Char removing

[Doug77]

I think this is the area for general discussion. I am new to ship modeling and this forum. So if I have made an error I apologize. My question is I am removing the char from the edges of the laser cut pieces, just how well does this need to be done. If there is still a little color but no loose char is that sufficient? Also to clean out the slots are there any special tools, thanks for any advice you may provide.

 

[Uwek]

I think this is the area for general discussion. I am new to ship modeling and this forum. So if I have made an error I apologize. My question is I am removing the char from the edges of the laser cut pieces, just how well does this need to be done. If there is still a little color but no loose char is that sufficient? Also to clean out the slots are there any special tools, thanks for any advice you may provide.

I would say:
It depends ......

Are you asking this in general, or related to a special part of a kit?

It depends f.e. if the surface where the char is or was visible or not - do you have to glue it and which kind or type of glue you will use......

 

[RDN1954]

I think this is the area for general discussion. I am new to ship modeling and this forum. So if I have made an error I apologize. My question is I am removing the char from the edges of the laser cut pieces, just how well does this need to be done. If there is still a little color but no loose char is that sufficient? Also to clean out the slots are there any special tools, thanks for any advice you may provide.

Hey Doug,
I'm also relative new to modeling and I've found that asking questions here in SOS will result in someone taking the time to answer one's questions. No need to apologize for errors though, at least I'm very sure I'm making my share of those.
About char removal, I think it's rather personal, but I like to remove it as good as I can from every single piece, not caring whether or not the parts remain visible. There are a few parts in my current build where I didn't dare going any further, because the marking was do se so deep into the material that the parts would have become too thin, so some char is still visible, but will be painted later on.
Have fun!
Johan

 

[Uwek]

Many thanks to Johan
one additional remark related to

There are a few parts in my current build where I didn't dare going any further, because the marking was do se so deep into the material that the parts would have become too thin, so some char is still visible, but will be painted later on.

According my personal experience it depends also how the designer and manufacturer designed the lasered parts.

When the designer took already the later char removal by the modeler into account or not



Here I try to show this in the oversized sketch

black lines are the wood, which was cut by a laser (red arrow) with brown is the char

Did the designer used, when he was transfering the measures from the 3D-model to the production design for the laser,
1) the center of the cut as the measure (blue), or
2) did he use the light blue line or
3) did he used the green measure after removing the char as the necessary correct size of the wooden part?

It is looking in the beginning very complicated, but after some work on a kit you can recognize it .....

In the beginning it makes sometimes sense to compare the parts with the drawings....

BTW: I remove as much as possible or all char from the parts
Using good needle files, sand paper, drum sander, etc. depending on the needs, sometimes the last touch I make often with a glass fibre eraser

 

[Signet]

As Ewe clearly shows, the very shape of the laser kerf/cut gives us a reason to remove the char. To my mind, there are 3 reasons to remove the char:

1) Appearance - char obviously doesn't look like the wood should, so complete removal is required for good looks, where it is visible.

2) As Ewe shows, there is always a slant or bevel on the edge of laser cuts. Yet, in 99% of the cases, there should not be. Meaning that removal of the slanted area, all of which is charred, is necessary to get a square end to the piece, allowing a true and close fit where it attaches to another.

3) Some have said that removal of char is required to obtain a strong glue joint; I've done tests that are contrary to this: there appears to be more variation in the glue and technique used than there is in whether char is removed or not.

So in the end, yes, it is pretty much necessary to remove the char. But I have also found, as you, that sometimes this results in the finished piece being smaller than desired/required. In that case, best judgement must prevail, or making possibly making a new piece.

 

[RegG]

Don't waste your time...if you can't see it then leave it. Char glues just fine from what I have seen over the years. Unless the piece does not fit properly I will not remove it. Admittedly it looks nice when removed but if you stripped back most builds you will see plenty of char underneath. Again, it is a matter of personal taste.

All the best!

Reg

 

[Doug77]

Thanks to all, a lot of valuable/useful information, my major concern was if I did not remove the char it would not create a strong bond and I did not want to necessarily remove to “white” wood because I would change the fit tolerances and both of my concerns were addressed so I know how to proceed without doing harm. Thanks so much, on with judiciously removing char!

 

[Experten]

Hi all,

Removing char is pretty easy. Give the parts a bit of a soak in acetone. The acetone breaks down the carbon, and makes it VERY easy to remove. Also, because acetone is a “high solvent” it will not cause warpage.

Best,

Mark

 

[danielsje]

I think this is the area for general discussion. I am new to ship modeling and this forum. So if I have made an error I apologize. My question is I am removing the char from the edges of the laser cut pieces, just how well does this need to be done. If there is still a little color but no loose char is that sufficient? Also to clean out the slots are there any special tools, thanks for any advice you may provide.

My take on char: I rarely remove char. I have found that pieces glue well with or without the char. I only consider removing char if the edge will be on open display and the char would detract from the finished look. Then again, I have left edge char in place as a darkened weathered look on pieces especially on the outer hull such as stern gallery braces. In my opinion, one does not need to remove char unless fitment is affected…that is a piece does not fit into another piece cleanly unless you lightly sand the pieces (This is not meant to remove the char but to lightly sand pieces for better fit)…or finish is affected.

 

[tommyg]

Don't waste your time...if you can't see it then leave it. Char glues just fine from what I have seen over the years. Unless the piece does not fit properly I will not remove it. Admittedly it looks nice when removed but if you stripped back most builds you will see plenty of char underneath. Again, it is a matter of personal taste.

All the best!

Reg

I'm far from an expert but I have never removed char and never had any negative results.

 

[bkempins]

I usually remove the char by wiping with a rag unless the part will be visible. Then i lightly sand the part.

 

[Derfla]

It's usually unnecessary to remove any char. I've built 8 kits and none have been structurally affected by leaving it if you're using white glue. I don't think any kit manufacturer works to a tolerance where the char will have an effect on fit. If it ever does effect the fit, a simple sand with medium grade paper will quickly remove it.

 

[Dave Stevens (Lumberyard)]

I don't think any kit manufacturer works to a tolerance where the char will have an effect on fit.

i have creating laser cutting file for kits and what i do is offset the cut by .015, the kerf of the laser is .006 so there is .009 tolerance,
cleaning off the char takes from .002 to .003 off the piece. If your acceptable tolerances are less than .006 you should be scratch building.
Over the years i have built so many projects and never clean the char totally, there is always some still on the wood and it has had not affect on the glue joint.