welding for my "keg cooler system"

So basicaly what im doing is just a small cooling fit my "poney" keg in. (Diameter 9" and tall of 25"). I got all my part for the cooling system. Condenseur, compresseur, dryer, tube capillary, suction copper tube OD 1/4 and discharge copper tube OD 3/16, evap and 2 valve.

But what i need now is to weld all of this together, my starting point is a Silver Weld, as far as my welding knowledge is concern, what i do next? What materials do i need and what the process?

Hi.

You want to make a phase-change system and deal with potentially high pressure system without knowledge about brazing ?? You'll need some training to avoid mistakes !

You just need a quite powerful torch (acetylene/oxygen or propane/oxygen is ideal) and maybe some flux to get scoured surfaces during process. You clean surfaces with some metal brush or steel wool, you apply some flux onto your surfaces to help joint forming, you put your parts together and you heat them at ~700 °C (copper color will become cherry red), then you apply your brazing rod (with torch out). Brazing has to flow itself to form the joint by capillarity. If not, continue to heat parts until a strong joint is formed.

Hey,

I know about refrigeration and about brazing only with Tin and on copper tube, but we all know tin melt point isnt high enough to do the job.

So here what I bought so far, Self-igniting Brazing torch kit (400 g of brazing fuel (Propylene)) with a high temperature of 1982 °C (3600 °F), this kit includes 2 flux-coated brazing rod, and some other rod (2 are copper/phos i think)... Actually that pretty much this : http://www.weeklyspecialsonline.com/home/w...52570D2004E2667

I think i should be good to go with this kit once i figure out which rod to use unless i need flux paste, if i do i guess there is one for silver brazing? I will prolly need extra rod too cause i will practice a lot before doing it on the real thing, so should i go with a 40% silver even its more expensive or a 6% will do. By the way, if its 40% silver, what is the other 60%??

Looking forward to your answers. Thanks

It's about the same between tin and silver, the major change is temperature . Your brazing torch seems good, it's like some Maxigas torchs here in France. It's ok to braze tubes, but not really for massive parts because it's not as powerful as a true torch. Flux is normally incorporated into silver rods, but you can use a special one to help a lot in some cases. It's written on the box anyway, each brazing/solder has its flux.

Silver rods are 6 or 40 % generally, you're right. At 40%, it's easier to use (lower fusion T°), but higher price... The other 60% is copper, so more copper into rod = higher T° to melt it = difficult work. You could use copper/phospore, despite it seems more difficult to use (higher T° ~800° !) but I believe it's cheaper, not sure. Here, people prefer 40% rods generally.

You should practice with 2 tubes in order to have an idea of the needed temperature and how to apply rod to make a good joint. If you know tin soldering, you won't have too much problem to make a proper silver brazing

I went shopping today for my project and i got a pack of 6 rods of silver alloy. It says Universal coated cadmium-free rod with high silver content for bazing ferrous metals, non-ferrous metals,...,copper alloys.

Typical Application : Ideal for joining and repairing stainless steel equipement used in ....refrigeration, etc...
Bonding Temperature : 570-620°C

Mine have a diameter of 1.6 mm (1/16) and the guys at the store says the flux was "includes on" the rod.

Even tho i dont know the % of silver, i think this should do the job?

What do you think?

Yeah, it seems good (copper alloys included in the description and bonding T° is good), but it's a bit strange that no mention of silver % was given
Maybe the "high silver content" means ~40 % for them, I don't know. Here, the silver % is commonly written on the rods package, it's quite obvious to indicate that piece of information...

If you understand french, here the spec of my rods http://www.soudotec.com/telechar/6020fc.pdf

One more thing, when i will be welding the capillary tube to the dryer, do i need to put a wet towel over my dryer because with the heat, it might do some damage...or not?

I've seen somewhere where people talking about wet towel and welding but i cant recall the exact saying.

Yeah we can speak french if you want, I'm french

Nothing about silver % into specs, but it's probably ~40 % because your rods allow the stronger mechanical strength according to their PDF. You can eventually protect the dryer with a wet towel because the chemical products inside (silicagel) could suffer from excessive heat...

J'ai pensé mettre une valve d'expansion thermostatique sur mon systeme, mais avec le dryer c'est pas fait pour etre souder mais plutot viser, est-ce que des "flare nuts" pourraient faire et remplacer une soudure ou il a des précaution a prendre?

Une TEV a peu d'utilité sur nos petits systèmes (peut-être pour un waterchiller, et encore...) et puis rien ne vaut une vraie brasure plutôt que des assemblages vissés, même si les flares sont faits pour ça. Certains utilisent plutôt des CPEV (système non régulé) à la place du capillaire pour pouvoir régler la détente, c'est bien moins cher, mais ça prend un peu de place.

vissé brasé ^^

brazing in the threading nice to disassembling

C'est parce que j'ai de la misere a trouver la bonne grosseur de tube capillaire, celui que j'ai le diametre est trop gros, contrairement a la TEV, avec les fitting c'est facile pour changer des composantes mais moin fiable...

http://www.kaeltetechnik-shop.at/index.php...ary-tubing.html

ou

http://www.bes.co.uk

Merci pour les liens.

Je continue a pratiquer mes brassure. Je trouve que mon tuyau devient vraiment noir. Est-ce normal? Est-ce possible de voir des photos ou video?

De plus j'ai remarqué qu'une fois la soudure faite, il a des résidus dans le tuyau, je sais pas si c'est a cause de ma flamme... mais il doit falloir nettoyer les tuyaux avant de mettre du gaz ou en faisant le vide cela se nettoyer automatiquement?

des résidus du flux et surement une oxydation du cuivre, en CuO qui est noir

C'est de la calamine, ça peut effectivement boucher un capilaire. Un coup d'acide et on en parle plus

Le coté acide est un nouveau pour moi, si je comprends bien l'acide est pour nettoyer l'extérieur de tuyau afin qu'il soit beau ou bien y'a une procédure a faire pour nettoyer l'intérieur des tuyaux?

ben gratter ça peut le faire, et l'acide aussi genre acide chloridryque

perso l'evapo ect je le brase puis je le rince pour enelever tout la "merde" puis je finis le système de facon hermétique avec un peu de propane dedans ça évite d'avoir de l'oxygène dedans

Alors si j'ai bien compris je vais nettoyer l'extérieur avec de l'acide ou autre produit qui pourrait fonctionné, j'ai un pompe a vide ici donc sa va aller bien pour retiré l'oxygène du systeme.

En mettant une serviette mouillées de chaque coté de mes brassure comme quand on brase le dryer sa évitera de noicir trop mes tuyaux?

wé tout a fait

Une derniere chose, du moin je l'espere, est-ce que seulement de l'eau et du savon pourrait suffire pour detecter les fuites ou je dois acheter quelque chose fait pour ca, autre que les machines électronique?

a prioris ça suffit ^^