New? sanding CA joint technique
 

Do you guys have trouble with CA joints (sanding like I do?) I just invented a sanding technique. (think I did anyway) You know how difficult sanding a joint smooth can be when CA is used and soft balsa is present? Many times I've used good ol' wood glue in the first place, just knowing that the sanding was coming. Anyway, when sanding the CA/balsa joint and it is giving you fits, grab the little dropper bottle of acetone and wet the joint and hit it with the sanding bar before the acetone evaporates. Bingo, the CA is softened right there at the sanding point enough that the job becomes a piece of cake. Also, speaking of acetone (CA debonder), have you tried using those little nose spray bottles (Ocean brand?) and refilling them with acetone, alcohol, or whatever? Works really cool. Better re-label them though!

Ernie

RE: New? sanding CA joint technique
 

For the most part, I quit using CA glues. They're too expensive, and the fumes are nasty[:@]
That sounds like a really good idea, because sometimes CA is the best adhesive for a certain job[>:]
But I was wondering if, and/or how the acetone affects the strength of the glue joints in the area you're sanding?

RE: New? sanding CA joint technique
 

I would be that the strength of the joint would still be just fine. Especially if you didn't just saturate the joint with acetone, but just a fine mist like he is saying. We're mainly talking about sheeting here anyway. Good tip, I'll keep it in mind!!!

RE: New? sanding CA joint technique
 

Ahhh, not to worry about the strength of the joint unless you are working with materials as thin as paper. The acetone only softens the surface of the CA a bit. Cured CA is extremely difficult to debond. The acetone evaporates in about 30 seconds anyway, so you have to hit the joint with the sandpaper pretty quick, and then add a few more drops of acetone as needed.

Another trick is to hit the centerline of CA hinges with a toothbrush and a few drops of acetone after the hinging job is complete. This gets any sharp, excess CA out of the hingeline and they bend a lot safer and smoother.

Ernie

RE: New? sanding CA joint technique
 

I think you may have hit on a winner there Ernie!

RE: New? sanding CA joint technique
 

While I love the idea for sanding joints, I would cringe at the thought of putting any amount of acetone on my CA hinges. Some of the acetone could get wicked up into the hinge, and continue to work on the glue until it softened enough to fail. CA hinges are designed to wick, and are very efficient at it. However, using the Acetone and toothbrush just in the hinge line--not the hinges itself--is a great idea to get that excess glue out of the way! The toothbrush could even be used as an applicator on the joints!!! I wouldn't use the toothbrush in my mouth again, though:D

RE: New? sanding CA joint technique
 

If you glued the CA hinges in correctly, the acetone should have no path to wick into!!

RE: New? sanding CA joint technique
 

Acetone softens CA. It could continue to soften and weaken the CA, and wick its way into the hinge.

Not really a point of argument. If you want to do it, then go for it. I'm not. THe other ideas in this thread are all great ones, and I appreciate the OP for sharing them.

I do tend to glue my CA hinges in correctly, as I've never had one fail. I also use the flex CA for hinges, and it makes a big difference in the flexability of the hinge after the glue sets.

RE: New? sanding CA joint technique
 

I wonder if the acetone would evaporate too quickly to matter on CA hinges?

RE: New? sanding CA joint technique
 

I'm not telling anyone to do anything, Not even saying I'll do it. Just stating the acetone will have no path to wick into if the hinge has been fully saturated with CA. Once the weave is filled with CA it will take alot of acetone to soften and "clean" the weave of CA before the acetone will wick into it.
If it is not a point of argument why argue it?

RE: New? sanding CA joint technique
 

Hey, the idea of using the flex CA is a good one. I'm usually on a budget though and grab the handy bottle of regular thin for the hinges. No way does any acetone wick it's way into the cured hinges, but along with the toothbrush it DOES clean any sharp, excess pieces of CA off of the centerline. It just evaporates to fast to do any unwanted damage. The result is a nicer moving part.

Thanks for your interest. Hopefully this can help someone!

Ernie

RE: New? sanding CA joint technique
 

Geez, who isn't on a budget any more? [>:]
Ernie, you have some great ideas! Thanks.

RE: New? sanding CA joint technique
 

Howdy OldScaleGuy. I bet you have some nice looking finishes on your scale planes and could write a few volumes on sanding. Do you use a hardwood sanding block that belonged to your grandfather, or?

Best of luck and take care,

Ernie

RE: New? sanding CA joint technique
 

Great ideas! Thanks!