Straightening bent aluminum angle.....

[fishrdan]

I bought a chunk of 3.5" x 3.5" x 1/4" structural aluminum angle and found that it's tweaked, definitely not a 90* angle as it should be. Does anyone have any ideas on how I can straighten it back to 90*. I have a good home shop, but nothing that I can apply enough pressure and bend it back into shape, no hydraulic press... Here are some pics, both ends, each leg, with a 1/16" drill bit under the square for reference.



I need to keep it looking good as it's being used for a swim platform bracket, so no beating it with a sledge hammer. (Not that it looked good to begin with, pretty beat-up piece of aluminum :facepalm

If all else fails, I'll call the supplier Monday.........

 

[jigngrub]

Re: Straightening bent aluminum angle.....

I would suspect your combination square is off further than the angle is, do you have a carpenters framing square to gauge it with instead?

I don't know of any home remedies for straightening 1/4" thick angle, and don't even think you could do it correctly with heat. I'm pretty sure anything you try like heating, beating, or both will only "scallop" it and it'll look a lot worse than it does now.

 

[fishrdan]

Re: Straightening bent aluminum angle.....

I have a framing square that I can double check it with tomorrow.

I'm pretty sure it's bent though. When I set on my miter saw, to clamp it for cutting, it was rocking against the fence. Thought I had some debris by the fence causing the rocking, but it was the bend angle :facepalm:.

I bought another piece of 3x3x1/4 angle that's just a hair off square, that one is close enough for govt. work

 

[GT1000000]

Re: Straightening bent aluminum angle.....

Definitely verify the "Squareness" of your square...
If you have a good bench vise, you might be able to clamp the piece in there using some wood to keep from marring the surface,
Then you can use a large crescent wrench or large slip joint pliers, again using wood on the jaws, to prevent marring, and you might be able to apply enough force to correct the angle...However, beware that this can cause work hardening of the angle and might lead to failure...
Another possibility is to use shims, or make a tapered shim out of scrap aluminum, on the swim platform side where they won't be visible to correct the angle...
Good Luck

 

[jbcurt00]

Re: Straightening bent aluminum angle.....

I have seen extruded aluminum angle 'cupped' similarly quite a few times. Unfortunately, I think it is a by-product of the manufacture of the angle. I doubt the supplier will have much recourse to offer, esp if you ordered a cut, rather then full length piece.

I doubt many (if any) of the angle will be a perfect 90*, some maybe less cupped, like the 2.5" sample, but I'd be surprised to find a perfect 90* angle in a pile of 20+/- pieces to choose from. And 20+/- is about how many I'd probably go thru & pick the best. With the cove inside radius, they aren't easily racked & stacked for transport either, so the strapping for shipment may tweak them some too.

For sure I wouldn't attempt to straighten it, by any means. Lots of effort, lots of down side, only up side is it may be nearer to 90*, for all the previously posted reasons.

Really, I don't think I'd be overly concerned, a 1/16" in 3.5" is less then 1/4" per foot, a common 'pitch' to direct water run-off. How far out does your platform come from the transom? Less then 2ft I suspect.......

I know it may not be ideal, but is your transom 90* to the water when at rest? Esp when someone climbs on & off the swim platform? When loaded on the trailer is it 90* to the ground? Does the boat cover, also cover the platform? Most people can notice 1/4":12" pitch, but I don't think anyone other then you will really care if they even notice.

There are plastic shims commercially available, very similar to 'normal' door & window installation shims. They're 1/2"-3/4" wide, @ 6" long, & 3/16" thick at the thickest end. You might use 1 or 2 of those (side by side, not stacked) along the topside of the angle, or behind where it bolts thru the transom, if you deem it absolutely necessary. The exposed gap could be filled w/ 3M 5200, to lock the shims in place. However, I think the shims & 5200 will be WAY more eye catching then a slight pitch.......

^^ my $0.02.

 

[glenn property of pam]

Re: Straightening bent aluminum angle.....

