burnishing T-slots

[samNZJP]

Hello everyone, 

See the attached photo - I was wondering how this person manages to burnish their T-slots so cleanly. Anyone have any insight into how they might be doing it?

Regards,

Sam

[immiketoo]

For thin leather like that, I use a cocobolo burnishing stick with a very thin slot and a light touch.  Just water is all you need.

[samNZJP]

Thanks,

Would you sand these parts?

[Matt S]

I use a wooden motorised burnishing wheel wherever possible. For thin stuff like that I keep the piece taut betrween finger and thumb of each hand and am careful to not tilt the piece at all. Exactly what substances I would use and in what order would depend on what that particular leather best responds to -- plain water, saddle soap, glycerine soap, diluted glue (hide, PVA, Arabic gum), shellac, beeswax...

[samNZJP]

would love it if you could give a quick breakdown on what types of leather you think responds best to each substance!

[chrisash]

You can get a good finish first use water  then after burnish rub bees way over the edge and re burnish all with a light hand

[Matt S]

2 hours ago, samNZJP said:

would love it if you could give a quick breakdown on what types of leather you think responds best to each substance!

Each particular leather responds differently, sometimes even different hides that are ostensibly prepared the same, and temperature can change the way they react. I can't really give you a list because I don't have one and the leathers you use will be different to the ones I use. I have "current favourite" methods for each type of leather I use but I try them out on a piece of scrap from the hide I'm using before burnishing a batch of pieces.

Veg tannages burnish quickly with plain water but I find it goes faster and the result is more durable with diluted glue. I usually use PVA because it's readily available, seals the leather well and doesn't go bad like hide glue does. Almost any water based glue will work -- PVA, wallpaper paste, gum arabic, hide glue... Particularly greasy veg tannages like bridle sometimes need a little help getting the stuff to penetrate the edges so this is where I might use plain water first, or some soap. Experiment a little but keep it simple.

The classical answer is that chrome tanned leathers don't burnish, but I've found that some will, to an extent, with a high-speed wheel and something like diluted PVA that physically seals the leather.

[bullmoosepaddles]

53 minutes ago, Matt S said:

like diluted PVA that physically seals the leather.

How much do you dilute the PVA glue? Do you do it in a small batch or a few drops at a time?  

Thank you Sir 

[chrisash]

Like the idea of PVA glue, must give it a try on chrome

[Matt S]

1 hour ago, bullmoosepaddles said:

How much do you dilute the PVA glue? Do you do it in a small batch or a few drops at a time?  

Thank you Sir 

I normally mix up a jar at a time, since it doesn't go mouldy on the windowsill behind the bench and I only have to do it once, which will do for several dozen belts. I don't measure it particularly, just put in a big dollop of PVA, top with warm water and give it a mix. If it doesn't penetrate the leather I pour some out and top with water. If it doesn't shine quickly when rubbed into a scrap of leather I pour a bit out and add more glue. I guess 4:1 water:glue is about average but it depends on what PVA I'm using at the time. The stuff sold to tradesmen seems to be "thicker" than the DIY stuff, or the stuff for glueing paper, but just about any PVA I've tried will work.

There's nothing particularly magic about PVA, most water-based glues will work on veg-tanned leathers, or at least all the ones I've tried. PVA just happens to be readily available, doesn't go mouldy when mixed up, and I think it gives a slightly more water-resistant seal than most other glues. I believe it polymerises rather than just drying by letting the water evaporate.

[Matt S]

18 minutes ago, chrisash said:

Like the idea of PVA glue, must give it a try on chrome

I find that a fast motorised burnisher is essential. It doesn't exactly burnish the leather, more stiffens/stabilises the edge. Then I rub in some beeswax and rub off the excess when it's hardened. This fills in the edge a little. A heated edge glazer tool may work instead of the burnisher, I just haven't had a chance to experiment much since I started using a lot of chrome leather.

[samNZJP]

that's what I need, a heated edge tool.

I'll try the PVA too, cheers!