Radiator Solder

[John Morrison]

As the heading shows, need to repair the rad. from my 4,

what is the thinking on the best of the new generation of solders and fluxes

to tackle this? and where should I buy it.

 

Ebay will be too slow, as I want the car Sunday, so looking at Screwfix, Toolstation or some such.

 

Cheers,

 

John.

[barkerwilliams]

John,

 

Only soldered a rad once and it was such a delicate task. I would suggest that you check the melting point of the solder, it commonly varies between 179 and 300'C. I would use the lowest temp I could buy to avoid damaging other joints with excessive heat.

 

Alan

[Fireman049]

.

Edited November 20, 2015 by Fireman049

[lynchpin]

Hi John

Repaired a couple of rads in the past that were leaking around the bottom spigot, used a blowlamp and normal gas fitter/plumber solder and separate flux to remove and refit spigot, also managed to repair the top seam in the past, but as Alan said you have to be careful of causing any other joints to fail with the heat..

 

Phil...

[RogerH]

Hi John,

if you need the car for Sunday why not use something like 'RadWeld'. This sorted a big leak I had on a Welsh week-end once (that is not a Leek).

 

Then get it sorted properly

 

Roger

[RobH]

As others have said above a rad is difficult to get hot enough to solder succesfully without disturbing other areas John - and you have to get the joint area very clean indeed. If its the matrix then Roger is spot-on with Radweld or similar. if its just a small weep from a joint rather than a full-on leak I have used JBWeld epoxy quite successfully on one of those - so far this has lasted three years with no sign of a problem.

[Rob Salisbury]

John, from personal experience, avoid the current generation "lead free" plumbers solder, it has a much narrower melting range than the old lead/tin stuff and is harder to get to flow into the joints. Car body solder with solder paste as the flux works quite well (it's pretty much the old style plumbers lead solder after all) , but the flux must be well washed off when finished.

Cheers Rob

[BrianC]

Following recommendations on this Forum I've always carried a bottle of K-Seal in our TRs although never (yet) needed to use them. However, recently my faithful 'Skippy the Skoda' developed a bad leak somewhere near the bottom of the radiator or matrix - difficult to tell where without major dismantling for which I had neither the time nor inclination. In desperation, as a temporary fix, I used 1/3 bottle of K-Seal, expecting notalot. Surprise, surprise - far from a temporary bodge, I think it may be a permanent solution until the old girl fails an MOT too expensively and goes to the great scrapheap in the sky. I have used other products in the past but K-Seal worked far quicker and more effectively than any thing previous. Well worth a try for a quick fix.

 

However, if it's a big hole or perforated area and accessible, then I would probably try JB weld with a small metal patch.

 

[N.B. Suggestions only for a quick fix and no substitute for longer term solution on a classic]

Edited October 29, 2015 by BrianC

[Motorsport Mickey]

K Seal is the product of choice for Stag owners, and if it can seal a Stag it must be good !

 

Mick Richards

[John Morrison]

Thanks Guys,

 

I carry K-Seal with me,but my rad problem is a collar in the header tank that has now 'cracked'

 

I fitted this years ago when I replaced the mechanical fan with electric, and wanted automatic switching, albeit with a manual overide.

 

Have checked all the usual suppliers, who list stock, and screwfix show a lead/tin solder with a melting point of between 183 and 234 C, so I will have a go with that

tomorrow, wish me luck.

 

John.

[stuart]

John if you wet a piece of rag and put it in a circle around where you are soldering the collar it will keep the heat in.

Stuart.

[Lebro]

I repaired a leaking joint between my header tank & the filler extension last year.

I used plumbers solder (lead / tin), and plenty of solder flux. By being very careful with the blowlamp it's not difficult to only melt the area you need to, & slowly build up a nice dome of solder over the crack.

 

Bob.

[ianc]

In 2001, I had a small weep from the top joint on the radiator - where the tube from the thermostat enters the header. I cleaned the area thoroughly, applied JB Weld (as suggested by Glen Hewitt of Protek) and all is well 14 years later.

Ian Cornish

[stuart]

I repaired a leaking joint between my header tank & the filler extension last year.

I used plumbers solder (lead / tin), and plenty of solder flux. By being very careful with the blowlamp it's not difficult to only melt the area you need to, & slowly build up a nice dome of solder over the crack.

 

Bob.

Usually caused by leaning on the extension while doing something under the bonnet. Always a good idea to have a strengthener fillet put in under it when having them re-built.

Stuart.

[Ian Vincent]

Usually caused by leaning on the extension while doing something under the bonnet. Always a good idea to have a strengthener fillet put in under it when having them re-built.

Stuart.

Or don't lean on the extension.

[stuart]

Or don't lean on the extension.

I know I keep telling people not to do it but they still do!

Stuart.

[john.r.davies]

Can't remember how it happened, but I once had a rad leak after qualifying practice in the morning. It was obvious, a small jet of water out of the front.

 

Drained, took out the rad (still hot), laid it down and dripped Araldite Rapid over the hole.

I was racing that afternoon, with no leak at all, then or thereafter.

 

John

[John Morrison]

Thanks All,

 

happy to report that I seem to have got away with this,

Screwfix solder and flux worked well, and the rad is back in the car,

I'm out this weekend, plan to belt over Kirkstone and down to Bowness-on-Windermere, so should be a half decent test.

 

John.

