+1 for Jacob's post about rubbed joints. It will also work with liquid hide glue, which I find preferable for occasional use.
Edge Jointing Thin Stock
- Thread starter custard
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Jacob
What goes around comes around.
Wood welder - we had one briefly (bought by workshop partner not me). Very expensive but worked OK. Potentially very dangerous but we had no accidents. Not cost effective for my workshop sharer - it's usually very easy to schedule your work to be doing something else whilst glue dries, or to leave it overnight. Depends what you are doing. Hot glue makes much more sense, see above, no clamping, no messing about!
Trafalgar
Established Member
D_W":1avc36kh said:
I took on some architectural work, just panels (no installs), at one point. It made sense at the time. It sold for very near what I paid for it.
profchris
Established Member
I'm skeptical about Jacob's assertion that musical instrument tops and backs were joined with rubbed joints. The plates flex too much to get a decent alignment.
All the methods I know use some form of clamping, though not much if using HHG. For example, I join ukulele tops and backs simply by taping the plates together along the join to keep them aligned, "tenting" the joint by putting a pencil underneath, then tapping panel pins next to the outer edges into a flat board. Glue in joint, remove pencil, press down, weight on top to keep them flat. Spanish guitar making tradition tends to use a flat frame to hold the plates flat, and then string wrapped round with wedges inserted to pull them together.
The joint is fitted by eye, but again the tradition tends to use a shooting board, planing the plates back to back (or front to front) and then working away on the gaps. No-one I know clamps between sacrificial boards because you need to check the joint against the light after each plane pass, and that's a lot of unclamping and realignment. With a shooting board hand pressure is enough to hold the plates for planing.
Door panels I know nothing of, but they're rigid enough for a rubbed joint.
That's not to say musical instruments don't use rubbed joints - that is a good way of fitting the much more rigid bridge (for some, but not all, shapes of bridge), and this is the high tension joint in an instrument!
All the methods I know use some form of clamping, though not much if using HHG. For example, I join ukulele tops and backs simply by taping the plates together along the join to keep them aligned, "tenting" the joint by putting a pencil underneath, then tapping panel pins next to the outer edges into a flat board. Glue in joint, remove pencil, press down, weight on top to keep them flat. Spanish guitar making tradition tends to use a flat frame to hold the plates flat, and then string wrapped round with wedges inserted to pull them together.
The joint is fitted by eye, but again the tradition tends to use a shooting board, planing the plates back to back (or front to front) and then working away on the gaps. No-one I know clamps between sacrificial boards because you need to check the joint against the light after each plane pass, and that's a lot of unclamping and realignment. With a shooting board hand pressure is enough to hold the plates for planing.
Door panels I know nothing of, but they're rigid enough for a rubbed joint.
That's not to say musical instruments don't use rubbed joints - that is a good way of fitting the much more rigid bridge (for some, but not all, shapes of bridge), and this is the high tension joint in an instrument!
Trafalgar
Established Member
I've never built a musical instrument in my life, and I'm sure that I never will, but I'm a little surprised to hear that stock would need to be glued into panels for instruments as small as ukuleles. I'm thinking I'd focus efforts on finding wider stock.
CStanford":hnkzm0lm said:
They're matched, like guitars. I'm sure you could get spruce wide enough to make full guitar tops, just as you can get maple wide enough to cap a les paul but I'm not aware of the reason for the bookmatch of any of it other than looks/symmetry.
Different story, maybe, for a string bass.
(I should add that some of the really expensive tops that I've seen that are done in a quilt are one piece, but I don't know that I've paid attention to know if that occurs on acoustic guitars. The upcharge for any figured wood on a guitar is absurd. $50-$150 worth of wood becomes an incremental charge of $500-$1500).
Jacob
What goes around comes around.
It's an option but most string instruments are book matched, top and bottom. Not so necessary with smaller ones of course, and single piece backs also feature on some top end instruments. There are all sorts of variations.CStanford":2erjvjhg said:
Jacob
What goes around comes around.
