Smoothing a welded block.

Gene Davis (Ga.) · Jul 3, 2021

Hello. I need some advice on smoothing a repair on a block that has been welded on the outside of the water jacket. This is an old weld and is a very big one. The welding was done with Ni-rod. There is weld in much of the area of the side so it must have really did a number on breaking out the side of the water jacket. The weld is really piled up in spots and has some pretty rough places.
I helped my father repair a block like this many years ago. When he finished the welding and the block had cooled he smoothed the rough stuff down a little with the grinder then used furnace cement for a smooth coating over the rough places in the welds. Furnace cement has gone the way of the Do Do birds, so what do you people use or suggest to use in place of the old furnace cement. this is an N-62 Continental engine block that I want to put in my Earthmaster tractor.

old · Jul 3, 2021

Something like JB weld or if you need something that will take more heat there is a type of stuff like the J.B. weld made for exhaust work

greenmech · Jul 3, 2021

I used Propoxy 20 a two part epoxy that worked on my International A block. Has not cracked in several years and held coolant. Ron MN

Steve@Advance · Jul 3, 2021

I would be scared to do much grinding on it. Possibly the reason it is piled up and rough was because the weld was porous and more weld was piled on top.

Might try just leveling over it with some type epoxy, even Bondo might work.

Tgrasher · Jul 3, 2021

To add to Old's advice, do one fill coat, sand flat, spread a skin coat, and texture it when it's almost set up, like the cast metal around the area.

moresmoke · Jul 3, 2021

JB weld. Been there done that.

SVcummins · Jul 3, 2021

I used this on a block I stitched a crack closed in same specs as belzonna but about half the price
Epoxy

Russ from MN · Jul 3, 2021

I welded the block on a Farmall A about 45 years ago, when I got done it still leaked a little, so I put some stop leak in it. Weld didn't look the best, so I fiber glassed over it and painted it. Didn't leak, and looked pretty good, lasted for years, sold it, don't know where it is now.

fixerupper · Jul 3, 2021

I usually grind the weld somewhat but leave it thicker than the base metal. Then I hit the welded with a needle scaler to make it look like cast. With a coat of paint a person has to pay attention to notice the weld. In your case I agree grinding it down might expose leaks the thick welding possibly was plugging. You could take your chances and still grind it down knowing you can plug leaks with one of the epoxys mentioned.

M-MAN · Jul 3, 2021

You can still get furnace cement at a hvac supply house.

wore out · Jul 4, 2021

Unless you are trying to pawn off a "repaired" block/tractor on an unsuspecting potential buyer WHY would you need to do this?

Also, dunno WHY the excess weld can't be ground away leaving a surface that doesn't need much "touching up" to conceal it.

FURNACE CEMENT on a tractor block, WHAT the heck?????

But if you REALLY need it it's still "out there" unlike the "dodo bird"! TSC even sells it.

If you can't find it anywhere else, "Extreme Heat" JB Weld is more or less "furnace cement", LOL.

https://www.jbweld.com/product/j-b-extremeheat

560Dennis · Jul 4, 2021

If a weld looks good , it problably is good. The repair will show if it was properly done. Had a super c that had a welded block lasted sixty years.

showcrop · Jul 4, 2021

Gene, I understand completely that you want the block in your Earthmaster to look good!

Crazy Horse · Jul 4, 2021

I've patched a couple of blocks with JB weld and fibreglass mat (random strand type) much like you would do with glassing a boat. I'd grind it down myself, nobody wants a messy looking repair, then once the JB is mixed, a bit of heat with a heat guy makes it runnier for the repair and it really soaks in nicely with the mat. Easier to do if the repair area is horizontal but vertical works too, you just have to be a bit more attentive to sagging or the JB running. You can even give it a second top coat using the same method. A thorough initial cleaning and surface prep of course is required.

BarnyardEngineering · Jul 4, 2021

Except that the block is already patched. He's just trying to make it look more presentable.

JB weld is perfect for this application.

Butch(OH) · Jul 4, 2021

Trick I learned is to sweep up a little pile of shop dirt and pick out the bigger stuff. Then spray the area with primer and throw some of the finer shop dirt on it while wet. You can practice on some scrap or thinner on a rag takes it all back off.

Stephen Newell · Jul 4, 2021

Any furnace cement I've ever used was water soluble even after it was dry and hard. I think if you are going to use a filler I would rather use JB Weld High Heat adhesive. It's suppose to be good to 400 degrees. Personally if I ground it smooth and caused it to leak again I would be inclined to go back over it with nickle weld. It may be who ever did it didn't have enough heat to make the weld work and why so much thickness was built up. It might also be the cast had so much impurities in it that nickle welding was a bad choice. It may should have been brazed. Brazing would work whether the cast was good or not.

Determined · Jul 4, 2021

(quoted from post at 06:42:02 07/04/21) I've patched a couple of blocks with JB weld and fibreglass mat (random strand type) much like you would do with glassing a boat. I'd grind it down myself, nobody wants a messy looking repair, then once the JB is mixed, a bit of heat with a heat guy makes it runnier for the repair and it really soaks in nicely with the mat. Easier to do if the repair area is horizontal but vertical works too, you just have to be a bit more attentive to sagging or the JB running. You can even give it a second top coat using the same method. A thorough initial cleaning and surface prep of course is required.

Crazy Horse Instead of heating the JB weld to get it runny you can mix it then thin it with some methyl hydrate, I do it all the time when repairing aluminum radiators, works real good.

Basically you lay the rad flat, mask shut the backside where the damage is then make a dam around the area to repair with some playdough or plumbers putty so when you pour in the thinned down JB weld it pools to a level slightly higher than the damaged tube to give a solid repair.

Gene Davis (Ga.) · Jul 4, 2021

No deception here or trying to pawn it off on someone. This is not something I am planning on selling. I use this tractor myself but I want it to look decent as there are many who have never heard of an Earthmaster much less seen one and I would like for it to look good. I probably will go with the J B weld as it is easily available here even the high heat version.

Geo-TH,In · Jul 4, 2021

Why?
If it isn't broken, why fix it??

Gene Davis (Ga.) · Jul 4, 2021

For looks George, that is the main reason. I am installing this engine in a tractor I use some.

grandpa Love · Jul 4, 2021

We have a couple tractors with ugly weld repairs, one is a block repair on our ford 640. Was like that when we go it, seller said he bought it like that. Part of it's history and shows how someone did the best they could back in the day when you fixed instead of throwing away. Runs great,gets used a lot,ain't worried about the looks, it's a scar or tattoo!
By the way, I've met Gene, he ain't gonna pawn it off on anyone!!! Good guy.

Crazy Horse · Jul 4, 2021

That's interesting, I will try it next repair. I have used JB and heat as well for rad repairs, your dam method is a good one. Amazing stuff, I assume it is a step or two up on quality than regular liquid resin like you would use on a boat (with mat), etc.

Smoothing a welded block.

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