We are welding together a forged steel balustrade, which is not a problem, but we have these cast iron spear points to put on the tops of the steel balusters. We got a 220 volt Lincoln MIG welder for the steel welding. We haven’t tried, but are told we can’t weld the cast to the steel. Do we have to braze them together? And can we do that with a MIG welder?
Discussion Forum
Discussion Forum
Up Next
Video Shorts
Featured Story

The Titan Impact X 440 offers great coverage with minimal overspray.
Featured Video
How to Install Cable Rail Around Wood-Post CornersRelated Stories
Highlights
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Fine Homebuilding Magazine
- Home Group
- Antique Trader
- Arts & Crafts Homes
- Bank Note Reporter
- Cabin Life
- Cuisine at Home
- Fine Gardening
- Fine Woodworking
- Green Building Advisor
- Garden Gate
- Horticulture
- Keep Craft Alive
- Log Home Living
- Military Trader/Vehicles
- Numismatic News
- Numismaster
- Old Cars Weekly
- Old House Journal
- Period Homes
- Popular Woodworking
- Script
- ShopNotes
- Sports Collectors Digest
- Threads
- Timber Home Living
- Traditional Building
- Woodsmith
- World Coin News
- Writer's Digest
Replies
Years ago I worked in a steel supply shop. I used to occasionally weld some cast to steel. I used ordinary rod 6011 or 6013. It held good enough for our puposes but it was weak.
blue
There is a discussion of this type of problem at:
http://www.abana.org/resources/discus/messages/2/80.html
If you have the option on using a stick welder, grab some high nickel rod, if not then your mig will probably be fine. This is non-structural, right?
The most important part with welding cast iron is to pre and post heat the pieces. Using a torch (propane torch is usually fine unless it's thick), heat up the cast pieces. You don't need to get it cherry, just hot. You might want to set your welder a bit lower since it will penetrate a bit more than normal. Do your weld, then thow the torch back on the piece. The idea is to allow the weld zone to cool at a uniform rate, to avoid stress cracking.
Hope that helps. If they are quite small pieces, you can just buzz them together. If you have a torch outfit and time/skill to braze them, that would be even better.
They'll stick no problem.
All those little cast doodads are stuck on that way.
Joe H
I would try it even without the pre-heating. Esp. if it just slips over the square bar. I few welds might crack, just buzz back over them.
-SRJ
In a previous life I was a welder. We did that all the time, sometimes its difficult to get a really nice looking weld but its definitely doable.
Done it with both regular welding rod and nickle rod.
There, thats all the welding I want to do for the next 25 years!
Doug
Hey quick question isn't that nickel rod 7028 I think that was the stuff I used in Alaska
God its been so long that I couldn't even make an educated guess. And that's the way I'm hoping to keep it!!!
I really don't have any idea.
Doug
Little stuff like a batch of spear point can just be put in an oven at 500F, then 7014 stick makes a decent looking weld on cast to mild steel - all you need is a few spots for non structural. Have an old kitchen oven in the barn/forge shop for just such occasions. Even fit a cracked transmission case into the old hotpoint oven once, used pure nickel rod on the transmission case though.
You want to preheat to around 500 degrees. If you're using a torch get a heat pencil in tht heat range.
Headstong, I'll take on anyone!
Not exactly welding but IMHO what you want to do is braze or solder the pieces together.
Brazing, around 1200 F, or silver soldering, as low as 500F depending on alloy, is plenty strong, actually stronger than most welds. Because they are much lower heat processes there are almost always fewer issues with differentials in expansion and material strengths that lead to stress fractures and failures.
Welding steel to iron often causes the iron to 'peel off' the weld area as the grainy and softer iron gives while the steel does not. Brazing materials and solders also have much more 'give' and gap filling capacity and can often absorb much of any differential. Filling any gaps might increase durability long-term by keeping water and corrosion out.
Another possibility would be to glue it with industrial epoxy. This would have the advantage of being easy to do as it requires no heat or power source. Just clean the parts, mix, apply and join. With a slip fit, or ones held together by gravity, even clamping might be unnecessary. For moderate strength joints the faster setting compounds, handling within 10 minutes and full strength in 24 hours, might be the material of choice.
Epoxy and the brazing or soldering materials can be grounds or worked smooth and made to maintain a good seal. Painting covering any color difference and providing a final seal. Brazing and soldering are traditional and well done, even if not painted, can be quite presentable as the filler is contained between the pieces and not noticeably exposed.
Thanks everyone. I think we'll just try a few pieces using the MIG after heating the pieces, and see how it goes. These are not structural, just ornamental. Thanks for the ideas.
Even though I am a certified welder, if these caps slipped over the tubing, I would probably just epoxy them on - it shouldn't take much and would be quick and easy...
That might be the easiest. And easy to try out. Thanks.
Agree..JB WELD is awesome stuff for things like that. Spheramid Enterprises Architectural Woodworks
"I don't think it's funny no more" Nick Lowe.
Agreed, JB Weld is one of my standbys. The standard stuff takes a while to set up but they have some quick setting stuff out now that I have yet to try. One other thing about epoxy is that if you want it to release, you just have to heat it above a certain temperature. Don't remember what that is 600 degrees??? I found that out at first when I repaired my favorite cup with epoxy and then put it in the microwave to warm my coffee only to have the repaired handle depart from the main part of the cup...
It is the only fix for plastic radiators on some newer vehicles, both my Toyota and GMC are sporting it proudly..goooood stuff. Spheramid Enterprises Architectural Woodworks
"I don't think it's funny no more" Nick Lowe.
Arvid,
A second for the epoxy route. Some super strong ones out there, but you must protect it with paint as epoxies degrade with UV ray (sunlight ) exposure.
WSJ
The welder will work, I've done lots of them that way.
As those things aren't real precision parts, try to keep them straight as you weld. They look kinda odd when you're all done & one or two are sitting at an angle.
Joe H