paul1966 Posted October 6 Report Share Posted October 6 I'm in the process of refurbishing an old church bench which has cast iron legs and brackets, on disassembling it today I managed to break one of the pieces that hold the back rest, as it won't be under a lot of stress i'm wondering if I can get away with JB weld, or the other option is drilling another hole in the main bracket. Or does anyone else have a better idea? Quote Link to comment Share on other sites More sharing options...
oldypigeonpopper Posted October 6 Report Share Posted October 6 Hello, If you do not have a stick welder pop to your nearest blacksmith Quote Link to comment Share on other sites More sharing options...
ditchman Posted October 6 Report Share Posted October 6 clean up material.....preheat the whole area...and weld with a pure nickle rod.....if you dont and use any other rod you will get HAZ...... you may get away with braizing that....and let it cool slowly Quote Link to comment Share on other sites More sharing options...
JohnfromUK Posted October 6 Report Share Posted October 6 Cast iron can be welded, but I understand it is not the easiest material to weld and best left to skilled welders used to working with cast iron. Quote Link to comment Share on other sites More sharing options...
Minky Posted October 6 Report Share Posted October 6 46 minutes ago, paul1966 said: I'm in the process of refurbishing an old church bench which has cast iron legs and brackets, on disassembling it today I managed to break one of the pieces that hold the back rest, as it won't be under a lot of stress i'm wondering if I can get away with JB weld, or the other option is drilling another hole in the main bracket. Or does anyone else have a better idea? You clumsy Arab. There is no problem welding cast iron.. BUT you have to use special low hydrogen welding rods,, ( disimilar Metal). They are pretty expensive. If you just use a standard mild steel rod the carbon level is high and the weld may look puka but what happens is that the cast breaks right next to the weld when it cools down. also it helps to gently peen the area after welding to reduce the structure stress. Another issue is that as there is a fixed distance across the bracket between the holes you may have to fit the bracket onto the stud or bolt position and then tack it. You may need to grind out a groove distance to fill with weld or else if you just weld it the bracket may not fit where it came from. Quote Link to comment Share on other sites More sharing options...
paul1966 Posted October 6 Author Report Share Posted October 6 4 minutes ago, Minky said: You clumsy Arab. There is no problem welding cast iron.. BUT you have to use special low hydrogen welding rods,, ( disimilar Metal). They are pretty expensive. If you just use a standard mild steel rod the carbon level is high and the weld may look puka but what happens is that the cast breaks right next to the weld when it cools down. also it helps to gently peen the area after welding to reduce the structure stress. Another issue is that as there is a fixed distance across the bracket between the holes you may have to fit the bracket onto the stud or bolt position and then tack it. You may need to grind out a groove distance to fill with weld or else if you just weld it the bracket may not fit where it came from. I know I couldn't believe it, it was the last rusted bolt on the bracket as well. I'll ask around and see if anyone has the skill to weld it, the bench must be over 50 years old so I'd rather have a repair that lasts. Quote Link to comment Share on other sites More sharing options...
bruno22rf Posted October 6 Report Share Posted October 6 However you fix it back together I would be tempted to bolt/river a piece of steel underneath to take any further pressure, I would imagine 5mm would do it but obviously you will need to do both sides. Quote Link to comment Share on other sites More sharing options...
paul1966 Posted October 6 Author Report Share Posted October 6 3 minutes ago, bruno22rf said: However you fix it back together I would be tempted to bolt/river a piece of steel underneath to take any further pressure, I would imagine 5mm would do it but obviously you will need to do both sides. I was thinking along those line myself, you won't actually see the bracket as it's behind the back rest. Quote Link to comment Share on other sites More sharing options...
Minky Posted October 6 Report Share Posted October 6 17 minutes ago, bruno22rf said: However you fix it back together I would be tempted to bolt/river a piece of steel underneath to take any further pressure, I would imagine 5mm would do it but obviously you will need to do both sides. This ain't a bad idea, BUT the support plate would have to be stainless steel because if it is just mild steel it will rust and in six months it will expand and probably snap the bracket again 13 minutes ago, paul1966 said: I was thinking along those line myself, you won't actually see the bracket as it's behind the back rest. Just because you hide up a repair. where it won't be ready be seen round the back, it doesn't make it a good repair. especially when subsequently it falls to bits. if this was a repair on a seat that our late queen or his majesty King Charles would sit would you do a repair like this.? Quote Link to comment Share on other sites More sharing options...
bruno22rf Posted October 6 Report Share Posted October 6 1 hour ago, Minky said: This ain't a bad idea, BUT the support plate would have to be stainless steel because if it is just mild steel it will rust and in six months it will expand and probably snap the bracket again Just because you hide up a repair. where it won't be ready be seen round the back, it doesn't make it a good repair. especially when subsequently it falls to bits. if this was a repair on a seat that our late queen or his majesty King Charles would sit would you do a repair like this.? I think it would take considerably more than 6 months to rust through 5mm steel plate tbh. But SS would most likely last eternally. If I were still in the engineering game I would supply and cut it for you but alas.... Quote Link to comment Share on other sites More sharing options...
amateur Posted October 6 Report Share Posted October 6 (edited) I would braze it, having bolted it together with a stainless backing plate. What are the dimensions? I may have an appropriate offcut Edited October 6 by amateur Quote Link to comment Share on other sites More sharing options...
