Gaps in Glued-Up Panels

[BKind2Anmls]

First the history:

I glued up several panels for a high chair/rocking horse/desk combo piece of furniture.

I took flat-sawn red oak and cut it into 1X1 strips. After jointing, planing, etc. I turned the strips 90 degrees so that the flat-sawn sides were glued together and straight grain appeared on top and bottom.

After sanding, the panels are 3/4" thick. There are two panels which are 35" x 20" and 4 panels that are 13" x 13". Among the panels there are a total of 4 small gaps, approximately 1" - 2" long and 1/8" to 1/4" deep where I apparently starved the glue joint.

Now the question:

Can I just fill these gaps with saw dust and epoxy without sacrificing strength? Do I have to rip these joints apart and reglue? I don't want to take a chance of the joint failing especially because a child will be using the furniture. What has been y'all's experience with small gaps in glued-up panels?

Thanks

---Susan

 

[jeff...]

I flood em with thin CA glue ---> http://www.ncwoodworker.net/forums/f64/dealing-lumber-checks-voids-11094

 

[BKind2Anmls]

Thanks for the link, Jeff. I did a search on "panel" and "gaps" and came up empty before.

I guess you are saying that I don't have to worry about the joint failing because of a small gap?

 

[jeff...]

I guess you are saying that I don't have to worry about the joint failing because of a small gap?

I can't say that - have no idea if the joint will fail because of a small gap :dontknow:

 

[cskipper]

I'd suggest sealing the wood before using CA on the gaps. CA stains.

 

[jeff...]

I'd suggest sealing the wood before using CA on the gaps. CA stains.

Does it really Cathy? I've not noticed any staining - it does leave a little white hue when I use acetone as an accelerator but sands of easy enough.

Thanks

 

[Travis Porter]

I would think you can fill them with whatever if your gaps aren't all the way through. If you are going to stain the wood, you might stain before doing any type of filler. Any ideas of what caused your gaps in the first place? If you are using clamps to pull boards together and close gaps then they are not straight and true in the first place and you may have issues with the joint failing.

 

[BKind2Anmls]

This is the first time I have glued up a panel which resulted in gaps. I think parts of the joint were glue-starved. I used Titebond Extended Time glue for the first time and won't be using it again. It is VERY runny (think diluted Elmer's) and I believe the glue didn't stay where I put it.

Since I haven't had this problem before I'm not sure how much of a gap a joint can withstand before it fails.

 

[FredP]

they may fail prematurely.:eusa_thin the best fix is to rip them on the glue lines and rejoint and glue again. if you fill them the line will always be there and they may still fail in time. if the panels will be too small after redoing them add another strip and recut to the size you want.

 

[cskipper]

Does it really Cathy? I've not noticed any staining - it does leave a little white hue when I use acetone as an accelerator but sands of easy enough.

Thanks

I used CA on an ambrosia maple bowl which had a split and it left gray areas. It walso did not want to take a finish. Might have been a fluke.

 

[DaveO]

This is the first time I have glued up a panel which resulted in gaps. I think parts of the joint were glue-starved. I used Titebond Extended Time glue for the first time and won't be using it again. It is VERY runny (think diluted Elmer's) and I believe the glue didn't stay where I put it.

Since I haven't had this problem before I'm not sure how much of a gap a joint can withstand before it fails.

