Home fill or Oxycon

[Newbie_Dave]

Hello all.


My wife and I are excited to be joining the ranks of glassblowers - as living proof that old dogs can learn new tricks.


We hope to retire somewhere between soon and eventually, so we are planning on throwing ourselves at our newfound love of glassblowing. To this end, we're going to build a studio in the garage to allow us to do it whenever and however much we can.


We'd like to build something that we're not going to outgrow so we're thinking to invest a bit to get the right equipment. We're buying a pair of Bethlehem Bravo Sharp Flame torches and now we need to decide on the right fuel solution. We have propane for the house and there happens to be a riser by the garage already, so we're simply going to put a regulator on that with a quick connect house to run through the garage window.


I've read through most of what's been posted in this forum and that has been helpful, so thank you to everyone who shares their knowledge and experience. The question that we find ourselves struggling with is:

1) Home fill package from Frog

- 2 10lpm Oxycon

- 60 tank

- Compressor

- All necessary connections


Or


2) 3-5 10lpm Oxycon alone

- Have heard mixed comments about ex20, but it looks most cost effective (maybe you get what you pay for?)

- Have heard good things about Regalia, including no heartbeat/breathing flow issues, but very expensive

- Have seen different thoughts about Oxycon for inner and tanks for outer (prefer not to deal with tanks)


We understand that the best solution depends on what you intend to be doing.

- Simple stuff for the foreseeable future. Boro Marbles, Jewelry, limited size


Would love to hear Pros/Cons/Best approach on the Tank package vs. a string of Oxycon.


Thank you for taking the time to help get us set up!

Dave/Shari

[echeveria]

If I could justify it, I would love to have a home fill. There are some groups on Facebook (Concentrated Lampworkers, Concentrated Lampwork for Adults) that are full of information. I need to kiln strike a lot of boro colors because I just don't generate a big oxygenated flame on my concentrator. I use an M15 mostly, with a variety of torches, but nothing huge.

It sounds like you are doing your homework, which is good. Not sure where you are in NC? Lots of glass being done in NC.

[rcktscientist]

The big choice is money/ease.
A Frog system is more expensive than making your own but you get customer support. If you have the funds, I'd say get the most supported choice. You don't want to spend glass-making time fussing around with your DIY oxy system, unless you like that sort of technical problem solving.
Personally, I make 1 - 1.5" boro marbles anytime with my Bobcat on 15lpm, no surge or storage tanks. Straight 10lpm oxycon for most work then flip on the Tee'd 5lpm for quicker melts. You could always start with 2x 10lpm if you choose the DIY route, then add to your system to fit your needs perfectly. Still pretty big flame if you take turns and give the torch 20lpm.
It's all about trade-offs.

[Newbie_Dave]

We are in Pittsboro. Learning at Jonathan Davis' studio.

I agree that budget can help to set up a higher end solution up front, such as the home fill.

I agree that we don't want to be messing around with a DIY at all.

The small Frog package has 60 gallon surge tank with 2 10lpm oxycons.
- I can't post links yet


Do folks agree that would be sufficient to drive the 2 Bravo torches inner and outer flames for 3 hour sessions?

[kevingreenbmx]

Originally Posted by Newbie_Dave

Do folks agree that would be sufficient to drive the 2 Bravo torches inner and outer flames for 3 hour sessions?

Should be plenty for that. you can also add more oxycons later if your demand increases over time.

[Newbie_Dave]

I believe that the compressor that comes with that package is only capable of supporting 2 oxycons. I'll check if that can be swapped out for the larger model, but that adds $1500, so it may tip the scales in favor of just buying 4 oxycons without a tank, and scaling up to 5, if it turns out to be necessary.

[kevingreenbmx]

Ah, it's been a while since I looked, I thought their base system could handle up to 4 oxycons. You can always use a relay box to expand it to control more cons, the compressor should be able to handle more fine, it's just the number of controlled power outlets available.

[rcktscientist]

The Independent Pack only runs 2x 10lpm. If you want to add more lpm, you'd have to change compressors when you add the extra cons but not before. The compressors all have an ideal lpm input range and that needs to match you cons collective output.
That system as-is will run both those torches for 3 hours.
At over $7k shipped, the Frog system is not cheap. But 4 good 10lpm cons might run you $4k anyway. Although, I have found several good used 10lpm cons for under $700 so if you did as well, it'd be more like $3k.

[Newbie_Dave]

Thank you, @rcktscientist. That's what I thought as well. Particularly appreciate the opinion on the sufficiency of the fill system for the 2 torches.

