PDA

View Full Version here: : Powder Coating a Dobsonian Telescope.


Juno
07-10-2017, 05:05 PM
Does the Secondary and Primary mirrors need to be removed when giving the scope to be powder coated?

Its currently a thought, but sometime in the future I want to have my Dob and base powder coated a different colour.

Kunama
07-10-2017, 05:55 PM
Everything that can be unbolted needs to be separated. Mirrors, focuser, screws, bolts etc....

Juno
07-10-2017, 07:05 PM
Dang, im not a pro on that sort of thing, and I have no one that can help me.


Would there be any other way that I can colour my scope with a durable paint that will last, and will make the tube nice and shiny? perhaps I can look at doing it on my own?

OzEclipse
08-10-2017, 08:30 AM
Powder coating is a durable and cosmetically pleasing finish. However, it is porous so water can get in and rust can occur on the steel substrate.

Paint it.

Joe

Juno
08-10-2017, 08:50 AM
What paint would you recommend? like what name of paint?

doppler
08-10-2017, 09:30 AM
Automotive acrylic lacquer, you can get spray cans from the likes of Auto Barn and Supercheap.

Juno
08-10-2017, 09:41 AM
Thank you!! will that work for the base as well? I dont want it as shiny as the tube, presuming the base is wood it wont be that shiny anyway.

doppler
08-10-2017, 12:28 PM
Car paint is very durable but expensive, you could probably use spray enamel cans on the base, unless you want to use the same colour on both. Most likely the base is factory coated with enamel any way.

OzEclipse
08-10-2017, 06:12 PM
Juno,

As Rick points out, car duco paint is very durable. It is designed to withstand permanent outdoor exposure in sun, rain, hot and cold for years. The spray cans are very expensive as Rick says.

1. You should rough up the surface with a nylon scourer to rough it up then wet sand the metal surface with 320 grade wet & dry paper.

2. There are numerous undercoat products, metal etching primers and which you only need if this is the first time the surface has been painted or if you sand back to bare metal. If the tube is already painted and you are repainting then you only need to wet sand, wash let it dry then paint.

3. To make a shiny finish, you'll need 3 coats of the paint then topcoat with 3 coats of clear finish.

4. if you are spraying, you need to strip the tube completely, Nuts, bolts, mirror and cell, spider, focusser and finders and their mountings.

This guy is a bit annoying to watch with his gun finger but he seems to know his stuff. One video has lots of handy tips, the other shows how to spray paint and lacquer to a shiny finish:

https://www.youtube.com/watch?v=7he7VBJaJ_E

https://www.youtube.com/watch?v=rn_J8CQDbGI

Good luck

Joe

Juno
08-10-2017, 06:58 PM
Ozeclipse,

Thank you so much for your effort in putting this information to me. However, I have never attempted nor with confidence know how to do such a preparation, and paint the scope in this way.


What would be the most simplest method of just going about to paint a scope and have the glossiness effect on the tube? or there is none? maybe im asking too much and it just can't be done.

OzEclipse
08-10-2017, 11:59 PM
If you are really worried about removing parts, then masking tape everything that shouldn't be painted.

As Matt [Kunama] said, "Everything that can be unbolted needs to be separated. Mirrors, focuser, screws, bolts etc...."

In this case, rather than remove, you'll have to mask all that stuff. Really fiddly work.

Make sure nothing can drip or spatter onto the optical surfaces.

This web page tells you all the steps :
http://www.dulux.co.nz/advice/how-to-paint-metal-surfaces.html

The really shiny finish comes from applying 2-3 clear gloss coats over the paint coats. But I've never tried this. A paint store can probably advise if a clear brush on polyurethane gloss can go over and bond to a gloss enamel. I've only ever used them on stained or raw wood.

Where do you live? If you strip the tube, and several of us are telling you that you should, I'm sure there is an IIS member in your area who would be willing to step in and help reassemble if you really get stuck?

The most important thing is, if you spray, you must strip the tube or you'll wreck the mirrors, if you brush, you might get away with it but you have to work very very carefully and mask everything.

Joe