At work we would put it over a piece of 3"-4" tube and use the hydraulic press to splay the ends as the 90 degree piece starts out correct. With out a press its going to be hard work as that stuff is stronger than it looks

 

[fishrdan]

Re: Straightening bent aluminum angle.....

Two 1/4" thick angles are being sandwiched to hold a piece of 3/8" plate, so the 3.5" angle being cupped inwards is causing a issue with clamping the 3/8" plate. The angles are pinching the aluminum plate, instead of the plate slipping in between the angles.

3.5" angle
3" angle
3/8" plate



I don't have a vise that's mounted secure enough to bend the 3.5 angle, won't be able to get enough pressure on it. I'd probably be lifting the bench off the ground before the aluminum bent.

At work we would put it over a piece of 3"-4" tube and use the hydraulic press to splay the ends as the 90 degree piece starts out correct. With out a press its going to be hard work as that stuff is stronger than it looks

Yup, I wished I had a hydraulic press right now,,, and some 3-4" pipe (great idea!)... This stuff is friggin strong and isn't going to bend back into shape without a lot of pressure. I was thinking something along those lines, setting the legs of the angle on a cutting board, so the legs slip, and whacking the 90* corner with a sledge hammer (using a piece of wood between the hammer and aluminum). Though, I'm under the impression that I could beat on it for 30 minutes and and not get anything but a good sweat. I also don't want to work it too much, work hardening as GT said.

jb, I thought of shimming it, but shimming isn't going to work well with the way I'm making the brackets. This is kind of halfazz, but I guess I could lay down a bed of JBweld (no jun intended) where the two angles sit against each other, to build a shim and square up the slot the plate slips in. That would be a lot of JB weld though, couple of big tubes :facepalm:

 

[jigngrub]

Re: Straightening bent aluminum angle.....

I'd bolt or weld up the sandwich first and then pull the tops of the 2 angles with bolts/clamps and bolt/weld.

 

[glenn property of pam]

Re: Straightening bent aluminum angle.....

wonder if you can heat it till light red (you have to turn off all shop lights to see it) then quench it to annel the aluminum. then it might bend. After a few weeks it should regain its strenth again

 

[fishrdan]

Re: Straightening bent aluminum angle.....

I'd bolt or weld up the sandwich first and then pull the tops of the 2 angles with bolts/clamps and bolt/weld.

The tops of the angles are too close together, so the problem is getting (forcing) the 3/8" plate in between the angles. I'm building this so the swim platform can be removed when needed, by simply removing a couple bolts and pulling the plate out of the angles. That means the angles need to be straight, or leaning away from the plate. I'm not worried about the 2.5" angle as it's leaning away from the plate and can be pulled in by the bolts, but the 3.5" angle is leaning towards the plate

wonder if you can heat it till light red (you have to turn off all shop lights to see it) then quench it to annel the aluminum. then it might bend. After a few weeks it should regain its strenth again

I'm not sure I could get that much heat into the aluminum, it's a big piece. I have a Bernzomatic MAPP torch, but don't think it would do the trick. It's worth a shot if I don't come up with anything else.

I tried to bend it square today and had the legs bent away about 1/8" in the opposite direction, but it snapped back to it's original shape when the clamps were removed... :facepalm:

 

[81 Checkmate]

Re: Straightening bent aluminum angle.....

You are not gona straighten it...it's extruded angle and Alum at that....it will just spring back, you would have to go way past 90 deg to get it to stay! It is what it is.....The only way is with a press.

Propane or Mapp gas wont work either. Not enough heat!
Now if it were steel that would be different.......

Id go with shimming it.

 

[GWPSR]

Re: Straightening bent aluminum angle.....

Id go with shimming it.

Or find someone with a mill who'd be willing to take it down to a perfect 90.

 

[fishrdan]

Re: Straightening bent aluminum angle.....