Next question:
Since the 60gal fill tank is not high pressure, I was told that it can be inside the workspace and doesn't need to reside outside.

What do folks think about that?

Thanks

[rcktscientist]

Originally Posted by Newbie_Dave

Thank you, @rcktscientist. That's what I thought as well. Particularly appreciate the opinion on the sufficiency of the fill system for the 2 torches.

Next question:
Since the 60gal fill tank is not high pressure, I was told that it can be inside the workspace and doesn't need to reside outside.

What do folks think about that?

Thanks

It may not be high pressure but as I recall it's still around 100psi. I would say if your comfortable having a regular air compressor (old oiled style w/tank) inside that space then you should be comfortable with this set up.

One bit of info: Those Bravos don't 'push' as much oxy through them so my Bobcat on 15lpm is considerably hotter and bigger than the Bravo centerfire on the same flow. Maybe something with the internals and their fluid dynamics. I use the Bravo on 15lpm occasionally when I need a particularly wide, bushy flame compared to the Bobcat, FYI.

[Newbie_Dave]

Thank you for the context. That helps me to make my own informed decision. Yes, the fill tank will hit 125psi. Not much different from the air compressor in the garage, other than the tank will contain O2.


I intend to spray some soapy water on the lines, hoses, seams, and connectors to confirm that there are no leaks.


We're convincing ourselves little by little that the home fill is the best strategic solution.

[echeveria]

Originally Posted by Newbie_Dave

We're convincing ourselves little by little that the home fill is the best strategic solution.

You'd be amazed what you can convince yourself of "little by little"

[Newbie_Dave]

Sometimes you just gotta take the effort to rationalize the decision that you know you wanted from the start.

[jesnbec73]

It's awesome that you guys are going to be doing it together, I'm training my wife to take over the studio now and I wish she had been part of it from the start. I spent many years answering awkward questions like 'Have you seen my frosting knife?' We're in Asheville, nice to see another tarheel.

[Newbie_Dave]

My wife has had me "trained" for years

I have a brother in Asheville! - Would be cool to see your shop, if/when we visit sometime. Saw your ETSY site. Beautiful.

[Newbie_Dave]

Since the group has been kind enough to share your knowledge/experience/opinions/guidance, just to keep you involved in our adventure:

We have started to collect various glass, tools, BoroTruView 3.0 glasses, and we picked up the first Bravo Sharp Flame.

Still struggling with the decision on the OxyCon solution, but with the high cost of what we "want" vs. what we "need" at this point, we're starting to lean in the direction of 3-5 10LPM concentrators. There seems to be high confidence from the folks we're hearing from that those would run the inner and outer torches for both of us, assuming we're not likely to run the outer very much and certainly not at the same time.

[jesnbec73]

Originally Posted by Newbie_Dave

Since the group has been kind enough to share your knowledge/experience/opinions/guidance, just to keep you involved in our adventure:

We have started to collect various glass, tools, BoroTruView 3.0 glasses, and we picked up the first Bravo Sharp Flame.

Still struggling with the decision on the OxyCon solution, but with the high cost of what we "want" vs. what we "need" at this point, we're starting to lean in the direction of 3-5 10LPM concentrators. There seems to be high confidence from the folks we're hearing from that those would run the inner and outer torches for both of us, assuming we're not likely to run the outer very much and certainly not at the same time.

I'm running a Bethlehem Stacks setup on two 10lpm cons, it's working pretty good, it took some getting used to without some kind of bypass, but I just use the other Oxygen knob to adjust the O2 to the torch I'm actually running, not sure that makes any sense, but the cost of tanked O2 is just too much for the small amount of work we do these days.

[Newbie_Dave]

I'd love to talk to you about it. Would that be possible?

[jesnbec73]

Absolutely, shoot me a PM.