I don't really know but my feeling is that volume production models would use the quickest and easiest method which would be rubbed joint with hot glue. Top end would be different - clamping and fewer risks taken with expensive bits of wood!profchris":1f2332s5 said:
custard
Established Member
I can't comment on musical instruments, but I've seen 8mm drawer bottoms jointed together in a fair few workshops, most of them fairly top end. Only one cramped them up (which is the way I was taught and it used to drive me to distraction), most use stretched masking tape on both sides to pull the joint together, and one or two used a PVA or hide glue rubbed joint, but always with the boards layed flat on taped or waxed battens. Personally I always thought cramping a drawer bottom was too pernickety because it's just not a particularly stressed joint given that it's free to float at the back edge.
Veneer is always taped on both sides when edge glued to pull it tight together. One advantage of edge gluing is that it can then go under the press with all tape removed, while veneer that hasn't been edge glued has to keep tape on the show surface (or in big workshops they use automated stitching machines). With softer timbers it's not uncommon for the tape to be pressed into the surface and to leave witness marks that aren't revealed until finish is applied, the finish then has to be removed and the entire surface scraped. I've seen craftsmen who tape up veneers and drawer bottoms not in the perpendicular straight lines as per Derek's photo, but as overlapping zig-zag lines. This means they save time by removing all the tape in one clean action and there's less chance they'll faff around picking off stray bits of tape with a scalpel.
Veneer is always taped on both sides when edge glued to pull it tight together. One advantage of edge gluing is that it can then go under the press with all tape removed, while veneer that hasn't been edge glued has to keep tape on the show surface (or in big workshops they use automated stitching machines). With softer timbers it's not uncommon for the tape to be pressed into the surface and to leave witness marks that aren't revealed until finish is applied, the finish then has to be removed and the entire surface scraped. I've seen craftsmen who tape up veneers and drawer bottoms not in the perpendicular straight lines as per Derek's photo, but as overlapping zig-zag lines. This means they save time by removing all the tape in one clean action and there's less chance they'll faff around picking off stray bits of tape with a scalpel.
woodbrains
Established Member
Hello,
Folding wedges between 2 battens that are screwed to a (waxed) board is my preferred way of clamping thin stock. Seems to work well and doesn't introduce any 'apexing' of the join, which sash cramps can do. It works with sawn veneers, too, though a brick can help here.
PVA and it's like, should be joined with a bit of pressure. I have rub jointed with PVA and it can be done if the joint has absolutely NO spring, but reality these glues need pressure, if you want to be certain of a permanent bond.
Mike.
Folding wedges between 2 battens that are screwed to a (waxed) board is my preferred way of clamping thin stock. Seems to work well and doesn't introduce any 'apexing' of the join, which sash cramps can do. It works with sawn veneers, too, though a brick can help here.
PVA and it's like, should be joined with a bit of pressure. I have rub jointed with PVA and it can be done if the joint has absolutely NO spring, but reality these glues need pressure, if you want to be certain of a permanent bond.
Mike.
Trafalgar
Established Member
Hey Mike: kitchy Latin music, but still interesting:
https://www.youtube.com/watch?v=c-ZnaNyDbOo (wish I still had my D-J 20!)
I'm suffering from the heat, so give me a break:
http://wreg.com/2017/07/21/excessive-he ... -counties/
... in for the day....
https://www.youtube.com/watch?v=c-ZnaNyDbOo (wish I still had my D-J 20!)
I'm suffering from the heat, so give me a break:
http://wreg.com/2017/07/21/excessive-he ... -counties/
... in for the day....
woodbrains
Established Member
CStanford":9w9ey54g said:
Hello Charlie,
It wasn't me, honest! :roll: his shop is nicer than mine, but I own some hammers!!! Besides, my video would be accompanied by kitschy prog rock, not Latin! It works, though.
I feel for you re. the heat. I struggle in hot British summers, heck knows how I'd manage there.
Mike.
Paddy Roxburgh
Established Member
Violin top plates (and violas, cellos and basses) are made from Norwegian Spruce and are usually rub jointed but the sycamore bottom plate is clamped, I don't know the reason for the different approach, but imagine it must be to do with the hardness of the wood. The arching and thicknessing is done after the jointing so it is quite a solid piece of timber when jointed. These are glued with hot hide glue.profchris":3gkssjlr said:
Jacob, when you say hot glue do mean hot hide glue from a pot or the stuff that comes out of a glue gun?
I have only jointed one pair of plates and was shown how to do it buy putting a no.7 in the vice and pushing the wood over the plane, aiming for a very slight hollow.