Susan it doesn't sound to me like you have glue-starved joints. Glue especially PVA type yellow glues aren't designed to be a gap filler. The boards you are gluing up have to fit together perfectly along their lengths. The actual glue line thickness between the board is so thin you shouldn't be able to see it. Even if you didn't get good glue coverage across all the surfaces it shouldn't result in any gaps, if your joints were fitted properly. I would suspect that in your jointing process something didn't end up perfectly square in the small areas where you are seeing the gaps and resulting in a not so well fitting joint.
I have made many cutting boards, which sound to be similar in construction to your panels and have had similar problems. My stock was glued up straight off the tablesaw, and if the stock shifted a little or my feed rate changed it might result in a less that perfectly flat cut in one small area of the glue edge of the board.
I don't think that you are going to have a glue line failure with the gaps that you mention. It sounds like they don't go all the way through the panel, nor are very long. The rest of the long grain glue surface will more than hold them together.
I do agree with either the CA/sanding dust filler, or the epoxy/sanding dust filler. For small gaps I use the CA, for larger it would be best to use epoxy. Be careful with both methods as neither take a stain or penetrating oil finish like the rest of the wood. If you are doing a clear top coat like lacquer then you will have no issues with either method.

MTCW,
Dave

 

[JimD]

My technique for filling little gaps is to put a little fine sawdust in the cracks when I am applying finish. I like this technique best when using water based finish that dries very quickly. I will probably do it on the kitchen table I am working on with poly, however. I did not joint the wood before face glueing 3, 1 inch thick pieces to make 3x3 legs. I have a few small gaps. I should have jointed them. Poly and most water based finishes are decent adhesives so filling a small crack with finish does not hide the gap real well but it helps things stay together and prevents collection of dust/dirt. If the crack is too large to fill with finish, I would cut the panel apart and re-glue.

Jim

 

[froglips]

Another thought, given the ripping of the pieces. Did you let them sit for a while before glueing them? This kind of cutting would release a lot of internal stresses that could work against you.

When doing this kind of cutting, I leave things a little oversized, then a second cut or extra jointing a few days or a week later so any stresses would become apparent.

If you have a bandsaw might I suggest ripping, as straight as practial, the starved joint. Any errors in the cut would cancel out. Or a quick trip back to the jointer. A bandsaw blade can cut a very narrow kerf.

I tend to fall on the side of redoing the joint. If there were stresses at play, this could be a telling sign.

Sounds like you are embarking on a fine project, so get us some pics!! We love those pics!

Good luck!
Jim

 

[BKind2Anmls]

Reply. Thanks all for your suggestions. I had not heard of someone using the actual finish and mixing it with sawdust before. Sounds like an interesting idea. During the dry clamping phase everything looked good. It didn't show up until I started sanding so the problem was just below the surface.

There is one joint in particular that I think I am going to rip and reglue. It makes me nervous and it definitely shows up. Where the joint is located, it shouldn't make too much of a difference with the width except with the continuity of the curves. It's a pattern from the Winfield Collection and the sides are both weirdly curved. If anyone else ever decides to make it, I created MDF templates that you could borrow.

FYI, I plan on using the Miller Dowel system to connect everthing. I haven't used it before but I like the thought of building without any metal.

My red oak varies from brown to very pale and I have decided to make the color difference a "feature" of the modern style of the chair instead of trying to color-match almost 150 1" boards. I am using cut-offs that I picked up from a molding mill several years ago.

I will probably be spraying it with a water-based poly/crosslinker or pre-cat lacquer...whichever I find first locally. This will be my first attempt at spraying. I bought the inexpensive Rockler system.

Let's see. Next I promised a night-light to another friend, a birdhouse to a fellow teacher, a picture frame to a golfing buddy, four display cases to my mentor, 30 pens to a client....one day I'll be able to make something just by looking through a book and thinking, "Cool! I'd like to make that." But I guess it's that way for most woodworkers. At least we have people who appreciate our efforts.


Thanks,

Susan

 

[JimD]

Susan,

You are unlikely to find it locally but I highly recommend Resisthane. You may find it at Highland Hardware and you can get it for sure at Hood finishing products (name may not be exactly right). It should be about $30/gallon delivered to your house. It sprays easily, drys quickly, and is rated for kitchen cabinets. They call it a pre-cat lacquer but that is just to describe it's characteristics. I spray it with a Wagner conversion gun straight out of the can. Others have reported good results with little blower systems like you apparently have.

Jim

 

[BKind2Anmls]

Thanks, Jim, I'll check it out.