Member postings for fizzy

Does everyone have a strip of adverts running right through every post they try to read? I know you have to have them, but whats the point of a forum if you cant read a darned thing??

How does one design the right hole?

I just tried machining some old brake block castings - nothing short of diamond tip will touch them. Theres hard, then theres too hard!

does it exist, where etc? I could weld it!

Ive yet to see a nice tig weld in propper brass....the high zinc content makes it spit and boil like a pig as the zink boils off, your welder must have had some low zinc stuff...anyone know where I can buy it?

I hate stainless even more - its a right sod to cut etc

would it be taboo to make a saddle tank for a 5" loco out of copper? I hate soldering and can easily tig the inside if I use cu.

g

I often use my electrolysis bath to remove paint and rust, indeed I have a full 5" chassis in there right now...but lastnight, dont ask me why, I left a set of wheels and axle in with the polarity reversed! I had it set to super high amps! 200 years of rust in 10 hours...I could cry....

Are brake blocks free to pivot therefore always touching the wheel, or are they locked in position to the brake arm?

will brass on cast last for a 2" water pump eccentric - gunmetal is very costly?

Ibe given up on the large tube aproach - no one seems to think its a good idea so I will opt for 7/16 copper tubes (I know this also carries its own cons in a steel boiler but lets not go there for now). Wil I get a better seal with 16g or 20g (I assume wall/rigidity plays a part in this? No fancy tube rollers im afraid, it will either be a hammer it home tapered mandrel or a tighten and squash rubber gromit jobby, again, any advice welcome...

probably worth pointing out that I have been making boilers for a good few years, horizontal, vertical and loco, up to 5" scale but always out of copper and always using convensional thinking - but following the norm doesnt excite me! Ive got books covering design of full scale and model boilers, all use the age old formulas (nothing wrong with that) but none tell me what to expect if I dont obey these principals - i suspect I know the feedback to this....

size proposed is grate area just over 22 sq inch, 6 no. tubes, 3/4 OD and 13" in length, if this helps?

can someone please explain this process to me...i thought it was akin to honing but now im confused???

thanks

my point is that new computer models show that very little heat is transfered via the tubes (apart from the first inch or so from the fitebox. I have recently read about a boiler with only one tube which runs fine. I know it will run well with lots of small bore tubes but does anyone have experience of using less and bigger. Computer models are all well and good until it comes time to pay for the boiler....

just finishing the design of my steel (yes...) 5" boiler. On paper I can get 4 big tubes to flow the same as 12 small ones. 4 is much easier to do than 12 - Ive made the firebox as bog as possible (22 sq inches grate), so will 4 big tubes be ok? Ive done a lot of reading and it seems that apart from the first inch or so the tubes contribute little to the steaming process. To aid steaming ive set the gap between firebox and outer at 1/4 inch. Tubes are to be steel. Any thoughts from outside the box welcome.

another couple of weekends should see it sorted!

"model engineers are an irrepressively friendly bunch"...this is sarcasm, right?

I struggled like mad with propane last time - and it wasnt easy with oxy the time before that! It will get hot enough but you will need to brick everything up and be patient for the heat to build.