# Can I solder this? **URL:** \ **Category:** Factual Questions\ **Created:** [January 4, 2006, 2:04am UTC](https://boards.straightdope.com/t/can-i-solder-this/338325 "2006-01-04T02:04:46Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![CynicalGabe](https://avatars.discourse-cdn.com/v4/letter/c/3e96dc/32.png) [@CynicalGabe](https://boards.straightdope.com/u/CynicalGabe)\ **Post date:** [January 4, 2006, 2:04am UTC](https://boards.straightdope.com/t/can-i-solder-this/338325/1 "2006-01-04T02:04:46Z")
I have a mechanical component that is loose. In order to fit in a new part (both pieces are steel), I had to grind down one part, but although I managed to install it, it wiggles unacceptably. Is there any way to get some solder to penetrate the small space (1/16 - 1/8) between the two pieces of steel? I just want enough in there to stabilize it, I don’t really need much in the way of strength there. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [January 4, 2006, 2:09am UTC](https://boards.straightdope.com/t/can-i-solder-this/338325/2 "2006-01-04T02:09:32Z")
What kind of steel? Stainless steel solders ok–we used to solder stainless steel banding straps for C-core transformers. It takes a beefy iron and a relatively active flux, and we used Sn-100 (pure tin) solder. I don’t know if standard 60-40 will do. However, other kinds of steels don’t solder so well, because oxides form too readily; these need to be welded. Unless you need electrical or thermal conductivity here, I would use something like JB Weld, which is a very strong 2-part epoxy designed for repairing metal items. ---
**Author:** ![CynicalGabe](https://avatars.discourse-cdn.com/v4/letter/c/3e96dc/32.png) [@CynicalGabe](https://boards.straightdope.com/u/CynicalGabe)\ **Post date:** [January 4, 2006, 2:13am UTC](https://boards.straightdope.com/t/can-i-solder-this/338325/3 "2006-01-04T02:13:18Z")
I’m not sure what kind of steel, just that it is not stainless. I have not information about it’s origin. I would weld it, but I need to remove one of the parts periodically for cleaning. I’d rather not have to resort to shims of some kind. 1: Shims suck. 2: This has to withstand repeated heavy shock-vibration. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [January 4, 2006, 2:22am UTC](https://boards.straightdope.com/t/can-i-solder-this/338325/4 "2006-01-04T02:22:51Z")
Don’t suppose you can do a closeup photo of the part in question? Might help us come up with a solution. Solder won’t work at all if it’s not stainless steel. The solder will just ball up and roll away, like water on a waxed car. ---
**Author:** ![SummoningDark](https://avatars.discourse-cdn.com/v4/letter/s/e19b73/32.png) [@SummoningDark](https://boards.straightdope.com/u/SummoningDark)\ **Post date:** [January 4, 2006, 2:23am UTC](https://boards.straightdope.com/t/can-i-solder-this/338325/5 "2006-01-04T02:23:13Z")
At work I solder all types of steel, including stainless. I would recommend a flux called stay-bright. it is basically hydrochloric acid with zinc chloride in it. it is nasty stuff, but you can get 60/40 to wet most anything(barring alumnium and titanium) with it. You might also try a solder called bridgit, which contains nickle and is good for filling gaps. I would recommend a propane torch instead of an iron for soldering large pieces. good luck! ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [January 4, 2006, 2:24am UTC](https://boards.straightdope.com/t/can-i-solder-this/338325/6 "2006-01-04T02:24:59Z")
Although, it just occurred to me that using a silicone RTV might do the trick. It’s got decent adhesive properties, resists shock and vibration well, is available in formulations for hi-temp applications and is relatively easily removed. ---
**Author:** ![SummoningDark](https://avatars.discourse-cdn.com/v4/letter/s/e19b73/32.png) [@SummoningDark](https://boards.straightdope.com/u/SummoningDark)\ **Post date:** [January 4, 2006, 2:28am UTC](https://boards.straightdope.com/t/can-i-solder-this/338325/7 "2006-01-04T02:28:50Z")
here is a link to JW harris: [http://www.jwharris.com/jwprod/solderalloys/#1](http://www.jwharris.com/jwprod/solderalloys/#1) they make bridgit and [http://www.jwharris.com/welref/faq/flux\_chart/](http://www.jwharris.com/welref/faq/flux_chart/) stay-clean ---
**Author:** ![CynicalGabe](https://avatars.discourse-cdn.com/v4/letter/c/3e96dc/32.png) [@CynicalGabe](https://boards.straightdope.com/u/CynicalGabe)\ **Post date:** [January 4, 2006, 2:35am UTC](https://boards.straightdope.com/t/can-i-solder-this/338325/8 "2006-01-04T02:35:51Z")
[Picture](http://www.gabemartinez.com/solder.jpg) The red circle shows the gap I’d like to fill. The stuff you can see in part of the gap is some plumbing flux I had tried to use on the off-chance that would work. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [January 4, 2006, 2:45am UTC](https://boards.straightdope.com/t/can-i-solder-this/338325/9 "2006-01-04T02:45:12Z")
Yeah, if you don’t want to go through the trouble of using **SummoningDark** ’s suggestion–not a bad one, just possibly more trouble than it’s worth, IMO–I think some RTV will do nicely, especially since you indicate mechanical strength isn’t a requirement. ---
**Author:** ![Duke\_of\_Rat](https://avatars.discourse-cdn.com/v4/letter/d/ad7895/32.png) [@Duke\_of\_Rat](https://boards.straightdope.com/u/Duke_of_Rat)\ **Post date:** [January 4, 2006, 4:35am UTC](https://boards.straightdope.com/t/can-i-solder-this/338325/10 "2006-01-04T04:35:22Z")
If it’s mild steel, the Stay Brite silver solder **SummoningDark** linked to will work great. Use Stay Brite silver solder and flux.