My Mini Trailer

[Simon Thomas]

Welcome back Simon...



Somewhat...

You need to find the balanced centre of the structure, not the measured centre; if you place the axle in the centre of the box, the front will be heaveir once you add the pull bar; likewise, if you add the pull bar then find the measured centre of the entire length, the rear will be heavy...

It takes a bit of trial & error but, if you simply place the axle under the completed frame (with pull bar & panels attached) you should be able to lift the front with ease but, with a slight resistance;

If it feel heavy, move the axle forward
If it's too light, move the axle back

Keep in mind, 1/4" can mean the difference between too light & too heavy...

Hi Fabroman,

It has been a while away and silent from this forum. I somehow would use a short pull bar. Let's see how balance it is later since I need to weld more parts to strengthen my earlier weld. Putting some parts would introduce some imbalance to my build, and let's see how it goes. So far the axle position is closely to the centre and not far off to say from a good balance.

 

[Simon Thomas]

Simon....couple of things.....you can build your running carriage onto angle iron and put differently spaced holes in your frame to move it forward or back to accommodate your load....

Also....with a motorbike trailer...either the ball or the hitch needs to be able to rotate....so you can lean the bike.....

Hi Poboy,

This is a good suggestion. Appreciate your view. However, thinking that this mini trailer is only for light use, travel at low speed, carry fixed load and travel only a km or less, I think this should be a simple build without any need to include differently spaced holes and enable to move it forward and back. I also worry since I have to surrender this build to old folk who is not really familiar with portable and adjustable parts, it may cause some trouble later. So I just welded the parts.

I have thought about how to put the hitch ball, and attach my mini trailer to the motorbike chassis with some consideration of safety feature. I hope to find the solution on this with the parts that I could find here. Once I have the solution, I will post the picture later.

 

[Simon Thomas]

Well Tony, I guess anywhere between half an inch towards front or back will effectively work out okay once the trailer is in use.

All I was thinking here is, the weight of the pull bar will not be too excessive at all
(or doesn't need to be at least) it's still a mini trailer,
and targeting maybe 20 kg of "weight" on the hitch empty,
together with a relatively short pull bar...
I'm not sure it's enough with just a centered axle,
let alone an offset towards the front axle.

But honestly, I don't know for sure since weight and length of the pullbar are yet unknown etc.
My guts tells me moving the axle towards the rear will increase the load on the hitch,
and reduce the chance of a back heavy 'loaded' trailer (the flying donkey again )
So I'd dial in on the safe side and keep saying "move the axle back a bit"
The empty trailer looks like it may only weigh in on about 50-75 kg when done,
so even the worst scenario will be maybe a load of 30-32kg on the hitch...*shrugs*

Maybe I'm missing something though ...

'sid

Hi Sid,

Even after have a complete build, it is still quite challenging to say whether it is balance or not after putting the load. Again like we both agree, this is a mini trailer which should be as simple as possible.

 

[Simon Thomas]

From a handling/ stability stand point, you should calculate ~5 to 10% of the intended load forward of the trailer axle center line. Neutral, or even worse rear weight bias causes potentially dangerous handling issues.

From all the studying I've done, figure on a 60/40 weight bias towards the front from the axle center line. This isn't an absolute, it just keeps popping as a good general guide line. Your results may vary.......

Hi Machinist@large,

Like your view. Yes agree that building something like this needs to have the stability feature. I have limited tool to measure the exact spot to place or align the trailer axle underneath the trailer body frame, however I have used the best estimate from the height and distance of the wheel to the main trailer body frame. Just in case it travel through some bumpy road with some load, at least it won't affect much the stability.

 

[landuse]

The build is coming along nicely Simon. I suppose you will only see when it is done if the weigh distribution is correct.

 

[Simon Thomas]

The build is coming along nicely Simon. I suppose you will only see when it is done if the weigh distribution is correct.

 

[Simon Thomas]

I prepared my stuffs yesterday evening in hope that I could do the painting of my mini trailer however the weather did not permit me.

Weather now year end is always windy and sometimes raining at our state. These are the 2 environmental elements challenging the good quality of painting work.

Have to wait patiently for the right time.

 

[OzFab]

I know the feeling

Just a thought though, wouldn't it be best to test the trailer before painting? That way you don't have to repaint it if there are any problems

 

[Simon Thomas]

I know the feeling

Just a thought though, wouldn't it be best to test the trailer before painting? That way you don't have to repaint it if there are any problems

Hi Fabroman,

I have the same thinking however these few days I started seeing the body frame has the rust here and there, and worrying the raining and wet season like this time would worsen it. I think it would be more difficult to paint if the body frame has lots of rusty spots here and there.

Generally, without painting, it is balance and stable. I have also welded the trailer tongue, only missed to take the photo. All the critical joint were also welded.

