Welding Tips and Tricks

We've all seen the big touring motorcycles pulling small trailers. The commercial ones can be crazy expensive ($1,500+). Many have turned to Harbor Freight bolt together trailers cut down (33"x39" deck) to fit a car top carrier with a max cargo weight of 150# (300# total cargo/trailer).

My intention was to go the HF route and weld it all together. However, I've found that cleaning the powder coating off the hard to reach places plus nothing has close tolerances its just not worth the effort to weld it together. I could suck it up and bolt it together but I want the pride of having welded my own trailer.

So, my question, keeping in mind I'm using an Integrity 140 (90 amp, 115 volt), would 1.5"x1.5x 16 gauge square tubing be strong/road worthy enough for this project?

Be nice, I'm a novice looking for education not criticism.

Thanks in advance!

Rog

Hi there,

Welcome to the forum,

First of all, You wont find any criticism here. We are a very down to earth group who values our community.

Now, to your questions,

To weld a trailer, you really need to be confident of your abilities to produce a weld that wont fail. I dont know your level of skill, and i can speak for the welder its self because they are not sold here in AUS, we dont have 110 volt, only 240. The fact remains we want you to give it a shot, and help you along the way. The tube you are intending, 1.6mm x 37mm should be quite adequate for a weld designed and made trailer. The way for you, as a novice to be sure of your welds is practice practice practice, preferably under the eye of somebody who knows whats what, but thats not the end of the world. The main thing is that you set up the exact material you are planning to use, in the joints you are using in position. (Flat is best for beginners, you can flip over your project.) I know material may be expensive. The thickness is the main thing so try and find some scrap. You can cut up old things and grind/ sand paint off. Then once you have done some practice welds, and havent burn any holes, and seem happy with the quality, take it outside and belt the living hell out of with a big hammer, untill the tube is flat, and or the welds break, make sure you hit it from a number of ways, so as to test its strength. Ideal would be flat tube with welds intact, but the welds holding untill the tubing is bent and battered is also good.

So go forth and practice, good luck.

Mick

Mick,
Thanks for your encouraging reply!

My experience level... I arc welded many years ago - so long ago that it doesn't count. With MIG, about a month. However, I'm practicing as much as I can and have recently made the move from flux core to Argon/CO2. All of the welds below were made with .025 wire and Argon/CO2 gas.

1"x1" 16 gauge tubing 1/8" Steel - the top weld was beveled 50% of the thickness. The bottom weld had no bevel at all. The top weld shows the penetration of the 50% beveled weld. How would you classify the penetration? OK? Not enough? Clearly the bottom weld doesn't have enough penetration. I think I've reached the limit of what my little welder can do - beveled 1/8" with a pass on the back as well (unless I move back to flux core).

One thing for sure that I'm struggling with is confidence in the strength of welds in general. I'll do some destructive testing later today - perhaps that will help my confidence?

Opinions on my welds please.

Rog

Hey - for a relative novice those welds look good - practice can only improve them - if you can do this consistently go ahead on the trailer - you already realised your smallish set won't penetrate far so proper prep is the key - the flat bit's you beveled are 90% there - just leave a small root gap next time & you will have a perfectly serviceable weld - unless you have alot of power in a mig the key is use as many open corner joints as possible or grind an edge prep - or allow a small gap - the mig will fill these just fine in one pass on thin gauge material.
The design & construction of the trailer will influence the strength probably as much or more than your welds so have a look at other similar manufactured trailers for " inspiration " - don't be shy putting in doubling plates and / or gussets - they don't need to be very thick or add much weight to vastly improve strength - the bought ones tend not to be done this way due to mass production costs.
Good luck with the project.

Thanks Brian!
I know we all can tend to "think" we're better than we actually so I'm trying to look at my skills soberly.

Question on adding gussets... would it be wise to tack those in when tacking everything else to help prevent warping? Of course moving around the frame and letting things cool between welds should help with preventing some warping.

Also, the suspension hanger brackets are 1/4" so I'd be welding 1/4" to 16 gauge. Should I consider adding some 1/8" plate to the 16 gauge then weld the brackets to the plate with multiple passes?

An " ideal" weld would be 100% penetration + a small reinforcement on the backside - your not too far off on the bevel edge prep plate - small root gap & you'd nail it - may take a little more practice to get the settings dialed in for the gap you use - but your looking good - bead looks quite consistent.

Adding the gussets & when to weld will vary a bit depending on where they are - not the answer you probably want to hear - but it's part personal preference / experience & just how much the components are loaded - I tend to " over build " everything - but it's not often anything I make breaks ! - as a general rule I'd weld them in after the main welds if they will obscure or make these welds difficult - I think do the continuous welds around all the main frame - then add in gussets where needed - if welding the box as mitres on the corners do the outside first then weld the mitres from the outside towards the inside corner - do that last - check & adjust the over all angle - then place the gusset- if the box has a rounded edge this helps as a sort of " prep ".

