tubes scraping paint off

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sorcerertd

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So, I'm working on some more hybrid blanks. On these, I'm pretty sure I'll need to have the tubes painted. Problem is that, once I have painted them, inserting the tubes scrapes the paint out. This seems to be specifically on the 12.5mm hole caps as the 10.5mm barrels seem to still fit OK. Assuming I need to widen the holes a little, any recommendations on what size or if there is a specific paint that will have good coverage in a very thin layer? I used acrylic (craft) paint, so I'm sure it's not the most durable, but the fit is tight enough that I suspect it would scrape pretty much anything off the inside of the blank.
 
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JohnU

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I always paint the hole so you won’t chance seeing your adhesive through the blank. If the hole is big enough you can paint both tube and hole, but I would suggest painting the hole first to see the clearance. That way the adhesive for gluing the tube in will act as a lubricant when sliding the tube in the hole to help not scrape paint from inside the hole.
 

carlmorrell

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What JohnU said. I would add, always wait a day after painting the blank. Just to make sure the paint has set. Opinions will vary, but I am a long time modeler and use only Tamiya paints. If it's a light color, I use two coats. But I think the big thing is a test fit to make sure you aren't scraping paint. Another tip, once I paint, I leave the blank vertical. If it is horizontal, the paint will settle along the blank. If it is vertical, the extra paint will end up at the end of the tube and can be removed with a knife.
 

Kenny Durrant

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Along the same as above I’d start with the hole first. I think I use the same type of paint your using. It’s a water base acrylic craft paint. After drilling the blank I use a rat tail file and clean out the hole. I’m not trying to team it out just remove and fibers that will stiffen and harden after painting. Then I’ll put a good coat of paint inside the blank and paint the tube. I’ve also found that epoxy glue acts like a lubricant and make inserting the tube easier without doing a lot of damage to the paint. I also believe that the key coat is the blank so if something happens to the tube while being inserted it shouldn’t be that big of a concern.
 

magpens

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@sorcerertd

To get past the tightness of a 12.5 mm drilled hole, which is 0.492" .... you could move up to a 0.500" drill .

I really don't know if metric drills are made in diameters of 12.6 mm, 12.7 mm, 12.8 mm, etc.

If they are, you could explore those possibilities. . Each increment of 0.1 mm amounts to about 0.0039"
 

sorcerertd

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I did paint the hole and not the tube. Did that yesterday and tested the fit before posting, which is when it scraped off quite a bit of it. Didn't really think to use the glue to help slide it in there, but I suspect it would have been too tight. I'll try clearing it out enough for the tube to slide through like they do in the 10.5 barrels.

Also, Mal, you I think you're onto something there. I'm going to drill in a scrap piece with a 1/2" bit and test that out. I just sharpened the 1/2", too, on the new drill doctor that showed up this week. :)
 
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Penchant 4

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I did paint the hole and not the tube. Did that yesterday and tested the fit before posting, which is when it scraped off quite a bit of it. Didn't really think to use the glue to help slide it in there, but I suspect it would have been too tight. I'll try clearing it out enough for the tube to slide through like they do in the 10.5 barrels.

Also, Mal, you I think you're onto something there. I'm going to drill in a scrap piece with a 1/2" bit and test that out. I just sharpened the 1/2", too, on the new drill doctor that showed up this week. :)
1/2" = 12.7mm.
 

sorcerertd

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I've always used Gorilla Glue for the tubes, but am not averse to using another method. Well, except CA. Definitely not using CA. Don't think I want to attempt tinting Gorilla Glue.
 
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