Holding small parts for soldering

[BETAQDAVE]

    I am having quite a time trying to hold two tiny pieces of thin wall brass tubing in place while soldering.  I have seen some people using wire to hold them in place but how can you do it without soldering the wire to the parts?  I have a soldering torch but it just seems to blow the parts away from each other.  Here is a photo of the parts in question and a sketch of how they go together below.

    The assembly is the deck end of the hawse pipe on the whaler Wanderer.  The flattened copper oval will serve as the lips of the pipe and will just be glued with CA once the pipe is inserted into a hole in the deck.  I have checked through this topic but don't see any posts concerning this problem.  Anyone have any suggestions?

[MEDDO]

 

Dave, I was having the same problem and at the last NRG meeting I asked Ken Foran (author of a great brass soldering book) the same question and he basically said to just use a regular soldering iron and skip the torch.  

[Richard Griffith]

Dave, and Mike, I prefer the torch.  It looks like you already have a ceramic block and T pins.  Anchor your ring to the block, add solder paste to it, then put tiny pieces of solder in the paste, then put your brass pipe on top.  Brace the pipe so it won't move.

Be sure the parts are clean, and you may have to hammer the solder into tiny flat pieces.  As soon as the solder melts, remove the heat.   Duff

[allanyed]

I assume you are silver soldering so an iron would not work,   I have a block of material made for soldering at most any temperature.  It is soft enough to dig into it which I have done on numerous occasions to hold a piece in place.  Hard to describe in words so if my explanation is unclear, I can try to post a photo or two to give you an idea of what has worked for me.   Using a wire to hold things in place does work but you would need to make sure it cannot be heated to the same temperature.  Clip on an alligator clip on the piece not to be soldered and it will draw away enough heat to keep the hold down piece from being soldered.  If it is still a problem, clip to the wire that is not to be soldered with a wet piece of cloth or tissue in the alligator clip as well.   

Allan

[vossiewulf]

I've yet to try it, but will at some point- most jewelers use thermoplastic for clamping operations when soldering. Heat the plastic with a torch, embed your pieces into it, let it cool, then solder, as long as you don't use excessive heat the plastic is supposed to hold fine.

[druxey]

A silver soldering trick I learned from a jeweler was to use soft iron wire to hold the parts. This may 'stick' a bit, but it does the trick nicely!

[xken]

Dave, try tinning the thicker copper ring first with a thin coating of solder plummer's 50/50. Then solder the elbow parts with Staybrite solder and leave excess solder in place then with soft binding wire hold the ring to the elbow and heat the edge of the ring the copper will carry the heat faster to the thinner brass and flow the joint. The 50/50 has a lower temp than the Staybrite.  Looking at the size of the parts you should be able to do this with a small 40 watt iron. Or if using a torch set the flame as small as possible. Make sure the iron is hot and use the correct flux. 

Another option is to us a wood plug through the ring to index the brass elbow while soldering; you will love the smell of burning wood in the morning. 

 

Solder Putty as mentioned above is available at  www.OttoFrei.com , but you should be able to do this no problem. Update: I just checked their site and they no longer sell the Solder Putty.

Edited February 16, 2019 by xken

[thibaultron]

Use aluminum wire, to hold the parts? I don't know if this would work, it might melt. The AL wire would, however, not stick to the parts.

[lmagna]

1 hour ago, thibaultron said:

Use aluminum wire

Might want to make it a LONG piece of aluminum wire! Aluminum transmits heat pretty well!

[No Idea]

I've done this type of joint many times and my solution has always been in the flux that you use.  You are trying to solder copper to brass but in a very small dimension.  There is no need for silver solder this is only required when strength or excess heat is present so soff solder is more than adequate.  Use a very acidic flux such as "power flow" which plumbers use but don't breath the fumes in.  Once the flux has turned to fluid just touch the joint with any type of soft solder and its job done.  You can either use a small flame or soldering iron it really doesn't matter  - its all about cleanliness of the joint and the acidic flux does this job nicely

[jhearl]

If you think you'll be doing a lot of soldering in your modeling career, you might want to consider a third-hand device like jewelers use. I bought one several years back and I use it a lot. They are quite expensive (about $150), but hugely superior to those cheap ones you see with alligator clips. It also makes a great general-purpose third hand for use when stropping blocks and many other purposes. I've never regretted buying mine. No question I'd be using it for something like this.

https://www.riogrande.com/product/grs-benchmate-double-third-hand-soldering-station/502042

 

[BETAQDAVE]

    Thanks for all the suggestions guys.  I finally ended up using one of those cheap third hand device and some wood dowels for my solution.  See my log on the whaling bark Wanderer for more details.

[vaddoc]

I found a solution with these forceps

 

https://www.amazon.co.uk/gp/product/B01AYLIH1S/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1

 

They are stainless steel, very robust and do not transmit heat. Very cheap also. There is a base that goes with it but you can also use whatever else. Highly recommended.

I prefer silver soldering as it is much more controlled. 

 

Vaddoc

[wefalck]

Ceramic self-closing tweezers can be got for less than 5€ for three these days in China. They should work even for silver soldering.

 

You can buy the tips seperately and I got some to equip my home-made third-hand with them.

Edited February 25, 2019 by wefalck

[svein erik]

You can also use aluminiums tape/strip inside the tube to hold parts together 

 

Svein.erik 

[BETAQDAVE]

    And here I sit with a big roll of that aluminum tape right here in my shop!  Who knew?

