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Thomas Coleman

different gram strength hide glue for center joint?

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Good question Tommy. I’ve only used 315 gram strength. However, I use different gel times (thickness) for different things following David Burgess article/posts. I don’t know how gram strength vs. gel time effects the strength of the join. I’m very interested in the responses you get. 

-Jim

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12 hours ago, Jim Bress said:

Good question Tommy. I’ve only used 315 gram strength. However, I use different gel times (thickness) for different things following David Burgess article/posts. I don’t know how gram strength vs. gel time effects the strength of the join. I’m very interested in the responses you get. 

-Jim

Maybe Mr. Burgess will chime in.  Do you know some keywords that might help me find the thread?

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315 with some rabbit skin glue and urea added, for impact strength and longer working time.  Slightly thinner than full strength, at 3:1.  Rub joint.  Gluing surfaces are warmed up first.

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18 hours ago, Thomas Coleman said:

Maybe Mr. Burgess will chime in.  Do you know some keywords that might help me find the thread?

I use Bjorn 315 for everything, controlling gel time and strength with the amount of water dilution.

This is a Maestronet thread which followed the Strad magazine article. I'll look later to see if I can find the article itself.

https://maestronet.com/forum/index.php?/topic/321117-latest-strad-trade-secrets-questions-for-gluemeister-burgess/&

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I’ve only ever used 192 and never had a problem, i was under the impression 192 would be more flexible than 315 ? 

Good joins , sizing, room temp, and rub join with a bit of suction at the end , a little puff of steam after it’s together if I’m worried 

 

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Thank you all for the helpful responses.  I mixed up some 315 according to Don Noon's ratio,  and I read Davids article and looked at E's link.  Everything was very helpful.  I'll give it a go.

 

 

 

 

 

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10 hours ago, David Burgess said:

I use Bjorn 315 for everything, controlling gel time and strength with the amount of water dilution.

This is a Maestronet thread which followed the Strad magazine article. I'll look later to see if I can find the article itself.

https://maestronet.com/forum/index.php?/topic/321117-latest-strad-trade-secrets-questions-for-gluemeister-burgess/&

Here's the article as it appeared in The Strad, more or less. Some version which I had saved:

http://burgessviolins.com/Strad glue article.pdf

 

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Thanks David.  I glued the plates up.  Went pretty smooth.  I also used a new-to-me clamping rig.  I liked everything and will continue using 315 and clamps until I see something in the results that I don't like.  I don't think that will happen.  The 315 works pretty much like the 192 but just a little more snottiness to it.  I don't think I'd wanna try it with less water than the 3:1 ratio.

 

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On 8/13/2018 at 6:53 AM, lpr5184 said:

For center joints I use grade 315 and mix it full strength.  

 

I don't know what "full strength" means, unless it refers to the dilution ratio used for penetration resistance testing of the glue in a gelled state. That may have something to do with what we use glue for, or it may not.

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1 hour ago, David Burgess said:

I don't know what "full strength" means, unless it refers to the dilution ratio used for penetration resistance testing of the glue in a gelled state. That may have something to do with what we use glue for, or it may not.

By full strength I mean mixing to the typical water to glue ratios mentioned in the chart for grade 315.

 

 

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12 minutes ago, lpr5184 said:

By full strength I mean mixing to the typical water to glue ratios mentioned in the chart for grade 315.

Whose chart?

For gluing on tops, I can get pretty close by mixing 13 grams of "315" glue with 82 grams water. Then I can get closer by measuring the gel time. But this is not at all what I would use for centerjoints, or gluing in a soundpost patch.

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22 minutes ago, David Burgess said:

Whose chart?

For gluing on tops, I can get pretty close by mixing 13 grams of "315" glue with 82 grams water. Then I can get closer by measuring the gel time. But this is not at all what I would use for centerjoints, or gluing in a soundpost patch.

When I bought glue from Eugene he sent the 40 Centuries and Still Holding.pdf  which has a chart.  I have been gluing my center joints with a 2-3/4 - 1 ratio (Weight, Water to Glue.) I have not had any failures. Do you think this is not a good ratio for center joins?

