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Would like to paint

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#1 Jond105

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Posted 15 February 2020 - 05:38 PM

I would like to paint a new OTA I just received and was wondering if it’s best to sand off old paint or save to just add over it. I also would like to know the best type of paint to go with. I tried researching this already, but some answers I couldn’t find. Powder coat then spray? Any help is appreciated. 



#2 Benach

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Posted 15 February 2020 - 05:43 PM

If you want the best result: sand blast the original paint off and powdercoat everything. Powdercoating doesn't work on paint very well and spray painting can give a nice result but it requires quite some skill to get an even result. Not recommended unless you are experienced.


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#3 Neptune

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Posted 15 February 2020 - 07:26 PM

If you want the best result: sand blast the original paint off and powdercoat everything. Powdercoating doesn't work on paint very well and spray painting can give a nice result but it requires quite some skill to get an even result. Not recommended unless you are experienced.

I used to paint professionally, if you are new, practice is key.  If painting, I would not sand the tube bare (if aluminum), but scuff it up with say, 400 grit wet and dry, then paint.  A fan type spray nozzle works so much better than the round dot type of applicator.  If possible have the tube spin slowly and apply the paint on the rotating tube, you will get a better finish.  Light first coat (let dry, see can for details ), then a nice wet coat for a smooth finish, but not so heavy you get runs. See first sentence.

 

David


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#4 Maryland Mike

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Posted 15 February 2020 - 07:26 PM

Would love to see before & after pics if you don’t mind sharing once completed. 


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#5 Tyson M

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Posted 15 February 2020 - 07:43 PM

Funny, I am going to paint an set of 1.75" steel legs off of a CG4, the white parts black. 

 

I think I am going to scuff it up lightly with 180 grit sand paper get rid of the gloss finish and go at it lightly with the primer.


Edited by Tyson M, 15 February 2020 - 08:03 PM.

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#6 Jond105

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Posted 15 February 2020 - 08:02 PM

I used to paint professionally, if you are new, practice is key.  If painting, I would not sand the tube bare (if aluminum), but scuff it up with say, 400 grit wet and dry, then paint.  A fan type spray nozzle works so much better than the round dot type of applicator.  If possible have the tube spin slowly and apply the paint on the rotating tube, you will get a better finish.  Light first coat (let dry, see can for details ), then a nice wet coat for a smooth finish, but not so heavy you get runs. See first sentence.

 

David

Good news is, I’ve painted before, even worked for a supplier for ppg before switching fields. I’m no professional though. I was wondering about using a lathe to rotate this on and do the light sanding. Thanks for the tip not to go bare. This is just a simple 90mm achro I’m going after with this. Reason I want to, tube has some scuffs I couldn’t get out and figured it be a nice project. 


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#7 Jond105

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Posted 15 February 2020 - 08:02 PM

Would love to see before & after pics if you don’t mind sharing once completed. 

WI’ll definitely do. 


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#8 jessebear

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Posted 15 February 2020 - 08:03 PM

I have a love/hate relationship with spray paint. I sanded my last project tube to bare aluminum but by the time I was ready to paint it had gotten too cold. I thought of polishing out the aluminum like I've done with some others, but ended up trying some vinyl wrap instead. I actually really, really like this stuff. I'll probably still paint it when the weather warms up, but for now I'm pretty happy with the results.

#9 Jond105

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Posted 15 February 2020 - 08:03 PM

Funy, I am going to paint an set of 1.75" steel legs off of a CG4, the white parts black. 

 

I think I am going to scuff it up lightly with 180 grit sand paper get rid of the gloss finish and go at it lightly with the primer.

Let me know how that goes. Any reason why just the white parts on the legs?



#10 Jond105

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Posted 15 February 2020 - 08:04 PM

I have a love/hate relationship with spray paint. I sanded my last project tube to bare aluminum but by the time I was ready to paint it had gotten too cold. I thought of polishing out the aluminum like I've done with some others, but ended up trying some vinyl wrap instead. I actually really, really like this stuff. I'll probably still paint it when the weather warms up, but for now I'm pretty happy with the results.

What type of wrap did you go with?



#11 Tyson M

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Posted 15 February 2020 - 08:35 PM

Let me know how that goes. Any reason why just the white parts on the legs?

Yea, it will be painted to match my black SV M2 mount and extension.  I had to slightly file down the sides of the permanent mounting peg anyways for the SV extension to fit securely to the tripod base.

 

The white tripod base and the bottom white part by the ends of the feet, will be painted flat black.


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#12 jessebear

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Posted 15 February 2020 - 09:12 PM

What type of wrap did you go with?

Automotive vinyl from Vvivid. Lots of options on their website and some smaller bits are available on Amazon. I am not good with vinyl and I would never attempt a more complex shape, but wrapping a telescope tube was surprisingly very easy. The adhesive on the Vvivid vinyl is very forgiving and can be re-positioned many times with a dry application. I went with their faux carbon fiber wrap just for fun since I'll be removing it to repaint later anyway. The texture hides imperfections pretty well - my guess is that a glossy finish wouldn't be so accommodating. 

 

8tmDMfP.jpg


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#13 Jond105

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Posted 15 February 2020 - 10:06 PM

Automotive vinyl from Vvivid. Lots of options on their website and some smaller bits are available on Amazon. I am not good with vinyl and I would never attempt a more complex shape, but wrapping a telescope tube was surprisingly very easy. The adhesive on the Vvivid vinyl is very forgiving and can be re-positioned many times with a dry application. I went with their faux carbon fiber wrap just for fun since I'll be removing it to repaint later anyway. The texture hides imperfections pretty well - my guess is that a glossy finish wouldn't be so accommodating. 

 

8tmDMfP.jpg

Thanks for this. Gave me such an awesome idea for my project. Seems the route I’m going. 