I am certainly no expert in this, (but the person teaching me was), so f there are any violin makers reading this who disagree I will bow (see what I did there) to your greater knowledge and experience.
Paddy
Jacob
What goes around comes around.
I'm told that the sycamore bottom plates were rub jointed the same but with two goes at it - the first one being to fill the grain with glue and the second one to actually glue it.Paddy Roxburgh":2sa4oj4y said:
Hide glue from a pot
Actually I have planed up a lot of plates of various sizes from thick table tops to thin box sides. Your no7 trick sounds difficult. My method is to plane up the meeting edges as well as you can, hold one plate in the vice vertically and sit the other on it. It's then obvious how it fits or doesn't fit and I then plane accordingly. Check they line up flat with a short straight edge (combi square ruler), check they don't rock due to high points, check no visible gaps, etc. It's quite easy and has the big advantage that the pieces are not under any pressure and you can see both sides of the join.
no5 plane is handy here for small stuff down to 6mm, no 7 for table top size pieces.
Paddy Roxburgh
Established Member
I've planned plenty of table tops, panels etc. I meant I've only one done pair of violin plates. For most edge jointing I would have the wood in the vice and plane in my hands, where possible with both peices at the same time, much as you have described.. I did the violin plates with the plane in the vice way because I was on a course and simply did what my teacher told me, didn't seem that difficult
AJB Temple
Finely figured
For what it is worth a lot of high end guitar backs are indeed bookmatched but a good many (we are talking high end here) are three piece, the centre piece being a cut off triangle. In most cases there is an inlay down the join line. I don't actually know, but I suspect this started when exotic high quality woods began to become scarce and very expensive. I bought a stock of rosewood and mahogany and ebony and spruce back in the 80's (then my main business took over and I stopped using the wood up!) and now the best stuff is crazy money.
I think the fashion for exotic tops on electric guitars started with PRS, when he started differentiating himself with " 10 tops". This was clever marketing. I think the tops (usually highly figured maple) were almost always bookmatched.
Fine, high altitude, spruce is also used for top end piano soundboards. I will have to look into how they joint that. I've seen them being made years ago but can't recall the jointing method now.
I think the fashion for exotic tops on electric guitars started with PRS, when he started differentiating himself with " 10 tops". This was clever marketing. I think the tops (usually highly figured maple) were almost always bookmatched.
Fine, high altitude, spruce is also used for top end piano soundboards. I will have to look into how they joint that. I've seen them being made years ago but can't recall the jointing method now.
AJB Temple
Finely figured
Edit - the factory was Ciresa and I went there when I did my violin making courses in Cremona. Sadly the website is very coy about how they make up and joint the soundboards.
Paddy Roxburgh
Established Member
Studying in Cremona must have been amazing, My whole life plan is to retire in the next ten years, escape the boatyard, the noise, the machines, the poisons, dust and sparks that I cover myself with on a daily basis, withdraw to my shed and make. violins. I would love to visit Cremona
iNewbie
Established Member
Paddy Roxburgh":4a7ojvhb said:
There used to be one of the worlds top Violin/Cello builder/repairers (and guitar) named Bharat Khandekar (Sgt.Pepper on MLP) who frequented a guitar forum and freely gave his knowledge away while some others guarded theres like the crown jewels. Shame some munts chased him off because his knowledge was invaluable. That forums loss...
You might find these posts of interest as AJB might. And as for Guitar tops, PRS basically took it further than Gibson did from the large Jazz guitars to the 50's tiger topped solids. The most highly coveted guitar is probably the '59 Les Paul with a flame top. PRS milked as much building info from their CEO of that period Ted McCarthy on how Gibson were so succesful. Its an interesting story. Theres a book by Gil Hembree called Ted McCarty 's Golden Era. Theres some video on YT on PRS talking about Ted, too - great stuff.
Anyway luthiery stuff:
http://www.mylespaul.com/threads/tonigh ... ost-652719
http://www.mylespaul.com/threads/is-the ... ost-714259
AJB should like this fingerboard method!
http://www.mylespaul.com/threads/the-gr ... ost-495656
Apologies for going off piste, Custard.
AJB Temple
Finely figured
Cremona is a tremendous experience. The only snag is that in order to do much meaningful training it helps a great deal if you can speak Italian. The first time I went on courses there my Italian was terrible, but my German wife had lived and studied there and was fluent, so she helped with a lot of translation.
