Aluminum Paste, ever work with it?

[Brian D]

I have a small aluminum part on my throttle control that a screw was installed cross thread. The head broke off when I was trying to remove it. So I ended up drilling it out. but the drill bit kept getting off center. The end result was creating a new hole with part of the screw still in the part. Long story short, I ended up getting the bits out and in the process made the hole a little larger.

I have this Aluminum Paste that I haven't used yet. It says it dries quickly and can be drilled. So I have nothing to lose and worked it into the hole. I had a chunk of it just sitting (left over) on the bench. When I got done forming the fill, I picked up the chunk and sure as you know what, it was solid.

Has anyone worked with this stuff? It will be interesting to see if I can drill a new hole and tap for 8-32 screw. If it works I would have save beaucoup bucks on a replacement part. This is a non-load bearing part and is used only to secure the cover of the throttle housing. So no worries there.

If this works I am going to start filling holes in my mast.

 

[Stu Jackson]

Brian, can you be more specific about the paste. Model #, manufacturer, photo of the tube?

 

[rgranger]

I wonder if you could “tap” a hole by simply putting the screw in while it was still wet?

 

[Stu Jackson]

I wonder if you could “tap” a hole by simply putting the screw in while it was still wet?

I tried it with JBWeld, didn't hold. That's why I asked Brian what he used.

 

[Brian D]

@Stu Jackson, Hy-Poxy Alum Fast Stick Aluminum Reinforced Epoxy Putty

I wonder if you could “tap” a hole by simply putting the screw in while it was still wet?

The hole would not be centered correctly unless I do the repair on the boat. In this case, I am working at home. That chunk I spoke about will be my test part. I will drill into that and then tap. My hopes are it will not flake apart.

 

[Stu Jackson]

Thanks, Brian, good luck.

 

[Brian D]

Thanks, Stu! Tomorrow I will do a test drill on the small block I made. I am interested to see how soft the inside will be. I will also cut a corner off to check density. It could be good stuff or it could be bad stuff.

 

[Ken Cross]

If there is enough material on your boat part the proper fix is a heli-coil

Ken

 

[Brian D]

Ken, I didn't even think of that, but unfortunately the hole was off-center. So it would have worked unless I took off more material. But thanks for the suggestion.

 

[DArcy]

Depending on the part, you may be able to drill a bigger hole, press in an aluminum dowel then drill a new hole. That way you can re-center. If not then try the Fast Stick. What do you have to lose? If it doesn't work out, and you can't find a replacement part, you may be surprised how cost effective getting something like that made at a machine shop is. There are shops online that will do one offs for you or you can probably find some small local shop that will just copy the part.

 

[Brian D]

Thought about having one built instead of buying, But decided to try on my own.

Here are some images so you can see what I am doing.

This image is of the good side of the part under repair. The screw is 8-32.

This image is the same good side with the screw removed. You can see how close the screw hole is to the edge.

Here is the other side, the repaired side. Hard to see but the Aluminum Paste has been inserted, dried, and filed.

Another image of the same repair but the underside.

And lastly, the remainder of the Aluminum Paste formed in a block for test drilling.

 

[jibes138]

I used an epoxy based thread repair on my forward hatch where the arm that holds it open mounts. You put the epoxy in the hole then coat the screw with release agent and insert it. After setting you unscrew the screw and have nice threads. This is still working after 23 years. The screw is under stress in high winds and from the weight of the hatch.

 

[DArcy]

Nice job Brian. Since that is a casting, it probably wasn't much stronger than your aluminum paste to begin with.
I did use similar stuff as a temporary repair on the end cap for a heat exchanger once. The wall in the middle had corroded away so I filled and machined back to the original geometry. It worked fine until the replacement part arrived.

 

[jssailem]

So if I am hearing the issue correctly, the Epoxy Aluminum can be a good temporary fix but not likely a permanent repair.

How often does a temporary fix become an ignored semi permanent repair? At least until the next boat owner comes along.

 

[DArcy]

It really depends on the part. In my case, failure would cause engine overheating and I was concerned with errosion more than tensile strength. In Brian's case it doesn't seem all that critical so why not call it permanent?

 

[gdudik]

A wise friend of mine once said, “there is nothing so permanent as a temporary fix”

 

[LeslieTroyer]

I’m with Stu on using a bolt/machine screw to form the threads. It would be very difficult to get the material close to the threads and end up with lots of surface area for the threads to hold on to. Drill and tap - just don’t smack the center punch too hard.

Les

 

[SG]

Helicoil Inserts - That's what I think you need to use. Unless you want to get into something like welding a plate on and mounting the part to that.

You have heat and vibration working against you.

https://www.amazon.com/s/?ie=UTF8&n...qmt=b&hvbmt=bb&hvdev=c&ref=pd_sl_8qycn974xr_b

 

[Gunni]

This is a variety of thickened adhesive epoxy. Not unlike a colloidal silica filler, the aluminum thickens the epoxy plastic and makes it easy to fill holes where epoxy would otherwise drain out before set. If you kneaded it up well, it should be uniformly hardened and good for drill and tap.

There are many formulations of epoxy, some better than others. None of them have good UV resistance, so if this one fails you might consider drilling it out again, lay it flat, tape the bottom of the hole and fill with pure West System epoxy, stronger than thickened epoxy and of known quality. Then paint the part to provide UV protection. Clean the hole with acetone to remove lubes and oils.

 

[rgranger]

I tried it with JBWeld, didn't hold. That's why I asked Brian what he used.

I've had some very good results with JB weld. I once had one of those "fast lube" places crack the oil pan on a Ford Ranger by over-tightening the nut. They said it was not them and it came cracked and leaking when I brought it in.... bla bla bla

Anyway, the Pan was only a $20 part but it was behind the transmission which was $300 in labor just to remove it. So... we cleaned out the oil with spirits, acetone and such and then filled in the hole with JB Weld, tapped a new hole and 8 years later when I sold the truck, it was till holding.