Thread: Offset Dawn Vice Repair

If you then intend to weld it at a latter date or have intensions of treating it as you would a vice.

All of the successful cast iron weld repairs I have ever achieved have been with clean breaks not contaminated with gunk or glue.
Cast iron has an ability to absorb contaminants. Some like oil can be soaked in solvent and also baked out.

Other contaminants like to glue and silastic type materials change as they are heated and remain in some form to foul the weld process.

It seems people choose the welder as a last resort after having tried all the other solutions.This is why welders can be very creative in calling people rude names. A skilled welder of cast iron can permanently weld repair certain types of cast iron but people won't learn that what seems a difficult and expensive weld repair is actually the cheap solution.

Grahame

Originally Posted by eskimo

So best I get the table of a yet third waldown welded is what your telling me?
Take it to cast iron welders and get the holes filled with cast rods or brazed?

I thought we talking about dawn cast iron vices.For that the best repair is cast iron oxy acetylene fusion welded.Next best is braze welding with Manganese bronze which for the OP would be the best if there is and Oxy welding set in his local area.

Obviously the OA operator will need to be competent.

but OK , for a cast iron Waldown table ,if you want to refurb "

If you want the table to look original cast iron weld it. For grey cast iron the colour match should be spot on after a skim.

For operational purposes Braze or JB weld.I have never used JB weld so I have nil experience on it.


Grahame

Originally Posted by eskimo

So best I get the table of a yet third waldown welded is what your telling me?
Take it to cast iron welders and get the holes filled with cast rods or brazed?

I take it someone has drilled holes through your table. I tackled this problem for a friend by getting a countersink and chamfering both sides of the hole and then taking a piece of aluminium round bar cut overlength and peened both sides into the chamfer so as to create a rivet of sorts, which was then easily able to be ground and filed flush.
The colour doesn't match, but the holes are filled and the "rivets" can easily be removed at a later stage if a welding repair is done.

Originally Posted by Karl Robbers

I take it someone has drilled holes through your table. I tackled this problem for a friend by getting a countersink and chamfering both sides of the hole and then taking a piece of aluminium round bar cut overlength and peened both sides into the chamfer so as to create a rivet of sorts, which was then easily able to be ground and filed flush.
The colour doesn't match, but the holes are filled and the "rivets" can easily be removed at a later stage if a welding repair is done.

This is good idea for individual holes but is harder to do when there are a bunch of overlapping holes, which is often the case.

I recently completed the bogging up this Tough DP table for the mens shed.



The table has more than 100 holes in it with many overlapping around the 3/4" hole that in the middle of this DP table.
As can bee seen, the edge of central hole at the top of the table was so badly chewed away it would have been a real challenge to fill by welding.
At one point I though about milling a stepped ring out of the table and welding in an annular insert but that may have weakened the table and the condition of the remainder of the drill didn't warrant such an effort.
The amount of damage was also the reason for using bog rather than JB weld which I have used before but as it is quite expensive I usually only use it on smaller fill jobs.

In the end I turned up a 3/4" diameter wooden plug to plug the central hole from underneath. I smeared the plug with vaseline and used a grey two part SS filled automotive bog. After it set I just sanded it all flat and knocked out the plug. Colour match is poor but at least the table is now flat and should not catch any material dragged across it. If they drill any more holes out of it they can refill them. I will take a photo of the finished thing next time I go to the mens shed

Getting the bog to bind to the CI was not easy because of the oily crap that filled up the holes and because many of the holes were more like smooth very shallow concave dimples as would be cut by drill tips. In the end I acid etched the surface of the holes with phosphoric acid and that seemed to work apart from a couple of the smallest ones that I notice have popped out since I did the job. It will be interesting to see how it goes in the long run. I'm sorry I didn't take

I would be interested in hear about ways to properly clean cast iron surfaces. I suspect that ultrasonic cleaning would be good at getting stuff out of metal pores but my US cleaner is not big enough to contain a DP table

[QUOTE=BobL;
I would be interested in hear about ways to properly clean cast iron surfaces. I suspect that ultrasonic cleaning would be good at getting stuff out of metal pores but my US cleaner is not big enough to contain a DP table [/QUOTE]

I have not welded cast iron myself, but have watched someone use my oxy/acetylene kit to do just that. Essentially, he followed the below instructions.

I have brazed and used a borrowed pyrometer to get some cast iron to around 500ºC then personally boiled from the emanating heat as I kept the temperature of the cast iron up for about 15-20 minutes to remove as much oil and what have you out of the pieces to be welded. It was a dawn vice as it happened, and it was February under a hot tin roof

I lifted this:

PreparationThe most important aspect of welding cast iron is to have the surface clean and free of defects prior to welding, since castings that have been in service are likely to be impregnated with oil or grease. All surface contaminations should be removed with solvents, commercial cleaners, or paint removers. Casting skin should be removed from surfaces to be welded. Blind cracks and pits must be completely dressed out to sound metal by mechanical means such as grinding, chipping, rotary filling or shot blasting. Cracks should be excavated to their full length and depth. Excavate spongy areas and pinholes.
Impregnated oil or other volatile matter can be eliminated by using an oxidizing oxy-acetylene flame to heat the casting or weld groove to approximately 900 F for about 15 minutes and then wire brushing, grinding or rotary filling to remove the residue. This method has the advantage of de-gassing the casting and removing some of the surface graphite as well.


From here. http://www.brazing.com/techguide/pro.../cast_iron.asp

Mick.

Thanks Mick. I might try that with the bog as well.