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View Full Version : Loctite 638 strength? Can I bodge it?!



Cenedd
02-21-2019, 06:02 PM
Well, I've managed to sucker myself again....but the learning curve will do me good. This is one of those "Oh, no problem dear, I'll be able to whip that up in a jiffy!" kind of holes I've dug myself. My wife was after a wall-mounted kitchen towel roll holder. Because of stuff in the way and where the batons are etc, an off-the-shelf isn't going to fit. Still, a bit of rod, something to stop it slipping off the end and a plate to screw it to the wall and we'll be done in.....oh.

So the problem is this. Rather than a foot of solid rod - too heavy - I found some scrapbinium tube that was perfect. Turned down nicely with a great finish. No idea what it is and specifically whether it would be weldable - sure as hell isn't weldable by me (yet!) for something that's going to be on display in the kitchen! Seemed to be conveniently sized to tap the end to M16 and connect the tube to a blind hole in the plate that screws to the wall. Trouble is that it's just a little on the large size and the thread came out a bit sloppy. Also underestimated how many 2mm pitch threads I'd get tapped into an 8mm deep blind hole (wouldn't want to go through and ruin the look of the part that won't be visible!) in the plate. That bit seems to hold but the thread in the tube is so sloppy, I can't tighten the faced end of the tube against the plate so that the tube doesn't wobble. I've got three thoughts; two of them are probably bad and the third is more of a pain than I would like.

1. Slather the thread of the stud that screws into the tube in Loctite 638 and hope it's strong enough to take axial strain. Is it?!
2. Bore the hole in the plate larger so the tube slides 8mm (10/32" ish) into the plate with a close (hopefully) fit and then loctite that. Not sure if this would be stronger/strong enough. Tube is just under 19mm diameter (3/4" ish)
3. Make a stud that's M16 on the plate end and M16.5 (or whatever fits) on the other. This would probably work....I'm just being lazy and want to know if I can get away with it :D

Appreciate the advice.
Gareth

nickel-city-fab
02-21-2019, 06:16 PM
I consider anything put together with Loctite 638 to be permanent as if welded. If the difference is less than half a MM I would think you'd be OK. I used to use the stuff to assemble pins and sleeves on Caterpillars. Hence I would vote for option 1.

brian Rupnow
02-21-2019, 06:48 PM
Loctite 638 is my main "go to" for anything requiring Loctite. It does have limitations on how much "slop" it has to take up. If in any doubt, use J.B.Weld. It will work with fits that have a full diametral slop of 1/16". As far as disassembling anything put together with 638 Loctite, a bit of heat from a torch makes it let go with no problem.

Seastar
02-21-2019, 07:27 PM
I vote for JB Weld.
I have used it to repair so many things they should give me an award.
Nothing has ever come apart after using it.
Just make sure the surfaces are clean.
Bill

Cenedd
02-22-2019, 02:11 PM
Thanks guys. Will try the 638 as I have it on the shelf. Order some JB Weld too just in case. It'll come in useful at some point, I'm sure.

Intended to try today but failed to get motivated. Perused the selection of portable bandsaws online instead. Current cordless saw is not up to the task...as it's arm-powered. Went for the Milwaukee deep cut mains powered. Don't need to be buying in to another battery system and the battery system I have (Bosch) doesn't have a deep cut saw...and there's a 4" bar making faces at me. Should be able to make a table for it to go vertical and it won't take up all of the space I don't have.