Zhumell Z100 100mm f/4 Newtonian

[Alan64]

The cell and the jack-nuts were washed with soap and water, then the magic of J-B Weld epoxy...

Each has a sizable yet controlled and tailored glob of the epoxy all round.   The plastic of the cell had been sanded previously, but was also scored with a knife in those areas.

<tick-tock, tick-tock, tick-tock>

[Alan64]

The screws were removed a while ago...

I had used a short section of a spent cable-tie, as a spatula, and to draw and slope the epoxy up the six sides of each jack-nut...

...waste not, want not.

[Alan64]

The silicone-placement template...

"Star light, star bright,
First star I see tonight.
I wish I may, I wish I might,
Have this wish I wish tonight." - Anonymous

[Alan64]

A toothpick-star, and each toothpick independently flexible...

The epoxy encasing the jack-nuts was sanded, and the areas for the silicone were scored.  Now to wash the cell, then to mask and blacken select areas...

[Alan64]

Three plastic spacers, .010" thick, to be inserted after the mirror is seated upon the silicone, and to ensure as perfect a centering as possible...

All of these aspects must be made and checked beforehand, and before the grand finale.

[RobertI]

Following in fascination .....

[Alan64]

The jack-nuts were primed, then the cell masked and matte-blackened in select areas...

Now to blacken the edge of the mirror itself...

[johninderby]

Not a good idea to to paint the sides or back of the primary mirror. Not only is it totally unnecessary and has zero benefits it has some downsides.  Painting the sides or back of the mirror will slow down the cooling of the mirror and if you ever want to have the mirror recoated it will cause problems.

Blacking the sides of the secondary is OK and while it doesn’t have any benifits optically it does help with setting up the secondary.

You will notice even the most expensive super premium newts leave the sides and back of the mirrors alone. 

Edited September 28, 2019 by johninderby

[Alan64]

Shhh, for pictures speak louder than words... 

Glamour shots...

I can't wait until I get my new GSO 32mm Plossl into this one, but it has to be blackened and flocked, too; so to wait.

[Alan64]

1 hour ago, johninderby said:

Not a good idea to to paint the sides or back of the primary mirror. Not only is it totally unnecessary and has zero benefits it has some downsides.  Painting the sides or back of the mirror will slow down the cooling of the mirror and if you ever want to have the mirror recoated it will cause problems.

Blacking the sides of the secondary is OK and while it doesn’t have any benifits optically it does help with setting up the secondary.

You will notice even the most expensive super premium newts leave the sides and back of the mirrors alone. 

My eco-friendly paint stripper, and a toothbrush, will remove every last bit of paint.  That is, if I ever do get these mirrors re-aluminised.

Although, I do realise that yours is a disclaimer in general, lest someone else comes along and wants to blacken their own. 

 

[Alan64]

There should be only two reflective surfaces within the optical-tube of a Newtonian: the aluminised surfaces of the primary and secondary mirrors.  

If you want to see glory.  Otherwise, carry on...

[Alan64]

The mirror is safely nestled under and within a canopy of gift-tissue, and until the paint cures...

Isn't it absolutely and utterly precious?

Edited September 28, 2019 by Alan64

[Alan64]

Before I secure the mirror into its cell, I need to sort out what I'm going to do to effect a tilting solution for the cell.  I have to cut those stainless-steel mounting screws to just the right length, so as not to touch the mirror's edge when battened down. That's going to hinge upon what I do about the mounting holes...

This is the steel-plate that I removed from the primary-cell of my 127mm "Bird Jones", and in favour of a far better solution...

It's of hot-rolled steel, and rather thin.  I will be using it for the tilting solution of this one's primary-cell...

[Alan64]

It's only about 130mm in diameter, but I only need three small pieces from it for this telescope.

[Alan64]

The point of no return...

I only need this much of an adjustment for each.  Unfortunately the tube doesn't extend out quite far enough...

Just three wee pieces, 1/2" wide, 7/8" in length...

Incidentally, throughout the spring and summer: wet, wet, wet.  However, within the last three weeks to a month, a drought, and nary an advantage have I taken of it.  I had begun working on this telescope just before the drought began.

There's no rhyme nor reason where there's an obsession, and a magnificent one at that.

[Alan64]

[Alan64]

[Alan64]

[Alan64]

[Alan64]

Why, they appear as soda- or beer-can pop-tabs; splendid.

In the end, those will be overlaid with a "veneer" of phosphor-bronze.

[Alan64]

The mounting-hole extensions were given a final shaping, sanding with 80-grit paper, and were then scored on both sides; one side for epoxying to the optical-tube, and the other for the epoxying of the phosphor-bronze sheet thereto...

[Alan64]

This is only a test-fitting, and to illustrate precisely what I'm after...

[Alan64]

The tube's substrates for the extensions were stripped of paint, roughened in the process, and to be scored...

From my humble sheet of phosphor-bronze, three sheetlets...

...which were then sanded with 80-grit paper and scored on one side...

Edited October 3, 2019 by Alan64

[Alan64]

The lamination of the extensions with bronze, and with J-B Weld steel-reinforced epoxy(made in Texas)...

A clamp of oak, hard-felt and wax-paper...

Double- and single-sided clear-tapes were also utilised, and to prevent shifting of the components...

 <tick-tock, tick-tock, tick-tock>

[Alan64]