The other reason is I will be taking time off this year end, and I exposing this stuff at my backyard to rain and wet weather within a few weeks would even worsen it.

The material used is newly and fresh from shop.

 

[OzFab]

Two words: phosphoric acid! It's a metal conditioner which removes surface rust (also found in Coca Cola...no, seriously, it is...)

Yes, lay a coat or two of primer on it but, I'd hold off on the paint for now...

 

[Simon Thomas]

Two words: phosphoric acid! It's a metal conditioner which removes surface rust (also found in Coca Cola...no, seriously, it is...)

Yes, lay a coat or two of primer on it but, I'd hold off on the paint for now...

Thanks Fabroman. This is a good advice. I just learned something new from you.

 

[OzFab]

This is a good advice.

Well, I try not to get into the habit of handing out bad advice...

 

[zbuck]

Nice job. If it were me I would use primer with sealer in it, you can buy it already mixed. As regular primer has pores and after time rust will show up.

 

[Simon Thomas]

Well, I try not to get into the habit of handing out bad advice...

Fabroman,

How do you normally handle the phosphoric acid to remove the rust? Do you dip the tissue, rag or cloth and wipe it or use sprayer bottle and spray on the rust?

I anticipate that phosphoric acid might be irritant if in contact with skin. We might need to wear some sort of rubber glove or something to avoid any contact with this chemical.

Please advise. Thanks.

 

[Simon Thomas]

Nice job. If it were me I would use primer with sealer in it, you can buy it already mixed. As regular primer has pores and after time rust will show up.

Hi Zbuck,

Thanks for visiting my work and comment. I intend to do some work this weekend.

How much is the different in term of durability if I just paint it with the normal paint without the primer? I may need to do double layer using normal paint without the primer. FYI, I have experience with some primer that does not help much or stay longer. In other cases, some primer will peel-off and crack and does not allow the next layer of paint to stick on it. Because of that, sometimes I use double layer of normal paint. The first layer acts as the primer. What do you think?

Please advise.

 

[Poboy kartman]

Hi Zbuck,

Thanks for visiting my work and comment. I intend to do some work this weekend.

How much is the different in term of durability if I just paint it with the normal paint without the primer? I may need to do double layer using normal paint without the primer. FYI, I have experience with some primer that does not help much or stay longer. In other cases, some primer will peel-off and crack and does not allow the next layer of paint to stick on it. Because of that, sometimes I use double layer of normal paint. The first layer acts as the primer. What do you think?

Please advise.

As a professional custom boat trailer and United States air force aircraft painter....I can say without hesitation....that no amount of final topcoats can come close to the benefits of a PROPERLY chosen and APPLIED primer....

Primers are specifically formulated to bond with naked metal surfaces and paints to compatible primers.....

No way do you get better results than that.......

 

[landuse]

The problem with primers usually peeling off is due to the metal not being clean enough. If there is oil, etc still on the metal, nothing is going to stick to it

 

[OzFab]

Fabroman,

How do you normally handle the phosphoric acid to remove the rust? Do you dip the tissue, rag or cloth and wipe it or use sprayer bottle and spray on the rust?

I anticipate that phosphoric acid might be irritant if in contact with skin. We might need to wear some sort of rubber glove or something to avoid any contact with this chemical.

Please advise. Thanks.

There will be safety instructions on the container but, personally, absolutely, rubber gloves (not the thin latex gloves) & eye protection must be used; a mask is also a good idea although the amount of fumes is minimal; it's not a highly corrosive acid but, it is an irritant & is diluted/neutralised with water...

For best results, dilute 1:1 with water in an open container then dip the applicator; for best results I suggest using either steel wool or scotchbrite.

When you're done, hose the whole thing down & wipe dry with a dry towel

The problem with primers usually peeling off is due to the metal not being clean enough. If there is oil, etc still on the metal, nothing is going to stick to it

Although this is absolutely true, it's not the only reason; some primers are simply rubbish, they're only designed to cover the surface, not bond to it...

For that you will need etch primer; it chemically bonds to the metal surface & allows other primers to bond do it

https://www.youtube.com/watch?v=ija2zCMPA2Y

Obviously, this guy doesn't know how to edit vids so, you may want to skip through to the relevant parts...

 

[Simon Thomas]

I did some works to my mini trailer last weekend. I managed to paint the body frame although the weather is hardly to forecast sometime. When there is sunny time between the cloudy sky, I took the opportunity.

I wrapped the suspension system, just want to have that part unpainted. Something that I wanted to show-off in my build.

 

[Simon Thomas]

My mini trailer after painted. How's the look in yellow? . I prefer yellow to ensure it is clearly seen in the evening, in case it needs to travel back from farm. At least this is the safety feature I put in my build.