Laser cut char

[ricky86]

Hi 

Sure it’s been covered 1000 times. Is it critical to remove the laser burn before glue.

Using Titebond 2. 

I can agree it might impede some absorption, but....

Things fit so nice and tight before removal.

Not so nice after. lol

 

Thank you 

 

OcCre Buccaneer

[Jaager]

PVA needs a porous and secure surface to produce a strong bond.  The color does not matter.  If it is a layer of loose carbon, the joint needs to be abraded down to a firm layer. If it is just color on a firm layer it does not.

It is probably good practice to use a sharp single edge razor blade to scrape the surface.  Scraping means that the edge is dragged over the surface ~10-15 degrees ? and not pushed like a chisel. In a tight slot - a #11 blade may be what fits.

Edited February 28, 2021 by Jaager

[ricky86]

Concise answer. Thank you Jaager

 

Rick

[Paul Jarman]

I personaly sand it off. Dosen't take long. I use a medium grade sandpaper. 

Paul

[BobG]

I carefully sanded the laser char off from areas that would be visible when I built the Medway Longboat. Otherwise, I only lightly sanded any surfaces that were to be glued if the laser char was heavy and dusty on them. I would just hit those areas lightly with sandpaper so that the char that remained was solid and not loose or too dusty. Those joints glued up nicely even though I did not completely sand off the char.

 

I did a small test where I glued up some scrap pieces of wood with char and some pieces with the char sanded off. Then I tried to break them apart and both were very strong without any noticeable difference. So now I only sand off char if it is particularly heavy and/or loose...just enough to give me a good fit between the pieces of wood to be glued. Many other modelers sand off all the char before gluing, however. 

[ricky86]

Thanks guys. I did notice the glue gets a good bite. This char isn't black. It looks more like a glaze. Its coming off OK. Just using a lighter touch. I was going down to fresh wood. Too deep. Not necessary. But, dare I say, some shims were on the first few parts.

Again, thanks for the responses.

Edited March 2, 2021 by ricky86