Another boat trailer build.

[Marchy001]

Hi team,

I'm entering the planning phase of rebuilding the frame of my boat trailer and I'm starting to come up with a few questions so thought I would start a new thread.

Trailer design is pretty simple and over the last 18 months or so I have replaced the running gear thinking the frame was not too bad. However a hole has opened up and it's not good enough to simply cut and shut the rusty bit so a new frame is the way ahead.

First question. It's currently made from 100x50RHS which is around 3.5mm wall thickness with galv coating on it so I'm assuming 3mm RHS. Should I just stick with the 3mm or go for 3.5 or 4mm on the new frame? Will going thicker reduce the amount of flex in the trailer or would a design modification be better to reduce flex?

I'm thinking I will just blank each section of the trailer and partially fill with Tectyl/fish oil and then paint the outside with kill rust or another HD coating that anyone may recommend?

Now for the fun question. Well it is for me any way. I'm currently running a 150amp mig that does ok but is a bit dated.
I'm thinking I stick/tig inverter as I want to learn to Tig one day. Any of the sub $1k units any good or do I need to aim higher with the $$$? No need for ally welding ability just decent DC tig and stick ability.

Anyway that's probably enough to start with as I'm sure I'll find more questions as time goes on. Some pics below of the frame last time I had it apart and the rusty spot.

Cheers

Marchy

http://images.tapatalk-cdn.com/15/06/15/bdee1b2f1c48d40892838dc6c5b60a3c.jpghttp://images.tapatalk-cdn.com/15/06/15/13cd4bcaaf6d25579b60abf9ebae8cf1.jpghttp://images.tapatalk-cdn.com/15/06/15/9fba1d71b30d7e68edbd715e5d26c108.jpghttp://images.tapatalk-cdn.com/15/06/15/3a26543909c4c84761bdaaca6fd62038.jpg

[brett62]

Without knowing what weight you are carrying makes it a little hard. Looking at the photos 3mm RHS will be fine for the main rails. If you want better strength in the trailer I would up size the cross members. If you are not going to galvanise the frame filling with oil is a good idea if you are happy with the extra weight that adds. If you go down that road buy gal RHS so you have a little extra protection inside. Are you planning on sandblasting and painting?. I would use PFC for the cross members so you can see any rust that may start.

Marchy as for a DC inverter welder the duty cycle of the machine can drive the price. If you were hanging off the welder going hard and using every day paying for a good quality machine is a must. I use a machine which was made in china like a lot of things these days. Cost me $2000.00 some 5 years ago and I have given it a pretty good work out. Its Everlast ac/dc pulse tig/stick and plasma,200amp and 15amp supply. If you are only after DC they will be much cheaper, just make sure that you get a high frequency unit as this will make it easier for you tig welding. You can look at them on the web. I had a problem with the plasma function and contacted them and they did not have a replacement machine in stock. Everything else worked fine so they sent me a brand new plasma cutter to use while they got my replacement machine. 3 weeks later a my new machine arrived and gave them a call to organise sending the old machine and their plasma back and they told me when I finish with the plasma they will organise to have both machines returned at their cost. I said I will be 6 months using it and they said no problem. I couldn't believe it. They are in Sydney if you want to have a chat to them.

Hope this helps

[Marchy001]

Good point on weight. In it's current state loaded it's just under 2t so don't want to make it a lot heavier if I can help it.
Would PFC be suitable as the main rails also or not an ideal material?

The rear cross member I replaced 2 years ago is sealed and full of Tectyl and so far is working well so was just going to replicate that on the rest of the trailer.
Unsure of the final process and coating I will use on the outside but I have had great success using cold galv and kill rust in the past. Re-coat every 18 months-2 years and all is good.

On the welder side by the sound of it I'm looking at the same company you went through so will probably go with one of their units when the time comes. It will only be a toy so duty cycle shouldn't create me any issues. A HF start DCtig / stick Is what I'll shoot for.

[brett62]

You can use PFC for the main rails. Many trailers have been built with it. You just need to weld gussets in the correct places or it will twist and flex more than you would like. If I was going with the PFC on the main rails I would be using 125mm which would have you also replacing the adjustment brackets.

[Marchy001]

Think I'll just stick with the RHS much simpler to build with too. May go PFC for cross members if it's easy enough to track down.

Next question. I'm out Ipswich way any good steel suppliers out here or will I need to travel a bit?

[610]

Hey mate direct steel supplies near dinmore or you could try the hagarty group at west ipswich

[brett62]

I purchase my steel from Citi Steel at Darr. I will PM the details to you with the stock list. Just another one you can get a prices from.


Think I'll just stick with the RHS much simpler to build with too. May go PFC for cross members if it's easy enough to track down.

Next question. I'm out Ipswich way any good steel suppliers out here or will I need to travel a bit?