#14 Neptune

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Posted 16 February 2020 - 09:25 AM

Good news is, I’ve painted before, even worked for a supplier for ppg before switching fields. I’m no professional though. I was wondering about using a lathe to rotate this on and do the light sanding. Thanks for the tip not to go bare. This is just a simple 90mm achro I’m going after with this. Reason I want to, tube has some scuffs I couldn’t get out and figured it be a nice project. 

Bare aluminum is finicky towards cheap primers. I found it really does not like to 'stick' to aluminum, brass, copper, etc. It chips easy. That's why I recommend just sanding the original paint.



#15 Neptune

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Posted 16 February 2020 - 09:28 AM

Funny, I am going to paint an set of 1.75" steel legs off of a CG4, the white parts black. 

 

I think I am going to scuff it up lightly with 180 grit sand paper get rid of the gloss finish and go at it lightly with the primer.

I would be leery of 180 grit. I would go no coarser than 320.


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#16 calypsob

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Posted 16 February 2020 - 09:52 AM

Yea automobile Vinyl wrap is definitely the least bit messy, and on EBAY there are TONS of options, there are more varieties of CF now than there were 6 years ago, and you can get all sorts of patters, colors mattes, gloss, 3d, 4d its nuts.  I happen to be refinishing a metal desk right now and would strogly suggest you use self etching primer if you go that route, It fills any scratches and sands super smooth before adding that top coat. I am just using regular old Krylon fusion.


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#17 Jond105

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Posted 16 February 2020 - 10:07 AM

Not going to go the CF route, but pretty excited to personalize this scope to me. Plus it was cheap so hopefully I can get it to turn out ok. Even with the wrap. 



#18 Jond105

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Posted 16 February 2020 - 10:15 AM

Automotive vinyl from Vvivid. Lots of options on their website and some smaller bits are available on Amazon. I am not good with vinyl and I would never attempt a more complex shape, but wrapping a telescope tube was surprisingly very easy. The adhesive on the Vvivid vinyl is very forgiving and can be re-positioned many times with a dry application. I went with their faux carbon fiber wrap just for fun since I'll be removing it to repaint later anyway. The texture hides imperfections pretty well - my guess is that a glossy finish wouldn't be so accommodating. 

 

8tmDMfP.jpg

Any tips to using wrap?



#19 Alan French

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Posted 16 February 2020 - 12:06 PM

Bare, polished aluminum has excellent thermal properties. High conductivity but low emissivity. Paints generally have high emissivity, so painted tubes cool well below ambient and get covered with dew. 

 

Clear skies, Alan


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#20 jessebear

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Posted 16 February 2020 - 12:27 PM

I'm happy to give tips, but bear in mind I am definitely not an expert on this. I also tend to ramble. Also, Alan raises a very good point about bare aluminum versus painted, and I'd think a vinyl wrap could make the issue even worse.

 

Make sure your surface is non-porous and clean. I blow off any remaining dust from sanding, clean with a degreaser, and follow up with alcohol wipes. Might be overkill, but it works for me. Also make sure your hands are clean and dry. Bare metal or painted surfaces shouldn't be an issue I would think. I've even gotten this stuff to adhere to the somewhat rough surface of 3D printed parts on a small refractor I've been building:

 

q9Re8Ur.jpg

 

You're going to have a seam where the vinyl comes together. I make sure it's on the bottom of the scope, but it'll be there regardless. Some vinyl pros can cut with such precision that the vinyl comes together perfectly, but I certainly can't so the vinyl overlaps by a couple millimeters. If the surface is patterned, it'll be even more difficult to make the seam 'invisible', so I say just roll with it.

 

Don't be afraid to re-position the stuff several times to get where you want it and oriented correctly - it's pretty forgiving so long as you don't touch the 'sticky' bit. At first I tried to cut the piece with perfect precision and line it up with the ends of the telescope. Waste of time, IMHO. Cut it overlarge, wrap the scope, then trim the ends with a hobby knife. Use the spare bits that you cut off for 'testing' things you want to wrap to make sure it will stick and/or cover imperfections in the surface (or verify you need to sand some more).

 

Wrap over screw holes, then run your finger over the wrap on top of them. It'll dent in a bit and show you where the hole is under the vinyl. Don't use a drill bit as it may 'grab' the vinyl and ruin it around the hole. Poke a small hole in the center instead and use your (sharp) hobby knife to cut the vinyl out over the hole.

 

Take care if you are wrapping your dew shield and using a cap that fits over the outer diameter (rather than a plug that goes into the inner diameter). The vinyl doesn't add a lot of thickness, but you need to be careful when putting the cap over it so it doesn't cause the vinyl to 'peel' back. I switched to an inner diameter plug on the small one I'm building to avoid this.

 

I can't think of much else, but there's some users on this forum who are very experienced in vinyl and I'm sure they'd be happy to add to this - or correct my thinking! There are also a lot of good Youtube videos for this sort of thing. Good luck!


Edited by jessebear, 16 February 2020 - 01:29 PM.

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#21 punk35

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Posted 16 February 2020 - 06:48 PM

To make a nice seam, overlap the wrap a little with the factory edge on top ( it should be pretty straight ) then score the under lap along the factory seam. Peel the top back, remove what you’ve cut from underneath, and you should have a perfect seam. 


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#22 punk35

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Posted 16 February 2020 - 06:59 PM

Bare, polished aluminum has excellent thermal properties. High conductivity but low emissivity. Paints generally have high emissivity, so painted tubes cool well below ambient and get covered with dew. 

 

Clear skies, Alan

Thanks, I didn’t know that. 



#23 daquad

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Posted 18 February 2020 - 12:01 PM

And polished with fine steel wool, they don't look half bad.

 

DSCN2102.JPG


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