Plugging holes in aluminum

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ldsgeek
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Plugging holes in aluminum

Post by ldsgeek » Mon Mar 05, 2018 7:40 am

I have a brake master cylinder that I need to move the mounting holes on. The new locations will overlap the existing holes so I need to plug those. I don't want to, nor do I have the tools to, weld them closed as I don't want to damage the rest of the master. Should I thread the holes and make aluminum screws to fill them, using loctite stud and bearing mount? Or would plain tight fitting plugs work, again using a loctite? I also have no idea what type of aluminum it is, chinese knock-off of a Brembo cylinder.

John Hasler
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Re: Plugging holes in aluminum

Post by John Hasler » Mon Mar 05, 2018 8:50 am

I'd tap the holes and use Loctite.

Magicniner
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Re: Plugging holes in aluminum

Post by Magicniner » Mon Mar 05, 2018 8:50 am

I know you don't have access to or the desire to use a blowlamp but for anyone else who searches and looks here because of the thread title Alutight low temperature welding wire would do this job very easily.

Some continue to say it's not actually welding but the original metal does slowly dissolve into the fill metal, I've used this to repair worn gun receivers and broken Myford change wheel covers (integrating bits of Aluminium plate to patch areas on the Myford bits with missing sections) and it gives a good structural repair with just a gas blowlamp as the heat source and some refractory around the part to concentrate the flame and reduce heat loss.

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warmstrong1955
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Re: Plugging holes in aluminum

Post by warmstrong1955 » Mon Mar 05, 2018 9:58 am

Can you slot them, and use large diameter and thicker flatwashers?
Or, could you enlarge the holes if necessary, and machine some bushings with offset holes?

Just a couple of different fixes I have doe on various things in the past, other than welding & redrilling.

Bill
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MrWhoopee
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Re: Plugging holes in aluminum

Post by MrWhoopee » Mon Mar 05, 2018 12:12 pm

In addition to thread and Loctite, leave the plugs long and peen them heavily to expand them into the threads, then finish flush.

ChipMaker4130
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Re: Plugging holes in aluminum

Post by ChipMaker4130 » Mon Mar 05, 2018 1:01 pm

How far do you need to move the holes? If it is 2/3 diameter or less, Bill (warmstrong1955) has the best suggestions. If it is more than that I would do as you said in your OP: thread the holes and make plugs to loctite in (make the plugs a very close fit and use the thin bearing mount or equivalent).

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SteveHGraham
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Re: Plugging holes in aluminum

Post by SteveHGraham » Mon Mar 05, 2018 3:55 pm

I suspect the aggravation, as well as the results, of the no-weld approach will make you wish you had welded.

I'm not a pro welder, but I think you are talking about 5-10 minutes of billable time, assuming you prepare and clean the holes before taking them to be welded. As you probably know, welding is 90% preparation and 10% or less welding.
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wlw-19958
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Re: Plugging holes in aluminum

Post by wlw-19958 » Mon Mar 05, 2018 4:11 pm

Hi There,

Is there enough material to enlarge the existing hole so that
it encompasses the area the new hole will occupy? If so, I would
do that and thread the new holes, install threaded plugs (with
Loctite®) and then drill your new holes.

Good Luck!
-Blue Chips-
Webb

ldsgeek
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Re: Plugging holes in aluminum

Post by ldsgeek » Mon Mar 05, 2018 6:58 pm

The holes are currently .25" diameter, spaced 1.75" apart. I need M8x1.25 spaced 1.93 apart, on pads about .375 thick. There's not enough material on either pad to move just one hole and still have enough left for strength (brake parts, always err on the side of caution). So I need to plug them both and move them about .090 on each end. I'm leaning toward thread, loctite and peening as that I can do without risk of warping from heat, and I don't have to locate someone with a tig willing to do such a small job.

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Bill Shields
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Re: Plugging holes in aluminum

Post by Bill Shields » Tue Mar 06, 2018 2:26 pm

why don't you just bore the existing holes over size on the correct center distance and stick in a mushroom headed plug with the m8 thread in it

need a drawing?
Too many things going on to bother listing them.

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Re: Plugging holes in aluminum

Post by Harold_V » Wed Mar 07, 2018 2:55 am

Bill Shields wrote:
Tue Mar 06, 2018 2:26 pm
why don't you just bore the existing holes over size on the correct center distance and stick in a mushroom headed plug with the m8 thread in it

need a drawing?
Like a stripper bolt.

H
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Bentworker
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Re: Plugging holes in aluminum

Post by Bentworker » Wed Mar 07, 2018 3:11 pm

You could drill and tap the holes larger, then make eccentric plugs.
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