Birch Ply alternative and thickness for dob base

[Ratlet]

2 hours ago, PeterStudz said:

It has provided, amongst other things, some stunning views of Jupiter, Saturn and Mars. And my daughter is especially fond of the planets. Picture from back in 2021, at around 4am at the end of a 2 hour session on Jupiter and Saturn. The first time Alice had seen these. Base obviously not finished.

@Ratlet, the crescent moon has a function. I use it as a handle to carry the base on its own. I also put in a round cabinet light. Useful when setting and packing up. 

@Bentley, I haven’t heard of that product, although it might come under a different name here in the UK. One of the issues that I’ve had when trying to order this kind of thing is that often the suppliers here assume that you are some kind of builder working on a house/building and consequently have minimum orders of silly amounts. And if you can order a small quantity equally silly minimum shipping charges. 

Loving the idea of a cabinet light.

This has definitely cause me to have a rethink of the contempt for normal ply. I think the wood looks really great.  

Cider also looks to have dropped really clear there.  Kit or from fruit?  Beaver man than I keeping glass demijohns on the floor

 

 

 

[Mr H in Yorkshire]

6 hours ago, PeterStudz said:

I haven’t heard of that product

By chance I was in my local agricultural merchants today - they sell everything, including I now know 'trailer board'. it's 18mm ply coated with black phenolic resin and on one side a mesh surface for grip. Not much more than ordinary ply. Based on that finding I'm sure the stuff must be available elsewhere should you need it. Just checked google - it's also known a s Buffalo board.

Edited March 20, 2023 by Mr H in Yorkshire

[Chaz2b]

On 19/03/2023 at 18:10, PeterStudz said:

 

I never have enough cider  As you know I make my own but cider varies and it’s difficult to get anything decent near me.

Thats because you don’t live in cider country…zummerzet! Taunton cider is back, they tell me they have the recipe for Autumn Gold but not the name! So  it will be called Taunton Gold.

Summer sun solar observing with a flagon of Taunton gold cider, can’t get any better.🥴

chaz

 

[PeterStudz]

4 hours ago, Ratlet said:

Loving the idea of a cabinet light.

This has definitely cause me to have a rethink of the contempt for normal ply. I think the wood looks really great.  

Cider also looks to have dropped really clear there.  Kit or from fruit?  Beaver man than I keeping glass demijohns on the floor

 

 

 

I’m sure normal ply would be fine. Although I thick it’s a good idea to hand select the best sheets.

As for the cider and going off topic. I have a DIY press. The apples are collected from local hedgerows from the beginning of September until late October. I then press in late October, sometimes the start of November. I start fermentation in a large buckets and then transfer to demijohns. I should get away from demijohns but I have a load secondhand and it’s nice to be able to see the cider. Eventually the cider is bottled and drunk from about a year onwards. Mostly the demijohns are stored down my shed, but I’ll bring some up to the house if I need to fiddle with any. Like in the recent picture - thats not all of this years.

 

Edited March 20, 2023 by PeterStudz

[saac]

Here's how I did it. The base is made from the same 18mm birch ply that I used for the main body. The setting circle is made from thinner cheaper ply (B&Q) 6mm.  The 6mm ply was cut into a ring onto which the protractor segments were then glued. The protractor segments were 3mm ply.  Rather than using varnish I stained then oiled everything. So far it's holding up well although there are always some modifications being planned   

Jim

[Paul M]

Birch ply would be my choice. Very nice to work with (given the right tools). But as nice a finish as birch ply gives, there are options! Unless you leave your scope outside, wallowing in mud and water, it doesn't need any particularly robust material.

Std 18mm MDF will last a billion years. Style it as you wish. Paint, nail varnish, creosote... OK, maybe not creosote, but just make it wipeable. So it just needs sealing. 

There is water resistant MDF, but in my time as a wood spoiler, it was green coloured so maybe limiting your finishing options.

Even water resistant chipboard is a possibility. The T&G flooring panels are ultra tough but will blunt your tools in an instant, yet only slightly faster that good birch ply..

The thing is with all sheet materials, is waste. If you take a cutting list to your local supplier, they may be happy to cut it but will charge you by the full sheet (half sheet if you are lucky) so 8 x 4 ft sheet it is!

Efficiency of numbers. If it needs 3/4 of a sheet to make 1 base then 3 sheets will make 4 bases. I once had a punter wonder into my workshop (comercial) and show me a picture of a bedside cabinet in the Argos catalogue. He wanted to know how much i could make one for, because Argos was trying to rip him off at £40, or whatever. I told him we could equal that if he wanted a few hundred units.. Otherwise it'd be  a few £hundreds for one unit.

[John]

The mount for my 12 inch Orion Optics based dob was made from 18mm baltic ply I seem to recall. It was very stable and quite light at about 10kg.

 

[Ratlet]

9 hours ago, saac said:

Here's how I did it. The base is made from the same 18mm birch ply that I used for the main body. The setting circle is made from thinner cheaper ply (B&Q) 6mm.  The 6mm ply was cut into a ring onto which the protractor segments were then glued. The protractor segments were 3mm ply.  Rather than using varnish I stained then oiled everything. So far it's holding up well although there are always some modifications being planned   

Jim

That looks phenomenal.  Do you have more pictures of the complete scope?

