boice1971

To be airtight for internal pressure your welds need to be nearly perfect. I'm a quality engineer and designer for an ASME pressure vessel shop and you'd be suprised to see the excellent "looking" welds that leak. Pinholes that you cannot even visibly see will leak. What PSI are you planning on having.

abj27

It's about the same as stock. They stick out a little further, but don't go down as far as the stock bumper. The way I see it, I'd much rather have a slighly worse approach angle that I'm not afraid to crunch, than a better angle that I don't want to risk scraping.

No kidding it is hard to get it airtight! I was planning on running about 120 PSI, but I'm starting to give up on that idea. Too many pinholes. Plus I don't have a real need for it now. When it comes time to get onboard air, I think I may just go with a powertank.

tc

As an owner of an air tank bumper, hopefully it's not too late to chime in:

If you add up what it takes to fill tires, even 5 gallons is piddly. Mine is maybe half that. It helps keep the compressor from running much due to cycling the air lockers and MAYBE would be enough to seat a bead, but it really won't be enough to run air tools or anything for long.

It's not going to explode. And besides, if you hit something hard enough for a bumper that beefy to crack, you REALLY have bigger problems to worry about.

Looks are no indication. Take soapy water and spray on there looking for bubbles. Then weld over that area, grind smooth, and test again.

I have worried about this myself. Fortunately, I live in CO and the air is so dry that I don't have to worry about condensation much, even in compressed air. I would highly recommend putting a drain valve at a low point like on a standard compressor though.

There is some stuff that people use to coat the inside of bicycle tubing that might work - it's kinda thin paint, you put in in there and spin the bicycle around so it coats all the surfaces. POR15 would probably work good too.

One warning - my air fitting is on the top pointing up. It is prone to getting junk in it. I would recommend mounting it horizontally on the back of the bumper or even vertically downwards in the middle with some protection around it (then it acts as the drain too)

monstertruckman

to slow down the rust on the inside you could always use wax oil. when i did my it came with a length of hose with a fitting on the end that sprays so just shove it in one end and pull it back slowly as it sprays the inside. same principle as used on chassi's and door pillars

abj27

Okay, it has been awhile since I posted on this thread. Been busy with other stuff. Got a new project in the garage:



Also got another job, and took a two week vacation in hawaii

So, I finally got back to work on it today. Got the holes cut for fog lights, now I'm trying to decide what look I want on the pipes for the lights. Let me know what you think. A couple pictures to illustrate what I mean:





The left pipe matches the angle of the bumper, just sticks out about .25 inch. The right sticks out and is cut off straight. I'm kind of leaning towards the straight cut right now. I had planned to do another pair on the bumper, but it is really annoying to cut out those holes without a plasma cutter or torch... so still undecided. Do I really need another pair of lights? Probably not, but who doesn't want more lights on their truck?

dirtoyboy

Looks awesome

waskillywabbit

iTrader: (-1)

That is why you do radiographic testing and a hydrostatic shop test.

The fitment of the bumper looks to have been rudimentary joints, nothing like a "butt joint" like you would find on a pressure vessel. Take beadlocks for example (the same idea), if you use a low voltage welder and fillet welds, you typically do not get the penetration needed to make airtight welds. Even with a high voltage welder it typically takes several tries at grinding and rewelding where there is visible porosity.


ASME PVE

blueyoda

If you really wanted it to be leak free a tig root pass is what you should have done. For all our pressure vessels, TIG ROOT, Mig or stick filler, 1500 psi no problem. Dosn't help you now, sorry for the hindsite advice.

dirtoyboy

I think you guys are falling on deaf ears

grant526

I'm trying to invision what your going for with the driving light "tubes"
But I'm not really getting it. Personally, I would definitely go with the same angle as the bumper. But I would also grind it flush, then weld it. Or cut the angle. grind it flush, then pull it back and set it in a touch before welding it in place. After which, I would grind the welds flush with the face again. That way nothing sticks past the face of the bumper and it's totally smooth and streamlined! But that's just me.
However, it does add a certain amount of character and accent having it either of the ways you've done it.

I'm looking forward to seeing the finished product

abj27

Thanks dirtboy.

Take a look at Wjwerdna's bumper. I basically stole the idea from him...

https://www.yotatech.com/forums/f88/...23/index2.html

As for the airtightness, I now realize how hard it is to get it airtight. I had seen it on some other bumper builds, and they made it sound like it was a piece of cake and worked first time without any hangups. Anyway, I've given up on that idea. No big loss though. Like I've said before, this is my first real fab project and I'm having lots of fun with it.

JCM4x89pu

this point was already touched on earlier with tc's post..

even though it doesnt sound like you are going with the compressed air, i just want to warn you of something..
if you are worried about rust on the inside of the bumper, compressed air is the last thing you want to put inside it.. the pressure will condense moisture from the air which will result in water inside your bumper. this is the reason compressors have a drainage valve for condensation.. and the water that drains out is always rusty.

just an idea... maybe since you already have air fittings on it, you could fill up the bumper from the top (CO2 is heavier than air) with CO2 from the nozzle of your MIG welder. you can leave both air fittings open, so youre filling through one, and air is being forced out the other... then seal them both off. that way the inside of the bumper cant oxidize.

ktown808

lookin good

grant526

JCM4x89pu- You make an interesting point I had not considered about keeping the bumper from rusting with dry CO2. Nitrogen would work the same way. But if you have a good air dryer on you compressor, you can do essentially the same thing. Just make sure you allow it to purge for several minutes.

abj27

Okay, I got this finished a few months ago. Moved and started grad school, so I been busy with other stuff. I did 2 coats of primer and 3 of rustoleum hammered black. I was pretty pleased with the paint job. Here it is installed:



Here are a couple side shots:





I like how well it matches the wheel-well. It hangs almost an inch past the body, which should give some good protection, with minimal hang-ups. I'm pretty happy with the way it turned out. Not perfect, but pretty good for a first try. So, there you go. I still haven't gotten any fog lights in though...

Let me know what you think. Unfortunately, I think I'm gonna try to sell my truck soon. I just don't drive it anymore, and I can't afford to insure and register a truck I never use. But when I graduate, I'll be looking for a first-gen runner!

toyminator2000

It looks like its smiling at us. Kind of like this smiley.

tc

Grinders and paint make welders who ain't...

I would grind the welds smooth.

grant526

Definitely gives the truck a different look!
Glad to see that you completed it. And that you seem happy with the results.

Thanks for posting the pics and getting back to the thread so we can see what you ended up with.

Good Luck in Grad school and I look forward to your 1st gen Runner build!!