# How to fix butt joint gaps?



## graemlourens

Hi Everybody.

I've glued up my outside bench for at the pond. This has been my first furniture woodworking project where accuracy mattered, and i already have learnt a hard lesson with dowels. They were so tight, that when trying to glue this together, i wasn't able to generate the force necessary to get all those tight dowels (28 at once) deep into the according holes.










I'm left with a lot of butt joint gaps!
The project is going to be stained and finished, but i've been reviewing some options to fill those gaps, as its going to be standing outside, in full rain, snow and what not. Those gaps will be hard to 'finish' and will be a perfect spot for moisture to soak into the end grain (as its pine, i have to seal up everything everywhere as good as possible)

I was looking at stainable wood putty, but i'm getting mixed feedback. Ones saying you may not putty Butt joints, ones saying those stainable wood fillers like minwax offers do not stain as they claim. And filling after finish seems to be the wrong way to go, now that i can still fill / fix & sandpaper as much as i want to.

Also i checked the Option of using glue & sawdust, but before i do anything, i wanted to do my research first…

I need you're experienced advice!
Any help warmely welcome.

Kind regards, Graem


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## JBrow

Graem Lourens,

Using a paste filler, whether wood putty or dust and glue, would be my option of last resort. I frequently fill long gaps using thin shims cut from project lumber. A well-fitting shim, unlike paste fillers, can produce a repair that is nearly invisible and it stays put and will not crack.

The gap to be filled is first cleaned and prepared for shim. A utility knife can often result in a gap wide enough to accept the shim to a consistent deep. The shim is prepared by first cutting a slither of wood from which the project is built to approximate size. The shim is then fine-tuned to fit snugly and deeply in the gap all along the length of gap. I find course grit sand paper works best on what is normally a fairly thin shim sometimes sanding a slight bevel along one edge to make it easier to press it deeply into the gap. Once I have the shim fitting exactly right, I apply glue to the shim and press the shim into the gap as deeply as possible. After the glue has cured, the excess shim is paired away with a chisel and sanded flush.


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## GR8HUNTER

I say lesson learned ….......just set it out …..when you build next 1 ….....check into biscuit's …..or drill hole 1 size bigger then dowels …......this way you have some room for glue also …...... good luck to you sir


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## graemlourens

Hi.

Thank you a lot for your feedback. I didn't even consider your idea JBrow, but it seems very simple and effective! I will give that a go, even if i think this will be a very finicky and tedious job to get those shims just right - but we will see, it definitively sounds the most promising to then stain & finish (assuming i don't make a huge glue-mess)

Concerning the dowels, yes indeed 1 size bigger hole next time. I did see to it that the dowels could be put in and removed by hand, but with so many dowels at once, i totally underestimated the force.

And also learnt that you can never have enough clamps 

But back to wood filler / paste / putty. Are these products unreliable and are there certain things to be aware of? Maybe somebody that has experimented with it could share a few words so i don't walk into the pittfalls ahead of me if i do decide to try.

Kind regards, Graem


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## rwe2156

Did you do a dry fit?
Sounds like the glue was seizing on you. Did you try to glue the whole thing up at once or stages?
Any filler needs to be waterproof, as does (did) the glue.


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## graemlourens

Hi.

Yes i did a dry assembly, but to be honest, i did not clamp everything to the tighest, just wanted to see that everything fits, that was a big mistake. I though the gaps would then disappear (nearly all) when clamping. But i had to take belt fasteners (like the ones you use to attach things to your roof of the car) and i never ever could put any kind of real force to those.

I assembled the back rest, and both leg parts (that i could separately glue) first. Let them dry, then all 4 parts came together (not possible to do it in various stages because of the dowels). 2 Sideparts, back rest and seat logs. (don't know how you call them)

Lesson learnt for sure. Dry assembly has to be exactly as it will be when glued up, and to make those holes for dowels muuuuch looser (and that i need to buy more clamps…. the ones i have nearly broke already, i guess i need some heavy duty pipe clamps for these kind of projects)

Glue is waterproof, yes.

Kind regards, Graem


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## dhazelton

Gotta have real clamps - you can use simple wooden wedges if you don't have a real need for the clamps beyond this one time build.


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## graemlourens

What a great idea… thank you! Very handy if once i have to clamp something longer than my clamps.

I will though be building a ton of furniture in future, so i think i'll be going for a decent set, but in the meanwhile i'll gladly try this relatively simple workaround!

Kind regards, Graem


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## jeffswildwood

First congratulations on a beautiful bench. I like the design! As for the gaps, unless they are big, I agree with Tony (GR8HUNTER). Lesson learned, stain and seal and put it out and enjoy it! Next time make your adjustments.


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## graemlourens

Hi Jeff.

Thank you very much for your feedback.

I can not take credit for the design. I saw this bench in a park around here, sat on it for a while, loved it, came back a few days later with a measuring tape and a laptop and 3d sketched it.

But its dead simple to make, and the next one will feature half lap joints or mortise and tenons, not sure yet what road to go down first. (need to try them all to pick my favorite!, really depends on the tools at hand i guess)

Kind regards, Graem


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## Kazooman

A bit more on using dowels. Don't go overboard on making the holes larger. A snug fit without binding is what you want. Your comment "to make those holes for dowels muuuuch looser" suggests that you might be headed too far in the loose fitting direction.

