separating glue-joints with hot airgun

[Magnus Hultin]

I wanted to share my experience of what I see as a quite easy (and so far successeful) method of opening glue joints. It has been tested in a community of enthusiasts in Sweden, working mostly with old wrecked up Levins (what else in Sweden?).

I guess the idea came up partly due to lack of more fancy equipment, like steamers.

The idea is to use hot air and expose the joint externally. I have personally used the method for dovetail neckjoints, fretboard overhangs, bridges, and bridge patches (yes, by heating from outside, after removing the bridge).

Some care must be taken to have a far enough distance, so the surface isn´t damaged, and You need to protect the surrounding surfaces from the heat.

Some pictures to illustrate, while removing the neck from a 1964 Goya F-27, which is a Goliath (Dread) with 12-fretted neck, slotted head and fanbraced top. A rather loud machine.

Heating and loosening of the fretboard overhang.

The neck joint is next.

It works quite well, I have used it several times and had no failures. One of the guys on our swedish forum had a bad experience where a pickguard caught fire, but it is a matter of not getting the heat to close. You should be able to stick Your finger in there.

[Jens Jacobsen]

[Ian Barker]

I'm keen to try this method for removing the tenon-jointed neck of my Epiphone 147.  My worry is 'how hot is too hot'?  (I've already toasted the fake-MOP dot markers getting the FBE loose). 

The finish is polyurethane.I have an infra-red thermometer to measure surface temperature, but does anyone know what temperature PU can withstand?

 

[Eugen C]

Hello

For bridges and fretboards removal I use an infrared bulb like this one:

http://img.diytrade.com/cdimg/1192158/13178998/0/1276830425/Philips... 

[onewent]

Eugen, can you tell a little more about this approach?  ..thanks, Tom

[Eugen C]

https://lh4.googleusercontent.com/-Vr_hQFenGKk/T8nirJtn63I/AAAAAAAA...

https://lh6.googleusercontent.com/-4hxiiPortSs/TtpZ3DAo91I/AAAAAAAA...

https://lh6.googleusercontent.com/-R8oEIcwI83g/TtpaAsoadfI/AAAAAAAA...

Just protect the top with thick paper and aluminium foil

[onewent]

So infrared will blister finish?  tw

[Ned Knepp]

HEAT will blister finishes. Infrared bulbs are made specifically to produce heat. A lot of heat.

[onewent]

I'm not that familiar..what are some advantages/differences to a luthier between using the typical 'heat lamp' and an infrared lamp (practical applications, besides where they fall on the spectrum etc)  ..thanks, Tom

[Ned Knepp]

 I guess I don't understand your question, Tom.

 Infrared lamps are heat lamps. I know of other lamps that produce heat, such as halogens but heat production is not the purpose of those lamps.  I understand that infrared lamps come in different wavelengths and configurations but I haven't investigated beyond that. I suppose it should be possible to research them easy enough on the Internet if you want to know. 

[Thomas James]

Original post: "I guess the idea came up partly due to lack of more fancy equipment, like steamers."

I would consider a recalculate on this method for some of the work posted. Steamers are almost mid-evil in concept, cost, and operation. The glue needs heat more than the wood.