Is it ok to weld the inside of a elbow to build it back up to last longer? The previous owner of my pump built up the inside of the elbow coming off the hopper. BTW its a 32 swing XL

It used to be SOP with a type of hardfacing rod.Now with the fancy liners they use,not so much.

We use hardfacing rod on all our elbows off the cone as well as the 7"-6" cone..as long as the host metal is thick enough to take it without burning through..also if you plan to do it, weld it in quarters allowing the whole elbow to cool before doing the next quarter or the ends will become deformed and the clamps will not fit properly..hope this helps

I know its been done where I work, but they would only do a few spots a day takeing a week or more to complete.

Yes,a common practice on the ass end.As for boom elbows a no-no,keep in mind many are double lined.After many times of build up the metal tends to become brittle and subject to failure.

The steel actualy becomes weaker but the trick is that the concrete in between the welds stands still while you pump so no wearing there. I hated it. Its a shit job to do and irritating to keep clean. But if your boss rather wants to spend his money on a new BMW than this is a way to save some bucks.

I also ran a swing 32xl. Loved it. I'm also welding certified in stick. I've welded them before but I would get a back up one and wrap it with burlap and pour warm water not cold water on it after i put a couple of rods down. Cold water is to shocking so warm will help without shrinking the metal. Some elbows have liners in them. I wouldnt weld on regular elbows like dual wall or esser. Regular or 1/4 wall pipe sure. The elbows on the ass end are very thick even the inner linning so hardfacing them is possible. I've ran lines, dots, spots u name it I've hardfaced it. Right yourname in it, doesnt matter, just remember to jump around with your passes not putting to much heat in one area or you'll warp it. Lay one pass and flip it or do the other side. If your on shop time then grab a fan and a chair, its going t be a while. I did them in a couple of days. Nowa rock valve, that was a different story.lol.

What are the labor costs and materials in welding as compaired to just buying a new 90?

You need to be very careful which elbows you are going to hard surface overlay.  If, for instance, you have a high manganese content, this can make the elbow extremely brittle.  Hard is good, brittle is not good at all.

The rod is expensive as is the time to apply it so I'm not too sure how far ahead you'd be by doing so, not at all if the thing blows up into a zillion pieces on the jobsite but it has been a common practice.  Cast elbows are relatively inexpensive, there are a bunch of different sources as well as chemistries. 

Chrome Carbide Lined elbows come with more wall thickness of Chrome Carbide than you could ever lay down by hand (same material as your hard surfacing rod) but without all the labor to apply it.

Can it be done?  Sure it could be, but is it going to be cost effective these days is a better question.

 Tom Johnston @ Con Forms