Home Made Dust Cap Advice

Hi Martin I think that there are a few ways of getting something "durable" my interpretation would be that you cuold stand on it in the dark and still use it!!
One way is to get a Wavin AJ riser ,it's used to raise the height of Wavin manhole covers to suit the height of your finished road,cant remember the size but will check for you tomorrow and you then get a piece of light plywood and fit it inside and THEN you buy a fibreglass repair kit at your local auto factors and "glass " the whole lot NByou may have to cut the AJ riser to size and I would recommend allowing for some self adhesive felt to fit on its inside,other than that make one from heavy card and soak it in glassfibre resin and coat with glass fibre matting and then gelcoat and sand to finish.
BTW RE Navy blue colour forget the spray can ,get a car body shop to make you up a 1/4 litre and apply it with a mohair /glosspaint 4" roller,much better !also the fibreglass will take that paint too,once it's primed with standard aerosol primer.
If your tube is Aluminium,galvanised steel or plastic ,rub down with 400 ga wet and dry sandpaper and then apply ISP its a liquid treatment from a Norwegian Co called OWATROL that allows you to over paint practically anything,if you have problems in sourcing Private Message me and I'll sort you out.
The other thing you may want to consider is the ventilation of the scope when the cover is in place I have ideas on that too if you're stuck as you want to stop dust ingression.
Hop this was some help
Eugene

Can anyone give me any suggestions on how to construct a durable dust cap that will slide on and off from the front of my 16" dobsonian. The tube diameter is 16".

Dont suppose you can buy a 16" bin lid? Just a thought

You can buy an end cap for a wavin pipe but you need the exact dim in mm (allowing for felt) dont think theyre available in that size.
I use exactly that on my 9.25" waterpipe dob.
Euge

Thanks Eugene!

That was very detailed info and exactly what i need to know. I am tempted just to make one out of card, paint it black and seal it as i need one made asap. Regarding the paint....brillant info. So if go to a car dealer they will make me up proper navy blue paint...but you suggest i dont spray it on.....would hand painting produce a poor finnish our could i get away with it?

Also my azimuth motion on the rocker box is a little stiff. The rocker box itself is very heavy, is there anything i can do to the teflon pads or box base to improve this motion? I read somewhere that rubbing polish onto the teflon pads can help, is this true or an old wives tale?

Thanks again, you have been a great help!

my azimuth motion on the rocker box is a little stiff. The rocker box itself is very heavy, is there anything i can do to the teflon pads or box base to improve this motion? I read somewhere that rubbing polish onto the teflon pads can help

Heard that about the polish myself too, but I wonder Martin if that will help you at all! Considering the weight involved, I'd bet thatafter a few hours usage/moving, that the weight of the unit has literally scraped all the polish off the teflon, and you're back where you started!

Just a thought, but on large Dobs, like yours, is it not more practical to have it mounted via ballbearings? I know its a little more expensve (considering the cost of this scope till now, its like eyepieces for an 8 inch!), but you will have super smooth motion, don't have to worry about oiling them, and are virtually maintenance free for up to 10 years! A pair of flange bearings would work...

...well, according the the schematic in my brain! Let me know if you want me to painstakingly draw it for you!



Seanie.

Would you not try something like WD40, it works great of gears and the like.
Its cheap and you can get it anywhere, and if it doesn't work its not too hard to remove.