeds to put a gorgeous coat of varnish on a bass. He told me he never cleans his brushes, just lets them harden after use, and that he thinks they stay in better shape this way...

nicklloyd · #17 10-31-2005, 08:39 AM