JB Weld to Build up Aluminium? 2

[triage]

I have an Aluminum component which was machined for me and in testing, found to have one surface that has too much material removed.

The area is 1" wide with a slight curve... The curve is too deep.

I was advised that JB Weld could be applied, then remachine the area to the correct profile.

Does JB Weld bond to Aluminium that strongly and is this a typical machining technique?

Thanks in Advance for your comments or experience.

 

[unclesyd]

JB Weld has a strong bond if the section is thick enough. The secret lies in the surface preparation of the Al part, it has to clean for the maximum bond strength.
When you go to machine the JB Weld you have to minimize the heat input. I usually cut dry or use a water based coolant. Don’t rush the cure time.

Another good material to use is Devcon/Permatex Aluminum liquid or putty.

Here is a starting point on machining.
Lathe speed: 140/160 ft/min
Cut: Dry or water based fluid
Tools: Carbide Top Rake 6° – Side/Front 8°F
Feed Rate (rough): Travel speed .015 Rough cut .020/ .060
Feed Rate (finishing): Travel speed .008/10 Finish cut .010
Polishing: Use 400-650 grit wet emery paper.

 

[gab4055]

You did not say how much material you need to add. if it is a large amount try filling with weld.

 

[triage]

gab4055
I am working with a concave surface that is about 1/16" too deep in the center, over a 1 X 1 inch area.

 

[griffengm]

Triage,
I've used some of the above materials and found that there are practical limits to them. If you intend to remachine the pocket you describe you may run into problems where the edges feather to very thin areas. Light cuts and sharp tools are the order of the day.
If the area is going to see pressure of say a shaft along these thin areas, be aware that the repair material may crack and flake. This becomes especially nasty if running cage type roller bearings as the repeated flex increases failure.
Heat cycling seems to have some effect but my experience is minimal on this one.
These seem to do best where loads are even and constant.
In order to keep the edges thick, ocassionally we removed a bit more material before building up.

Griffy

 

[triage]

Thanks for all of your input, "griffengm" called it.

As a test, one piece was preped and machined. It worked
and looked perfect, however the repaired surface is in a moderate wear spot and very quickly was compromised during operation, where the edges feather to zero.

Its time to call this a wrap and make new pieces from stock material.

regards,
Triage