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Mark Pearse

soldering iron or torch? advice please

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I want to make some metalwork parts for the model, & some of the parts have multiple flanges where they probably can't all be attached at the same time. I have't done any soldering or brazing & was wondering if an iron would be better if there's more than one flange to attach...would a torch tend to soften any joints already done?

 

thanks, below shows one of the parts

 

post-10631-0-58785900-1470793617.jpg

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jud   

Most will say Silver Solder which is good and you will need a torch to do it. You can obtain solder with different melting points that would allow you to do the work in steps. I would probably braze the flanges on one at a time, You can fabricate a heat sink to protect earlier work while working your way around. You also can obtain a putty like, "Heat Stop" from Brownells. Heat Stop would work with Silver Soldering also.

jud :pirate41:

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lehmann   

For a part that big (mass) you'll need a very large soldering iron to get the metal hot enough to allow a good bond for solder.     Large irons don't lend we to small parts, so this is therefore probably a job for a torch.   However, with either solder or brazing rod, you'll have to set up a jig to hold the flanges to the tube while you're heating it because this job will have to be done in one go, or, as you say, if you try one joint at a time, the others will slip off.  

 

One alternative is a micro-torch, which has a small, hot flame, but you have to be quick before the heat gets to the other flanges.  And, they're not cheap and work best on a hot fuel like oxy-acetylene.  Even with a micro-torch, I'd set up a jig.

 

Nice sketch, and I which I were working on such a large scale.

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Moxis   

First I would tie all the flanges tight around the tube through those holes using aluminium wire. Aluminium because it doesn't stick into parts when soldering. Then I would flux the joints and solder all at one go with soft solder, not silver. This because soft soldering doesn't need so much heat than silver soldering, and the part keeps better it's shape and is easier to clean after soldering. And yes, I would also use a micro torch, not soldering iron. There are micro torches available that use cigarette lighter gas as fuel. They are cheap and easy to use & refill.

Edited by Moxis
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allanyed   

Mark,

IMHO, soft solder is great for circuit boards, wiring and plumbing.  For ship modeling silver solder is easier and stronger for what you want to do.  The last thing you need is to be rigging your model and have one of the ears pop off when tensioning a line.   As said above, jig the pieces together and/or use several different melt points of solder.  If you do go with silver, paste is really easy to work with versus chips of silver.  Having done both, I stay with the paste on small parts.   Good luck

Allan

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I don't know if this helps at all but I was new to soldering in respect to making models. I purchased for Toolzone in the UK their item no. HB288. It is a micro butane soldering iron and blow torch which you fill from an ordinary gas lighter refill. The soldering tip is removable so that you can use the device as either an iron or a torch. I have found the torch to be wonderful with a very small, very hot flame absolutely perfect for models.

 

I found by lining up the pieces to be soldered, add a paste flux to exactly the place you want fixed, a tiny amount of solder which will stick to the flux, apply heat until the solder melts and hey presto, job done. I discovered that the solder will go exactly where the flux was placed which enabled me to do very small soldering work.

 

Hope this helps.

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Moxis   

It might be that you guys there have better (lower temperature melting) silver solder than we do in this part of the world. Some years ago the solder material including antimony (?) was banned here, and we only have solder available that melts in almost the same temperature as brass. This makes silver soldering very hard, because you very easily melt also the brass parts you are going to attach together.

I have used both methods, and have noticed soft soldering to be much easier that that with high temperature silver, and I have never found any problems with disintegrating parts with my models when soft soldered properly.

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CDW   

Here in the USA, those little butane gas fuel containers we use to fill our micro torches and/or cigarette lighters have become very hard to find. Stores that used to carry them in inventory no longer stock them. When I do find someone who has them in stock, I buy as many as I can and keep them for future use.

 

I agree with what most here have said. Use a micro torch and solder rather than a soldering iron for this job.

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Chasseur   

I agree with Allen. If you have the cash visit a shop that makes jewelry and purchase the smallest diameter of soft silver solder they sell. A jig is definitely the way to go to keep alignment. I also use a special liquid acid flux. The flux causes fumes so wear an N-95 mask. The low melting point silver solder will give high tensile strength and you can solder stainless steel, copper, brass, nickel alloys, nickel, chrome plated metal and iron.

 

The stuff is awesome!

 

Jeff

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allanyed   

It has been a while, but cigar shops always had butane as the lighters for cigars are nothing more than a mini torch, and yes, that is what I used for silver soldering before I bought my mini torches. 

 

Allan

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It has been a while, but cigar shops always had butane as the lighters for cigars are nothing more than a mini torch, and yes, that is what I used for silver soldering before I bought my mini torches.

 

Allan

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I've been silver soldering for several years now using a butane "pencil" torch purchased at one of the big box home centers (Lowes or Home Depot). For solder and flux I buy silver solder paste from a jeweler's supply. I use Rio Grande, but all of the online suppliers carry it. Like the wire, it comes in grades from "extra easy" to "hard," with increasing melting points. The paste itself is a mixture of flux, very fine solder power and an inert grease, and comes in a hypodermic style tube. For most small fittings, I take a fine price of wire and pick up just a trace of paste and apply it to the workpiece where I want the joint (the work should be as clean as possible), hit it with the torch and pickle it once the bond has been made. You can make EXTREMELY small joints this way, like soldering a .3mm ring to the end of a peice of wire to make a railing stantion for a 1/16 scal model.

 

The pencil touch works for almost every job, as long as it's fairly small. However, if you're working with a larger peice of brass, use a regular plumbers torch with propane or MAP gas. I had to do this to solder blades onto a heavy propellor hub for a 1:64 scale sub. The hub was just to heavy.

 

BTW, if you are looking for butane, the big box stores sell it where they stock the torches. Same kind of can that you use for lighters.

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A few years ago I put this video on-line about just this subject.

 

I am sorry it is so long and not that exciting. But I tried to convey the idea that 'small is for small, and anything large needs a big one'. Besides it has a some suggestions about flux.

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I have a mini torch that hooks up to a propane cylinder via a braided hose. It has screw on tips of different sizes and a screw on nozzle so it can be used as a soldering iron or a torch. I got it several years ago from Micro Mark. I have used the larger tip to solder some pretty big joints. It works great and propane cylinders are easy to find.

 

Roger Pellett

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jud   

Acquired a US Oxy Acetylene mini torch as a gift, it has 5 different brazing or soldering tips. Haven't had the need to use it yet, but checked, it will hook up to either one of my Oxy Acetylene setups and use their regulators.  Will need to go to the shop or wheel a set of tanks down to the house to use the mini, if I choose the house, I  will probably leave the tanks and regulators outside, unhandy but the risk of acetylene collecting on the floor would be reduced.  Acetylene needs watching and good ventilation is a must. In the shop, the doors are usually open, if not there are plenty of openings at floor level to allow heavy gas to get out. This mini torch looks well made and should heat well for soldering or brazing on the properly sized objects. Were it setup with small portable tanks and regulators, I would expect most modelers would prefer it over other heat sources for soldering, the heat is fast and can be concentrated as it is with full scale torches..

jud

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