How to make glued edges look better?

[JeremyG]

So I use Barge cement to glue up my leather pieces.  The glue works great, the problem is when I then go to finish the edge, you can always see the little lines of glue rather than just a perfectly smooth edge.  Usually what I do is glue up the pieces, then trim to size, sand the edge, then burnish with tokonole using a wooden edge slick.  No matter how much i sand you can always see the lines.  I see other people's work with utterly glass-like edges where they obviously were glued together.  Is it because of the type of glue I'm using?  Any advice would be appreciated.

[Danne]

Make sure to hammer down your edges really good, and also let it cure before sanding. I have no problem with this and I use both water based and solvent based contact cement. Here is a burnished edge on two layers of leather (bad photo) but no visible glue line. I can't remember if I used water based or solvent based glue on this one.

With natural veg tan without dye on edges you will of course see a little transition between layers. But when I look at your photo I see "gaps" 

 

Edited November 20, 2020 by Danne

[Rahere]

There's so many possibles.

1. I'd suggest thinning the leather near the sides so it's no longer fibrous, just collagen.
2. Glueing: spread it from the middle to the edge with a scraper. Let it nearly dry before joining. Then apply pressure. Now scrape and sand.
3. If there's still space, see if water expands the fibres.The edge seal should get in there. Be prepared to put a layer on, then sand it again, and reseal.

 

[battlemunky]

I have noticed that if I let it dry thoroughly before joining, whether it be Barge, Weldwood, or water based Aquilum, the joint is far less visible. Having said that, on an unstained edge there will always be some type of line visible.

[TargetRockLeather]

If the cement in the can is getting thick due to the solvent evaporating I find that the glue lays on top of the leather and forms sort of a rubber gasket between the layers of leather. I recently added some thinner to the can of Barge cement which made it less thick (as when it was new). Now the cement penetrates more and doesn't leave a layer of rubber between the layers of leather. For me it made a noticeable difference.

[Tugadude]

I don't know if this is happening to the OP's example, but I know that when I use glues, sometimes I am afraid that it will show too much on the edge so I tend to spread it too thin.  I like the suggestion above about carrying the glue all the way to the edge with a spatula or scraper.  If the glue is sparingly-applied, that might account for the gaps.

[fredk]

10 hours ago, TargetRockLeather said:

If the cement in the can is getting thick due to the solvent evaporating I find that the glue lays on top of the leather and forms sort of a rubber gasket between the layers of leather. . . .

yes, I've noticed that too.

I glue, clamp up, sometimes tap with a rubber mallet then sew it up. I leave a margin for cutting off so after sewing I use a good sharp knife and straight edge to cut that allowance off, which cuts thru the glued section and if I've done it right the leather there is well glued. I bevel the edge corners then slick it up.

[Rahere]

The pressure forms the join's strength. Yes, of course you'll have a line, it depends on your approach to the edge finish whether you leave it as a feature or not. Edge burnishing simply polishes the edge, leaving it visible. Edge coating covers it over. You can fill the edge too, sanding/scraping a coating back.

[TargetRockLeather]

13 hours ago, Rahere said:

Edge burnishing simply polishes the edge, leaving it visible.

I find that in my scenario, where there is a noticeable layer of rubber, I can't get a really good burnish along the center. Glue doesn't burnish. That's the most annoying thing about having the glue layer.

[JeremyG]

On 11/23/2020 at 8:27 AM, Rahere said:

There's so many possibles.

1. I'd suggest thinning the leather near the sides so it's no longer fibrous, just collagen.
2. Glueing: spread it from the middle to the edge with a scraper. Let it nearly dry before joining. Then apply pressure. Now scrape and sand.
3. If there's still space, see if water expands the fibres.The edge seal should get in there. Be prepared to put a layer on, then sand it again, and reseal.

 

 

On 11/20/2020 at 8:41 AM, Danne said:

Make sure to hammer down your edges really good, and also let it cure before sanding. I have no problem with this and I use both water based and solvent based contact cement. Here is a burnished edge on two layers of leather (bad photo) but no visible glue line. I can't remember if I used water based or solvent based glue on this one.

With natural veg tan without dye on edges you will of course see a little transition between layers. But when I look at your photo I see "gaps" 

 

 

On 11/23/2020 at 9:47 AM, battlemunky said:

I have noticed that if I let it dry thoroughly before joining, whether it be Barge, Weldwood, or water based Aquilum, the joint is far less visible. Having said that, on an unstained edge there will always be some type of line visible.

 

On 11/24/2020 at 12:46 AM, TargetRockLeather said:

If the cement in the can is getting thick due to the solvent evaporating I find that the glue lays on top of the leather and forms sort of a rubber gasket between the layers of leather. I recently added some thinner to the can of Barge cement which made it less thick (as when it was new). Now the cement penetrates more and doesn't leave a layer of rubber between the layers of leather. For me it made a noticeable difference.

 

On 11/24/2020 at 8:06 AM, Tugadude said:

I don't know if this is happening to the OP's example, but I know that when I use glues, sometimes I am afraid that it will show too much on the edge so I tend to spread it too thin.  I like the suggestion above about carrying the glue all the way to the edge with a spatula or scraper.  If the glue is sparingly-applied, that might account for the gaps.

 

On 11/24/2020 at 11:01 AM, fredk said:

yes, I've noticed that too.

I glue, clamp up, sometimes tap with a rubber mallet then sew it up. I leave a margin for cutting off so after sewing I use a good sharp knife and straight edge to cut that allowance off, which cuts thru the glued section and if I've done it right the leather there is well glued. I bevel the edge corners then slick it up.

All good suggestions.   Thanks everyone

[johnv474]

You can also switch adhesives to Leathercraft Cement or Renia Aquilim contact cement.  They dry clear.  That is by far the easiest solution.  Unless you are making unstitched shoes, the bond is plenty strong.  Side note: white glues work better with Tokonole.