Fixing hole in tank

[jacktheripper]

I was cleaning up my Homelite 450 project when I noticed a screw in the bottom of the case. I unscrewed it and gas started pouring out. Somehow a self tapping sheeter screw with rubber washer was holding in all the gas. How should I go about plugging this?

 

[Kdrweld]

With the possible white death corrosion looking at other areas in the picture, you may have to JB weld and use a tank liner like POR-15 or find a good welder that can do magnesium

 

[jacktheripper]

With the possible white death corrosion looking at other areas in the picture, you may have to JB weld and use a tank liner like POR-15 or find a good welder that can do magnesium

Shining a flashlight into the tank, there is luckily no corrosion inside of the tank. There is just a very minimal amount on the bottom exterior. The small amount of corrosion seems to not be active at all.

 

[hacskaroly]

How should I go about plugging this?

I am not that familiar with that saw and looking at the IPL didn't help either, I can't tell if the fuel tank/ bar oil tank come apart or if they are glued together. I think JB Weld will be a good option here. Clean up the site as best as you can and then patch with JB Weld. Try to get enough on the inside so it pushes out a little when it settles and acts like a plug. Easier if you can get to the inside of the tank easily, but I think still doable working from the outside.

Edit: I have been using JB Weld quit a bit to fix and patch older McCulloch's, Reed-Prentice and Husqvarna saws.

 

[jacktheripper]

The other thing I was thinking about is some sort of nut/bolt combo with rubber washers on either side.

 

[hacskaroly]

The other thing I was thinking about is some sort of nut/bolt combo with rubber washers on either side.

With that you risk having something sticking out and potentially catching on something. One thing you could do is put some JB weld on, fit a small square cut from an aluminum can in the JB Weld as a patch and when that dries, put a little more JB Weld over the top, sand smooth and then prime/paint. Having that aluminum sandwiched between the JB Weld may add some extra strength. I have been really happy with working with JB Weld, it has its pluses and minuses to setting up really hard, plus - very durable, minus - takes a bit of work to sand down if you don't flatten as you put it on.

 

[Sloughfoot]

I would think if pressed in fuel lines and tank vents don't leak then a tight fitting low profile rubber plug you could drill the tank to fit would work.

 

[Shane¹]

I would thread it with an 1/8 inch pipe tap then screw a brass plug in with loctite on it until it tightens up then grind the outside flat.

 

[Jay Hansen]

I have fixed a couple of holes in tanks using JB Weld applied from the outside only. Just make sure it's roughed up a little, is clean and completely free of oil. You can sand it flat, paint it, and it should last well.
Ask JJ or Mark Heimann about JB Weld, they're masters with it.

 

[JimG.]

pop rivet and redkote?

 

[beaglebriar]

Drill and tap. 1/8” pipe plug should work as long as it’s thick enough. Install with red locktite or maybe epoxy. I remember @Stump Shot posting about a similar fix.

 

[Stump Shot]

Drill and tap. 1/8” pipe plug should work as long as it’s thick enough. Install with red locktite or maybe epoxy. I remember @Stump Shot posting about a similar fix.

It will work as long as the area involved has a little bit of "meat" to it to make a couple few threads. Being a tank and not a crankcase how much that's inside doesn't matter. A brass Allen head plug should be easy to keep from sticking out too far.
The ultimate fix is to have it welded, this of course may require it be taken apart. Everything else for a fix is somewhere in-between up to just putting the screw back in that was taken out and not worry about it until it develops further.
In other words, the level of fix should be congruent with the level of usage the saw is to see.

 

[old guy]

I've had great sucsses with JBWELD.

 

[fredx]

JB weld is some pretty good stuff, as with any repair like that - prep is very important. I would use a wire wheel on the end of an angle grinder then wipe it down with your prefered solvent ( denatured alchaol , rubbing alchaol, acetone etc... ) prior to application. You could also use a flap disc instead of the wire wheel. Doubt very seriously you would be able to find anyone who would or even could weld magnesium

 

[Stump Shot]

Doubt very seriously you would be able to find anyone who would or even could weld magnesium

@srcarr52 @tree monkey @dall
just a few off the top of my head around here besides all the welding shops out there...

 

[fredx]

As far as drilling and tapping it- I am not saying it wouldnt work, but you have to take into consideration how thick that metal is- ist it even thick enough to get even two full threads in it, and pipe threads are spaced apart bigger and although there are straight pipe threads most are on a taper. If I was dead set on going the drill & tap route ( which I would not do personally ) I would use the smallest diameter with a fine thread pitch to get the most threads in there. Just my 2 cents / opinion.

 

[fredx]

@srcarr52 @tree monkey @dall
just a few off the top of my head around here besides all the welding shops out there...

I would be curious as to how many of those have actually welded magnesium-- honestly as it is extremely uncommon
and just because there are welding shops around doest mean they all can weld any / everything.

 

[Sloughfoot]

My money's on @jacktheripper figuring out how to weld magnesium.

 

[Stump Shot]

I would be curious as to how many of those have actually welded magnesium-- honestly as it is extremely uncommon
and just because there are welding shops around doest mean they all can weld any / everything.

All of them, I wouldn't have listed them otherwise. @srcarr52 welded countless chainsaws cases and cylinders both saving them from the scrap heap.

 

[fredx]

Thats great to hear- its not a common alloy at all to weld