[Newbie_Dave]

Hello again everyone. Moving forward with other important components. Next is ventilation. I found something that looks powerful, variable, quiet, and not crazy expensive. Any thoughts about this?

https://iaq.na.panasonic.com/ventila...mixed-flow-fan

[rcktscientist]

Originally Posted by Newbie_Dave

Hello again everyone. Moving forward with other important components. Next is ventilation. I found something that looks powerful, variable, quiet, and not crazy expensive. Any thoughts about this?

https://iaq.na.panasonic.com/ventila...mixed-flow-fan

That might be enough if your system is efficient enough. Minimize bends and run distance, use rigid duct vs flexible duct, be smart about your hood/inlet shapes and locations, etc.
I run about 800cfm for a single work station with some inefficiencies, and it's on the low end of acceptable range. With 2 torches running your idea may not be enough. Also, the static pressure rating of a fan is highly important for performance; the higher the better for pushing air through tight spaces.
I can run some calculations for you if you'd like. I'd just need a basic layout of your planned system (run length(s), duct diameter, fan specs, and hood shape)

[Newbie_Dave]

Originally Posted by rcktscientist

I can run some calculations for you if you'd like. I'd just need a basic layout of your planned system (run length(s), duct diameter, fan specs, and hood shape)

THANK YOU !

It will be as simple as we can make it so:

~10-15' from the window to the further of the two torches
I don't need hoods. We can just have an extra piece of duct that comes down to each workstation with a damper on the end.
Maybe an extra ~5' to account for some distance between the suspended duct and the torches.
I would think that 10" ducts are good enough. Yes?

CoPilot indicated that a static pressure of .5 - 1 was good for a glassblowing workstation. Do you agree ?

Here is a link to the fan performance, which shows ~800 CFM at static pressure of 1 and drops off quickly after that.
https://vortexpowerfans.com/media/57a0fe0a9562e.pdf

I used CoPilot with these numbers and it suggested that I would need 1400-1600 CFM and 2 of the Vortex S-1000s would work. I could daisy chain two of them or use 1 for each station with separate ducts.

There were various other roof/window/inline fans that it suggested would be good enough to provide a target of 1600 CFM that are still 120V, low noise, variable speed.

Thoughts ?

[rcktscientist]

Originally Posted by Newbie_Dave

THANK YOU !

It will be as simple as we can make it so:

~10-15' from the window to the further of the two torches
I don't need hoods. We can just have an extra piece of duct that comes down to each workstation with a damper on the end.
Maybe an extra ~5' to account for some distance between the suspended duct and the torches.
I would think that 10" ducts are good enough. Yes?

CoPilot indicated that a static pressure of .5 - 1 was good for a glassblowing workstation. Do you agree ?

Here is a link to the fan performance, which shows ~800 CFM at static pressure of 1 and drops off quickly after that.
https://vortexpowerfans.com/media/57a0fe0a9562e.pdf

I used CoPilot with these numbers and it suggested that I would need 1400-1600 CFM and 2 of the Vortex S-1000s would work. I could daisy chain two of them or use 1 for each station with separate ducts.

There were various other roof/window/inline fans that it suggested would be good enough to provide a target of 1600 CFM that are still 120V, low noise, variable speed.

Thoughts ?

When I plug your numbers in for a 15' run of 10" duct with 1 90deg turn, I get a static pressure of 0.21 that the fans would need to overcome. At that static pressure the S-800 delivers about 700 CFM. So, you'd need two of them that somehow connect to 10" ducting in parallel (not in series) in order to get the right air velocity at the torch, about 2600 feet per second with 4200 being ideal. I'm not sure about static pressure at a glass workstation but I do know that 4200fps air velocity is used as a standard for fume hoods so that's what I use. I've heard some people say 3000fps is good enough and they could very well be right.

If you run them individually, use 6" duct and it should be better performance than when run together. About 3200fps. Plus it allows you to run one torch while not having to run both fans.

Either way, I think those 2 fans together should work for your application. Try to use 2X 45deg instead of 1X 90 deg for bends or make the bend diameter large to improve performance. Also, try and make a laminar flow inlet (looks like a trumpet bell) for each torch, that should help as well.

[Newbie_Dave]

Thank you so much for the extra effort and the guidance.

So to summarize:
If I use the Vortex system, go with two of them.
Run separate ducts.
Go with 6 inch rather than 10.
Connect whatever hood or larger duct at each workstation.
This configuration would support the draw that we need for safe ventilation

Yes?

Thank you

[rcktscientist]

Originally Posted by Newbie_Dave

Thank you so much for the extra effort and the guidance.

So to summarize:
If I use the Vortex system, go with two of them.
Run separate ducts.
Go with 6 inch rather than 10.
Connect whatever hood or larger duct at each workstation.
This configuration would support the draw that we need for safe ventilation

Yes?

Thank you

That's what my calculator says. It predicted my current ventilation very closely so I believe it's useful. My gut, however, says that a 6" fan is too small. Perhaps do 2x 8" fans instead so that you have some margin to turn it up. My setup is sufficient but it would be nice to be able to go "turbo" sometimes.