I was unable to find the post about filling spaces around dovetails, so i need someone to fill me in on the “sawdust & crazy glue” fix. Do I place the sawdust into the space and add the glue or the other way around? Or do I have it all wrong?
Any help will be appreciated.
Jim
My memory’s good, it’s just short.
Replies
good morning jim,
being rather new at dovetails, i've had to study this issue a good deal. what seems to work best for me is to avoid the sawdust and glue method altogether. it's just too difficult to get a good match. although painstaking and slow, cutting endgrain or shortgrain dutchman to carefully match pins or tails that have gaps, works out best for me.
eef
eef: Okay, so what's a good
eef:
Okay, so what's a good way to slice off a piece of cherry that's about 1/64" or less thick? Do I taper it, are there tricks to getting a proper fit, etc?
Thanks, Jim
My memory's good, it's just short.
A method I recently found by accident in Tage Frid book has worked well for me. I saw the gap with my dovetail saw to make a uniform width. I set the table saw to cut off a strip just slightly thicker than the saw cut, just a hair. Cut an isosceles triangle from the strip, and gently flatten with a metal hammer so that it will slide into the saw cut with only slight friction. Water in white or yellow glue or hide glue will cause the strip to thicken slightly, and the gap is pretty hard to see most times.
My explanation isn't very good, so I'd suggest you review the details in the book before trying it.
Tage Frid
Don:
I have the book, so looking it up was fairly easy. Your explanation was good, but the book had pictures.
It sounds a lot like what eef was talking about, so I thank you and eef.
Someone on Knots always has some good advice for me when I need it.
Thanks again, Jim
My memory's good, it's just short.
hey jim,
that tage book is what got me cutting dovetails. when step by step instructions for how to do something come with step by step instructions for fixing any subsequent mistakes, count me in.
it is time consuming to make little tapered dutchman but the results can be heart warming. i use the waste pieces from cutting the pins and tails for making the patches and i cut with chisel, file with rasp and sand, flatten and taper with a fixed belt sander. most of the gaps and mistakes vanish. cutting dt's really does improve with practice and i get a little better each time. i learned a long time ago that eef is one who learns from making and fixing his mistakes.
what are you making with all that dovetail cutting?
eef
Dovetail fixes
eef:
I'm making a chest of drawers. The carcase is dovetailed together and the drawers and the base will be dovetailed as well. There will be a total of seven drawers. The stretchers and the dividers all are fitted with sliding dovetails. I have several that need a little tweaking, so to speak. There are also a few that need some major tweaking. This is definitely a learning experience.
Thanks to all for the advice,
Jim
My memory's good, it's just short.
Hardness of wood
Jim,
The best way, of course, is to make the joint fit well in the first place!
I taught myself to hand saw dovetails on western maple. Not that easy, and most of my joints required a LOT of fitting and eventually went together with gaps, no less. Then I tried a softer wood (luan). I literally cut the joints and pressed it together for a perfect fit. The soft wood compresses a lot, which makes it easy to fit well. I'll have to experiment with joining different kinds of wood. At dovetailing demonstrations, they often use one hard wood and one soft wood so that the joint goes together beautifully the first time.
chris,
a while back there was a discussion about this compression factor. seems as though it was viewed as a "crutch" or weakness on the part of the woodworker to rely on compression of softer woods to get tight fitting dt's. i've only got one thing to say about that, THANK GOD FOR THE PHYSICS OF COMPRESSION!!!
eef
Well fitting dovetails
Chris:
I really would like to get dovetails that just slide into place and look beautiful, I'm just not yet at that point. Maybe if I brought some of my instruments home from the office I could make the dovetails like I do a filling in a patient's mouth. They'd be a lot smaller of course.
Some of my dovetails look good, but certainly not all of them. I'm working on it though. Maybe when I get to drawers I'll have improved a bit or I'll tell my grandson to not open the drawers.
Thanks for the tips,
Jim
My memory's good, it's just short.
alternatives
Another alternative would be to trim them all to be euqally loose, and then give them all gold fillings. ;-)
Jim,
There are a number of fixes for gaps atween the pin and the tail in a DT joint. Some are better than others. Which is acceptable depends on how visible the joint is and whether the gap is significantly weakening the joint or merely an unattractive mistake in an otherwise well-made and strong joint.
If strength is not an issue the best filler is either beaumontage (for larger gaps) or hard wax. Beaumontage is a mix of shellac and wax, sold in sticks of various colours. Hardwax sticks are made of beeswax mixed with a relatively high proportion of carnuba wax, which is very hard. Both beaumontage and hardwax can be perfectly matched colour-wise to the timber.
Both can also be melted into the gaps with a heated artists pallete knife or similar. Osmosis or some similar action seems to help sucks the hot liquified stuff into the gap. You can even buy a small self-heating spatula that runs off a single 1.5volt AA battery. Once the beaumontage or wax sinks into the gap and hardens it is easy to smooth the excess away leaving a near-invisible repair albeit that repair is only cosmetic.
