The Revolver

[SamIAmUBUF]

Others should comment on this, but......I do believe it is possible to clamp TOO tightly.  If you have really well-planed glue surfaces that mate perfectly, and very closed-pore wood on either side, it is possible to clamp too tight and squeeze out too much glue, leaving you with a weak joint.

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I just read somewhere else that suggested that instead of gluing two perfectly planed surfaces that you rough up the surfaces with coarse sandpaper first --the idea is that your raise the fibers, which then mesh together with the glue, strengthening the joint and making it possible to achieve a near invisible glue line.

Now, that's a long sentence.

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I usually go over the surface with a rasp.

[Mattia]

I just read somewhere else that suggested that instead of gluing two perfectly planed surfaces that you rough up the surfaces with coarse sandpaper first --the idea is that your raise the fibers, which then mesh together with the glue, strengthening the joint and making it possible to achieve a near invisible glue line.

Now, that's a long sentence. 

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Seriously, don't. It's complete and utter nonsense, just like those 'toothing planes' desinged to give the glue something to 'bite' into. I think it was Forest Labs, in the US, that did some testing circa WWII regarding what kind of joints held up best (they were comparing planed and sanded joints in wood being used for aircraft construction). Hands down, a freshly planed joint beats out a sanded/roughed up joint. And if it's tight, it's tight, and you won't find the glue line. I know I can't easily locate the centrelines on the acoustic tops I've jointed.

With the exception of epoxy, which likes something to 'bite' into, and needs to have glue left in the joint (ie, they're easier to starve), glues used in woodworking work best on FRESHLY planed surfaces, followed by freshly scraped, followed by sanded (I don't go past 220. Or below it, really). The reason I've seen bandied about for this is that a freshly planed surface is perfectly flat, there's no sawdust/contaminants in it, and you've got chemically 'free' ends on the wood fibres, that are looking to bond with something. Leave 'em out for a while, they're oxidise/reduce in the air, but given a chance, glue will do the trick. Undoubtedly, you can get good results with rough surfaces (glues have evolved, after all), but for the best surfaces, freshly plane prior to glueup.

As I understand PVA chemistry, it chemically bonds the two porous surfaces together. Sinks into the surface a little (works on porous materials only), and presto! The glue itself isn't very strong (cohesive strength is negligible; epoxy's the only one that's good at keeping itself together), ie any gaps/areas where the glue line is thicker than absolute minimum thickness mean weak spots. This is doubly true for Hot Hide glue.

Getting tightly fitting gluing surfaces is key. If you can do that with an edge tool (planes, chisels, scrapers), by all means to, sanding is good too, but don't go roughing up your surfaces unless you're using epoxy, which needs something to 'grip' onto, unlike PVA/AR or Hide glues.

[SamIAmUBUF]

I just read somewhere else that suggested that instead of gluing two perfectly planed surfaces that you rough up the surfaces with coarse sandpaper first --the idea is that your raise the fibers, which then mesh together with the glue, strengthening the joint and making it possible to achieve a near invisible glue line.

Now, that's a long sentence. 

←

Seriously, don't. It's complete and utter nonsense, just like those 'toothing planes' desinged to give the glue something to 'bite' into. I think it was Forest Labs, in the US, that did some testing circa WWII regarding what kind of joints held up best (they were comparing planed and sanded joints in wood being used for aircraft construction). Hands down, a freshly planed joint beats out a sanded/roughed up joint. And if it's tight, it's tight, and you won't find the glue line. I know I can't easily locate the centrelines on the acoustic tops I've jointed.

With the exception of epoxy, which likes something to 'bite' into, and needs to have glue left in the joint (ie, they're easier to starve), glues used in woodworking work best on FRESHLY planed surfaces, followed by freshly scraped, followed by sanded (I don't go past 220. Or below it, really). The reason I've seen bandied about for this is that a freshly planed surface is perfectly flat, there's no sawdust/contaminants in it, and you've got chemically 'free' ends on the wood fibres, that are looking to bond with something. Leave 'em out for a while, they're oxidise/reduce in the air, but given a chance, glue will do the trick. Undoubtedly, you can get good results with rough surfaces (glues have evolved, after all), but for the best surfaces, freshly plane prior to glueup.

