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Old 27-12-2021, 01:39 PM
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Jezkerwin (Jeremy)
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Building a replacement base for 10" Dob

Hi All,
I have a 10" Bintel Dobsonian and I've been waiting quite some for a replacement wooden base since my old one got damaged.


It was suggested that I could build a replacement one and was curious if anyone has any info like instructions on building one that I could use?


Thanks.
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  #2  
Old 30-12-2021, 11:01 PM
Saturnine (Jeff)
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Hi Jeremy

What part of the base is damaged, pictures would help here, it easy enough to get some 18m plywood from an hardware store and cut into the desired shape if you are handy with tools.
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Old 31-12-2021, 10:02 AM
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Scorpius51 (John)
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10" Dob base replacement

Hi Jeremy

A year or two ago I replaced the base on my Bintel 10" Dob when it was damaged by flooding in our garage. Fortunately the scope was untouched as I had installed a plastic bag over the lower part of the OTA. However, the MDF base was trashed.

I decided to rebuild the base with 18mm marine ply to the same dimensions and pattern as the original base. Fortunately, I was able to re-use the original azimuth bearing after removing the mud and mulch that had inundated the garage. The other fittings, including the eyepiece holder and base handle, were also re-used. I also replaced the original fixed rubber feet with large rubber-wheeled locking castors.

I am extremely happy with the result and believe that the new base is much better than the original. I have attached a few images of the finished product.
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Last edited by Scorpius51; 31-12-2021 at 11:06 AM.
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  #4  
Old 31-12-2021, 02:36 PM
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mura_gadi (Steve)
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Hello,

I just used the original pieces to trace onto marine ply. Then the jigsaw, drill, sandpaper and seal.

Clamp the two side panels together to ensure a symmetric finish when drilling and making the alt cutout etc.

The bits are very basic re the base etc, try and keep the dust barrier around the greased bearings.


Steve
Ps. Make sure your ply is "A" bonded, that means the all ply sheets are glued with 100% coverage between layers with a water resistant glue and no gaps.

Pps. If you're handy at wood work check out sites like "dobstuff" for ideas past the standard GSO/SW base designs.
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Old 01-01-2022, 09:31 AM
ausastronomer (John Bambury)
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Hi Jeremy,

I agree with everyone's suggestion of using the old base as a template and just copying it for your new base.

The only other thing I would suggest is using Baltic Birch Ply instead of Marine Ply. Baltic Birch Ply uses Hardwood (Usually Silver Birch or similar) on all the internal cores and both faces and uses Waterproof A Bond (Formaldehyde) Glue. It is what just about all of the professional telescope builders use including Peter Read at SDM and Dave Kreige at Obsession. Marine Ply uses softwood (often Hoop Pine) on all cores and both faces and also uses Waterproof A Bond (Formaldehyde) Glue. While Marine Ply offers the ultimate weatherproofing, it isn't physically as durable, or as strong, as Baltic Birch Ply and is prone to dings and nicks, being of all softwood construction. 18mm Baltic Birch Ply uses 13 x Hardwood Laminations, whereas 18mm Marine Ply uses 9 x Softwood Laminations.

If you were taking the telescope swimming I would suggest marine ply. On the basis you will be using it on land, I would suggest Baltic Birch Ply each and every time. You can then finish it off with a stain and polyurethane clear, or use Marine Varnish. Baltic Birch Ply is more weather resistant than you will ever need for a telescope. If it wasn't the best choice, the professional telescope builders wouldn't be using it, they would be using marine ply.

18mm Baltic Birch Ply $132 per sheet


18mm Marine Ply $132 per sheet

Cheers
John B
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  #6  
Old 08-01-2022, 09:35 PM
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Jezkerwin (Jeremy)
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Thanks for the suggestions. Unfortunately I no longer have the base as after it suffered outside damage I thought I could just order a replacement from Bintel, but I stupidly didn't check how long it would take to get in before getting rid of the old one.


Perhaps around March they might get stock in.
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