Blow-off arm support, weld or solder?

Postby jkp » Sun Sep 03, 2017 16:48

I could do with a bit of advice regarding the blow-off arm support on a new ss FV.

support.jpg
support.jpg (75.28 KiB) Viewed 383 times


As you can see in the picture it wasn't attached by the manufacturer. On contacting them they suggested spot welding it to the side of the FV. Problem is I've never done any welding before. Soldering seems a lot easier (and safer!), while requiring far less equipment. Would a silver solder be strong enough or appropriate for this job?

User avatar
jkp
Brewer
 
Posts: 961
Joined: Sun Apr 06, 2014 14:34
Location: China

Re: Blow-off arm support, weld or solder?

Postby HTH1975 » Sun Sep 03, 2017 18:26

You're gonna need a damn big soldering iron for that job. I just about get by with a 100w iron for soldering my star ground points on a guitar amplifier chassis.

That looks like a nice piece of kit. I'd get a pro to spot weld it - nice and neat.

2016: 330L brewed (72 gallons, over 8 firkins)
2017: 105L brewed
Drinking: store-bought beer as my bar is dry
Conditioning: choc-coffee oatmeal wheat stout, various ciders, cherry 'brett' brown ale, imperial Pilsner.
Fermenting: Bock (6.5%), IPA (5.5%), Pale Ale (4.5)
User avatar
HTH1975
Brewer
 
Posts: 1088
Joined: Sun Jan 24, 2016 19:16
Location: Thirsk, North Yorkshire

Re: Blow-off arm support, weld or solder?

Postby jkp » Mon Sep 04, 2017 03:49

For solding I was thinking more along the lines of a blow torch to provide the heat.

I know getting someone in to do it is the easy option (although I don't think there is any guarantee they'll do a good job), but I like the idea of learning a new skill and doing it myself.

User avatar
jkp
Brewer
 
Posts: 961
Joined: Sun Apr 06, 2014 14:34
Location: China

Re: Blow-off arm support, weld or solder?

Postby sledgehammer » Mon Sep 04, 2017 18:47

get somebody experianced to tig weld it for you
it will be a neater job once polished up and it will be stronger
tig welding =tungsten inert gas welding to do this you need the welder, pure argon gas and a stainless steel filler rod
i doubt you would get sufficient heat into the the stainless with a normal blow torch to do a good job of the silver soldering
but i do commend you for wanting to have a go and learn a new skill

steve
sledgehammer
Brewer
 
Posts: 79
Joined: Fri Apr 04, 2014 21:35

Re: Blow-off arm support, weld or solder?

Postby Kev888 » Thu Sep 07, 2017 14:40

There is risk of damage involved, as well as time/money, so presumably there is a reason for you to tackle this yourself instead of returning it?

As a DIYer, I personally would not go near the side of the FV/tank itself with a blow torch or a tig welder. Unless you are good (or lucky) there seems huge chance of it warping under the heat of either, or blowing holes through in the case of the Tig welder. Spot welding may work better, it is done on a lot of thin metal, but I've not tried it on stainless so can't say for sure.

In spite of the name, silver soldering is more or less brazing. It would therefore be strong enough, but the parts need to be glowing hot to melt the silver solder, and special stainless flux is needed. Aside from risk of warpage, you may struggle to get enough heat into it with a hand held blow torch, a really good one would likely be needed, a mapp gas type probably. Then there is need to clean and passivate the stainless afterwards or it may rust and pit.

I'm not sure of the context, not having one of these. Is it just a bracket that could be fixed anywhere - e.g. to one of the box-section legs with stainless self-tappers or something of that sort?

Kev
User avatar
Kev888
Brewer
 
Posts: 268
Joined: Wed Jul 30, 2014 15:32
Location: UK

Re: Blow-off arm support, weld or solder?

Postby jkp » Thu Sep 07, 2017 18:26

Return it? That concept doesn't really exist over here.

The FV is jacketed, so it isn't like welding to the actual wall of the FV. That would be something completely different. All the same I take your point, and I certainly don't want to mess it up. Even if I do decide to DIY it I'd certainly make sure I can do a good job beforehand.

User avatar
jkp
Brewer
 
Posts: 961
Joined: Sun Apr 06, 2014 14:34
Location: China

Re: Blow-off arm support, weld or solder?

Postby PhatFil » Sun Sep 10, 2017 03:34

i cant make out whats what in the picture, or understand exactly what the blow off arm support is ? but if its just a bit of Structural stainless steel thats not going to be in contact with your valuable brew and the surface your considering attaching it to is the external jacket skin, silver solder would certainly be strong enough US distillers who have silver soldered 2" ticlamp flange ferules to SS kegs have swung the kegs about by the fitting..

However why not consider some liquid metal/jb-weld or an epoxy putty to glue the bits together, a lot cheaper easier and simpler to finish neatly, And such products boast significant strength?
User avatar
PhatFil
Brewer
 
Posts: 1044
Joined: Thu Apr 03, 2014 10:52

Re: Blow-off arm support, weld or solder?

Postby jkp » Sun Sep 10, 2017 16:50

PhatFil wrote:i cant make out whats what in the picture, or understand exactly what the blow off arm support is ? but if its just a bit of Structural stainless steel thats not going to be in contact with your valuable brew and the surface your considering attaching it to is the external jacket skin, silver solder would certainly be strong enough US distillers who have silver soldered 2" ticlamp flange ferules to SS kegs have swung the kegs about by the fitting..

However why not consider some liquid metal/jb-weld or an epoxy putty to glue the bits together, a lot cheaper easier and simpler to finish neatly, And such products boast significant strength?


Thanks, that gives me something else to look into.

I have seen videos of the soldered fitting on ss kegs, and that's what gave me the idea it would be a possible solution here.

The support is just like a standard pipe support. A clamp section that holds onto the pipe, while the other end (what you can see in the red circle) attaches to whatever is providing the support. In this case the outside wall of the fermenter jacket is supposed to fulfill that role. Hope that's clearer.

User avatar
jkp
Brewer
 
Posts: 961
Joined: Sun Apr 06, 2014 14:34
Location: China

Re: Blow-off arm support, weld or solder?

Postby PhatFil » Mon Sep 11, 2017 22:23

Ah much clearer, is the 'blow off tube' connected to all the sanitary tubing and pressure guage assembly pictured or is it simply dropping down behind?

even so it looks like a substantial mass.. If you have a sacraficial or non critical vertical SS surface i would be very tempted to test some epoxy-metal putty by sticking a blob to some stainless and testing how much mass it can support?
User avatar
PhatFil
Brewer
 
Posts: 1044
Joined: Thu Apr 03, 2014 10:52

Re: Blow-off arm support, weld or solder?

Postby jkp » Tue Sep 12, 2017 04:32

Indeed the end of the blow-off arm connects to the pressure gauge and pressure relief valve you can see there. It's not particularly heavy, but without the support it's left to a tri-clover fitting at the top to take the weight.

I'll certainly try out things on scrap ss before touching the FV.

Thanks!

User avatar
jkp
Brewer
 
Posts: 961
Joined: Sun Apr 06, 2014 14:34
Location: China


Who is online

Users browsing this forum: No registered users and 3 guests