The biggest factor usually welding parts of dissimilar thickness on a frame subject to flexing is fatigue at the ends of the thicker part - it would be a good idea to use a doubling plate as you mentioned - take it about 1/3rd the width of the 1/4" plates past where they end & cut them so they taper off gradually to almost but not a point (!) tear drop shapes work fairly well - try to run the weld around the pointed end - don't have a stop or start there as this is where fatigue cracks start from - ( on thicker stuff it's common ( UK anyway ) to run the weld to the pointed end & then run on a little way then flare them out )
The 1/4" I would think will need to be multi pass as you suggest given you smallish welder - if you get too much build up due to lack of heat you can always dress some of the root run down with a grinder while still hot, then go back for another pass or even preheat with a torch if you have to- not sure with you set what to expect- the smallest Mig Ive ever had was a 200amp - a small weave doing a "C" shape tracing the forward edge of the puddle should help.

Again, thanks!

You've been a great help and encourager!

I've also been emailing Kevin at www.KevinCaron.com and you've both been saying the same things. So, I think I'll give it a try!

bcbh,

I would like to add...

That I have NOTHING to add. You've gotten rock-solid advice. I've designed and built suspensions for over-the-road semi trailers, and everything you've been told fits the engineering.

The pictures of your welds show you have the skill for the metal-to-metal part, as well, regardless of the somewhat limited capabilities of the machine.

The sole piece of advice I would throw in, considering the max power of your machine, is to preheat the 1/4" stuff to 350-400*, if you can. 1/4" is at the limit of that machine and you'll be bouncing off the duty-cycle otherwise.

Share pictures, when you're done!

Steve S

Hey,

glad we could help, remember to keep posting pics of your project progress.

Mick

I'll certainly keep y'all posted on the progess.

Ordering material today, picking it up tomorrow, should have the frame built by tomorrow night.

Thank you gentlemen!

I don't know what you plan to use for the clamshell part to keep it light weight, but the Sears X-cargos can often be had for free or very little money on Craigslist. The free ones may be missing the keys. If the keys are missing write down the number on the lock and go to Thule's website (they make the Sears units) and order a new pair. You could also paint the clamshell with the Rustoleum spray paint for plastics.

D
The Sear 20 cubic foot carrier is the one I'll use. I was able to pick one up off of Craig's List for 1/3 the normal price.

I'm just about complete with the trailer. All the remains is getting it inspected by the State Patrol (a requirement here in Colorado) after I install the lights. A thread with the build details will come after that.

The folks here have been a great help and a source of encouragement!

bcbh,

That's great!

When someone goes quiet for a couple weeks, we never know if they've got their hood down, or gave up .

Let us know how the HP inspection goes, but I'm betting your "In like Flynn".

Looking forward to the build photos...

Steve S

One down side to building a trailer that I've discovered...

I have to wait until Monday for the Colorado Highway Patrol to inspect it! I guess I get to exercise patience.

Pix to follow soon.

Nice job on the welds. I'd trust it.

As promised, here are some pix of the project.

I ended up making the rails and the center cross member out of 1.5"x1.5" 1/8". The front and rear cross members are 1.5"x1.5" 16 gauge. The tongue is 2"x2" 1/8" tube.

It's time to prep the 1/8" rails. Rear leaf spring mount. Axle

Since I can only add 3 images per post....

The frame is finally finished and ready for lights and paint. Connected to the Jeep and ready to go!
A good friend of mine really helped me out. I sent him all the measurements and he put them in Visio, so now we have plans. Thanks Ray! We pulled the trailer to Denver a couple of times this weekend. I was encouraged when the cars behind us weren't swerving trying to miss trailer parts (even after we hit some bumps). I'm really pleased with how well it tracks.

I really would like to thank you all for the wisdom and encouragement! Now I'm ready to build another one!

Rog

Hey,

That looks really great. I glad it worked out well.

Mick

Very nice trailer - looks great - hopefully saved you some $ and gave you the satisfaction of making it how you wanted it.

If you make another you may find you can save a little more weigh by using either a rubber sprung axle or independent rubber suspension units - they also have the bonus of being quieter in operation they are fine on small trailers of limited weight but I still prefer a solid " real " axle for heavier stuff.

All the best with you future projects.

Compared to purchasing a new trailer of this type I saved about 50%. However, my satisfaction level is WAY HIGH! Will I do it again? You betcha!

The suspension is where I'll certainly make a change. I just started looking at Timbren and Dexter axles.

Ya never said it, but I assume the CHP was happy, since you posted about pulling it to Denver and back. Did they have any comments or recommendations? Or was it just "You passed"? It's a nice looking unit, shoulda been worth at least a compliment from the inspector.

Nice work!

Steve S

DOH! I guess I did leave that part out. Basically it was a check the lights inspection. Nothing exciting.