[MikeF]

As the heading shows, need to repair the rad. from my 4,

what is the thinking on the best of the new generation of solders and fluxes

to tackle this? and where should I buy it.

 

Ebay will be too slow, as I want the car Sunday, so looking at Screwfix, Toolstation or some such.

 

Cheers,

 

John.

to answer your question directly for the record:

The solders used to manufacture (remanufacture) our radiators are high lead alloys - more than 95% - balance tin, sometimes with a little silver. They have softening/melting points from around 300C according to precise composition.

If by new generation you mean lead free solders, these are conversely very high tin alloys, balance 0.5 - 0.7 copper, the better performing (electronic) types have a little silver added. The melting range is from 227C. The best to be said about them is that user benefits are hard to discern over the alloys they replace.

I would not recommend using these high tin alloys on existing solder joint repairs (say a cracked joint or leaking tube seam. The resulting alloy mix will not be homogenous and therefore is more likely to fail at the interface of the tin rich and lead rich zones [from vibration and thermal cycling].

You can still get high lead alloy solders, but will probably have to ask for them or order on line. [Leaded alloys are still permitted on non-potable water pipes and for non electrical/electronic use.] For sure the alloys are available industrially.

 

As remarked above body solder could be used as that is typically 60% lead balance tin (melting range 183 -237C).

At a pinch you probably could use tin/lead electronic grade alloy (63% tin balance lead), although an even lower melting point at 183C, the joint metallurgy will probably be less discontinuous than with high tins. The lower melting range and better spreading could also be advantageous as it gives a bigger margin before disturbing the 300C alloys.

 

 

Mike

Edited November 1, 2015 by MikeF

[oxf2]

Another victim of the dread leak-at-radiator-to-long-neck-joint. And no, I haven't been leaning on it!

So when using a lead/tin alloy solder, the greater the percentage of tin, the lower the melting point of the alloy, right?

I think MikeF in the post above says an alloy of as much as 63% tin (37% lead) is good for fixing the long-neck joint leak.

Any dos and donts on choice of flux?

(Also, not sure if I can work Stuart's wet rag tip into this, given the 90 degree angles involved.)

[Lebro]

I use Plumbers flux (any hardware store), & a reel of non fluxed 40/60 solder.  The key is to make the brass completely clean, & free of any foreign matter before you start, then lots of flux on the area to be soldered, then when using the blowtorch be careful to only melt the solder in the area you are repairing, i.e. don't let the rad get too hot or you will lose a lot more solder from around the joint, keep the heat localised. You will find you can play with the heat such that the solder in the repair area is kept just soft enough that you can add to it without it all falling off.

Good luck

Bob

[BlueTR3A-5EKT]

Did mine this year with 2 part putty.   Not pretty but working ok   The issue for me was to NOT remove the apron 

 

[Charlie D]

When I was an apprentice with the GPO in 1966 we spent six months with “Cable jointers”, fixing cable faults in lead sheathed cables.
Some of the older guys were expert plumbers; with a vat of molten solder they could ladle some out, pour it over a joint, catch the excess underneath in a moleskin cloth, and wrap it around the end of the joint just like you would with P38 body filler.

It seemed to stay plastic for ages and they were true artists.

I often wondered about relative melting points of the solder and the cable sheath. I pondered about the lead/tin content of both.
If you asked them such questions they would just laugh and say :

“You college kids have to understand that there are some things you just can’t get from reading a book. ”

So true.

Charlie.

[Ian Vincent]

3 minutes ago, Charlie D said:

When I was an apprentice with the GPO in 1966 we spent six months with “Cable jointers”, fixing cable faults in lead sheathed cables.
Some of the older guys were expert plumbers; with a vat of molten solder they could ladle some out, pour it over a joint, catch the excess underneath in a moleskin cloth, and wrap it around the end of the joint just like you would with P38 body filler.

It seemed to stay plastic for ages and they were true artists.

I often wondered about relative melting points of the solder and the cable sheath. I pondered about the lead/tin content of both.
If you asked them such questions they would just laugh and say :

“You college kids have to understand that there are some things you just can’t get from reading a book. ”

So true.

Charlie.

As a student apprentice, I spent two weeks at the BICC cable jointing school being taught to put a lead sleeve around a joint. As I learned from painful experience, if you get the lead too hot while you are wiping it, the whole lot can fall off into the palm of your (ungloved) hand. 

Rgds Ian

[stuart]

14 hours ago, Charlie D said:

When I was an apprentice with the GPO in 1966 we spent six months with “Cable jointers”, fixing cable faults in lead sheathed cables.
Some of the older guys were expert plumbers; with a vat of molten solder they could ladle some out, pour it over a joint, catch the excess underneath in a moleskin cloth, and wrap it around the end of the joint just like you would with P38 body filler.

It seemed to stay plastic for ages and they were true artists.

I often wondered about relative melting points of the solder and the cable sheath. I pondered about the lead/tin content of both.
If you asked them such questions they would just laugh and say :

“You college kids have to understand that there are some things you just can’t get from reading a book. ”

So true.

Charlie.

GPO and latterly BT used to have their own spec for the solder sticks that they used for jointing, I used to have a source of that and it was the best Tin/lead/antimony mix of all and it was great to do panel repairs with, alas now I have to put up with the standard Frost restoration supplies mix which is nowhere near as good. Otherwise I have to buy it by the ton.

Stuart.