[wefalck]

I made some excentric cam-action pins from aluminium-rod to fit into the holes of these ceramic soldering plates:

 

[BANYAN]

Thanks Eberhard, that clears up my separate query to you

 

cheers

 

Pat

[Paul_of_England]

If you twist two lengths of Iron/binding wire together they form a spiral, so there is much less surface area of the wire touching the work to be heated.  This does not completely eliminate sticking, but it substantially reduces it. 

You could use a heat paste in conjunction with the wire and that really helps to stop the wire sticking, this product is good:https://www.gemcuts.com.au/technoflux-paste

 

  

[Roger Pellett]

I recently bought a spool of 1/32 in dia Aluminum MIG welding wire for about $10.00.  Solder does not stick to Aluminum and melts well below Aluminum’s 1200F melting point.  Better for wiring parts together than iron or steel.  I also custom fabricate little clips from a piece of thin walled aluminum angle that I salvaged from a yard sign.

 

 I  keep several thicknesses (1/64in to 1/8in) of inexpensive craft  plywood in stock.  This can be cut as needed to hold small parts.  For example, a strip of 1/64in or 1/32in plywood with one end nailed or screwed to a larger block of wood makes  “spring” for pressing two pieces to be soldered together.  The wood chars, but it’s disposable.

 

Consider changing your sequence.  It might be easier to solder two larger more easily clamped pieces together, cutting to finished size after they have been soldered.  A rotary tool fitted with a thin cutting disc easily cuts brass tubing.

 

I realize that professionals do wonderful work with torches, but for most of us using a torch is doing things the hard way.  If not adjusted properly, the flame lays down an oxide layer that solder won’t penetrate.  The flame can also blow away very light weight objects, and the hot flame can burn or melt easily fabricated wooden or aluminum holding jigs.  Furthermore, the very hot flame is not needed to melt soft solders and can damage nearby work.

 

When I decided to complete my Benjamin Noble Lake Freighter model with its extensive brass fabrication, I rearmed myself with an array of soldering equipment:

 

A Weller fine tip 15watt corded iron

A Weller 25 watt cordless iron

A 40 watt corded iron

A homemade resistance soldering probe

A Bluefire Propane/MAP gas torch

 

So far, the only tool that I have needed is the 25 watt cordless iron.  With an easily flowing small diameter lead free solder it works for almost everything.

 

Roger

 

 

 

[Toolmaker]

As a follow up to Roger’s post and in agreement with him, I am also a supporter of the soldering iron. My personal preference is a gas powered item. For the most part, ship fittings are lightweight enough to need only soft soldering.

My preferred method for holding parts in place is masking tape.

That may sound doubtful but it is easier to explain in clear pictures. I hope this is seen as helpful rather than indulgent.

Here you can solder between the masking tape and when the tape is removed then solder the rest if you feel it’s necessary. I didn’t. 
 

The next two pictures are the all brass bridge. Almost all the parts were soldered whilst held in place with masking tape.

 

Some similar examples

 

Parts were usually taped to a heat resistant tile or held in self grip tweezers.

 

Another example is the Carley floats.

 

 

Minimum size was also not a barrier.

This method of soldering has been discussed before but I thought it worth showing some ideas regarding holding.

Thats definitely me done here on soldering 😂.

 

Thank you

Paul

 

Edited March 13, 2023 by Toolmaker

[wefalck]

What masking tape are you using? In the past I tried painters' masking tape but the glue on it melts and leaves some residues that are not so easy to remove.

[Toolmaker]

2 hours ago, wefalck said:

What masking tape are you using? In the past I tried painters' masking tape but the glue on it melts and leaves some residues that are not so easy to remove.

Its Tamiya modellers masking tape. Its fairly low tack and in normal use doesn't leave residue. I think for the most part its about keeping the heat very localised which you can do with a fine nosed soldering iron. I generally use a small radiused nose rather than flat.

 

I hope that helps

 

Paul

[wefalck]

Have to try that - have both Tamiya masking tape and a selection of soldering irons of various sizes and a small (reflow) heat gun for no-touch soldering.

 

[Toolmaker]

You can see here the type of iron I use;

The method is simple enough;

Have the joint clean and fixed in place. 
Load the hot iron with solder.

Using a modellers paint brush, paint the joint with liquid flux and immediately offer the loaded iron to the joint.

 

The brass immediately heats up and the solder transfers from the iron to the joint.

 

lastly, avoid any stupid methods of seeing if the iron is hot!

Thanks

 

Paul

[druxey]

Very useful techniques and advice - particularly the last bit! Owch. Thanks, Paul.

[wefalck]

Learned that in my teens

Edited March 13, 2023 by wefalck

[Bob Cleek]

This new product may have come on the market since the inception of this post. It's really the best all-purpose holding system I've ever seen. Very strong and rigid holding ability. Heavy steel base. Arms attach with rare-earth magnets. Flexible arms stay put. Not like those "third hand" holding gizmos that have been around forever and never stay where you want them. High quality alligator clips, too. Reasonably priced. QuadHands® - Helping Hands Tool

 

[druxey]

Quad hands? I count five of them.

[robert952]

@druxy yep...there's five hands on this version.  The one pictured has strong magnets (rare earth?) and you can place the flex arms anywhere on the plate.  I have one of these and one with screw mounted arms in each corner from a similar company prodctu offering.   (a similar but different company's product) has 6 holes - one in each corner and holes in center of the long side of the rectangle.  The companies also sell arms separately.  IMO well worth the money spent.