As I understand PVA chemistry, it chemically bonds the two porous surfaces together. Sinks into the surface a little (works on porous materials only), and presto! The glue itself isn't very strong (cohesive strength is negligible; epoxy's the only one that's good at keeping itself together), ie any gaps/areas where the glue line is thicker than absolute minimum thickness mean weak spots. This is doubly true for Hot Hide glue.

Getting tightly fitting gluing surfaces is key. If you can do that with an edge tool (planes, chisels, scrapers), by all means to, sanding is good too, but don't go roughing up your surfaces unless you're using epoxy, which needs something to 'grip' onto, unlike PVA/AR or Hide glues.

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I'd like to see this smooth/rough gluing surface debate resolved to some extent. other than this post, are there any good arguments you guys can post?

[Mattia]

I'd like to see this smooth/rough gluing surface debate resolved to some extent. other than this post, are there any good arguments you guys can post?

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I don't know about here, but this has been discussed at length at the MIMF.com (register to read the discussions in the library). Every time it comes up, the consensus is that planing is best, scraping next best, sanding best after that, and that no wood surface needs 'roughing up' unless you're gluing stuff together with Epoxy. The fact surfaces need to be perfect, tight, and smooth is something that's underlined strongly whenever hot hide glue comes up as an option. PVA is less picky, but the same still holds true.

You could do your own tests, of course, but my bet is that all methods will give you a perfectly strong joint. But I still trust a scientific study dealing with joint failure in airplane parts (much more extensive testing than anything you or I will be willing spend time/matierals performing at home), and the rationale makes perfect sense to me, while the 'rough things up' school of thought doesn't s'much.

[SamIAmUBUF]

I'd like to see this smooth/rough gluing surface debate resolved to some extent. other than this post, are there any good arguments you guys can post?

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I don't know about here, but this has been discussed at length at the MIMF.com (register to read the discussions in the library). Every time it comes up, the consensus is that planing is best, scraping next best, sanding best after that, and that no wood surface needs 'roughing up' unless you're gluing stuff together with Epoxy. The fact surfaces need to be perfect, tight, and smooth is something that's underlined strongly whenever hot hide glue comes up as an option. PVA is less picky, but the same still holds true.

You could do your own tests, of course, but my bet is that all methods will give you a perfectly strong joint. But I still trust a scientific study dealing with joint failure in airplane parts (much more extensive testing than anything you or I will be willing spend time/matierals performing at home), and the rationale makes perfect sense to me, while the 'rough things up' school of thought doesn't s'much.

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my only problem with relying on a study like this is that the properties of wood and metal are vastly different (not that it's really going to matter. the "do not rough" team is winning me over at this point anyway .) That aside, your point is taken. thanks for your input

Edited December 12, 2005 by SamIAmUBUF

[thegarehanman]

Did you not read what mattia posted? Mattia specifically mentioned that the study was in regards to wood. Why on earth would it make a difference whether you sanded metal or not before welding it together(it wouldn't)...or did you think they were gluing metal together?

Is it april fools or something?....n/m, it's december.

Edited December 12, 2005 by thegarehanman

[SamIAmUBUF]

Did you not read what mattia posted? Mattia specifically mentioned that the study was in regards to wood. Why on earth would it make a difference whether you sanded metal or not before welding it together(it wouldn't)...or did you think they were gluing metal together?

Is it april fools or something?....n/m, it's december.

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lol no, I missed half of that. I guess I just assemed he was talking about metal, I didn't seem to consider any pivotal wood-wood joints on an airplane. (and, yes I realize you don't glue metals. that's what I was getting at when refering to the vastly different properties of metal vs. wood) Please excuse me, I'm extremely tired right now. finals week is taking it's toll, and I'm only one day into it.

Any more contributions to the actual topic at hand?