You need to allow somewhere for the excess glue to squeeze out. If you put a bunch of glue in the hole and then insert a fairly snug fitting dowel the glue gets pushed to the bottom of the hole and that's as far as the dowel can go. You can purchase dowels that are scored along their length or simply use a utility knife or other tool to score your own making channels for the glue to flow through. The total depth of the two holes should be a bit more than the dowel so that it doesn't bottom out.


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## graemlourens

Hi Kazooman.

Yes, you're absolutely right. And i do know i'll have to be careful not going too far, but using the same drill size as the dowel is, didn't work for me it seems. I'll go one size bigger and see if that does the trick.

The dowels that i have, they have the scores along the side, so perfect for glue-squeeze-out.
I think that if i could have done the glueing in smaller parts (i'd have to design it differently) it would have been no problem, but getting the force for 28 dowels including a snug fit, was just over-enthusiastic 

Kind regards, Graem


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## distrbd

Another possibility for having those gaps is, you probably did not drill the holes deep enough ,it's always better to measure and compare the depth of the holes with the length of the dowels. I always drill 1/16" deeper than what's needed.
If you are planning to use dowels in your future projects I highly recommend shaving 15-20 spare dowels to make them narrower so they can easily fit in the holes, keep them in a sealed jar, use them for dry fitting/ testing your project before the final glue-up.


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## jwmalone

Gr8hunter has it, lesson learned. Also you built that from pine to sit out in the weather, it will shrink and you will have gaps anyway fixing them now is pointless. Its a very nice bench. Next time I would consider using a wood better suited for exterior applications like cedar or something, even then outside furniture uses slightly different approach to joinery techniques than inside to allow for the extreme changes in temp and humidity.


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## graemlourens

While reading about using dowels, i did read that one should drill slightly deeper than the dowel, and i made sure that was the case everywhere.

The hint of the slightly smaller dowels for dry fitting is a very good hint, thank you! You guys are flooding me with great insights, i really appreciate it.

Concerning the wood. As it really as a practise object i didn't want to use any good wood, and furthermore i'm still looking for a good local dealer here in Warsaw.

Kind regards, Graem


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## jwmalone

Well its a very nice practice piece. Are you in Poland or U.S.


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## graemlourens

I'm currently living in Poland. Just found out you guys also have a 'Warsaw' that was new to me!

Kind regards, Graem


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## jwmalone

Yea we have several city's or towns named Warsaw. Indiana, Missouri had a lot of Polish settlers they both have a Warsaw. WE have a town named for every other city on the European continent aswell lol.


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## canadianchips

If you are staining this, putty's , fillers will always be seen. Try to fit tighter when finishing with stain.
Option on this one might be paint. You can use epoxy filler and cover with paint !
Glue and sawdust will also leave a different color.


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## marshallmosby56

Considering the environment your beautiful bench as I must say, is going to be in having a lot of moisture, dust etc, the best bet would be to use silicon sealants. You can check online for those and learn about the same as they come from different manufacturers and so it would be better to choose the one best suited for your DIY project.


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## graemlourens

Hi Everybody.

A late update: You guys got me thinking a lot, and i decided to take my time and experiment on test pieces.

- I tried glue & sawdust, not very easy, and its like endgrain, it soaks up all that stain, way more than the normal wood.
- I bought various putty's / fillers and currently waiting for them to try, but as the gaps are considerable, its a multi-stage process (putty does shrink in size) and i don't think that staining will work well.

The last comment brought me to the idea i'll probably follow: I'll finish the bench as is, and seal the cracks afterwards with colorless silicone that will work for outside usage and bond to the finish well. It will not optically 'close' the cracks, but it will prevent moisture of creeking in there, and for me thats more important. On the second bench i'll be more careful and will see if i can get it perfect this time 

Thx again for all your insights, i really do appreciate the time every one of you took to give your opinions.

Kind regards, Graem


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## 000

I wouldn't use silicone. I would use DAP Dynafex 230. Regular caulk that you get at the big box store.
Silicone is too messy and turns funky after a year or so. The Dap is (they claim) 100% waterproof and is made for Exterior Windows and Door Trim. Water cleanup, And it comes in colors that may be close to your finish?
https://www.dap.com/dap-products-ph/dynaflex-230-premium-indooroutdoor-sealant/


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## jwmalone

Jbay is right.


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## runswithscissors

Another approach: If the gaps are sufficient, use a hacksaw blade to saw through all of your dowels (or at least the problematic ones) and start over. Better than a hacksaw blade would be an oscillating multi tool. I'm quite fond of Harbor Freight's version, even if it is the cheapest you can buy. Best deal on blades is from Grizzly.


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## Cooler

I suspect that your problem was "hydraulic pressure". The wet glue creates as seal for the air behind it and it works like a shock absorber. What I do is take a knife to the dowel and make a lengthwise slice to allow the air to escape. Or I use manufactured dowels with the grooves already done.

I would use one of these: http://www.craftsmanspace.com/sites/default/files/free-knowledge-articles/wooden_dowels.jpg


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## graemlourens

Thx a lot for your comments.

@Cooler, i did use the dowels you have in your link at the right side. But the fit was so tight (now i know much too tight) that with the glue i had the mentioned hydraulic pressure problem.

I'm preparing for an identic second bench and will see if this time i get it just right.

But i'm not surprised i had gaps. I was not able to joint these logs at all (none of them), i only had a planer, and my mitre saw station was balacing wood on wacky elements. I'm currently moving to my brand new shop and will now be busy for at least 2 months just building support furniture, and then going back to projects 

Kind regards, Graem


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## marshallmosby56

Checked out DAP Dynafex work. Really impressed. Thanks for making me wiser.


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