If strength is an issue then Eef's dutchman is the way to go, as the patch will not just fill the unsightly gap but also join the pin and tail as they were meant to be joined. Personally I favour the use of veneers of the same timber, which can be pushed into the gap with grain at the same orientation as either the pin or the tail. The DT gaps are often around the width of veneer (0.4 - 0.6mm). If necessary the veneer can be doubled-up or even scraped a bit thinner. Or the gap can be opened up with a fine saw, or even a knife blade, sufficient to get the veneer in as-is.
A piece of glued veneer, when a tightish fit in the gap, will dry to form wood-to-wood bonds, so does add strength. Sawdust and glue (unless its epoxy) is not going to provide any strength. The ideal veneer thickness is where you cannot get it in dry but it will slide home when lubricated with the wet glue. Watering PVA glue down just a tiny bit helps to keep it wet and slippery enough to give time for stuffing the veneer in. It also ensures the veneer swells a bit once in place, to help make the bond.
Lee Valley used to sell a great pizza-box full of fair-sized pieces of veneer of just about every species you heard of. I bought mine years ago for $32 and still have 90% of it. It's been used not just for gap filling but also for dutch patches, decorating small boxes, fattening overcut tenons and other such tasks where only a small amount of veneer is needed. This boxful of veneers is one of those multi-use items that every woodwoodworker should have tucked away in a bench drawer somewhere.
Lataxe, who has veneered over many a faux-pas.
Yet another fix for sloppy loose dovetails is to split the pin with a slender chisel, then drive a tapered wedge into the split. This can either be carefully matched for an inconspicuous fix, or made to be a "design element". :-O
I've seen enough old blanket chests in this region that are wedged at every pin, to conclude that for some element of the period cabinetmaking community at least, it was accepted practice on large case pieces to deliberately cut the joints loose, then wedge the joints of the case together after a stress-free assembly. Git 'er done!
Ray
this may have been a repair application for old carcasses, for joints that may have loosened up,
ron
Veneer pieces
Lataxe:
Lee Valley still sells the pizza box of veneers, but there is no guarantee I'll get the wood I want. I called them and they said it's just a mix. I'll try making my own first.
By the way, I have a daughter living in Wales. She getting her PHD at Swansea University.
Thanks for the tips,
Jim
My memory's good, it's just short.
Crazy Glue Fix
Use the thin crazy glue. Place a few drops on the gap and hit the area with a random orbital sander without the shop vac turned on. You may need to do this 2-3 times to completely fill a gap.
This only works for very small gaps, but can also be used for any joinery or even small pores. For most finishes the fix isn't noticeable. For larger gaps use veneer or any of the other ideas above.
Simon
Depending on how 'bad' the gap is.. I would use a slice (wedge) of the same wood and carefully hammer it into the crack with a bit of glue. Sand or plane off. Usually almost invisable if somebody is not specifically looking for it.
Smash the pins
I have heard that you can cut your pins so that they are 1/16" proud of the tail side and then take a hammer and smash the end grain of the pin into the gaps. I have never tried it so I don't know how well it works. I'd imagine it may only be useful in softwoods???
mv,
think it was brother tage who suggested that fix. so i tried it and although my gaps were somewhat less than 1/16", the result looked like poo-poo. the gaps did close but the end grain looked as though it had been hit with a blunt punch and a steel hammer which, in fact, is how i did it. not pretty. dutchman better.
eef
Eef,
I have the feeling that Mr Fried was having a little joke with his hammer-splat tekneek. He was apparently known for his naughty humours and teasing of the naive. A wwodworking equivalent of the apprentice being sent for a long weight.
Lataxe
Reminded
That reminds me, Lataxe.
You owe me a board stretcher, and a left handed smoke curler.
I'm right handed. Therefore, this right handed curler you sent me is worthless.
Actually the practice of wetting the end of the pin and lightly striking it with a ball pein hammer is called "bishoping" and has been around, probably forever. Never tried it myself, but I did see a video of Tage once where he referred to the practice, and I think it is a favorite of Mr. Underhill.
In common work, especially in soft timbers, many workers allow the pins of a drawer back to run through the sides about 1⁄16 in. and hammer down the pins of the dovetail. This is called "bishoping the dovetails," and is unnecessary if the work be properly made and fitted.
http://sawdustmaking.com/woodjoints/dovetails.htm
-Chuck
chris,
"bishoping"
as a
chris,
"bishoping"
as a survivor of a catholic school, it is difficult not to imagine the hidden violence in that term. then again perhaps "peening the bishop" connotes yet more...
thanks for that website, i've bookmarked it.
eef
Well, the best way to deal with gaps in your dovetails is to cut them more accurately in the first place, especially if they will be seen.
Bench
I recently went through this on my bench.
If you're working with nice lumber, spalted maple in my case, you can only cut it so many times before you run short of nice, spalted maple.
So a repair technique is valuable.
The difference between an apprentice and a journeyman is that a journeyman knows how to fix his mistakes.
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