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Finger joints, glue, box build question

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Forum topic by Chashint posted 09-06-2016 12:31 AM 559 views 0 times favorited 14 replies Add to Favorites Watch
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Chashint

38 posts in 110 days


09-06-2016 12:31 AM

I am building some boxes.
They have finger joints and the lid/bottom is captured in a dado.
I cut the lid off of the box after the it is assembled / glued.
My question is how do y’all deal with the hard dried glue squeeze out on the interior corners?
The first box I built I tried using a chisel, a razor blade, and sand paper to try and clean it but I still had a couple of places where I could see the glue reside after I applied the finish inside the box.
There were also some undesired marks on the wood from cutting the glue off.
Is there a trick to use when the inside joints are not accessible before the glue is cured?

-- Regards, Charlie


14 replies so far

View MadMark's profile

MadMark

976 posts in 913 days


#1 posted 09-06-2016 01:53 AM

Two words: felt lining

M

-- Madmark - Madmark2150@yahoo.com Wiretreefarm.com

View bandit571's profile

bandit571

14536 posts in 2143 days


#2 posted 09-06-2016 02:00 AM

Masking tape. Keeps the glue in the joints..

Of course, just a quick wipe with a wet finger can do wonders, too…

Didn’t have enough wood to make it one piece, lid was done seperately…

-- A Planer? I'M the planer, this is what I use

View JBrow's profile

JBrow

814 posts in 380 days


#3 posted 09-06-2016 02:56 AM

Chashint,

Removing cured glue from inside corners is difficult and time consuming at best. Omitted from the tools you listed that is helpful is a cabinet scraper. This tool can get into tight spaces and the does a fair job of removing cured glue. Also sanding the joint with a wooden sanding block along the length of the joint can also be effective. However, since I assume this would be sanding across the grain, the visible scratches left after the glue has been removed must now be sanded out. Therefore using the highest grit possible that will do the job and then sanding the corners with the grain to final grit could work. But getting all the scratches left from cross grain sanding is almost as difficult as removing hardened glue. But whatever method used to remove the hardened glue, applying mineral spirits or water (which will raise the grain and require some more light sanding) before applying finish can reveal glue that has not be removed.

I can think of several options for avoiding or reducing this problem…

Obviously limiting the amount of glue applied to the joint will reduce squeeze out, but some squeeze out somewhere on the inside corners is probably inevitable.

One approach would be to dry assemble the finger joints in clamps. Then apply masking tape on the inside of the box where the joint comes together, ensuring the tape is firmly adhered all along the length of the joint. When the box is glued and squeeze out occurs, it will deposit on the masking tape, which can be removed when the lid is cut free.

Another approach is to dry assemble the box in clamps to protect fingers that get glue and then apply finish on the inside of the box, keeping the finish off any other surfaces that will be glued. Once the finish has cured, the box can be glued up. Squeeze out deposited on the finished wood should be easier to remove. This method may require some touching up of the finish after the lid is cut free, but the touch ups should blend well with the already freshly applied finish.

The last and my least favored approach is to cut the lid free before the glue has fully cured, so the glue squeezed out is soft and fairly easily removed but has sufficiently cured to keep the box together. Since flushing up the finger joints on the outside of the box could be messy and introduce unwanted stresses to the partially cured joints, a carrier board may be needed (if the fingers are proud of the surface of the sides). The carrier board (a flat board with parallel faces) would be short enough to fit between the fingers, wide enough to be stable, and thick enough to elevate the finger off the saw’s table. The side of the box positioned on the carrier board, which is on the saw’s table, should help keep the box running true against the saw’s fence. Some double sided tape would hold the carrier board to the box making the operation a little safer.

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Chashint

38 posts in 110 days


#4 posted 09-06-2016 03:10 PM

Thank you.

-- Regards, Charlie

View gfadvm's profile

gfadvm

14940 posts in 2150 days


#5 posted 09-06-2016 11:53 PM

Shellac the inside of the box before glue up.