enfieldspares Posted October 6 Report Share Posted October 6 (edited) Cast iron should as far as I understand be pre-heated to a very high temperature before being welded. It cannot, again as far as I know and when I have had such welded, be welded cold as you would weld mild steel to mild steel for example. In Leicester I use a guy up on Unit 6, Maidstone Road up in Highfield. Thomas Brown. Advertises as TGB Welding. He has welded cast iron for me. Also a tang on a sword - so he might remember that. He won't necessarily be cheap however. Edited October 6 by enfieldspares Quote Link to comment Share on other sites More sharing options...
paul1966 Posted October 7 Author Report Share Posted October 7 21 hours ago, amateur said: I would braze it, having bolted it together with a stainless backing plate. What are the dimensions? I may have an appropriate offcut Dimensions are 4 cm X 22.5 cm Quote Link to comment Share on other sites More sharing options...
amateur Posted October 7 Report Share Posted October 7 4 minutes ago, paul1966 said: Dimensions are 4 cm X 22.5 cm I'll look through my offcuts tomorrow Quote Link to comment Share on other sites More sharing options...
paul1966 Posted October 7 Author Report Share Posted October 7 12 minutes ago, amateur said: I'll look through my offcuts tomorrow Ok thanks mate Quote Link to comment Share on other sites More sharing options...
amateur Posted October 7 Report Share Posted October 7 Have you brazed before? Quote Link to comment Share on other sites More sharing options...
paul1966 Posted October 7 Author Report Share Posted October 7 many years ago yes Quote Link to comment Share on other sites More sharing options...
amateur Posted October 7 Report Share Posted October 7 If you don't have any rods, Halfords have 2 x fluxed rods @ £4.99 which will work with a MAPP gas torch, or better, oxy-propane. Quote Link to comment Share on other sites More sharing options...
sky gipsy Posted October 8 Report Share Posted October 8 All the replies may be helpful but you were given the correct answer to your problem by Ditchy right at the beginning! Look on the Bay and you'll find sellers offering a few pure nickel 2.5mm electrodes for a tenner or so (they're not cheap, but very good). I've used them many times in the past, often without prevheat and saved countless old iron castings. Quote Link to comment Share on other sites More sharing options...
amateur Posted October 8 Report Share Posted October 8 (edited) 17 hours ago, amateur said: I'll look through my offcuts tomorrow Regrettably, I have nothing that would suit. eBay do list this though. eBay.co.uk 281140501301 That is 40mm x 3mm x 300mm stainless £7.01 Edited October 8 by amateur Quote Link to comment Share on other sites More sharing options...
paul1966 Posted October 8 Author Report Share Posted October 8 6 hours ago, amateur said: Regrettably, I have nothing that would suit. eBay do list this though. eBay.co.uk 281140501301 That is 40mm x 3mm x 300mm stainless £7.01 Thanks for looking, ordered some of ebay being delivered tomorrow Quote Link to comment Share on other sites More sharing options...
amateur Posted October 8 Report Share Posted October 8 1 minute ago, paul1966 said: Thanks for looking, ordered some of ebay being delivered tomorrow No problem. If I were you I'd bolt it to the stainless backing plate (made to fit the bench, rather than the cast iron), having chamfered the joint, heat it on firebricks to bright red with a MAPP or oxypropane torch and fill the break with braze, then let it cool slowly. This way you should avoid dimensional discrepancies and the problems of welding cast iron. Keep us updated. Quote Link to comment Share on other sites More sharing options...
ditchman Posted October 8 Report Share Posted October 8 (edited) 8 hours ago, sky gipsy said: All the replies may be helpful but you were given the correct answer to your problem by Ditchy right at the beginning! Look on the Bay and you'll find sellers offering a few pure nickel 2.5mm electrodes for a tenner or so (they're not cheap, but very good). I've used them many times in the past, often without prevheat and saved countless old iron castings. back in the early 80's i did a fair bit of cast welding....and also castings...we used nickle rods as what is called a "buttering layer"...on the casting sides ...then we could use rutile or lo-hydrogen as a filler...we did that so the big castings could be machined afterwards ...and as the rutile or lo-hy didnt contact the casting it didnt cause "carbon pick -up" or make a heat affected zone.... the rods i used back then were only 6" long and were 3.25mm...and even then they were over ten bob (50p) a rod......they were the smootest rod i have ever burnt ...even smoother than a satinex..........but damned if i can remember the name of them...you could only use them downhand i have used non-pure nickle rods....with not very good results...(think the company tried to make a multi positional rod) https://www.r-techwelding.co.uk/welding-equipment/arc-stick-welding-electrodes/hard-face-cast-iron-copper-and-aluminium-r-tech-welding/pure-nickel-arc-welding-electrodes Edited October 8 by ditchman Quote Link to comment Share on other sites More sharing options...
enfieldspares Posted October 8 Report Share Posted October 8 Again as the OP is in Leicester maybe Guildea Welding at Paigle Road, Aylestone which is the old Aylestone Gun Company premises. Quote Link to comment Share on other sites More sharing options...
welsh1 Posted October 9 Report Share Posted October 9 Yoy can gas weld cast iron, but you need to clean it well bring it slowly up to heat in a blanket, weld it and then very slowly cool it with a heat blanket, but be prepared because the slightest breeze and you will hear the ping of it cracking. one of the hardest test pieces of my Military welding course was the cast iron. This is your best option, cover it with heated fire bricks when finished in a draught free area. On 08/10/2024 at 16:39, amateur said: No problem. If I were you I'd bolt it to the stainless backing plate (made to fit the bench, rather than the cast iron), having chamfered the joint, heat it on firebricks to bright red with a MAPP or oxypropane torch and fill the break with braze, then let it cool slowly. This way you should avoid dimensional discrepancies and the problems of welding cast iron. Keep us updated. Quote Link to comment Share on other sites More sharing options...
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