I also use 315 for everything except gluing the top plate to the ribs and the fingerboard to neck. I'll then use  grade 192 and dilute it to a ratio that I have found to be good for easy removal.

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3 hours ago, Thomas Coleman said:

Thanks David.  I glued the plates up.  Went pretty smooth.  I also used a new-to-me clamping rig.  I liked everything and will continue using 315 and clamps until I see something in the results that I don't like.  I don't think that will happen.  The 315 works pretty much like the 192 but just a little more snottiness to it.  I don't think I'd wanna try it with less water than the 3:1 ratio.

 

Thomas, The "snottiness" can be reduced by melting the glue once then refrigerating it until it gels and remelting it. The glue will then act more fluid even though you have not added any water. This will make a better bond with out the slipping and sliding of thicker glue. I will use the same glue perhaps three times putting it in the fridge between uses. After that the glue starts to lose strength.

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40 minutes ago, nathan slobodkin said:

Thomas, The "snottiness" can be reduced by melting the glue once then refrigerating it until it gels and remelting it. The glue will then act more fluid even though you have not added any water. This will make a better bond with out the slipping and sliding of thicker glue. I will use the same glue perhaps three times putting it in the fridge between uses. After that the glue starts to lose strength.

Cool!  Between gluing the spruce and the maple, the glue cooled down to semi-solid again.  Upon reheating ,the "body" had improved noticeably. 

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5 hours ago, Thomas Coleman said:

Thanks David.  I glued the plates up.  Went pretty smooth.  I also used a new-to-me clamping rig.  I liked everything and will continue using 315 and clamps until I see something in the results that I don't like.  I don't think that will happen.  The 315 works pretty much like the 192 but just a little more snottiness to it.  I don't think I'd wanna try it with less water than the 3:1 ratio.

 

How did you determine the 3:1 ratio. Can you show your clamping jig?

 

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23 minutes ago, lpr5184 said:

How did you determine the 3:1 ratio. Can you show your clamping jig?

 

I weighed the glue and the water.  I think thats what your article recommended, yes?  Here are two photos.  Nothing fancy, but worked very well for me.  There is also a video on my instagram but it's kinda boring. 

https://www.instagram.com/thomascoleman.violins

 

Anyway, everyones advice/help was all useful.  thanks again.

IMG_4935.jpg

IMG_4936.jpg

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1 hour ago, Thomas Coleman said:

I weighed the glue and the water.  I think thats what your article recommended, yes? 

Yes but the chart recommends 2-3/4 :1 for maple and 2-1/2 :1 for spruce.

Just curious of how you determined to use a 3 :1 ratio.

Thanks for the photos.

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3 hours ago, nathan slobodkin said:

Thomas, The "snottiness" can be reduced by melting the glue once then refrigerating it until it gels and remelting it. The glue will then act more fluid even though you have not added any water. This will make a better bond with out the slipping and sliding of thicker glue. I will use the same glue perhaps three times putting it in the fridge between uses. After that the glue starts to lose strength.

Thanks Nathan!

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The ratio of 1: 3 is too thick for me, after doing some tests I have developed a ratio of 1: 4 that for my gluing system (pouring the glue instead of brushing) works better.

I think my glue is high strength (315?), but here in Italy it seems that there is no way to know these numbers of strength from the sellers, so mine is just a guess.

However, I melt new glue every time for the center joints, soaked overnight and heated up to 70° C.

I use a clamping system very similar to that of Thomas Coleman for the back, and with similar but lighter clamps for the top  because it seems to me that the weight of the clamps can distort the top when the two pieces are not very thick at the edges.

 

 

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35 minutes ago, Davide Sora said:

I use a clamping system very similar to that of Thomas Coleman for the back, and with similar but lighter clamps for the top  because it seems to me that the weight of the clamps can distort the top when the two pieces are not very thick at the edges.

Hi Davide, as always, your method could not be more elegant! Where did you buy the small Dubuque looking clamps for the top?

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