[Ratlet]

11 hours ago, PeterStudz said:

I’m sure normal ply would be fine. Although I thick it’s a good idea to hand select the best sheets.

As for the cider and going off topic. I have a DIY press. The apples are collected from local hedgerows from the beginning of September until late October. I then press in late October, sometimes the start of November. I start fermentation in a large buckets and then transfer to demijohns. I should get away from demijohns but I have a load secondhand and it’s nice to be able to see the cider. Eventually the cider is bottled and drunk from about a year onwards. Mostly the demijohns are stored down my shed, but I’ll bring some up to the house if I need to fiddle with any. Like in the recent picture - thats not all of this years.

 

I mostly make beer.  I built all my kit myself as I was working in a lab at the time and could basically order whatever valves and instrument tubing I needed.  It's the reason some of it is rather to 15kpsi lol.

The 5 gallon plastic carboys are great for larger batches.  I went to a fermenter king chubby last year.  It's basically a clear plastic pressure vessel with a floating dip tube so you can ferment with a bit of pressure to get a cleaner beer for lagers.  The real beauty of it is that I can drop the temperature of the fridge I use as a fermentation chamber when it's done and serve right out of the fermenter.

I wouldn't say we are off topic.  Your press is made from wood as is the shelf in my fermentation vessel.

I'm going to go and get some samples of plywood an veneers and try out some combinations and finishes to see what works. 

Edited March 21, 2023 by Ratlet

[PeterStudz]

6 hours ago, Ratlet said:

I mostly make beer.  I built all my kit myself as I was working in a lab at the time and could basically order whatever valves and instrument tubing I needed.  It's the reason some of it is rather to 15kpsi lol.

The 5 gallon plastic carboys are great for larger batches.  I went to a fermenter king chubby last year.  It's basically a clear plastic pressure vessel with a floating dip tube so you can ferment with a bit of pressure to get a cleaner beer for lagers.  The real beauty of it is that I can drop the temperature of the fridge I use as a fermentation chamber when it's done and serve right out of the fermenter.

I wouldn't say we are off topic.  Your press is made from wood as is the shelf in my fermentation vessel.

I'm going to go and get some samples of plywood an oak veneers and try out some combinations and finishes to see what works. 

Looks Good! Although for me and cider keeping it in anything plastic is out. You can get away with the initial strong fermentation in a plastic vessel (which is what I do/use) but I mature mine for about a year before drinking. After a few months air can get diffuse through plastic and the cider will start turning acetic. Glass and stainless steel are great but a stainless steel vessel is expensive. So I transfer mine into demijohns in order to mature a bit longer and to drop clear. Even then air will slowly diffuse through the rubber bung and airlock and if not careful you’ll get a film yeast. Glass bottles with crown caps are great and will keep the air out, but I’ve got a few weeks before I start the bottling process.

It’s personal but I prefer my cider still (no bubbles) and bone dry - as God intended  And the advantage of lots of smaller batches in demijohns plus using bottles is that no one bottle tastes the same. I also prefer it cellar temperature. Well, for me it’s shed temperature. And if one demijohn turns bad I haven’t lost the whole lot!

Having said all of that I might invest in an all in one stainless steel fermenter. Although I’d still end up bottling. 

[saac]

10 hours ago, Ratlet said:

That looks phenomenal.  Do you have more pictures of the complete scope?

Here's a few more. It's our school telescope, made possible by @andrew s'  kind donation of of the glassware.  There is a build thread some where.  The setting circles are a relatively new addition, about 3 years ago.  It has encoders on both  axis, these were really added just as vehicle to explore arduino programming for a lunchtime astro club. In the field we have good enough success using the manual setting circle and a wixi for the alt coordinate. It is a big beast, heavy with it, but I wanted a design that would provide a bit of theatre and catch the kids eyes; maybe inspire them a little.  The design itself is a salute to telescopes made by John Waite of Waite Research . 

Jim.

 

[Ratlet]

6 minutes ago, saac said:

Here's a few more. It's our school telescope, made possible by @andrew s'  kind donation of of the glassware.  There is a build thread some where.  The setting circles are a relatively new addition, about 3 years ago.  It has encoders on both  axis, these were really added just as vehicle to explore arduino programming for a lunchtime astro club. In the field we have good enough success using the manual setting circle and a wixi for the alt coordinate. It is a big beast, heavy with it, but I wanted a design that would provide a bit of theatre and catch the kids eyes; maybe inspire them a little.  The design itself is a salute to telescopes made by John Waite of Waite Research . 

Jim.

 

Blooming heck.  That's practically an art piece!

[saac]

22 minutes ago, Ratlet said:

Blooming heck.  That's practically an art piece!

Lol thanks ratlet. That is what I was aiming for, something that would make the kids say "what is that".  And that is exactly what they say when they see it first time - "is that a cannon?"  You know for all its weight, it is a delight to use , it is perfectly balanced. The view of M42 is mindblowing, it is like you are falling into the nebula and walking inside it.   My classroom is on the ground floor so it is easy enough to get it outside. If the moon is out during the day we can easily have it out and setup in about 15 minutes.  For the next modification I'm toying with the idea of putting some graphic design onto the mirror lid, maybe laser cut or route the zodiac constellations with their symbols. 

Jim