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

View Luthierman's profile

Luthierman

157 posts in 547 days


#6 posted 09-07-2016 12:27 AM

Since I make my boxes with a sliding top I always have access to the inside. I use a wet rag and the edge of a dull chisel. Sometimes I just let it dry and use one of my very sharp mortising chisels.

-- Jesse, West Lafayette, Indiana

View kiefer's profile

kiefer

4881 posts in 2127 days


#7 posted 09-08-2016 12:47 AM

Try this
Tape up the insides of the corners (see the pictures ) and clamp and the squeeze out will come off when you remove the masking tape after you separate the lid when the glue has dried .
http://lumberjocks.com/projects/107614
Here is the link to Ver2 of my corner clamp which works on any corner type .
http://lumberjocks.com/projects/120593

Klaus

-- Kiefer https://www.youtube.com/user/woodkiefer1/videos

View Chashint's profile

Chashint

38 posts in 110 days


#8 posted 09-08-2016 02:23 AM

I am trying tape on the inside joints of this box and will let y’all know how it works out for me.
Box building is something I want to get real good at, so there will be more boxes on the way.
If the tape is not enough of an improvement I will just go down the list of recommendations until I get it figured out.
I appreciate everyone taking the time to try and help me.
Thank you.

-- Regards, Charlie

View shipwright's profile

shipwright

7163 posts in 2258 days


#9 posted 09-08-2016 04:37 AM

Stop using PVA glue.
Use hide glues and you can do all your cleanup with warm water.
You can also skip the clamps most of the time.
Just sayin …..

-- Paul M ..............If God wanted us to have fiberglass boats he would have given us fibreglass trees. http://thecanadianschooloffrenchmarquetry.com/

View Chashint's profile

Chashint

38 posts in 110 days


#10 posted 09-09-2016 01:59 AM

The tape worked much better than I expected it to.
There was some clean up to do but it was minimal and the tape made the glue form a very thin line I had cut right in the corner.
Much better than trying to get the glue off of a bigger area.
I will add another suggestion along with the tape on the next box.
Thanks for the tips.

-- Regards, Charlie

View johneone's profile

johneone

8 posts in 3511 days


#11 posted 09-10-2016 03:24 AM



Stop using PVA glue.
Use hide glues and you can do all your cleanup with warm water.
You can also skip the clamps most of the time.
Just sayin …..

- shipwright

+1

-- John from Murrieta

View newwoodbutcher's profile

newwoodbutcher

552 posts in 2310 days


#12 posted 09-10-2016 04:38 AM

I got the scraper from Benchcrafted when I ordered my vise hardware after hearing of it’s praise ( hereI think). Wow is this a great scraper. You have four carbide edges on a wide blade (1 1/2”?) about an eighth inch thick on a crooked wooden Handel that is perfect for scraping off glue squeeze out. I love it! But I agree taping the inside corners is the right answer.

-- Ken

View a1Jim's profile

a1Jim

115201 posts in 3037 days


#13 posted 09-10-2016 01:36 PM

I think using hide glue is a good option or you can make your boxes with sliding bottom similar to lutherman’s tops ,clean up the inside and then glue the sliding bottom in place,let dry and cut the top off. This is done with drawers all the time.

-- http://artisticwoodstudio.com Custom furniture

View splintergroup's profile

splintergroup

815 posts in 682 days


#14 posted 09-10-2016 02:25 PM

I use ‘Waxlit” which is basically a wax that can be removed with solvent (mineral spirits).

I wipe the outside surfaces around the fingers with a thin coating. The glue will not stick to this and pops off easily.
Afterwards I remove the wax with a solvent soaked rag (several times, allowing the previous wipe to dry first).

Typically I’ll pre-finish the inside of a box before assembly which also goes a long way to preventing squeeze-out problems.

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