[Mattia]

my only problem with relying on a study like this is that the properties of wood and metal are vastly different (not that it's really going to matter.  the "do not rough" team is winning me over at this point anyway .) That aside, your point is taken. thanks for your input

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The properties of wood may be different, yes (I believe Spruce was the wood in question in those tests), but the mechanism through which glues work is the same, and the basic structure of wood is the same. Of course, you've got oily, hard to glue woods as well, and those may requires some de-oiling (although again, there be arguments on that front), or maybe the use of epoxy (which does like a rougher surface).

Gluing Metal is a completely different subject, natch. I've glued silver for inlay (good ol CA), but I'd probably go with epoxy or polyurethane for dissimlar materials.

[SamIAmUBUF]

my only problem with relying on a study like this is that the properties of wood and metal are vastly different (not that it's really going to matter.  the "do not rough" team is winning me over at this point anyway .) That aside, your point is taken. thanks for your input

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The properties of wood may be different, yes (I believe Spruce was the wood in question in those tests), but the mechanism through which glues work is the same, and the basic structure of wood is the same. Of course, you've got oily, hard to glue woods as well, and those may requires some de-oiling (although again, there be arguments on that front), or maybe the use of epoxy (which does like a rougher surface).

Gluing Metal is a completely different subject, natch. I've glued silver for inlay (good ol CA), but I'd probably go with epoxy or polyurethane for dissimlar materials.

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good insight. thanks again.

[thegarehanman]

Finals? Ha! I spit in the face of finals. In 3 hours I have a Calculus final. Later this week I have a philosophy and chemistry final as well. Am I tired or discouraged? No. I stab exams in the face like so many brave warriors. Just have to keep reminding yourself that in 5 days, you(we) get a break.

[SamIAmUBUF]

Finals? Ha! I spit in the face of finals. In 3 hours I have a Calculus final. Later this week I have a philosophy and chemistry final as well. Am I tired or discouraged? No. I stab exams in the face like so many brave warriors.    Just have to keep reminding yourself that in 5 days, you(we) get a break.

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good luck on the calc final. I've been there 3 times (calc I, II, and III)

[erikbojerik]

Well, here's my contribution to this debate. I just finished two identical Strat bodies, chambered alder with 1/4" cocobolo top, all woods from the same rough boards. An oily open-grained wood on top of a dry closed-grained wood. I sanded a forearm contour into both of the alder blanks, steamed the coco tops, bent them over and clamped them (without glue) and held them in place for 2 days. When I lifted the tops, both sprang back a bit leaving a ~1/2" gap between the top and the forearm contour.

I glued the tops on one at a time, using Titebond (original). On the first, I wiped the coco hard with acetone, hit both glue surfaces quick with 60-grit, then glued & clamped for 2 days. No problems save for a small gap in the glue line at the waist.

Did everything the same on the second, except I forgot the 60-grit rough up. Guess what? The coco top pops off the forearm contour about 60 seconds after I pull the clamps.

The only down-side I see to roughing up first is that you can potentially mess up perfectly straight surfaces and leave yourself a messy-looking joint. But if you do it right it won't, and it certainly can't hurt the structural integrity.

[Mattia]

Well, here's my contribution to this debate.  I just finished two identical Strat bodies, chambered alder with 1/4" cocobolo top, all woods from the same rough boards.  An oily open-grained wood on top of a dry closed-grained wood.  I sanded a forearm contour into both of the alder blanks, steamed the coco tops, bent them over and clamped them (without glue) and held them in place for 2 days.  When I lifted the tops, both sprang back a bit leaving a ~1/2" gap between the top and the forearm contour.

I glued the tops on one at a time, using Titebond (original).  On the first, I wiped the coco hard with acetone, hit both glue surfaces quick with 60-grit, then glued & clamped for 2 days.  No problems save for a small gap in the glue line at the waist.

Did everything the same on the second, except I forgot the 60-grit rough up.  Guess what?  The coco top pops off the forearm contour about 60 seconds after I pull the clamps.