The supplier looked at the pics said they would send out another piece of 3.5" aluminum angle, and check to make sure the piece is square before shipping it out. I'm not 100% certain I'll get a "perfectly" square piece, but as long as it's better (more square) than the 3" piece of aluminum, I should be good to go.

 

[81 Checkmate]

Re: Straightening bent aluminum angle.....

Mighty good of the supplier to do that for you......Very nice!

 

[Alwhite00]

Re: Straightening bent aluminum angle.....

I am not sure how you are going to fabricate this removeable platform but it seems as if being not perfectly 90 is a problem what happens if it bends from use? Are you having support struts? How are you sealing everything? just curious how this is going to work, Not that it can't just never have seen one before.

LK

 

[gm280]

Re: Straightening bent aluminum angle.....

The supplier looked at the pics said they would send out another piece of 3.5" aluminum angle, and check to make sure the piece is square before shipping it out. I'm not 100% certain I'll get a "perfectly" square piece, but as long as it's better (more square) than the 3" piece of aluminum, I should be good to go.

You don?t have to necessarily have a huge hydraulic press to straighten that. You could just as easily buy a cheap bottle jack and lay the angle aluminum down on some solid surface and take the bottle jack and put it on top of the corner and put it under a huge solid object or structure like a huge heavy truck or some solid material that can?t move and jack the bottle jack until you get it bent/straightened. Bottle jacks can be bought for very little and will have some huge capabilities? Just an idea if your second piece doesn?t work? You could also apply some heat as well while doing that, BUT aluminum will take a lot of heat to get hot enough to assist in the effort. That is why they make heat-sinks out of aluminum for electronic componets... Also cut the aluminum to desired lengths will make your effort even easier because it will take less pressure and heat to bent/straighten... Good luck! :watermelon:

 

[jbcurt00]

Re: Straightening bent aluminum angle.....

Again, is the transom 90* to the water?

Your drawing makes it look like it is going to be:

What boat has a transom 90* to the water?

 

[fishrdan]

Re: Straightening bent aluminum angle.....

I am not sure how you are going to fabricate this removeable platform but it seems as if being not perfectly 90 is a problem what happens if it bends from use? Are you having support struts? How are you sealing everything? just curious how this is going to work, Not that it can't just never have seen one before.

LK

Well,, I'm hoping it doesn't bend from use, thus the 1/4" angle and 3/8" plate. No support struts, just the angle cut plate, similar to what I've seen on ski-boats, though I'm making the boat side bracket longer, about 10" long. All through hull penetrations will be above the water line, but sealed up with 5200, 2 bolts thru-hull/bracket.

the bottle jack and put it on top of the corner and put it under a huge solid object or structure like a huge heavy truck

Also cut the aluminum to desired lengths will make your effort even easier because it will take less pressure and heat to bent/straighten... Good luck! :watermelon:

I considered those 2 things while baking out in the garage Sunday, but didn't think our truck was heavy enough to bend the angle, and didn't want to chop it up if the supplier wanted the tweaked piece back.

 

[fishrdan]

Re: Straightening bent aluminum angle.....

Again, is the transom 90* to the water?

Your drawing makes it look like it is going to be:

What boat has a transom 90* to the water?

Here is a side view of the bracket, 14 degrees to match the transom and keep the platform level to the boat.

View attachment 196497

The swim platform will sit on top of the angle cut plate aluminum. (With a couple more unpictured aluminum angles attaching the swim platform to plate aluminum).

I could have just gone with a 3-4 $30 SS brackets, but that would have been too easy

 

[Alwhite00]

Re: Straightening bent aluminum angle.....

Here is a side view of the bracket, 14 degrees to match the transom and keep the platform level to the boat.

View attachment 196497

The swim platform will sit on top of the (red) angle cut plate aluminum, with a couple more aluminum angles.

I could have just gone with a 3-4 $30 SS brackets, but that would have been too easy

so where are the 90 deg brackets going? How deep is the platform? 2'?

LK