The only down-side I see to roughing up first is that you can potentially mess up perfectly straight surfaces and leave yourself a messy-looking joint.  But if you do it right it won't, and it certainly can't hurt the structural integrity.

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Heh. That's the mysteries of glues for ya.

I've glued down maple tops that were slightly out of flat, using scraped surfaces, and they worked great. And I've read enough horror stories about Cocobolo's difficult gluing (even with filtch matched pieces) to be wary of attributing the failure to the lack of sanding. There's clamping, unevenly matched gluing surfaces (unless you're a human CNC, that's always a factor), amount of oil in that particular piece, amount of glue.

Me, I'm sticking to a freshly planed surface, or at least a freshly scraped surface. What might've happened with the second set is that you didn't present 'fresh' wood surfaces to glue, and if you'd roughed it up with a scraper, you'd have gotten a better bond. Too many variables here to definitively say that sanding has a beneficial effect, and I'm still gonna go with the scientific results over an empirical data point or two. Martin used to use toothing blades on their bridges to 'increase adhesion', but that don't mean it acutally did.

[SamIAmUBUF]

Well, here's my contribution to this debate.  I just finished two identical Strat bodies, chambered alder with 1/4" cocobolo top, all woods from the same rough boards.  An oily open-grained wood on top of a dry closed-grained wood.  I sanded a forearm contour into both of the alder blanks, steamed the coco tops, bent them over and clamped them (without glue) and held them in place for 2 days.  When I lifted the tops, both sprang back a bit leaving a ~1/2" gap between the top and the forearm contour.

I glued the tops on one at a time, using Titebond (original).  On the first, I wiped the coco hard with acetone, hit both glue surfaces quick with 60-grit, then glued & clamped for 2 days.  No problems save for a small gap in the glue line at the waist.

Did everything the same on the second, except I forgot the 60-grit rough up.  Guess what?  The coco top pops off the forearm contour about 60 seconds after I pull the clamps.

The only down-side I see to roughing up first is that you can potentially mess up perfectly straight surfaces and leave yourself a messy-looking joint.  But if you do it right it won't, and it certainly can't hurt the structural integrity.

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to avoid a messy-looking joint, I don't rough within 1/16" of a surface that will be visible after gluing. obviously there are exceptions, but it works well for large pieces (like neck-through instruments)

[erikbojerik]

to avoid a messy-looking joint, I don't rough within 1/16" of a surface that will be visible after gluing.

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+1

FWIW, both coco tops were from the same plank, as was all the alder. All if it cut & planed on the same day, both tops glued down within 2 days of each other the following week. Same batch of glue bought new the previous week, same number of clamps in the same places, glued up indoors under climate control....same batch of acetone, paper towels all from the same roll....yadda yadda yadda.

[SamIAmUBUF]

there it is before all the routing. I'll get you a more recent pic as soon as I have one

Edited February 2, 2006 by SamIAmUBUF

[scottyd]

looks like a carl thompson!!

[SamIAmUBUF]

looks like a carl thompson!!

it's roughly based (bassed) on a couple of Ritter models and the BC Rich Wave

[scottyd]

very nice indeed

[erikbojerik]

Great body shape! I love it.

Only thing that concerns me is that the low-B hole looks a bit close to the edge. But if you're going to cap the front (or back) of the headstock, then you should be fine.

[SamIAmUBUF]

Great body shape! I love it.

Only thing that concerns me is that the low-B hole looks a bit close to the edge. But if you're going to cap the front (or back) of the headstock, then you should be fine.

I've been seriously considering it

[scottyd]

I really dont think its needed the hole looks about the same as my ibanez sr 406 ill measure it once i find my friggin calipers

[SamIAmUBUF]

I really dont think its needed the hole looks about the same as my ibanez sr 406 ill measure it once i find my friggin calipers

thanks for the offer, that would be great. let me know when you find your friggin calipurs

[Hydrogeoman]

Looks nice. Is the neck angled?

[SamIAmUBUF]

Looks nice. Is the neck angled?

nope